:root{--ink:#173b3d;--muted:#6a7b78;--paper:#f7f4ec;--cream:#efe8da;--teal:#0e6866;--orange:#e87543;--yellow:#f4c95d;--line:#d8d0bf;--white:#fffdf8;--shadow:0 18px 60px #173b3d1f}*{box-sizing:border-box}body{margin:0;background:var(--paper);color:var(--ink);font-family:"Times New Roman",Times,"Songti SC","STSong","SimSun","NSimSun","Noto Serif CJK SC",serif}h1,h2,h3,.display,.lead,.question-text,.review-question,.option-text,.explain{font-family:"Times New Roman",Times,"Songti SC","STSong","SimSun","NSimSun","Noto Serif CJK SC",serif}.brand{text-decoration:none;color:var(--ink)}button,a,input,summary{-webkit-tap-highlight-color:transparent}button:focus-visible,a:focus-visible,summary:focus-visible{outline:3px solid var(--orange);outline-offset:4px}button:disabled{cursor:not-allowed;opacity:.45}button:disabled:hover{transform:none}button,input{font:inherit;min-height:42px}button{cursor:pointer}.shell{min-height:100vh;overflow:hidden;position:relative}.shell:before{content:"";position:fixed;inset:0;pointer-events:none;background:radial-gradient(circle at 90% 8%,#f4c95d33 0 10%,transparent 30%),radial-gradient(circle at 8% 70%,#0e686611 0 18%,transparent 38%)}header{height:76px;border-bottom:1px solid var(--line);display:flex;align-items:center;justify-content:space-between;padding:0 clamp(20px,5vw,72px);position:relative;z-index:2;background:#f7f4ece8;backdrop-filter:blur(10px)}.brand{display:flex;align-items:center;gap:12px;font-weight:700;font-size:20px;letter-spacing:.03em}.brand-mark{width:38px;height:38px;display:block;object-fit:contain;transform:none;background:transparent}.brand small{display:block;color:var(--muted);font-size:10px;font-weight:500;letter-spacing:.12em;text-transform:uppercase}.header-actions{display:flex;align-items:center;gap:18px}.status{font-family:"Times New Roman",Times,"Songti SC","STSong","SimSun",serif;font-size:17px;font-weight:600;color:var(--ink)}.ghost{border:1px solid var(--line);background:transparent;padding:10px 15px;color:var(--ink);border-radius:999px}main{width:min(1200px,calc(100% - 40px));margin:0 auto;padding:42px 0 80px;position:relative;z-index:1}.view{display:none;animation:rise .45s ease both}.view.active{display:block}@keyframes rise{from{opacity:0;transform:translateY(12px)}to{opacity:1;transform:none}}.kicker,.status,.meta,.q-num,.timer,.q-dot,.score,.score-big,.brand-mark,.art-label,.art-footer{font-family:"Times New Roman",Times, serif}.kicker{font-size:11px;color:var(--teal);letter-spacing:.18em;text-transform:uppercase;margin-bottom:17px}.display{font-size:clamp(38px,7vw,82px);line-height:.98;letter-spacing:-.06em;max-width:800px;margin:0}.lead{color:#3e5d5b;max-width:650px;font-size:18px;line-height:1.8;margin:25px 0 0}.accent{color:var(--orange)}.hero{display:grid;grid-template-columns:1.25fr .75fr;gap:54px;align-items:end;padding:10px 0 56px;border-bottom:1px solid var(--line)}.hero .display{font-size:clamp(45px,6.5vw,76px);line-height:1.2;letter-spacing:-.05em}.hero .lead{font-size:16px;line-height:1.9;margin-top:23px}.hero-art{min-height:305px;background:var(--ink);color:var(--white);padding:28px 30px;position:relative;overflow:hidden;display:flex;flex-direction:column;justify-content:space-between;box-shadow:var(--shadow);background-image:linear-gradient(#ffffff07 1px,transparent 1px),linear-gradient(90deg,#ffffff07 1px,transparent 1px);background-size:28px 