@font-face {
  font-family:"MathForm Unicode";
  src:url("assets/fonts/DejaVuSans.ttf") format("truetype");
  font-style:normal;
  font-weight:400;
  font-display:swap;
}

@font-face {
  font-family:"MathForm Unicode";
  src:url("assets/fonts/DejaVuSans-Bold.ttf") format("truetype");
  font-style:normal;
  font-weight:700;
  font-display:swap;
}

:root {
  --ink:#143d35;
  --ink-2:#214e45;
  --green:#0e7b65;
  --green-2:#14997c;
  --green-pale:#e2f3ed;
  --cream:#f5f5ef;
  --paper:#fffef9;
  --yellow:#f4ca50;
  --yellow-pale:#fff4cc;
  --orange:#e8702c;
  --orange-pale:#fff0e5;
  --blue:#377fa8;
  --blue-pale:#e7f2f8;
  --purple:#7257a6;
  --purple-pale:#f1ebfb;
  --coral:#d95757;
  --aqua:#1b8fa3;
  --red:#b64336;
  --red-pale:#fbe9e6;
  --muted:#6e817a;
  --line:#d7e0dc;
  --line-strong:#aabbb5;
  --shadow:0 18px 46px rgba(20,61,53,.10);
  --shadow-soft:0 8px 24px rgba(20,61,53,.07);
  --display:"MathForm Unicode","DejaVu Sans","Segoe UI",Arial,sans-serif;
  --serif:var(--display);
  --sans:var(--display);
}

*{box-sizing:border-box}
html{scroll-behavior:smooth;font-family:var(--sans);font-kerning:normal;text-rendering:optimizeLegibility}
body{margin:0;color:var(--ink);background:var(--cream);font:15px/1.65 var(--sans);letter-spacing:0;word-spacing:normal}
button,input,select,textarea{font:inherit}
button{color:inherit;cursor:pointer}
button:focus-visible,input:focus-visible,select:focus-visible,textarea:focus-visible{outline:3px solid rgba(244,202,80,.9);outline-offset:3px}
.hidden{display:none!important}
.eyebrow{margin:0 0 6px;color:var(--green);font-size:11px;font-weight:700;letter-spacing:.1em;text-transform:uppercase}
.button{min-height:45px;padding:10px 18px;border:1px solid transparent;border-radius:12px;font-size:13px;font-weight:700;transition:.18s ease}
.button:hover{transform:translateY(-1px);box-shadow:var(--shadow-soft)}
.button.primary{color:#fff;background:var(--green)}
.button.primary:hover{background:var(--green-2)}
.button.secondary{border-color:var(--line-strong);background:#fff}
.button.secondary:hover{border-color:var(--green);color:var(--green)}
.text-button{padding:7px 2px;border:0;color:var(--green);background:transparent;font-size:12px;font-weight:850}

.topbar{height:66px;position:sticky;top:0;z-index:40;display:grid;grid-template-columns:280px 1fr auto;align-items:center;padding:0 22px;color:#fff;background:var(--ink);box-shadow:0 5px 20px rgba(14,47,40,.17)}
.brand{display:flex;align-items:center;gap:11px;padding:0;border:0;color:#fff;background:transparent;text-align:left}
.brand-mark{width:42px;height:42px;display:grid;place-items:center;border-radius:13px;color:var(--ink);background:var(--yellow);font:700 25px var(--serif);box-shadow:inset 0 0 0 1px rgba(0,0,0,.05)}
.brand strong,.brand small{display:block}.brand strong{font-size:17px}.brand small{color:#ff4d4d;font-weight:bold;font-size:9px;letter-spacing:.11em;text-transform:uppercase}
.topnav{height:100%;display:flex;align-items:center;justify-content:center;gap:3px}
.topnav-item{height:100%;padding:0 14px;border:0;border-bottom:3px solid transparent;color:#bcd0ca;background:transparent;font-size:11px;font-weight:800}
.topnav-item:hover,.topnav-item.active{color:#fff;border-color:var(--yellow)}
.source-actions{display:flex;align-items:center;gap:8px}
.source-pill{max-width:220px;padding:8px 11px;display:flex;align-items:center;gap:7px;border:1px solid rgba(255,255,255,.18);border-radius:99px;color:#dbe8e4;background:rgba(255,255,255,.06);font-size:10px}
.source-pill i{width:8px;height:8px;flex:0 0 auto;border-radius:50%;background:#6cd4ae;box-shadow:0 0 0 4px rgba(108,212,174,.13)}
.source-pill.warning i{background:var(--yellow)}.source-pill.error i{background:#ff8275}
.source-pill span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.icon-button{width:39px;height:39px;border:1px solid rgba(255,255,255,.18);border-radius:11px;color:#fff;background:rgba(255,255,255,.06);font-size:18px}
.icon-button.syncing{animation:spin .8s linear infinite}
@keyframes spin{to{transform:rotate(360deg)}}

main{min-height:calc(100vh - 66px)}
.app-view{display:none}.app-view.active{display:block}
#view-library{padding-bottom:70px}
.library-hero{min-height:410px;padding:64px max(28px,calc((100vw - 1280px)/2));display:grid;grid-template-columns:minmax(0,1.1fr) minmax(380px,.8fr);gap:70px;align-items:center;color:#fff;background:
  radial-gradient(circle at 80% 5%,rgba(244,202,80,.18),transparent 25%),
  linear-gradient(135deg,#143d35 0%,#1c564b 62%,#0c7560 100%)}
.hero-copy h1{max-width:720px;margin:8px 0 16px;font:700 clamp(36px,4.4vw,56px)/1.35 var(--display);letter-spacing:0; text-transform: uppercase;}
.hero-copy h1 em{color:var(--yellow);font-style:normal}
.hero-copy>p:last-of-type{max-width:660px;margin:0;color:#d4e2dd;font-size:15px}
.hero-actions{margin-top:27px;display:flex;gap:10px}.hero-actions .secondary{color:#fff;border-color:rgba(255,255,255,.35);background:rgba(255,255,255,.06)}
.continue-card{padding:22px;display:grid;grid-template-columns:150px 1fr;gap:22px;align-items:center;border:1px solid rgba(255,255,255,.18);border-radius:20px;background:rgba(255,255,255,.09);box-shadow:0 24px 60px rgba(0,0,0,.12);backdrop-filter:blur(12px)}
.book-visual{height:205px;position:relative;display:flex;flex-direction:column;align-items:center;justify-content:center;border-radius:9px 17px 17px 9px;color:var(--ink);background:linear-gradient(145deg,#f9d65e,#edb832);box-shadow:inset 9px 0 0 rgba(255,255,255,.2),0 16px 30px rgba(0,0,0,.18)}
.book-visual::after{content:"";position:absolute;right:9px;top:0;bottom:0;width:2px;background:rgba(20,61,53,.15)}
.book-visual span{font-size:13px;font-weight:950;letter-spacing:.18em}.book-visual strong{font:700 78px/1 var(--serif)}.book-visual small{font-weight:900}
.continue-card .eyebrow, .hero-copy .eyebrow {color:var(--yellow)}.continue-card h2{margin:5px 0 8px;font:700 21px/1.38 var(--display);overflow-wrap:normal}.continue-card p:not(.eyebrow){margin:0;color:#edf6f3;font-size:13px;line-height:1.55}.continue-card>div:last-child>small{color:#f5fbf9;font-size:11px;font-weight:700}
.progress-track{height:8px;margin:17px 0 7px;overflow:hidden;border-radius:99px;background:rgba(255,255,255,.18)}.progress-track i{height:100%;display:block;border-radius:inherit;background:var(--yellow);transition:width .35s ease}

.library-toolbar,.library-content{width:min(1280px,calc(100% - 42px));margin:auto}
.library-toolbar{padding:38px 0 20px;display:flex;align-items:end;justify-content:space-between}.library-toolbar h2{margin:0;font:700 29px var(--serif)}
.select-field{min-width:190px}.select-field span,.practice-filters label span,.form-field>span{display:block;margin-bottom:5px;color:var(--muted);font-size:10px;font-weight:850}.select-field select,.practice-filters select,.form-field input{width:100%;min-height:43px;padding:9px 12px;border:1px solid var(--line-strong);border-radius:10px;color:var(--ink);background:#fff}
.book-shelf{display:grid;grid-template-columns:260px 1fr;gap:22px;align-items:start}
.book-card{min-height:300px;padding:26px;position:sticky;top:88px;overflow:hidden;border-radius:20px;color:#fff;background:linear-gradient(155deg,var(--green),var(--ink));box-shadow:var(--shadow)}
.book-card::after{content:"M";position:absolute;right:-14px;bottom:-47px;color:rgba(255,255,255,.08);font:700 190px var(--serif)}
.book-card small,.book-card strong,.book-card span{display:block;position:relative;z-index:1}.book-card small{color:#bcd8cf;font-weight:850;letter-spacing:.12em}.book-card strong{max-width:180px;margin:18px 0 10px;font:700 34px/1.1 var(--serif)}.book-card span{color:#d7e6e1;font-size:11px}
.chapter-list{display:grid;gap:12px}
.chapter-card{overflow:hidden;border:1px solid var(--line);border-radius:16px;background:#fff;box-shadow:var(--shadow-soft)}
.chapter-head{padding:18px 20px;display:flex;align-items:center;gap:14px;border-bottom:1px solid var(--line);background:linear-gradient(90deg,#fff,var(--green-pale))}
.chapter-number{width:42px;height:42px;display:grid;place-items:center;border-radius:12px;color:#fff;background:var(--green);font:700 17px var(--serif)}
.chapter-head h3{margin:0;font:700 20px/1.35 var(--display)}.chapter-head small{color:var(--muted);font-size:11px;font-weight:700}
.lesson-list{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:1px;background:var(--line)}
.lesson-link{min-height:82px;padding:14px 16px;display:grid;grid-template-columns:36px 1fr auto;gap:11px;align-items:center;border:0;background:#fff;text-align:left;transition:.18s ease}
.lesson-link:hover{position:relative;z-index:1;background:#f2fbf7;box-shadow:inset 4px 0 0 var(--green)}.lesson-link>span:first-child{width:34px;height:34px;display:grid;place-items:center;border-radius:10px;color:var(--green);background:var(--green-pale);font-size:11px;font-weight:700}.lesson-link strong{display:block;font-size:13px;line-height:1.45}.lesson-link small{color:var(--muted);font-size:10px}.lesson-link i{color:var(--green);font-style:normal;font-size:18px}.lesson-link.completed>span:first-child{color:#fff;background:var(--green)}

.reader-shell{width:min(1440px,100%);margin:auto;display:grid;grid-template-columns:310px minmax(0,1fr);min-height:calc(100vh - 66px)}
.book-toc{height:calc(100vh - 66px);position:sticky;top:66px;overflow:auto;padding:28px 18px;border-right:1px solid var(--line);background:#eef3f0}
.toc-head{padding:0 10px 16px}.toc-head h2{margin:0;font:700 23px var(--serif)}
.toc-chapter{margin-bottom:9px;border:1px solid var(--line);border-radius:12px;background:#fff}.toc-chapter>strong{padding:11px 12px;display:block;border-bottom:1px solid var(--line);font-size:11px}.toc-lesson{width:100%;padding:9px 12px;display:flex;align-items:center;gap:8px;border:0;border-bottom:1px solid #edf1ef;background:#fff;text-align:left;font-size:10px}.toc-lesson:last-child{border:0}.toc-lesson:hover,.toc-lesson.active{color:var(--green);background:var(--green-pale)}.toc-lesson span{width:23px;height:23px;display:grid;place-items:center;border-radius:7px;background:#edf2ef;font-size:8px}.toc-lesson.active span{color:#fff;background:var(--green)}
.lesson-reader{max-width:980px;width:100%;margin:0 auto;padding:32px 54px 70px}
.breadcrumb{margin-bottom:28px;color:var(--muted);font-size:10px}.breadcrumb button{padding:0;border:0;color:var(--green);background:transparent}
.lesson-header{padding-bottom:24px;display:flex;align-items:flex-start;justify-content:space-between;border-bottom:1px solid var(--line)}.lesson-header span{color:var(--green);font-size:11px;font-weight:700;letter-spacing:.1em}.lesson-header h1{margin:7px 0 10px;font:700 clamp(28px,3.4vw,40px)/1.28 var(--display);letter-spacing:0}.lesson-header p{margin:0;color:var(--muted);font-size:13px}
.bookmark-button{width:45px;height:45px;border:1px solid var(--line);border-radius:50%;color:var(--green);background:#fff;font-size:24px}.bookmark-button.active{color:var(--ink);background:var(--yellow)}
.lesson-sections{padding:12px 0}.lesson-section{margin:22px 0;padding:25px 28px;border:1px solid var(--line);border-radius:17px;background:var(--paper);box-shadow:var(--shadow-soft)}
.lesson-section.objectives{border-left:6px solid var(--green);background:var(--green-pale)}.lesson-section.warmup{border-left:6px solid #d5a514;background:var(--yellow-pale)}.lesson-section.theory{border-left:6px solid var(--blue);background:var(--blue-pale)}.lesson-section.example{border-left:6px solid var(--purple);background:var(--purple-pale)}.lesson-section.remember{border-left:6px solid var(--coral);background:#fff0ee}.lesson-section.practice{border-left:6px solid var(--orange);background:var(--orange-pale)}.lesson-section.media{border-left:6px solid var(--aqua);background:#e6f7f9}
.section-heading-row{display:flex;align-items:center;gap:14px;margin-bottom:13px}.section-heading-row>div{min-width:0}.section-icon{width:46px;height:46px;flex:0 0 auto;display:grid;place-items:center;border-radius:14px;color:#fff;background:var(--green);font-size:23px;box-shadow:0 6px 14px rgba(20,61,53,.13)}.warmup .section-icon{color:var(--ink);background:var(--yellow)}.theory .section-icon{background:var(--blue)}.example .section-icon{background:var(--purple)}.remember .section-icon{background:var(--coral)}.practice .section-icon{background:var(--orange)}.media .section-icon{background:var(--aqua)}
.section-label{display:inline-flex;margin-bottom:3px;color:var(--green);font-size:10px;font-weight:700;letter-spacing:.09em;text-transform:uppercase}.lesson-section h2{margin:0;font:700 21px/1.4 var(--display)}.lesson-prose{font:16.5px/1.85 var(--sans)}.lesson-prose h3{margin:10px 0;font-size:19px;line-height:1.5}.lesson-prose p{margin:8px 0}.lesson-prose ul{padding-left:24px}.lesson-prose li{margin:6px 0}
.lesson-practice-callout{margin-top:24px;padding:24px;display:flex;align-items:center;justify-content:space-between;gap:20px;border-radius:18px;color:#fff;background:linear-gradient(120deg,var(--ink),var(--green))}.lesson-practice-callout h2{margin:0 0 4px;font:700 22px var(--serif)}.lesson-practice-callout p{margin:0;color:#d1e2dc;font-size:11px}
.reader-footer{padding-top:30px;display:flex;justify-content:space-between}

.page-heading{width:min(1280px,calc(100% - 42px));margin:auto;padding:44px 0 25px;display:flex;align-items:end;justify-content:space-between;gap:25px}.page-heading h1{margin:4px 0 7px;font:700 clamp(28px,3.2vw,39px)/1.28 var(--display);letter-spacing:0}.page-heading>div>p:last-child{margin:0;color:var(--muted);font-size:13px}
.practice-filters{display:flex;gap:10px}.practice-filters label{min-width:210px}
.practice-shell{width:min(1280px,calc(100% - 42px));margin:0 auto 70px;display:grid;grid-template-columns:minmax(0,1.35fr) minmax(330px,.65fr);gap:22px;align-items:start}
.paper-card,.result-card,.connect-card,.sync-card,.exam-runner{min-width:0;border:1px solid var(--line);border-radius:18px;background:var(--paper);box-shadow:var(--shadow)}
.paper-meta{padding:12px 24px;display:flex;justify-content:space-between;border-bottom:1px solid var(--line);color:var(--muted);font-size:9px;font-weight:850;letter-spacing:.08em;text-transform:uppercase}.paper-meta span:first-child{padding:4px 8px;border-radius:99px;color:var(--green);background:var(--green-pale)}
.question-heading{padding:27px 30px 20px;display:flex;align-items:flex-start;gap:14px}.question-heading>div{min-width:0}.question-heading>b{width:38px;height:38px;flex:0 0 auto;display:grid;place-items:center;border-radius:12px;color:#fff;background:var(--green);font-size:14px}.question-heading h2{margin:0 0 6px;font-size:14px}.question-heading p{margin:0;overflow-wrap:anywhere;font:18px/1.7 var(--sans)}
#practiceForm,.exam-paper>.response-renderer{min-width:0;padding:0 30px 28px}.response-renderer{min-width:0;min-height:190px}
.paper-actions{margin-top:25px;padding-top:16px;display:grid;grid-template-columns:auto 1fr auto auto;gap:9px;align-items:center;border-top:1px solid var(--line)}
.choice-list{display:grid;gap:9px}.choice{padding:12px 14px;display:flex;align-items:flex-start;gap:10px;border:1px solid #dedfd4;border-radius:11px;background:#fff}.choice:hover{border-color:var(--green)}.choice input{margin-top:3px;accent-color:var(--green)}
.response-label{display:block;margin:12px 0 5px;color:var(--muted);font-size:10px;font-weight:850}.answer-input{width:100%;min-height:47px;padding:10px 12px;border:0;border-bottom:2px solid var(--line-strong);color:var(--ink);background:#fff;font:18px var(--serif)}
.unit-row,.word-final{display:grid;grid-template-columns:1fr 180px;gap:12px}.inline-blank{width:95px;margin:0 4px;padding:4px 7px;border:0;border-bottom:2px solid var(--green);background:#fff;text-align:center}.blank-sentence{padding:18px;border-radius:12px;background:#fff;font:18px/2 var(--serif)}
.rank-row,.match-row,.tf-row{margin-bottom:8px;padding:10px 12px;display:grid;grid-template-columns:minmax(0,1fr) 190px;gap:12px;align-items:center;border:1px solid #dedfd4;border-radius:10px;background:#fff}.rank-row select,.match-row select,.tf-row select{min-height:39px;padding:7px;border:1px solid var(--line-strong);border-radius:8px;background:#fff}
.place-table,.data-table{width:100%;border-collapse:collapse;background:#fff}.place-table th,.place-table td,.data-table th,.data-table td{padding:9px;border:1px solid var(--line);text-align:center;font-size:10px}.place-table input,.data-table input{width:64px;padding:7px;border:1px solid var(--line-strong);border-radius:7px;text-align:center}
.vertical-math{width:230px;margin:4px auto 18px;padding:15px 28px;text-align:right;font:24px/1.5 ui-monospace,monospace}.vertical-math .line{border-bottom:2px solid var(--ink)}.vertical-math .operator{float:left}
.bar-chart{min-height:210px;padding:16px 12px 0;display:flex;align-items:flex-end;justify-content:space-around;gap:10px;border-left:2px solid var(--line-strong);border-bottom:2px solid var(--line-strong);background:#fff}.bar-wrap{height:180px;flex:1;display:flex;flex-direction:column;justify-content:flex-end;align-items:center;gap:4px}.bar{width:min(55px,70%);border-radius:7px 7px 0 0;background:linear-gradient(var(--green-2),var(--green))}.bar-wrap small{font-size:9px}
.geometry-box{width:min(330px,80%);aspect-ratio:1.6;margin:12px auto 24px;position:relative;border:4px solid var(--green);background:#f7fbf9}.geometry-box span{position:absolute;width:23px;height:23px;display:grid;place-items:center;border-radius:50%;background:var(--yellow);font-size:10px;font-weight:900}.geometry-box .a{left:-14px;top:-14px}.geometry-box .b{right:-14px;top:-14px}.geometry-box .c{right:-14px;bottom:-14px}.geometry-box .d{left:-14px;bottom:-14px}
.fraction-grid{display:grid;grid-template-columns:repeat(4,58px);gap:5px;justify-content:center;margin:22px}.fraction-cell{width:58px;height:58px;border:2px solid var(--green);border-radius:8px;background:#fff}.fraction-cell.selected{background:var(--yellow)}
.word-fields{display:grid;gap:9px}.word-fields textarea,.word-fields input{width:100%;padding:10px 11px;border:1px solid #d6d8cf;border-radius:9px;background:#fff;font:17px var(--serif)}
.hint-panel{margin-top:17px;padding:13px 15px;border-left:4px solid var(--yellow);border-radius:9px;background:var(--yellow-pale);font-size:12px}
.result-card{position:sticky;top:88px;padding:22px}.result-empty{min-height:330px;display:grid;place-content:center;text-align:center;color:var(--muted)}.result-empty span{width:75px;height:75px;margin:auto;display:grid;place-items:center;border:7px solid var(--green-pale);border-radius:50%;color:var(--green);font-size:28px}.result-empty h2{margin:13px 0 4px;color:var(--ink);font:700 21px var(--serif)}.result-empty p{max-width:270px;margin:0}
.score-head{padding-bottom:17px;display:flex;align-items:center;gap:14px;border-bottom:1px solid var(--line)}.score-circle{width:82px;height:82px;flex:0 0 auto;display:grid;place-items:center;border-radius:50%;color:#fff;background:var(--green);box-shadow:inset 0 0 0 7px rgba(255,255,255,.18);font:700 22px var(--serif)}.score-head h2{margin:1px 0;font:700 20px var(--serif)}.score-head p{margin:0;color:var(--muted);font-size:10px}
.criteria{margin:15px 0;display:grid;gap:7px}.criterion{padding:10px;display:grid;grid-template-columns:22px 1fr auto;gap:9px;align-items:start;border-radius:9px;background:#f5f7f5}.criterion i{width:22px;height:22px;display:grid;place-items:center;border-radius:50%;font-style:normal;font-size:9px;font-weight:900}.criterion.pass i{color:var(--green);background:var(--green-pale)}.criterion.partial i{color:#8c650c;background:var(--yellow-pale)}.criterion.fail i{color:var(--red);background:var(--red-pale)}.criterion strong{display:block;font-size:11px}.criterion small{color:var(--muted);font-size:9px}.criterion b{font-size:10px}.solution-box{padding:13px;border-left:4px solid var(--yellow);border-radius:9px;background:var(--yellow-pale);white-space:pre-line;font:14px/1.65 var(--serif)}

.assessment-grid{width:min(1280px,calc(100% - 42px));margin:0 auto 65px;display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.assessment-card{padding:22px;border:1px solid var(--line);border-radius:17px;background:#fff;box-shadow:var(--shadow-soft)}.assessment-icon{width:45px;height:45px;display:grid;place-items:center;border-radius:13px;color:#fff;background:var(--green);font-weight:900}.assessment-card h2{margin:17px 0 6px;font:700 21px var(--serif)}.assessment-card>p{min-height:38px;margin:0;color:var(--muted);font-size:11px}.assessment-meta{margin:17px 0;display:flex;gap:7px;flex-wrap:wrap}.assessment-meta span{padding:5px 8px;border-radius:99px;background:var(--green-pale);font-size:9px;font-weight:800}.assessment-card .button{width:100%}
.exam-runner{width:min(1280px,calc(100% - 42px));margin:0 auto 70px;overflow:hidden}.exam-header{padding:17px 22px;display:flex;align-items:center;justify-content:space-between;color:#fff;background:var(--ink)}.exam-header h2{margin:0;font:700 22px var(--serif)}.exam-clock{text-align:right}.exam-clock small,.exam-clock strong{display:block}.exam-clock small{color:#bcd2cb;font-size:9px}.exam-clock strong{font-size:20px}.exam-layout{display:grid;grid-template-columns:180px 1fr}.exam-nav{padding:18px;display:grid;grid-template-columns:repeat(4,1fr);align-content:start;gap:7px;background:#edf3f0}.exam-nav button{height:35px;border:1px solid var(--line);border-radius:8px;background:#fff;font-size:10px}.exam-nav button.active{color:#fff;background:var(--green)}.exam-nav button.answered{border-color:var(--green);box-shadow:inset 0 -3px 0 var(--green)}.exam-paper{border:0;border-radius:0;box-shadow:none}.exam-paper>.response-renderer{padding-top:0}.exam-paper .paper-actions{margin:0 30px 28px}

#progressContent{width:min(1280px,calc(100% - 42px));margin:0 auto 70px}.progress-kpis{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.progress-kpi{padding:19px;border:1px solid var(--line);border-radius:15px;background:#fff;box-shadow:var(--shadow-soft)}.progress-kpi small{display:block;color:var(--muted);font-size:9px;font-weight:850;letter-spacing:.09em}.progress-kpi strong{display:block;margin:5px 0;font:700 34px var(--serif)}.progress-kpi span{color:var(--muted);font-size:10px}.progress-panels{margin-top:18px;display:grid;grid-template-columns:1fr 1fr;gap:18px}.progress-panel{padding:22px;border:1px solid var(--line);border-radius:16px;background:#fff}.progress-panel h2{margin:0 0 14px;font:700 22px var(--serif)}.attempt-row,.skill-row{padding:11px 0;display:grid;grid-template-columns:1fr auto;gap:12px;border-bottom:1px solid var(--line)}.attempt-row:last-child,.skill-row:last-child{border:0}.attempt-row strong,.skill-row strong{display:block;font-size:11px}.attempt-row small,.skill-row small{color:var(--muted);font-size:9px}.attempt-score{color:var(--green);font-weight:900}.mini-track{width:120px;height:7px;margin-top:5px;overflow:hidden;border-radius:99px;background:#edf1ef}.mini-track i{height:100%;display:block;background:var(--green)}.empty-state{padding:35px;text-align:center;color:var(--muted)}