28px}.hero-art:after{content:"";position:absolute;width:200px;height:200px;border:1px solid #f4c95d99;border-radius:50%;right:-50px;top:18px;box-shadow:0 0 0 25px #f4c95d1a,0 0 0 50px #f4c95d0b}.hero-art .big{font-size:86px;line-height:1;letter-spacing:-.08em;color:var(--yellow);position:relative;z-index:1}.hero-art .big span{font-size:22px;letter-spacing:-.03em;color:#d6e5db}.art-label{font-size:10px;letter-spacing:.15em;color:#b1c9c0}.hero-art p{max-width:230px;font-size:14px;margin:0;line-height:1.8;color:#d6e5db;position:relative;z-index:1}.art-footer{display:flex;justify-content:space-between;font-size:9px;color:#9ebdb1}.section-head{display:flex;align-items:end;justify-content:space-between;margin:38px 0 16px}.section-head h2{font-size:30px;letter-spacing:-.04em;margin:0}.section-head span{font-family:"Times New Roman",Times,"Songti SC",serif;font-size:12px;color:var(--muted)}.exam-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.exam-card{background:var(--white);border:1px solid var(--line);padding:22px;min-height:226px;display:flex;flex-direction:column;justify-content:space-between;transition:.25s}.exam-card:hover{transform:translateY(-4px);box-shadow:var(--shadow)}.exam-card.locked{opacity:1;background:#f1eee6}.exam-card.locked h3,.exam-card.locked p{color:#8a9289}.exam-card .meta{font-size:11px;color:var(--teal);display:flex;justify-content:space-between}.exam-card h3{font-size:29px;letter-spacing:-.04em;font-weight:500;margin:20px 0 8px}.exam-card h3 span{color:var(--orange)}.exam-card.locked h3 span{color:#9b9c90}.exam-card p{color:var(--muted);font-size:13px;line-height:1.65;margin:0}.paper-badge{padding:4px 7px;background:#e7e3d9;color:#778075;border-radius:2px;font-family:"Songti SC","STSong","SimSun",serif;font-size:11px}.paper-badge.ready{background:#e1eee7;color:var(--teal)}.exam-card-bottom{display:flex;justify-content:space-between;align-items:center;margin-top:23px;border-top:1px solid var(--line);padding-top:14px}.exam-card-bottom>span{font-size:12px;color:var(--muted)}.exam-card-bottom .primary{padding:9px 13px;font-size:13px}.coming-soon{font-size:11px!important}.primary{border:0;background:var(--teal);color:var(--white);padding:12px 18px;border-radius:3px;font-weight:600;transition:.2s}.primary:hover{background:var(--ink);transform:translateY(-1px)}.secondary{border:1px solid var(--teal);background:transparent;color:var(--teal);padding:11px 17px;border-radius:3px;font-weight:600}.auth-layout{display:grid;grid-template-columns:1.2fr 1fr;gap:100px;align-items:center;min-height:calc(100vh - 230px);padding:25px 0 35px}.auth-intro{padding:25px 0}.auth-intro .display{font-size:clamp(48px,6.7vw,86px);line-height:1.23;letter-spacing:-.045em}.auth-intro .lead{font-size:18px;line-height:1.9}.intro-stats{display:flex;gap:45px;margin-top:50px;padding-top:25px;border-top:1px solid var(--line)}.intro-stats b{display:block;font-size:32px;font-weight:500;letter-spacing:-.04em}.intro-stats span{display:block;font-size:11px;color:var(--muted);margin-top:6px}.auth-caption{font-size:11px;color:var(--muted);margin-top:35px;letter-spacing:.06em}.login-card{width:100%;background:var(--white);border:1px solid var(--line);padding:36px 34px;box-shadow:var(--shadow)}.login-card h2{font-size:29px;margin:0 0 14px;letter-spacing:-.03em}.login-card>p{color:var(--muted);font-size:13px;line-height:1.8;margin:0 0 28px}.field{display:grid;gap:8px;margin:16px 0}.field label{font-size:12px;color:var(--muted)}.field input{width:100%;border:1px solid var(--line);border-radius:3px;background:#fffef9;padding:13px 14px;font-size:14px;outline:none}.field input:focus{border-color:var(--teal);box-shadow:0 0 0 3px #0e68661a}.auth-tabs{display:flex;border-bottom:1px solid var(--line);gap:25px;margin-bottom:22px}.auth-tabs button{padding:10px 0;border:0;background:transparent;color:var(--muted);font-size:13px}.auth-tabs button.active{color:var(--teal);border-bottom:3px solid var(--teal);font-weight:600}.full{width:100%;min-height:48px}.error{color:#b34f38;font-size:12px;line-height:1.6;min-height:20px;margin:10px 0}.login-card .auth-footnote{margin:18px 0 0;font-size:11px;color:var(--muted)}.filters{display:flex;justify-content:space-between;gap:15px;flex-wrap:wrap;margin:20px 0}.filter-group{display:flex;gap:5px;flex-wrap:wrap}.filter{padding:9px 13px;background:transparent;border:1px solid transparent;color:var(--muted);font-size:13px;border-radius:3px;min-height:36px}.filter.active{background:var(--ink);color:var(--white)}.filter:not(.active):hover{background:var(--cream);color:var(--ink)}.resume-banner{display:flex;align-items:center;justify-content:space-between;gap:18px;padding:22px;background:#e9eee1;border:1px solid #becbb7;margin-top:25px}.resume-banner strong{font-size:15px}.resume-banner p{font-size:13px;color:var(--muted);margin:8px 0 0}.live-dot{display:inline-block;width:7px;height:7px;border-radius:50%;background:var(--teal);margin-right:10px;box-shadow:0 0 0 4px #0e68661a}.history{background:var(--white);border:1px solid var(--line);margin-top:0}.history-row{display:grid;grid-template-columns:1.4fr .8fr .7fr .7fr;gap:12px;padding:15px 18px;border-bottom:1px solid var(--line);font-size:14px;align-items:center}.history-row:last-child{border-bottom:0}.history-row.head{font-size:12px;color:var(--muted);text-transform:uppercase}.history-row small{display:block;color:var(--muted);font-size:11px;margin-top:5px}.history-row .score{color:var(--teal);font-size:20px}.history-row .score small{display:inline;font-size:11px}.text-button{border:0;background:transparent;color:var(--teal);font-size:13px;padding:6px 0;text-align:left;min-height:36px}.empty-state{padding:32px;text-align:center}.empty-state>span{font-family:"Times New Roman",Times,serif;color:var(--orange);font-size:11px;letter-spacing:.1em}.empty-state h3{font-size:23px;margin:15px 0 10px}.empty-state p{font-size:14px;color:var(--muted);line-height:1.7}.exam-toolbar{display:flex;justify-content:space-between;gap:25px;align-items:start}.exam-toolbar h1{font-size:35px;margin:0 0 14px;letter-spacing:-.04em}.exam-toolbar p{font-size:13px;color:var(--muted);line-height:1.7}.timer-wrap{text-align:center;flex:none}.timer-wrap>span{display:block;font-size:11px;color:var(--muted);margin-bottom:8px}.timer{background:var(--ink);color:var(--yellow);font-size:25px;padding:14px 18px;min-width:145px;text-align:center}.timer.warning{background:var(--orange);color:white}.timer-wrap .save-state{margin:8px 0 0;font-size:11px;cursor:pointer;min-height:16px}.save-state.save-error{color:#b34f38}.progress{height:5px;background:var(--cream);margin:16px 0 28px}.progress i{display:block;height:100%;background:var(--teal);width:0;transition:.2s}.exam-layout{display:grid;grid-template-columns:minmax(0,1fr) 240px;gap:22px}.question-card{background:var(--white);border:1px