.connect-layout{width:min(1280px,calc(100% - 42px));margin:0 auto 22px;display:grid;grid-template-columns:1fr 1fr;gap:18px;align-items:start}.connect-card,.sync-card{padding:23px}.connection-methods{margin-bottom:20px;display:grid;grid-template-columns:1fr 1fr;gap:10px}.connection-methods label{padding:13px;display:flex;gap:9px;border:1px solid var(--line);border-radius:11px;background:#fff}.connection-methods input{accent-color:var(--green)}.connection-methods b,.connection-methods small{display:block}.connection-methods b{font-size:11px}.connection-methods small{color:var(--muted);font-size:9px}.form-field{display:block;margin:15px 0}.form-field small{display:block;margin-top:5px;color:var(--muted);font-size:9px}.check-field{margin:12px 0;padding:12px;display:flex;gap:10px;border-radius:10px;background:var(--yellow-pale)}.check-field.priority-field{border:1px solid #b9dfd2;background:var(--green-pale)}.check-field input{accent-color:var(--green)}.check-field b,.check-field small{display:block}.check-field b{font-size:11px}.check-field small{color:var(--muted);font-size:9px}.connect-actions{display:flex;justify-content:flex-end;gap:9px}
.sync-summary{padding:15px;border-radius:12px;background:var(--green-pale)}.sync-summary h2{margin:2px 0;font:700 21px var(--serif)}.sync-summary p{margin:0;color:var(--muted);font-size:10px}.sync-summary .source-priority{margin-top:9px;padding-top:8px;border-top:1px solid rgba(14,123,101,.18);color:var(--ink)}.sync-summary.error{background:var(--red-pale)}.sync-table{margin-top:14px}.sync-row{padding:8px 2px;display:grid;grid-template-columns:1fr auto auto;gap:10px;border-bottom:1px solid var(--line);font-size:10px}.sync-row span{color:var(--muted)}.sync-row b{min-width:65px;text-align:right}.sync-status{padding:3px 7px;border-radius:99px;color:var(--green);background:var(--green-pale);font-size:8px;font-weight:900}.sync-status.missing{color:var(--red);background:var(--red-pale)}
.architecture-note{width:min(1280px,calc(100% - 42px));margin:0 auto 70px;padding:21px;display:flex;align-items:center;gap:9px;flex-wrap:wrap;border:1px solid var(--line);border-radius:16px;background:#fff}.architecture-note>strong{width:100%;margin-bottom:5px}.architecture-note>span{padding:7px 9px;border-radius:8px;background:var(--green-pale);font-size:10px;font-weight:800}.architecture-note>i{color:var(--green);font-style:normal}.architecture-note>p{width:100%;margin:8px 0 0;color:var(--red);font-size:10px}
.snapshot-card{width:min(1280px,calc(100% - 42px));margin:0 auto 22px;padding:23px;display:grid;grid-template-columns:minmax(0,1.3fr) minmax(260px,.7fr) auto;gap:20px;align-items:center;border:1px solid #b9dfd2;border-radius:18px;background:linear-gradient(120deg,#fff,var(--green-pale));box-shadow:var(--shadow-soft)}.snapshot-card h2{margin:2px 0 6px;font:700 22px/1.35 var(--display)}.snapshot-card p:not(.eyebrow){margin:0;color:var(--muted);font-size:12px}.snapshot-card code{padding:2px 5px;border-radius:5px;background:rgba(255,255,255,.75);font-size:.92em}.snapshot-card>small{grid-column:1/-1;color:var(--muted);font-size:10px}.snapshot-status{padding:12px;border-radius:11px;background:rgba(255,255,255,.75)}.snapshot-status strong,.snapshot-status span{display:block}.snapshot-status strong{font-size:12px}.snapshot-status span{margin-top:3px;color:var(--muted);font-size:10px;line-height:1.5}.snapshot-card .button{min-width:190px}

/* V4: công thức KaTeX được đóng gói cục bộ và co giãn trên màn hình học sinh. */
.katex{font-size:1.08em}.katex-display{max-width:100%;margin:1em 0;overflow-x:auto;overflow-y:hidden;padding:4px 2px}.lesson-prose .katex-display,.solution-box .katex-display{padding:10px 4px;border-radius:10px;background:#f8fbfa}.question-heading .katex{font-size:1.12em}.choice .katex,.tf-row .katex,.rank-row .katex,.match-row .katex{font-size:1.04em}.katex-error{padding:2px 5px;border-radius:5px;background:#fff0ed;color:var(--red)!important;font-family:var(--body)!important}.math-help{padding:12px 14px;border-left:4px solid var(--yellow);border-radius:10px;background:#fff8d8;color:var(--ink);font-size:11px;line-height:1.6}.math-help code{padding:2px 5px;border-radius:4px;background:#fff;font-family:ui-monospace,SFMono-Regular,Consolas,monospace}

/* Hệ màu và cỡ chữ rõ ràng cho màn hình học sinh. */
.topnav-item{font-size:12px}.brand small{font-size:10px}.source-pill{font-size:11px}
.chapter-card{--chapter-accent:var(--green);--chapter-pale:var(--green-pale)}
.chapter-card:nth-child(4n+2){--chapter-accent:var(--orange);--chapter-pale:var(--orange-pale)}
.chapter-card:nth-child(4n+3){--chapter-accent:var(--blue);--chapter-pale:var(--blue-pale)}
.chapter-card:nth-child(4n+4){--chapter-accent:var(--purple);--chapter-pale:var(--purple-pale)}
.chapter-card .chapter-head{background:linear-gradient(90deg,#fff 20%,var(--chapter-pale))}
.chapter-card .chapter-number{background:var(--chapter-accent)}
.chapter-card .lesson-link:hover{background:var(--chapter-pale);box-shadow:inset 4px 0 0 var(--chapter-accent)}
.chapter-card .lesson-link>span:first-child{color:var(--chapter-accent);background:var(--chapter-pale)}
.chapter-card .lesson-link i{color:var(--chapter-accent)}
.chapter-card .lesson-link.completed>span:first-child{color:#fff;background:var(--chapter-accent)}
.toc-chapter>strong{font-size:12px}.toc-lesson{font-size:11px;line-height:1.45}.toc-lesson span{font-size:9px}
.lesson-practice-callout .button.primary{color:var(--ink);background:var(--yellow);box-shadow:0 8px 18px rgba(0,0,0,.14)}
.lesson-practice-callout .button.primary:hover{background:#ffdb68}
.paper-meta{font-size:10px}.response-label{font-size:11px}.choice{font-size:14px;line-height:1.55}
.assessment-card:nth-child(3n+2) .assessment-icon{background:var(--orange)}.assessment-card:nth-child(3n+3) .assessment-icon{background:var(--purple)}
.assessment-card>p{font-size:12px;line-height:1.6}.assessment-meta span{font-size:10px}
.breadcrumb{font-size:11px}.bar-wrap small{font-size:10px}.criterion strong{font-size:12px}.criterion small{font-size:11px;line-height:1.45}.criterion b{font-size:11px}.exam-clock small{font-size:10px}
.progress-kpi small{font-size:10px}.progress-kpi span{font-size:11px}.attempt-row strong,.skill-row strong{font-size:12px}.attempt-row small,.skill-row small{font-size:10px}
.empty-state{font-size:13px;line-height:1.65}

.toast{position:fixed;left:50%;bottom:22px;z-index:70;padding:11px 18px;border-radius:99px;color:#fff;background:var(--ink);box-shadow:var(--shadow);font-size:11px;font-weight:800;opacity:0;pointer-events:none;transform:translate(-50%,16px);transition:.18s ease}.toast.show{opacity:1;transform:translate(-50%,0)}
.loading-screen{position:fixed;inset:0;z-index:90;display:grid;place-content:center;justify-items:center;color:#fff;background:var(--ink);transition:.3s ease}.loading-screen.done{opacity:0;pointer-events:none}.loading-mark{width:68px;height:68px;margin-bottom:14px;display:grid;place-items:center;border-radius:20px;color:var(--ink);background:var(--yellow);font:700 39px var(--serif);animation:pulse 1.2s ease-in-out infinite}.loading-screen small{color:#bcd3cc}@keyframes pulse{50%{transform:scale(1.06)}}
.startup-error{position:fixed;left:50%;bottom:20px;z-index:100;width:min(620px,calc(100% - 28px));padding:14px 18px;display:flex;justify-content:center;gap:8px;border:1px solid #e6b9b9;border-radius:12px;color:#7d2424;background:#fff0f0;box-shadow:var(--shadow)}

@media (max-width:1100px){
  .topbar{grid-template-columns:230px 1fr auto}.topnav-item{padding-inline:9px}
  .library-hero{grid-template-columns:1fr;gap:34px}.continue-card{max-width:620px}
  .practice-shell{grid-template-columns:1fr}.result-card{position:static}
  .assessment-grid{grid-template-columns:repeat(2,1fr)}
  .progress-kpis{grid-template-columns:repeat(2,1fr)}
}
@media (max-width:820px){
  .topbar{height:auto;min-height:64px;grid-template-columns:1fr auto;padding:9px 13px}.topnav{grid-column:1/-1;order:3;overflow:auto;justify-content:flex-start}.topnav-item{height:42px;white-space:nowrap}.source-pill{display:none}
  main{min-height:calc(100vh - 106px)}.library-hero{padding:42px 22px}.book-shelf,.reader-shell,.connect-layout{grid-template-columns:1fr}.book-card{position:relative;top:0;min-height:200px}.lesson-list{grid-template-columns:1fr}.book-toc{height:auto;position:relative;top:0;border-right:0;border-bottom:1px solid var(--line)}.lesson-reader{padding:28px 20px 55px}.lesson-practice-callout{align-items:flex-start;flex-direction:column}.page-heading{align-items:flex-start;flex-direction:column}.practice-filters{width:100%;flex-direction:column}.practice-filters label{min-width:0;width:100%}.assessment-grid{grid-template-columns:1fr}.exam-layout{grid-template-columns:1fr}.exam-nav{grid-template-columns:repeat(8,1fr)}.progress-panels{grid-template-columns:1fr}.connection-methods{grid-template-columns:1fr}.snapshot-card{grid-template-columns:1fr}.snapshot-card .button{width:100%}
}
@media (max-width:520px){
  .brand small{display:none}.source-actions .icon-button{width:36px;height:36px}.library-hero{padding:36px 17px}.hero-copy h1{font-size:41px}.hero-actions{flex-direction:column}.continue-card{grid-template-columns:105px 1fr;padding:15px}.book-visual{height:155px}.book-visual strong{font-size:57px}.library-toolbar,.library-content,.page-heading,.practice-shell,.assessment-grid,.exam-runner,#progressContent,.connect-layout,.snapshot-card,.architecture-note{width:calc(100% - 24px)}.library-toolbar{align-items:flex-start;flex-direction:column;gap:12px}.select-field{width:100%}.question-heading{padding:22px 17px}.question-heading p{font-size:18px}#practiceForm,.exam-paper>.response-renderer{padding-inline:17px}.paper-actions{grid-template-columns:1fr 1fr}.paper-actions span{display:none}.paper-actions .text-button{grid-column:1/-1}.unit-row,.word-final,.rank-row,.match-row,.tf-row{grid-template-columns:1fr}.fraction-grid{grid-template-columns:repeat(4,45px)}.fraction-cell{width:45px;height:45px}.reader-footer{gap:8px}.reader-footer .button{flex:1}.progress-kpis{grid-template-columns:1fr}.page-heading .button{width:100%}.exam-nav{grid-template-columns:repeat(6,1fr)}.connect-actions{flex-direction:column}.connect-actions .button{width:100%}
}