solid var(--line);padding:34px 36px;min-height:540px}.q-top{display:flex;justify-content:space-between;align-items:center;gap:12px;margin-bottom:22px}.q-num{color:var(--teal);font-size:13px}.q-topic{font-size:11px;padding:6px 9px;background:var(--cream);color:#765e40;max-width:60%;text-align:right}.question-card h2{font-size:26px;line-height:1.45;margin:0 0 18px}.question-text{font-size:22px;line-height:2.05;white-space:pre-wrap;overflow-wrap:anywhere;color:#112b2d;letter-spacing:.01em}.options{display:grid;gap:12px;margin:30px 0}.option{display:flex;gap:14px;width:100%;align-items:center;min-height:62px;border:1px solid var(--line);border-radius:3px;background:#fffefb;padding:15px 18px;text-align:left;transition:.18s}.option:hover{border-color:var(--teal)}.option.selected{border-color:var(--teal);background:#e6f0e9}.option-key{width:28px;height:28px;border:1px solid var(--teal);border-radius:50%;display:grid;place-items:center;font-family:"Times New Roman",Times,serif;font-style:italic;font-size:15px;flex:none;color:var(--teal)}.option.selected .option-key{background:var(--teal);color:#fff}.option-text{font-size:19px;line-height:1.65;overflow-wrap:anywhere;color:#173b3d}.question-figure{display:block;width:auto;max-width:100%;max-height:290px;object-fit:contain;margin:25px auto}.answer-tools{display:flex;justify-content:space-between;align-items:center;border-bottom:1px solid var(--line);padding:0 0 10px}.answer-tools>span{color:var(--muted);font-size:12px}.q-actions{display:flex;justify-content:space-between;align-items:center;gap:10px;margin-top:30px}.q-actions>span{color:var(--muted);font-family:"Times New Roman",Times,"Songti SC",serif;font-size:12px}.q-actions button{min-width:100px;font-size:13px}.side-panel{background:var(--white);border:1px solid var(--line);padding:18px;height:max-content;position:sticky;top:24px}.side-panel h3{font-size:20px;margin:0 0 15px}.q-grid{display:grid;grid-template-columns:repeat(5,1fr);gap:7px}.q-dot{border:1px solid var(--line);border-radius:2px;background:transparent;color:var(--muted);height:35px;min-height:35px;font-size:13px}.q-dot.current{border-color:var(--teal);color:var(--teal);outline:2px solid var(--orange);outline-offset:1px}.q-dot.done{background:var(--teal);color:#fff;border-color:var(--teal)}.submit-btn{width:100%;margin-top:20px}.legend{display:flex;gap:15px;font-size:11px;color:var(--muted);margin-top:18px}.legend span{display:flex;align-items:center;gap:6px}.legend i{display:inline-block;width:9px;height:9px;border:1px solid var(--line)}.legend .filled{background:var(--teal);border-color:var(--teal)}.mini-note{font-size:12px;line-height:1.6;color:var(--muted);margin-top:14px}.score-rule{font-size:11px;line-height:1.7;color:var(--muted);text-align:center;margin-top:12px}.result-hero{background:var(--ink);color:var(--white);padding:38px 40px;display:grid;grid-template-columns:1fr 220px;gap:30px;align-items:center}.result-label{color:#bed2c5;font-size:13px;margin-bottom:18px}.result-hero h1{font-size:42px;line-height:1.35;margin:0 0 18px}.result-hero p{color:#cfe0d5;margin:0;font-size:14px;line-height:1.7}.score-big{font-size:75px;letter-spacing:-.06em;color:var(--yellow);text-align:right}.score-big small{font-size:14px;letter-spacing:0;color:#cfe0d5;display:block}.breakdown{display:grid;grid-template-columns:repeat(3,1fr);gap:12px;margin:25px 