/* V4: bộ trả lời theo khối, sơ đồ, dựng hình và nhập công thức. */
.response-block{min-width:0;display:block;margin:0 0 18px;padding:15px;border:1px solid var(--line);border-radius:13px;background:#fff}
.response-block textarea,.response-block input,.response-block select{font-family:var(--sans)}
.response-block textarea{width:100%;padding:11px 12px;border:1px solid var(--line-strong);border-radius:9px;resize:vertical;font-size:16px;line-height:1.65}
.response-block math-field{width:100%;min-width:0;max-width:100%;min-height:58px;padding:10px 12px;border:1px solid var(--line-strong);border-radius:10px;background:#fff;font-size:24px}
.field-help{display:block;margin-top:6px;color:var(--muted);font-size:10px}
.multi-field-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:10px}.multi-field-grid label span{display:block;color:var(--muted);font-size:10px;font-weight:700}
.table-scroll{max-width:100%;overflow:auto}.snapshot-buttons{display:flex;gap:8px;flex-wrap:wrap}.snapshot-buttons .button{min-width:170px}
.visual-response{min-width:0;padding:16px}.bar-model-editor,.geometry-editor{min-width:0;max-width:100%;overflow:hidden;border-radius:11px;background:#f8fbfa}
.bar-model-toolbar,.geometry-toolbar,.freehand-toolbar{padding:10px;display:flex;align-items:center;gap:7px;flex-wrap:wrap;border-bottom:1px solid var(--line)}
.bar-model-toolbar button,.geometry-toolbar button,.freehand-toolbar button,.bar-controls button,.remove-row{min-height:35px;padding:6px 10px;border:1px solid var(--line-strong);border-radius:8px;background:#fff;font-size:11px;font-weight:700}
.geometry-toolbar button.active{color:#fff;border-color:var(--green);background:var(--green)}.geometry-toolbar span{margin-left:auto;color:var(--muted);font-size:10px}
.bar-model-rows{padding:12px;display:grid;gap:10px}.bar-model-row{display:grid;grid-template-columns:120px minmax(180px,1fr) auto 90px 75px 34px;gap:8px;align-items:center}
.bar-model-row>input{min-width:0;padding:8px;border:1px solid var(--line-strong);border-radius:8px}.bar-segments{min-height:38px;display:flex;align-items:center;overflow-x:auto}.bar-segments i{width:40px;height:30px;flex:0 0 40px;border:2px solid var(--green);border-right:0;background:var(--green-pale)}.bar-segments i:last-child{border-right:2px solid var(--green)}
.bar-controls{display:flex;align-items:center;gap:4px}.bar-controls b{min-width:25px;text-align:center}.remove-row{padding:5px;color:var(--red)}
.geometry-board{width:100%;height:440px;border:0!important;border-radius:0 0 11px 11px;background:#fff}.JXGtext{font-family:var(--sans)!important}
.freehand-canvas{display:block;width:100%;height:auto;aspect-ratio:15/7;border-radius:0 0 11px 11px;background-color:#fff;background-image:linear-gradient(#edf2ef 1px,transparent 1px),linear-gradient(90deg,#edf2ef 1px,transparent 1px);background-size:24px 24px;touch-action:none}

@media (max-width:820px){
  .bar-model-row{min-width:0;grid-template-columns:minmax(0,1fr) 72px 34px}.bar-model-row>input:first-child{grid-column:1/-1}.bar-segments{grid-column:1/-1}.bar-controls{grid-column:1/-1;justify-content:flex-start}.bar-model-row [data-row-value],.bar-model-row [data-unit]{min-width:0;width:100%}.geometry-toolbar span{width:100%;margin-left:0}.geometry-board{height:360px}.snapshot-buttons{width:100%}.snapshot-buttons .button{width:100%}
}
@media (max-width:520px){.multi-field-grid{grid-template-columns:1fr}.geometry-board{height:310px}.response-block{padding:11px}.response-block math-field{font-size:20px}}

@media (max-width:520px){
  .hero-copy h1{font-size:35px;line-height:1.4}
  .continue-card h2{font-size:18px;line-height:1.4}
  .continue-card p:not(.eyebrow){font-size:12px}
  .lesson-header h1{font-size:28px;line-height:1.3}
  .lesson-section{padding:21px 18px}
  .section-heading-row{gap:11px}.section-icon{width:42px;height:42px;font-size:20px}
  .lesson-section h2{font-size:19px}.lesson-prose{font-size:16px;line-height:1.8}
}

/* =========================================================
   MATHFORM V4.2 · BƯỚC GIẢI, CHỨNG MINH, MA TRẬN, ĐỒ THỊ
   CSS được đặt tập trung tại đây để dễ bảo trì.
   ========================================================= */
.solution-steps-editor,.proof-steps-editor,.matrix-editor,.function-graph-editor{display:grid;gap:10px}
.steps-toolbar,.proof-toolbar,.graph-toolbar{display:flex;flex-wrap:wrap;gap:7px;align-items:center;justify-content:space-between;padding:9px;border:1px solid var(--line);border-radius:10px;background:#f7faf9}
.steps-toolbar .toolbar-actions,.proof-toolbar .toolbar-actions,.graph-toolbar .toolbar-actions{display:flex;flex-wrap:wrap;gap:6px}
.steps-toolbar button,.proof-toolbar button,.graph-toolbar button,.solution-step button,.proof-row button{min-height:34px;padding:6px 10px;border:1px solid var(--line-strong);border-radius:8px;background:#fff;color:var(--ink);font-size:11px;font-weight:800;cursor:pointer}
.steps-toolbar button:hover,.proof-toolbar button:hover,.graph-toolbar button:hover,.solution-step button:hover,.proof-row button:hover{border-color:var(--green);color:var(--green)}
.solution-step{display:grid;grid-template-columns:38px minmax(0,1fr) auto;gap:9px;align-items:start;padding:11px;border:1px solid var(--line);border-radius:11px;background:#fff}
.solution-step-number{display:grid;place-items:center;width:32px;height:32px;border-radius:50%;background:var(--green-pale);color:var(--green);font-weight:900}
.solution-step-main{display:grid;gap:6px;min-width:0}.solution-step-label{font-size:12px;font-weight:850}.solution-step-help{font-size:10px;color:var(--muted)}
.solution-step textarea,.proof-row textarea{width:100%;min-height:66px;padding:10px;border:1px solid var(--line-strong);border-radius:9px;resize:vertical;font:inherit}
.solution-step input,.proof-row input,.matrix-cell{width:100%;min-height:44px;padding:8px;border:1px solid var(--line-strong);border-radius:9px;background:#fff}
.solution-step math-field,.matrix-grid math-field,.function-graph-editor math-field{display:block;width:100%;min-height:52px;padding:9px 11px;border:1px solid var(--line-strong);border-radius:9px;background:#fff;font-size:21px}
.step-actions{display:flex;flex-direction:column;gap:5px}.step-actions button{min-width:36px;padding:4px}
.proof-row{display:grid;grid-template-columns:36px minmax(0,1fr) minmax(0,.8fr) auto;gap:9px;align-items:start;padding:10px;border:1px solid var(--line);border-radius:10px;background:#fff}
.proof-row strong{display:grid;place-items:center;width:30px;height:30px;border-radius:50%;background:var(--yellow-pale)}
.proof-field{display:grid;gap:4px}.proof-field span{font-size:10px;font-weight:750;color:var(--muted)}
.matrix-wrap{max-width:100%;overflow:auto;padding:6px}.matrix-grid{display:grid;gap:7px;min-width:max-content;align-items:center}.matrix-bracket{display:flex;align-items:stretch;gap:8px}.matrix-bracket:before,.matrix-bracket:after{content:"";width:9px;border-top:2px solid var(--ink);border-bottom:2px solid var(--ink)}.matrix-bracket:before{border-left:2px solid var(--ink)}.matrix-bracket:after{border-right:2px solid var(--ink)}
.function-graph-board{width:100%;height:350px;border:1px solid var(--line-strong);border-radius:10px;background:#fff}.graph-message{font-size:11px;color:var(--muted)}
.manual-review-note{padding:9px 11px;border-left:4px solid var(--yellow);border-radius:9px;background:var(--yellow-pale);color:#72570d;font-size:11px}

/* Hồ sơ học sinh và trạng thái bài duyệt */
.student-chip{min-height:39px;max-width:190px;padding:7px 11px;display:flex;align-items:center;gap:8px;border:1px solid rgba(255,255,255,.18);border-radius:11px;color:#fff;background:rgba(255,255,255,.06);font-size:10px;font-weight:800}
.student-chip span{max-width:135px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.student-chip i{font-style:normal;font-size:17px}
.student-profile-card{margin-bottom:18px;padding:21px;border:1px solid #b9dfd2;border-radius:17px;background:linear-gradient(120deg,#fff,var(--green-pale));box-shadow:var(--shadow-soft)}
.student-profile-card h2{margin:2px 0 5px;font:700 22px var(--display)}.student-profile-card>p{margin:0 0 15px;color:var(--muted);font-size:11px}
.student-profile-grid{display:grid;grid-template-columns:1fr 1fr auto;gap:10px;align-items:end}.student-profile-grid label span{display:block;margin-bottom:5px;color:var(--muted);font-size:10px;font-weight:850}.student-profile-grid input{width:100%;min-height:43px;padding:9px 12px;border:1px solid var(--line-strong);border-radius:10px;background:#fff}
.attempt-status{display:inline-flex;margin-top:4px;padding:3px 7px;border-radius:99px;font-size:8px;font-weight:900}.attempt-status.pending{color:#7a5a00;background:var(--yellow-pale)}.attempt-status.graded{color:var(--green);background:var(--green-pale)}.attempt-status.local{color:var(--muted);background:#edf1ef}.attempt-feedback{display:block;margin-top:4px;color:var(--muted);font-size:9px;font-style:italic}
.review-sync-row{margin:0 0 16px;display:flex;justify-content:flex-end}.review-sync-row .button{min-width:210px}

/* Chế độ hiển thị theo cấp học */
body.grade-primary .question-heading p{font-size:20px;line-height:1.8}
body.grade-primary .response-label{font-size:12px}
body.grade-primary .choice{min-height:56px;font-size:16px}
body.grade-primary .answer-input{min-height:54px;font-size:21px}
body.grade-primary .response-block math-field{min-height:64px;font-size:25px}
body.grade-primary .button{min-height:49px;font-size:14px}
body.grade-primary .solution-step-label{font-size:14px}
body.grade-secondary .question-heading p{font-size:18px}

@media(max-width:680px){
  .solution-step{grid-template-columns:32px minmax(0,1fr)}.step-actions{grid-column:2;flex-direction:row}.proof-row{grid-template-columns:32px minmax(0,1fr)}.proof-field,.proof-row button{grid-column:2}.function-graph-board{height:285px}
  .student-profile-grid{grid-template-columns:1fr}.student-profile-grid .button{width:100%}.student-chip{display:none}.review-sync-row .button{width:100%}
}

/* =========================================================
   MATHFORM V4.2.5.10 · BÌA SÁCH THỰC TẾ TỰ ĐỔI THEO LỚP
   Ảnh mặc định đặt tại assets/covers/toan-{lớp}-tap-{học kỳ}.webp
   ========================================================= */
.cover-frame{
  position:relative;
  overflow:hidden;
  aspect-ratio:3/4;
  border-radius:11px 18px 18px 11px;
  background:linear-gradient(145deg,#f9d65e,#edb832);
  box-shadow:0 16px 32px rgba(0,0,0,.2);
}
.book-cover-image{
  position:absolute;
  inset:0;
  z-index:2;
  width:100%;
  height:100%;
  display:block;
  object-fit:contain;
  object-position:center;
  opacity:0;
  background:#fff;
  transition:opacity .2s ease;
}
.cover-frame.has-cover .book-cover-image.is-loaded{opacity:1}
.book-cover-fallback{
  position:absolute;
  inset:0;
  z-index:1;
  display:flex;
  flex-direction:column;
  align-items:center;
  justify-content:center;
  color:var(--ink);
  background:linear-gradient(145deg,#f9d65e,#edb832);
}
.book-cover-fallback::after{
  content:"";
  position:absolute;
  right:9px;
  top:0;
  bottom:0;
  width:2px;
  background:rgba(20,61,53,.15);
}
.book-cover-fallback span{
  font-size:13px;
  font-weight:950;
  letter-spacing:.18em;
}
.book-cover-fallback strong{
  margin:0;
  max-width:none;
  color:var(--ink);
  font:700 78px/1 var(--serif);
}
.book-cover-fallback small{
  color:var(--ink);
  font-weight:900;
  letter-spacing:0;
}

/* Bìa trong khung tiến độ */
.book-visual{
  width:150px;
  height:auto;
  min-height:0;
  display:block;
  padding:0;
  background:transparent;
  box-shadow:0 16px 30px rgba(0,0,0,.18);
}
.book-visual::after{content:none;display:none}
.hero-book-cover{border-radius:inherit}

/* Bìa bên trái thư viện */
.book-card{
  min-height:0;
  padding:0;
  position:sticky;
  top:88px;
  overflow:visible;
  border-radius:0;
  color:var(--ink);
  background:transparent;
  box-shadow:none;
}
.book-card::after{content:none;display:none}
.library-cover-frame{
  width:100%;
  min-height:0;
  box-shadow:0 18px 42px rgba(20,61,53,.18),0 0 0 1px rgba(20,61,53,.08);
}
.book-card-caption{
  margin-top:13px;
  padding:13px 15px;
  border:1px solid var(--line);
  border-radius:13px;
  background:#fff;
  box-shadow:var(--shadow-soft);
}
.book-card-caption small,
.book-card-caption strong,
.book-card-caption span{
  display:block;
  position:static;
  z-index:auto;
  max-width:none;
}
.book-card-caption small{
  margin:0;
  color:var(--muted);
  font-size:10px;
  font-weight:850;
  letter-spacing:.08em;
}
.book-card-caption strong{
  margin:5px 0 3px;
  color:var(--ink);
  font:700 19px/1.3 var(--display);
}
.book-card-caption span{
  color:var(--muted);
  font-size:10px;
  line-height:1.5;
}

@media(max-width:820px){
  .book-card{position:relative;top:0;max-width:260px;margin:0 auto 8px}
}
@media(max-width:520px){
  .continue-card{grid-template-columns:105px 1fr}
  .book-visual{width:105px;height:auto;min-height:0;aspect-ratio:3/4}
  .book-cover-fallback strong{font-size:57px}
  .book-card{max-width:220px}
}

/* FIX: Nút Xem kết quả gần nhất bị trắng chữ */
.latest-result-btn,
.view-latest-result-btn,
[data-action="view-latest-result"] {
  display: inline-flex !important;
  align-items: center;
  justify-content: center;

  min-width: 200px;
  min-height: 46px;
  padding: 10px 18px;

  background: #ffffff !important;
  color: #08745f !important;
  -webkit-text-fill-color: #08745f !important;

  border: 1px solid #d3e2dd !important;
  border-radius: 12px;
  font-weight: 700;
  text-decoration: none !important;

  opacity: 1 !important;
  visibility: visible !important;
}

.latest-result-btn:hover,
.view-latest-result-btn:hover,
[data-action="view-latest-result"]:hover {
  background: #f1faf7 !important;
  color: #065c4c !important;
  -webkit-text-fill-color: #065c4c !important;
}

/* Firebase Auth + phân quyền công cụ quản trị */
[data-admin-only][hidden]{display:none!important}
.auth-pill{max-width:190px;padding:8px 11px;display:flex;align-items:center;gap:7px;border:1px solid rgba(255,255,255,.18);border-radius:99px;color:#dbe8e4;background:rgba(255,255,255,.06);font-size:10px;font-weight:750}
.auth-pill i{width:8px;height:8px;flex:0 0 auto;border-radius:50%;background:#9fb5ae;box-shadow:0 0 0 4px rgba(159,181,174,.12)}
.auth-pill.is-user i{background:#6cd4ae;box-shadow:0 0 0 4px rgba(108,212,174,.13)}
.auth-pill.is-admin{color:#fff;border-color:rgba(244,202,80,.55);background:rgba(244,202,80,.12)}
.auth-pill.is-admin i{background:var(--yellow)}
.auth-pill.is-error i{background:#ff8275}
.auth-pill:disabled{cursor:wait;opacity:.72}
.auth-pill span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
html[data-mathform-admin="false"] [data-admin-only]{display:none!important}
@media(max-width:820px){.auth-pill{max-width:140px}.auth-pill span{max-width:105px}}
@media(max-width:520px){.auth-pill{width:38px;height:38px;padding:0;justify-content:center}.auth-pill span{display:none}}


/* =========================================================
   HỌC THỬ 3 BÀI ĐẦU CỦA CHƯƠNG ĐẦU TIÊN Ở MỖI LỚP
   ========================================================= */
.trial-access-notice {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin: 0 0 22px;
  padding: 18px 20px;
  border: 1px solid #b8ded3;
  border-radius: 18px;
  background: linear-gradient(135deg, #effbf7, #ffffff);
  box-shadow: 0 12px 28px rgba(16, 78, 65, 0.08);
}
.trial-access-notice > div { display: grid; gap: 4px; }
.trial-access-notice span { color: #08745f; font-size: 0.76rem; font-weight: 900; letter-spacing: 0.09em; }
.trial-access-notice strong { color: #173f37; font-size: 1rem; }
.trial-access-notice small { color: #61736e; line-height: 1.45; }
.trial-access-notice .button { flex: 0 0 auto; }

.lesson-link.is-locked,
.toc-lesson.is-locked {
  cursor: pointer;
  background: #f7f8f8;
  color: #68736f;
  border-color: #dde3e1;
}
.lesson-link.is-locked:hover,
.toc-lesson.is-locked:hover {
  background: #fff8ec;
  border-color: #e8c98e;
  transform: translateY(-1px);
}
.lesson-link.is-locked > i { color: #9a6b16; }
.lesson-access-badge {
  display: inline-flex;
  align-items: center;
  margin-left: 8px;
  padding: 2px 7px;
  border-radius: 999px;
  font-size: 0.62rem;
  font-style: normal;
  font-weight: 900;
  letter-spacing: 0.04em;
  vertical-align: middle;
}
.lesson-access-badge.trial { color: #06705c; background: #dff7ef; }
.lesson-access-badge.locked { color: #875d10; background: #fff0cf; }

.toc-lesson { align-items: center; }
.toc-lesson > b { min-width: 0; flex: 1; text-align: left; font-weight: 700; }
.toc-lesson > small {
  margin-left: auto;
  padding: 2px 6px;
  border-radius: 999px;
  background: #e8f7f2;
  color: #08745f;
  font-size: 0.62rem;
  font-weight: 900;
  white-space: nowrap;
}
.toc-lesson.is-locked > small { background: #fff0cf; color: #875d10; }

.topnav-item.access-locked::after {
  content: "🔒";
  margin-left: 5px;
  font-size: 0.72rem;
}

.access-locked-panel {
  display: flex;
  align-items: center;
  gap: 20px;
  padding: 28px;
  border: 1px solid #dfd7c7;
  border-radius: 20px;
  background: linear-gradient(135deg, #fffaf0, #ffffff);
}
.access-locked-panel > span { font-size: 2.4rem; }
.access-locked-panel h2 { margin: 4px 0 8px; }
.access-locked-panel p { margin: 0 0 16px; color: #66736f; }

.access-dialog-backdrop {
  position: fixed;
  inset: 0;
  z-index: 10000;
  display: none;
  place-items: center;
  padding: 20px;
  background: rgba(8, 32, 27, 0.58);
  backdrop-filter: blur(4px);
}
.access-dialog-backdrop.show { display: grid; }
.access-dialog {
  position: relative;
  width: min(520px, 100%);
  padding: 30px;
  border-radius: 22px;
  background: #ffffff;
  box-shadow: 0 28px 70px rgba(6, 38, 31, 0.28);
  text-align: center;
}
.access-dialog-icon { display: block; margin-bottom: 8px; font-size: 2.6rem; }
.access-dialog h2 { margin: 6px 0 10px; color: #173f37; }
.access-dialog > p:not(.eyebrow) { margin: 0 auto; max-width: 430px; color: #65746f; line-height: 1.6; }
.access-dialog-actions { display: flex; justify-content: center; gap: 10px; flex-wrap: wrap; margin-top: 22px; }
.access-dialog-close {
  position: absolute;
  top: 12px;
  right: 14px;
  width: 36px;
  height: 36px;
  border: 0;
  border-radius: 50%;
  background: #eef3f1;
  color: #31554d;
  font-size: 1.4rem;
  cursor: pointer;
}

@media (max-width: 720px) {
  .trial-access-notice { align-items: stretch; flex-direction: column; }
  .trial-access-notice .button { width: 100%; }
  .lesson-access-badge { display: flex; width: fit-content; margin: 5px 0 0; }
  .toc-lesson > small { display: none; }
  .access-locked-panel { align-items: flex-start; padding: 20px; }
  .access-dialog { padding: 26px 18px 20px; }
  .access-dialog-actions .button { width: 100%; }
}


/* Đăng nhập MathForm: ID/mật khẩu nội bộ hoặc Google/Gmail */
.mathform-login-backdrop{
  position:fixed;
  inset:0;
  z-index:11000;
  display:none;
  place-items:center;
  padding:20px;
  background:rgba(8,32,27,.62);
  backdrop-filter:blur(5px);
}
.mathform-login-backdrop.show{display:grid}
.mathform-login-dialog{
  position:relative;
  width:min(480px,100%);
  max-height:calc(100vh - 32px);
  overflow:auto;
  padding:30px;
  border-radius:22px;
  background:#fff;
  box-shadow:0 30px 80px rgba(6,38,31,.32);
  color:#173f37;
}
.mathform-login-dialog h2{margin:6px 0 8px;font-size:1.8rem}
.mathform-login-intro{margin:0 0 20px;color:#65746f;line-height:1.55}
.mathform-login-close{
  position:absolute;
  top:12px;
  right:14px;
  width:36px;
  height:36px;
  border:0;
  border-radius:50%;
  background:#eef3f1;
  color:#31554d;
  font-size:1.4rem;
  cursor:pointer;
}
.mathform-login-form{display:grid;gap:15px;text-align:left}
.mathform-login-form label{display:grid;gap:7px}
.mathform-login-form label>span{font-size:.82rem;font-weight:800;color:#294f46}
.mathform-login-form input{
  width:100%;
  min-height:46px;
  box-sizing:border-box;
  padding:11px 13px;
  border:1px solid #c7d5d1;
  border-radius:11px;
  background:#fff;
  color:#173f37;
  font:inherit;
  outline:none;
}
.mathform-login-form input:focus{border-color:#0b8b70;box-shadow:0 0 0 3px rgba(11,139,112,.12)}
.mathform-login-form small{color:#73817d;line-height:1.45}
.mathform-password-row{display:grid;grid-template-columns:1fr auto;gap:8px}
.mathform-password-row button{
  min-width:58px;
  border:1px solid #c7d5d1;
  border-radius:11px;
  background:#f4f8f7;
  color:#31554d;
  font-weight:800;
  cursor:pointer;
}
.mathform-password-submit{width:100%;min-height:46px}
.mathform-login-error{
  margin:0;
  padding:10px 12px;
  border:1px solid #f2b7ae;
  border-radius:10px;
  background:#fff2ef;
  color:#a43123;
  font-size:.88rem;
  line-height:1.45;
}
.mathform-login-divider{display:flex;align-items:center;gap:10px;margin:18px 0;color:#899590;font-size:.78rem;font-weight:800}
.mathform-login-divider::before,.mathform-login-divider::after{content:"";height:1px;flex:1;background:#e1e8e5}
.mathform-google-login{display:flex!important;align-items:center;justify-content:center;gap:10px;width:100%;min-height:46px}
.mathform-google-mark{display:grid;place-items:center;width:25px;height:25px;border-radius:50%;background:#fff;border:1px solid #d8dfdd;color:#4285f4;font-weight:900}
.mathform-login-note{display:block;margin-top:13px;color:#77847f;line-height:1.5;text-align:center}
.mathform-login-dialog button:disabled,.mathform-login-dialog input:disabled{opacity:.65;cursor:wait}
@media(max-width:520px){
  .mathform-login-backdrop{padding:10px}
  .mathform-login-dialog{padding:25px 17px 20px;border-radius:17px}
  .mathform-login-dialog h2{font-size:1.5rem}
}

/* ==========================================================
   MATHFORM — TĂNG CỠ PHÂN SỐ/CÔNG THỨC INLINE TRÊN WEB HỌC SINH
   Giữ nguyên dữ liệu và logic chấm; chỉ cải thiện khả năng đọc.
   ========================================================== */

/* Cỡ nền cho công thức nằm cùng dòng với văn bản. */
.katex {
  font-size: 1.16em;
}

/* Lý thuyết, đề bài và lời giải cần dễ đọc hơn chữ thường. */
.lesson-prose .katex,
.question-heading .katex,
.solution-box .katex,
.response-renderer .katex,
.feedback-box .katex,
.teacher-feedback .katex {
  font-size: 1.26em;
}

/* Câu hỏi là vị trí quan trọng nhất: phân số không còn quá nhỏ. */
.question-heading .katex {
  font-size: 1.30em;
}

/* Đáp án lựa chọn vẫn lớn hơn trước nhưng không làm hàng quá cao. */
.choice .katex,
.tf-row .katex,
.rank-row .katex,
.match-row .katex {
  font-size: 1.18em;
}

/* Học sinh tiểu học cần công thức rõ hơn một mức. */
body.grade-primary .lesson-prose .katex,
body.grade-primary .question-heading .katex,
body.grade-primary .solution-box .katex,
body.grade-primary .response-renderer .katex {
  font-size: 1.34em;
}

body.grade-primary .choice .katex,
body.grade-primary .tf-row .katex,
body.grade-primary .rank-row .katex,
body.grade-primary .match-row .katex {
  font-size: 1.24em;
}

/* Không phóng to lặp lại đối với công thức dạng một dòng riêng. */
.katex-display > .katex,
.lesson-prose .katex-display > .katex,
.question-heading .katex-display > .katex,
.solution-box .katex-display > .katex {
  font-size: 1.12em;
}

@media (max-width: 760px) {
  .lesson-prose .katex,
  .question-heading .katex,
  .solution-box .katex,
  .response-renderer .katex {
    font-size: 1.25em;
  }

  body.grade-primary .lesson-prose .katex,
  body.grade-primary .question-heading .katex,
  body.grade-primary .solution-box .katex,
  body.grade-primary .response-renderer .katex {
    font-size: 1.30em;
  }
}

/* ==========================================================
   MATHFORM — BẢN VÁ 2: PHÂN SỐ INLINE CÙNG CỠ CHỮ XUNG QUANH
   :has(.mfrac) chỉ phóng to công thức có phân số, không làm
   các công thức khác bị quá lớn.
   ========================================================== */

/* Tạo đủ chiều cao dòng để tử số/mẫu số không bị ép nhỏ hoặc chạm dòng. */
.lesson-prose,
.question-heading,
.solution-box,
.response-renderer,
.feedback-box,
.teacher-feedback,
.choice,
.tf-row,
.rank-row,
.match-row {
  line-height: 1.82;
}

/* Chrome/Edge hiện đại: phóng to riêng công thức có \frac hoặc \dfrac. */
.lesson-prose .katex:has(.mfrac),
.question-heading .katex:has(.mfrac),
.solution-box .katex:has(.mfrac),
.response-renderer .katex:has(.mfrac),
.feedback-box .katex:has(.mfrac),
.teacher-feedback .katex:has(.mfrac),
.choice .katex:has(.mfrac),
.tf-row .katex:has(.mfrac),
.rank-row .katex:has(.mfrac),
.match-row .katex:has(.mfrac) {
  font-size: 1.52em;
  margin-inline: .06em;
  vertical-align: -0.10em;
}

/* Đề bài và lý thuyết tiểu học: tăng thêm một mức để phân số rõ như chữ. */
body.grade-primary .lesson-prose .katex:has(.mfrac),
body.grade-primary .question-heading .katex:has(.mfrac),
body.grade-primary .solution-box .katex:has(.mfrac),
body.grade-primary .response-renderer .katex:has(.mfrac) {
  font-size: 1.60em;
}

/* Phương án lựa chọn giữ gọn hơn một chút để không làm thẻ quá cao. */
.choice .katex:has(.mfrac),
.tf-row .katex:has(.mfrac),
.rank-row .katex:has(.mfrac),
.match-row .katex:has(.mfrac) {
  font-size: 1.42em;
}

/* Không phóng quá lớn công thức dạng display đứng riêng một dòng. */
.katex-display .katex:has(.mfrac),
.lesson-prose .katex-display .katex:has(.mfrac),
.question-heading .katex-display .katex:has(.mfrac),
.solution-box .katex-display .katex:has(.mfrac) {
  font-size: 1.22em;
  vertical-align: baseline;
}

/* Fallback cho trình duyệt chưa hỗ trợ :has(). */
@supports not selector(.katex:has(.mfrac)) {
  .lesson-prose .katex .mfrac,
  .question-heading .katex .mfrac,
  .solution-box .katex .mfrac,
  .response-renderer .katex .mfrac,
  .choice .katex .mfrac {
    font-size: 1.20em;
  }
}

@media (max-width: 760px) {
  .lesson-prose,
  .question-heading,
  .solution-box,
  .response-renderer,
  .choice {
    line-height: 1.76;
  }

  .lesson-prose .katex:has(.mfrac),
  .question-heading .katex:has(.mfrac),
  .solution-box .katex:has(.mfrac),
  .response-renderer .katex:has(.mfrac) {
    font-size: 1.46em;
  }

  .choice .katex:has(.mfrac) {
    font-size: 1.36em;
  }
}


/* ==========================================================
   TIẾN ĐỘ — XEM LẠI BÀI LÀM RÕ ĐÁP ÁN VÀ CÔNG THỨC
   ========================================================== */
.stored-answer-grid{display:grid;gap:12px;margin-top:10px}
.stored-answer-card{padding:16px 18px;border:1px solid var(--line);border-radius:14px;background:#fff;box-shadow:0 5px 16px rgba(20,61,53,.05)}
.stored-answer-label{display:block;margin-bottom:8px;color:var(--green);font-size:11px;font-weight:700;letter-spacing:.07em;text-transform:uppercase}
.stored-answer-value{font-size:17px;line-height:1.75;white-space:pre-wrap;overflow-wrap:anywhere}
.stored-answer-empty{display:block;color:var(--muted);font-size:13px;font-style:italic}
.stored-answer-math{min-height:42px;display:flex;align-items:center;font-size:18px}
.stored-answer-math .katex{font-size:1.42em}
.stored-answer-math .katex:has(.mfrac){font-size:1.60em;vertical-align:-.10em}
#progressContent .hint-panel .katex:has(.mfrac){font-size:1.48em;vertical-align:-.08em}
#progressContent .lesson-section{background:var(--paper)}

@supports not selector(.katex:has(.mfrac)){
  .stored-answer-math .katex .mfrac,
  #progressContent .hint-panel .katex .mfrac{font-size:1.22em}
}

@media(max-width:760px){
  .stored-answer-card{padding:14px}
  .stored-answer-value{font-size:16px}
  .stored-answer-math .katex{font-size:1.32em}
  .stored-answer-math .katex:has(.mfrac){font-size:1.48em}
}

/* --- Tùy chỉnh Bảng nhập liệu (.place-table, .data-table) --- */
.place-table, 
.data-table {
    color: #000 !important; 
    white-space: normal !important; 
}

.place-table th, .place-table td, 
.data-table th, .data-table td {
    font-size: 15px !important; 
    font-weight: 500 !important; 
    color: #000 !important; 
    padding: 8px 6px !important; 
}

/* Cột 'Đọc số' cuối cùng */
.place-table td:last-child {
    text-align: left !important;
    min-width: 140px;
}

/* SỬA LẠI PHẦN NÀY */
.place-table input, 
.data-table input {
    font-size: 16px !important;
    font-weight: bold !important;
    color: #000 !important;
    text-align: center !important; 
    
    /* TUYỆT CHIÊU MỚI TƯƠNG THÍCH MỌI TRÌNH DUYỆT */
    width: 7ch !important; /* Ô luôn luôn rộng chính xác bằng 7 chữ số */
    max-width: 100% !important; /* Đảm bảo không bao giờ bị tràn ra khỏi bảng */
    
    padding: 6px 2px !important; 
    border: 2px solid #7a7a7a !important; 
    border-radius: 6px !important;
    box-sizing: border-box !important;
}

/* =========================================================
   BỐ CỤC SÁCH: VIẾT SỐ RỒI ĐỌC SỐ
   Build: book-write-read-1
   ========================================================= */
.book-write-read-block{
  margin-top:4px;
  padding:4px 18px 8px;
  border:1px solid var(--line);
  border-radius:15px;
  color:#0b0b0b;
  background:#fff;
}
.book-write-read-list{display:grid;gap:0}
.book-write-read-item{padding:18px 0 20px;border-bottom:1px solid #dfe7e3}
.book-write-read-item:last-child{border-bottom:0}
.book-write-read-source{display:flex;align-items:flex-start;gap:9px;color:#090909;font-size:20px;font-weight:500;line-height:1.58}
.book-write-read-source p{margin:0;min-width:0}
.book-write-read-letter{flex:0 0 auto;color:#090909;font-weight:800}
.book-write-read-answers{display:grid;grid-template-columns:minmax(150px,.38fr) minmax(280px,1fr);gap:16px;margin:13px 0 0 31px}
.book-write-read-answer{display:block;min-width:0}
.book-write-read-answer>span{display:block;margin:0 0 7px;color:#111;font-size:15px;font-weight:800;line-height:1.35}
.book-write-read-answer .answer-input{
  width:100%;
  min-height:52px;
  padding:10px 12px;
  border:1.5px solid #78938b;
  border-radius:10px;
  color:#000;
  background:#fff;
  font:600 19px/1.4 var(--sans);
  box-shadow:inset 0 1px 0 rgba(20,61,53,.03);
}
.book-write-read-answer .answer-input::placeholder{color:#6a7470;opacity:1;font-weight:500}
.book-write-read-answer .answer-input:focus{border-color:var(--green);box-shadow:0 0 0 3px rgba(14,123,101,.12);outline:0}

/* Chữ trong các bài nhiều ô thông thường cũng rõ hơn ở cấp tiểu học. */
body.grade-primary .response-block{color:#0b0b0b}
body.grade-primary .multi-field-grid label span{color:#111;opacity:1;font-size:15px;font-weight:800;line-height:1.4;margin-bottom:7px}
body.grade-primary .multi-field-grid .answer-input{color:#000;background:#fff;font-weight:600}

@media (max-width:760px){
  .book-write-read-block{padding:2px 13px 6px}
  .book-write-read-item{padding:16px 0 18px}
  .book-write-read-source{font-size:18px;line-height:1.55}
  .book-write-read-answers{grid-template-columns:1fr;margin-left:27px;gap:11px}
  .book-write-read-answer>span{font-size:15px}
  .book-write-read-answer .answer-input{min-height:50px;font-size:18px}
}


/* ===== NÂNG CẤP ĐỘ RÕ NÉT CHO TẤT CẢ DẠNG BÀI ===== */
:root{
  --answer-ink:#000000;
  --answer-label:#203a35;
  --answer-border:#8ca6a0;
  --answer-border-strong:#6f8d86;
}

/* Nội dung trong khu vực làm bài phải đậm, rõ, màu đen */
.response-renderer,
.response-renderer *{
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  text-rendering:optimizeLegibility;
}

.response-block,
.response-block p,
.response-block div,
.response-block label,
.response-block legend,
.response-block span,
.response-block small,
.response-block b,
.response-block strong,
.response-block td,
.response-block th{
  color:var(--answer-ink);
}

/* Tiêu đề/nhãn trong các khối trả lời */
.response-label,
.multi-field-grid label span,
.choice-list .choice > span,
.tf-row > span,
.rank-row > span,
.match-row > span,
.response-block legend,
.block-label,
.table-scroll caption{
  color:var(--answer-label) !important;
  opacity:1 !important;
  font-weight:800 !important;
}

.response-label{
  font-size:15px !important;
  line-height:1.45 !important;
  margin:0 0 10px !important;
}

/* Ô nhập, ô chọn, textarea, select */
.answer-input,
.response-block textarea,
.response-block select,
.response-block input:not([type="radio"]):not([type="checkbox"]),
.place-table input,
.data-table input,
.inline-blank,
.word-fields textarea,
.word-fields input{
  color:var(--answer-ink) !important;
  background:#fff !important;
  border:1.6px solid var(--answer-border) !important;
  border-bottom:2.4px solid var(--answer-border-strong) !important;
  border-radius:12px !important;
  box-shadow:none !important;
  font-family:var(--display) !important;
  font-size:22px !important;
  font-weight:700 !important;
  line-height:1.4 !important;
  letter-spacing:0 !important;
}

.answer-input,
.response-block input:not([type="radio"]):not([type="checkbox"]),
.place-table input,
.data-table input,
.inline-blank,
.word-fields input{
  min-height:54px !important;
  padding:10px 14px !important;
}

.response-block textarea,
.word-fields textarea{
  min-height:96px;
  padding:12px 14px !important;
}

.response-block select{
  min-height:50px !important;
  padding:9px 12px !important;
  font-size:19px !important;
  font-weight:700 !important;
}

.answer-input::placeholder,
.response-block textarea::placeholder,
.response-block input::placeholder,
.word-fields input::placeholder,
.word-fields textarea::placeholder{
  color:#6c7673 !important;
  opacity:1 !important;
  font-weight:600;
}

/* Các bài nhiều ô trống */
.multi-field-grid{
  gap:14px 16px !important;
}
.multi-field-grid label span{
  font-size:16px !important;
  line-height:1.4 !important;
  margin-bottom:8px !important;
}

/* Các bài chọn đáp án */
.choice-list{
  gap:12px !important;
}
.choice{
  min-height:64px !important;
  padding:14px 16px !important;
  border:1.5px solid #c8d4d0 !important;
  border-radius:14px !important;
  background:#fff !important;
  font-size:22px !important;
  font-weight:600 !important;
  line-height:1.5 !important;
}
.choice > span{
  color:#000 !important;
  font-size:22px !important;
  font-weight:600 !important;
  line-height:1.5 !important;
}
.choice input{
  width:18px;
  height:18px;
  margin-top:5px !important;
}

/* Đúng/sai, nối cặp, sắp xếp */
.tf-row,
.rank-row,
.match-row{
  border:1.5px solid #c8d4d0 !important;
  border-radius:12px !important;
  background:#fff !important;
}
.tf-row > span,
.rank-row > span,
.match-row > span{
  font-size:20px !important;
  font-weight:600 !important;
  line-height:1.5 !important;
}

/* Bảng nhập liệu */
.place-table, .data-table{
  color:#000 !important;
}
.place-table th, .place-table td,
.data-table th, .data-table td{
  color:#000 !important;
  font-size:16px !important;
  line-height:1.45 !important;
}
.place-table th, .data-table th{
  font-weight:800 !important;
}
.place-table td, .data-table td{
  font-weight:600 !important;
}

/* Khối đặc biệt */
.blank-sentence,
.vertical-math,
.math-help,
.field-help{
  color:#000 !important;
}
.blank-sentence{
  font-size:22px !important;
}
.field-help{
  font-size:13px !important;
}

/* Bố cục sách: Viết số rồi đọc số */
.book-write-read-item .book-write-read-source,
.book-write-read-source > span,
.book-write-read-source > p{
  color:#000 !important;
}
.book-write-read-source{
  font-size:21px !important;
  font-weight:600 !important;
  line-height:1.55 !important;
}
.book-write-read-answers label > span{
  color:var(--answer-label) !important;
  font-size:16px !important;
  font-weight:800 !important;
}
.book-write-read-answers .answer-input{
  font-size:22px !important;
}

/* Ưu tiên cho tiểu học */
body.grade-primary .response-label{font-size:16px !important;}
body.grade-primary .multi-field-grid label span{font-size:17px !important;}
body.grade-primary .answer-input,
body.grade-primary .response-block input:not([type="radio"]):not([type="checkbox"]),
body.grade-primary .response-block textarea,
body.grade-primary .response-block select{font-size:23px !important;}
body.grade-primary .choice,
body.grade-primary .choice > span,
body.grade-primary .tf-row > span,
body.grade-primary .rank-row > span,
body.grade-primary .match-row > span{font-size:23px !important;}

@media (max-width:820px){
  .choice, .choice > span, .tf-row > span, .rank-row > span, .match-row > span{font-size:20px !important;}
  .answer-input, .response-block textarea, .response-block select, .response-block input:not([type="radio"]):not([type="checkbox"]) {font-size:20px !important;}
  .response-label, .multi-field-grid label span{font-size:15px !important;}
}

@media (max-width:520px){
  .choice, .choice > span, .tf-row > span, .rank-row > span, .match-row > span{font-size:18px !important;}
  .answer-input, .response-block textarea, .response-block select, .response-block input:not([type="radio"]):not([type="checkbox"]) {font-size:18px !important;}
  .response-label, .multi-field-grid label span{font-size:14px !important;}
}


/* ===== ĐIỀU CHỈNH VỪA RÕ - KHÔNG QUÁ TO - KHÔNG TRÀN ===== */

/* Chuẩn chung: cỡ chữ khu vực làm bài tương đương đề bài */
.response-label {
  font-size: 15px !important;
  font-weight: 800 !important;
  line-height: 1.45 !important;
}

.multi-field-grid label span,
.book-write-read-answers label > span,
.block-label {
  font-size: 15px !important;
  font-weight: 750 !important;
  line-height: 1.4 !important;
}

/* Ô nhập: rõ nét nhưng không lớn hơn đề bài */
.answer-input,
.response-block textarea,
.response-block select,
.response-block input:not([type="radio"]):not([type="checkbox"]),
.inline-blank,
.word-fields input,
.word-fields textarea {
  font-size: 18px !important;
  font-weight: 600 !important;
  line-height: 1.45 !important;
}

.answer-input,
.response-block input:not([type="radio"]):not([type="checkbox"]),
.inline-blank,
.word-fields input {
  min-height: 48px !important;
  padding: 8px 11px !important;
}

/* Trắc nghiệm, đúng/sai, nối cặp, sắp xếp */
.choice,
.choice > span,
.tf-row > span,
.rank-row > span,
.match-row > span {
  font-size: 18px !important;
  font-weight: 600 !important;
  line-height: 1.5 !important;
}

.choice {
  min-height: 55px !important;
  padding: 11px 14px !important;
}

/* Bảng: không ép cột Đọc số thành chữ dọc */
.table-scroll {
  width: 100%;
  max-width: 100%;
  overflow-x: auto !important;
  -webkit-overflow-scrolling: touch;
}

.place-table,
.data-table {
  width: 100% !important;
  min-width: 900px !important;
  table-layout: fixed !important;
}

.place-table th,
.place-table td,
.data-table th,
.data-table td {
  color: #000 !important;
  font-size: 18px !important;
  font-weight: 600 !important;
  line-height: 1.35 !important;
  padding: 9px 7px !important;
  white-space: normal !important;
  overflow-wrap: normal !important;
  word-break: normal !important;
  vertical-align: middle !important;
}

/* Độ rộng hợp lý cho từng nhóm cột của bảng giá trị hàng */
.place-table th:first-child,
.place-table td:first-child,
.data-table th:first-child,
.data-table td:first-child {
  width: 120px !important;
}

.place-table th:last-child,
.place-table td:last-child,
.data-table th:last-child,
.data-table td:last-child {
  width: 230px !important;
  min-width: 230px !important;
  text-align: left !important;
}

.place-table input,
.data-table input {
  width: 100% !important;
  min-width: 0 !important;
  max-width: 100% !important;
  min-height: 46px !important;
  padding: 7px 8px !important;
  font-size: 18px !important;
  font-weight: 600 !important;
  text-align: center !important;
}

/* Bố cục viết số rồi đọc số */
.book-write-read-source {
  font-size: 18px !important;
  font-weight: 600 !important;
  line-height: 1.55 !important;
}

.book-write-read-answers .answer-input {
  font-size: 18px !important;
  font-weight: 600 !important;
}

/* Tiểu học: giữ rõ nhưng không phóng quá lớn */
body.grade-primary .response-label {
  font-size: 15px !important;
}

body.grade-primary .multi-field-grid label span {
  font-size: 15px !important;
}

body.grade-primary .answer-input,
body.grade-primary .response-block input:not([type="radio"]):not([type="checkbox"]),
body.grade-primary .response-block textarea,
body.grade-primary .response-block select,
body.grade-primary .choice,
body.grade-primary .choice > span,
body.grade-primary .tf-row > span,
body.grade-primary .rank-row > span,
body.grade-primary .match-row > span {
  font-size: 18px !important;
}

/* Điện thoại */
@media (max-width: 820px) {
  .place-table,
  .data-table {
    min-width: 860px !important;
  }

  .answer-input,
  .response-block textarea,
  .response-block select,
  .response-block input:not([type="radio"]):not([type="checkbox"]),
  .choice,
  .choice > span,
  .tf-row > span,
  .rank-row > span,
  .match-row > span {
    font-size: 17px !important;
  }
}

@media (max-width: 520px) {
  .answer-input,
  .response-block textarea,
  .response-block select,
  .response-block input:not([type="radio"]):not([type="checkbox"]),
  .choice,
  .choice > span,
  .tf-row > span,
  .rank-row > span,
  .match-row > span {
    font-size: 16px !important;
  }
}


/* ===== MỞ RỘNG KHUNG LÀM BÀI - THU GỌN KHUNG KẾT QUẢ ===== */

/*
 * Màn hình rộng:
 * - Khu vực làm bài dùng toàn bộ phần chiều rộng còn lại.
 * - Khung kết quả giữ cố định khoảng 290 px.
 * - Khoảng cách giữa hai khung giảm xuống 16 px.
 */
.practice-shell {
  width: min(1440px, calc(100% - 28px)) !important;
  grid-template-columns: minmax(0, 1fr) 290px !important;
  gap: 16px !important;
}

/* Thu gọn khung kết quả nhưng vẫn đủ chỗ đọc nội dung */
.result-card {
  padding: 18px !important;
}

.score-head {
  gap: 11px !important;
}

.score-circle {
  width: 70px !important;
  height: 70px !important;
  font-size: 19px !important;
}

.score-head h2 {
  font-size: 18px !important;
}

.score-head p {
  font-size: 10px !important;
  line-height: 1.45 !important;
}

.criterion {
  padding: 9px !important;
  grid-template-columns: 21px minmax(0, 1fr) auto !important;
  gap: 7px !important;
}

.solution-box {
  padding: 11px !important;
  font-size: 13px !important;
}

/*
 * Làm chữ ở các khối thông thường rõ như bảng:
 * chỉ tăng độ rõ/đậm, không tăng quá kích thước của đề bài.
 */
.response-block,
.response-block label,
.response-block legend,
.response-block span,
.response-block p,
.response-block div {
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}

.response-label,
.multi-field-grid label span,
.choice > span,
.tf-row > span,
.rank-row > span,
.match-row > span,
.block-label {
  color: #102f2a !important;
  opacity: 1 !important;
  font-family: var(--display) !important;
  font-weight: 700 !important;
}

.multi-field-grid label span,
.choice > span,
.tf-row > span,
.rank-row > span,
.match-row > span {
  font-size: 18px !important;
  line-height: 1.5 !important;
}

/* Các câu điền nhiều ô như câu 3, 4, 8 */
.multi-field-grid {
  gap: 15px 16px !important;
}

/* Khi khung làm bài rộng hơn, bảng 7 cột có thể hiển thị đủ trên desktop */
@media (min-width: 1181px) {
  .place-table,
  .data-table {
    min-width: 0 !important;
    width: 100% !important;
  }

  .table-scroll {
    overflow-x: visible !important;
  }

  .place-table th,
  .place-table td,
  .data-table th,
  .data-table td {
    font-size: 17px !important;
    padding: 9px 6px !important;
  }

  .place-table th:last-child,
  .place-table td:last-child,
  .data-table th:last-child,
  .data-table td:last-child {
    width: 210px !important;
    min-width: 210px !important;
  }
}

/* Màn hình trung bình: giảm khung kết quả thêm một chút */
@media (min-width: 1101px) and (max-width: 1250px) {
  .practice-shell {
    width: calc(100% - 20px) !important;
    grid-template-columns: minmax(0, 1fr) 270px !important;
    gap: 12px !important;
  }

  .result-card {
    padding: 15px !important;
  }
}

/* Từ 1100 px trở xuống vẫn xếp khung kết quả xuống dưới như logic cũ */
@media (max-width: 1100px) {
  .practice-shell {
    width: calc(100% - 24px) !important;
    grid-template-columns: 1fr !important;
  }
}


/* ===== BÀI 4: TRÒ CHƠI HÁI BƯỞI - BIỂU THỨC CHỨA CHỮ ===== */
.expression-harvest-game{
  padding:18px!important;
  color:#102f2a;
  border:1px solid #c8d9d3;
  border-radius:16px;
  background:#fffdf8;
}
.harvest-game-heading{
  display:flex;
  align-items:center;
  gap:12px;
  margin-bottom:14px;
}
.harvest-game-heading b{
  display:block;
  font-size:20px;
  line-height:1.3;
}
.harvest-game-heading small{
  display:block;
  margin-top:3px;
  color:#5b716a;
  font-size:13px;
  line-height:1.45;
}
.harvest-game-badge{
  display:grid;
  width:48px;
  height:48px;
  place-items:center;
  border-radius:50%;
  background:#e5f5d8;
  font-size:27px;
}
.harvest-tree{
  position:relative;
  min-height:190px;
  margin:12px 0 18px;
  padding:42px 18px 20px;
  overflow:hidden;
  border:1px solid #c8d9d3;
  border-radius:18px;
  background:
    radial-gradient(circle at 50% 42%,#70b853 0 14%,transparent 15%),
    radial-gradient(circle at 35% 48%,#76bd58 0 16%,transparent 17%),
    radial-gradient(circle at 65% 48%,#76bd58 0 16%,transparent 17%),
    radial-gradient(circle at 50% 58%,#5ea845 0 21%,transparent 22%),
    linear-gradient(#f5fbef 0 72%,#dce9c8 72% 100%);
}
.harvest-tree::after{
  content:"";
  position:absolute;
  left:calc(50% - 16px);
  bottom:0;
  width:32px;
  height:82px;
  border-radius:12px 12px 0 0;
  background:#8b5a2b;
}
.harvest-tree-title{
  position:absolute;
  z-index:2;
  top:10px;
  left:14px;
  padding:5px 10px;
  border-radius:999px;
  color:#0b5d4f;
  background:rgba(255,255,255,.88);
  font-size:12px;
  font-weight:800;
}
.harvest-fruits{
  position:relative;
  z-index:3;
  display:flex;
  flex-wrap:wrap;
  justify-content:center;
  gap:10px;
  max-width:620px;
  margin:auto;
}
.harvest-fruit{
  display:grid;
  width:52px;
  height:42px;
  place-items:center;
  border:2px solid #d8a41f;
  border-radius:50% 50% 46% 46%;
  color:#8b3f0b;
  background:#ffd761;
  box-shadow:0 4px 0 rgba(120,85,20,.15);
  font-size:17px;
  font-weight:900;
}
.harvest-expression-grid{
  display:grid;
  grid-template-columns:repeat(3,minmax(0,1fr));
  gap:12px;
}
.harvest-expression-card{
  position:relative;
  display:grid;
  grid-template-rows:auto 48px;
  gap:9px;
  min-width:0;
  padding:14px;
  border:1px solid #b9cdc6;
  border-radius:13px;
  background:#fff;
}
.harvest-card-number{
  position:absolute;
  top:-9px;
  left:-7px;
  display:grid;
  width:27px;
  height:27px;
  place-items:center;
  border-radius:50%;
  color:#fff;
  background:#0e7c66;
  font-size:12px;
  font-weight:900;
}
.harvest-expression{
  display:block;
  padding-left:8px;
  color:#111;
  font-size:17px;
  font-weight:750;
  line-height:1.45;
  overflow-wrap:anywhere;
}
.harvest-expression-card .answer-input{
  width:100%;
  min-width:0;
  height:48px;
  color:#000;
  border:1.5px solid #78978e;
  border-radius:9px;
  background:#fff;
  font-size:18px;
  font-weight:650;
  text-align:center;
}
@media(max-width:900px){
  .harvest-expression-grid{grid-template-columns:repeat(2,minmax(0,1fr))}
}
@media(max-width:560px){
  .expression-harvest-game{padding:12px!important}
  .harvest-expression-grid{grid-template-columns:1fr}
  .harvest-tree{min-height:210px}
}


/* ===== BÀI 6: ĐẶT TÍNH DỌC VÀ THỬ LẠI ===== */
.vertical-arithmetic-block{padding:18px!important}
.vertical-arithmetic-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}
.vertical-arithmetic-item{min-width:0;padding:17px;border:1px solid #cbd8d4;border-radius:14px;background:#fff}
.vertical-arithmetic-head{display:flex;align-items:baseline;gap:9px;margin-bottom:13px;color:#000;font-size:18px;line-height:1.45}
.vertical-arithmetic-head>b{color:var(--green);font-size:18px}.vertical-arithmetic-head>span{font-weight:650}
.vertical-operation{width:min(210px,82%);margin:0 auto 12px;padding:4px 8px;color:#000;font:700 23px/1.35 var(--display);text-align:right}
.vertical-operand{min-height:34px}.vertical-bottom{display:grid;grid-template-columns:30px 1fr;gap:5px}.vertical-bottom>span{text-align:left}.vertical-bottom>b{font:inherit}
.vertical-operation-line{margin-top:3px;border-top:2px solid #183b34}
.vertical-division-expression{display:flex;justify-content:center;align-items:center;gap:10px;min-height:82px;margin-bottom:12px;color:#000;font:700 23px/1.3 var(--display)}
.vertical-arithmetic-answers{display:grid;grid-template-columns:minmax(0,1fr) minmax(110px,.45fr);gap:10px}
.vertical-arithmetic-answers label:only-child{grid-column:1/-1}
.vertical-arithmetic-answers label>span{display:block;margin-bottom:6px;color:#183b34;font-size:15px;font-weight:800}
.vertical-arithmetic-answers .answer-input{min-height:48px!important;font-size:18px!important;font-weight:650!important}
.vertical-check-answer{grid-column:1/-1}
.vertical-check-answer .answer-input{text-align:left!important}
@media(max-width:760px){.vertical-arithmetic-grid{grid-template-columns:1fr}.vertical-arithmetic-item{padding:14px}.vertical-arithmetic-head{font-size:17px}.vertical-operation,.vertical-division-expression{font-size:21px}}
@media(max-width:440px){.vertical-arithmetic-answers{grid-template-columns:1fr}.vertical-arithmetic-answers label{grid-column:auto!important}.vertical-check-answer{grid-column:1!important}}


/* ===== BÀI 7: ĐỌC VÀ ĐO GÓC TỪ HÌNH ===== */
.angle-measurement-block{padding:18px!important}.angle-measurement-heading{margin-bottom:14px;font-size:18px;font-weight:850;color:#153f36}.angle-measurement-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px}.angle-measurement-item{position:relative;min-width:0;padding:15px;border:1px solid #c9d8d3;border-radius:15px;background:#fff}.angle-measurement-item.is-example{background:#f4faf7}.angle-item-head{display:flex;gap:8px;align-items:baseline;min-height:26px;color:#123d34}.angle-item-head>b{color:var(--green);font-size:18px}.angle-item-head>span{font-size:15px;font-weight:700}.angle-diagram-wrap{display:grid;place-items:center;min-height:150px;margin:6px 0}.angle-svg{display:block;width:100%;max-width:270px;height:auto;overflow:visible}.angle-svg text{font-family:var(--sans);font-size:10px;fill:#153f36}.angle-svg .protractor-arc,.angle-svg .protractor-base{fill:none;stroke:#234b42;stroke-width:2}.angle-svg .major{stroke:#45665f;stroke-width:1.2}.angle-svg .minor{stroke:#9ab0aa;stroke-width:.7}.angle-svg .angle-ray{stroke:#176fbd;stroke-width:3;stroke-linecap:round}.angle-svg .angle-ray.accent{stroke:#0c91b8}.angle-svg .angle-arc{fill:none;stroke:#e18421;stroke-width:3}.angle-svg .angle-vertex{fill:#0d7d68}.angle-svg .vertex-label,.angle-svg .ray-label{font-size:12px;font-weight:800}.angle-svg .degree-label{font-size:14px;font-weight:900;fill:#b74b22}.clock-angle-svg .clock-face{fill:#fff;stroke:#344f49;stroke-width:4}.clock-ticks line{stroke:#405e56;stroke-width:1.4}.clock-numbers text{font-size:9px;font-weight:800}.clock-hand{stroke:#172f2a;stroke-linecap:round}.clock-hand.minute{stroke-width:3}.clock-hand.hour{stroke-width:5}.angle-answer>span{display:block;margin-bottom:6px;font-size:15px;font-weight:800}.angle-answer-input{display:grid;grid-template-columns:1fr 34px;align-items:center;border:1px solid #86a29a;border-radius:10px;overflow:hidden;background:#fff}.angle-answer-input input{border:0!important;border-radius:0!important;min-height:48px!important;font-size:19px!important;font-weight:750!important}.angle-answer-input>b{display:grid;place-items:center;height:100%;border-left:1px solid #cbd8d4;font-size:21px}.angle-example-badge{position:absolute;right:12px;top:12px;padding:4px 9px;border-radius:999px;background:#dff2eb;color:#0b705d;font-size:12px;font-weight:850}
@media(max-width:760px){.angle-measurement-grid{grid-template-columns:1fr}.angle-measurement-item{padding:13px}.angle-diagram-wrap{min-height:130px}}

/* Bài 8: phân loại góc trong layout angle_measurement */
.angle-classification-answer select.answer-input{width:100%;min-height:50px;border:1px solid #86a29a;border-radius:10px;background:#fff;color:#102f2a;font-size:18px;font-weight:750;padding:8px 12px}
.angle-classification-answer select.answer-input:focus{outline:3px solid rgba(14,124,102,.15);border-color:#0e7c66}


/* ===== VISUAL FIRST: TÀI NGUYÊN TRỰC QUAN ===== */
.visual-assets{display:grid;grid-template-columns:repeat(auto-fit,minmax(min(100%,320px),1fr));gap:16px;margin:18px 0 4px}
.visual-asset-card{min-width:0;margin:0;padding:12px;border:1px solid #c7d8d2;border-radius:15px;background:#fff;box-shadow:0 8px 22px rgba(18,61,53,.07)}
.visual-asset-card.aspect-card{max-width:520px;margin-inline:auto}
.visual-asset-card.aspect-wide{grid-column:1/-1}

/* Sửa lỗi ảnh nhỏ bị phóng to tràn viền */
.visual-asset-card img,
.visual-asset-svg > svg,
.visual-asset-source > img,
.visual-asset-source > .visual-asset-svg,
.visual-asset-source > .visual-asset-svg > svg {
  display: block;
  max-width: 100%;
  width: auto !important; /* Không bắt buộc ảnh nhỏ phải căng đầy 100% chiều ngang */
  height: auto;
  max-height: 450px;
  object-fit: contain;
  margin-inline: auto; /* Tự động căn giữa màn hình */
}

.visual-asset-card figcaption{margin-top:9px;color:#385b53;font-size:13px;font-weight:800;text-align:center}
.visual-asset-missing{padding:18px;border:1px dashed #d39987;border-radius:10px;color:#a1422f;background:#fff5f1;text-align:center}
.question-visuals{padding:0 30px}.question-visuals:empty{display:none}
.question-visuals .visual-assets{margin-top:0}
.lesson-section .visual-assets{margin-top:20px}
.visual-assets.is-compact{grid-template-columns:repeat(auto-fit,minmax(min(100%,220px),1fr));gap:9px;margin:8px 0}
.visual-assets.is-compact .visual-asset-card{padding:7px}
.visual-assets.is-compact .visual-asset-card figcaption{font-size:11px}
@media(max-width:760px){
  .question-visuals{padding:0 17px}
  .visual-assets{grid-template-columns:1fr;gap:12px}
  .visual-asset-card{padding:8px;border-radius:12px}
  .visual-asset-card img,.visual-asset-svg>svg{max-height:none}
}

/* SVG file-first display hotfix 4.2.12.1 */
.visual-asset-source{display:block;min-width:0}
.visual-asset-source>[hidden]{display:none!important}

/* V4.2.15.2 — Ô chữ trong bảng tự xuống dòng và tự giãn */
.data-table textarea.table-textarea,
.place-table textarea.table-textarea {
  width: 100% !important;
  min-width: 0 !important;
  min-height: 52px !important;
  max-height: 240px !important;
  box-sizing: border-box !important;
  padding: 8px 10px !important;
  border: 1.6px solid var(--answer-border) !important;
  border-bottom: 2.4px solid var(--answer-border-strong) !important;
  border-radius: 12px !important;
  background: #fff !important;
  color: #000 !important;
  font-family: var(--display) !important;
  font-size: 18px !important;
  font-weight: 600 !important;
  line-height: 1.45 !important;
  text-align: left !important;
  white-space: pre-wrap !important;
  overflow-wrap: anywhere !important;
  resize: none !important;
  overflow-y: hidden !important;
}

/* =========================================================
   TINH CHỈNH KHOẢNG CÁCH TỬ SỐ VÀ MẪU SỐ (BÀI 57)
   ========================================================= */

/* Đẩy tử số lên trên một chút */
.choice .katex .mfrac .vlist > span:nth-child(3) {
    transform: translateY(-0.15em) !important;
}

/* Kéo mẫu số xuống dưới một chút */
.choice .katex .mfrac .vlist > span:nth-child(1) {
    transform: translateY(0.15em) !important;
}

/* Đảm bảo ô trắc nghiệm đủ chiều cao không bị cắt viền */
.choice {
    align-items: center !important;
    min-height: 72px !important; 
}

/* Khắc phục chữ "Nhập phép biến đổi..." bị mờ và dính */
math-field::part(placeholder) {
    font-family: var(--sans) !important;
    font-style: normal !important;
    letter-spacing: 0.5px !important;
    opacity: 0.7 !important;
}
.ML__placeholder {
    font-family: var(--sans) !important;
    font-style: normal !important;
    letter-spacing: 0.5px !important;
}

/* V4.3 Local First */
.local-studio-shortcut{position:fixed;right:14px;bottom:14px;z-index:9999;padding:8px 12px;border-radius:999px;background:#123d35;color:#fff;text-decoration:none;font:700 12px/1.2 system-ui;box-shadow:0 8px 24px rgba(0,0,0,.2)}
.local-studio-shortcut:hover{background:#0b806b}