0}.stat{background:var(--white);border:1px solid var(--line);padding:20px}.stat b{font-size:38px;margin:10px 0;font-weight:500;color:var(--teal);display:block}.stat b small{font-size:13px;margin-left:7px;color:var(--muted)}.stat.wrong-stat b{color:var(--orange)}.stat.blank-stat b{color:#9f7d2f}.stat span{color:var(--muted);font-size:13px}.result-analysis{background:#ecebdd;border:1px solid var(--line);padding:25px;margin-top:25px}.result-analysis h3{font-size:23px;margin:0 0 12px}.result-analysis p{font-size:14px;color:var(--muted);line-height:1.8}.topic-chips{display:flex;gap:7px;flex-wrap:wrap;margin:14px 0}.topic-chips>span{background:#ece8dc;border:1px solid #dbd6c8;padding:6px 9px;font-size:12px;border-radius:2px}.topic-chips b{font-weight:400;color:var(--muted);margin-left:8px}.review-head{display:flex;justify-content:space-between;align-items:center;margin:34px 0 14px}.review-head h2{margin:0;font-size:30px}.review-controls{display:flex;align-items:center;gap:10px}.review-controls button{font-size:13px}.review-card{background:var(--white);border:1px solid var(--line);padding:28px 30px;margin:16px 0}.review-card.correct{border-left:5px solid var(--teal)}.review-card.wrong{border-left:5px solid var(--orange)}.review-meta{font-family:"Times New Roman",Times,"Songti SC",serif;font-size:12px;color:var(--muted);display:flex;justify-content:space-between}.review-card h3{font-size:22px;margin:13px 0}.review-question{font-size:20px;line-height:2.0;color:#173b3d;white-space:pre-wrap}.answer-line{display:flex;gap:14px;align-items:center;flex-wrap:wrap;font-size:15px;padding:12px 0;color:#46615e}.answer-line>span{margin-left:10px}.answer-line strong{color:var(--teal)}.review-card details{border-top:1px solid var(--line);margin-top:12px}.review-card summary{list-style:none;display:flex;justify-content:space-between;cursor:pointer;font-size:14px;font-weight:600;padding:17px 0;color:var(--teal)}.review-card summary::-webkit-details-marker{display:none}.explanation-content{font-size:16px;line-height:1.95;padding-bottom:5px;overflow-wrap:anywhere}.knowledge-box{padding:16px 20px;background:#eaf0e6;border:1px solid #cfddc9;border-left:4px solid var(--teal);margin:16px 0}.knowledge-box h4,.steps-box h4,.table-box h4,.after-box h4{margin:0 0 8px;font-size:14px;color:var(--teal);font-family:"Songti SC","STSong","SimSun",serif}.knowledge-box p{margin:0;font-size:15px;line-height:1.9}.steps-box{margin:18px 0}.steps{padding-left:24px;margin:8px 0}.steps li{padding:8px 10px;margin:8px 0;border-radius:4px;cursor:pointer;transition:background .15s;font-size:15px}.steps li:hover{background:#f1eee4}.steps li::marker{font-family:"Times New Roman",Times,serif;color:var(--teal);font-size:14px;font-weight:bold}.after-box{padding:16px 20px;background:#eef3f7;border:1px solid #cadbe7;border-left:4px solid #2b6cb0;margin:18px 0}.after-box h4{color:#2b6cb0}.after-box p{margin:6px 0;font-size:15px;line-height:1.85}.pitfall{background:#f6eddd;border-left:4px solid var(--orange);padding:15px 18px;font-size:14.5px;line-height:1.85;color:#7a4b2a;margin-top:16px}.pitfall b{display:block;font-size:13.5px;margin-bottom:4px;color:#b34f38}.table-box{margin:18px 0}.table-scroll{overflow:auto;margin:10px 0}table{width:100%;border-collapse:collapse;font-size:14px;text-align:left}th,td{border:1px solid var(--line);padding:10px 14px;white-space:nowrap}th{background:#edeadd;font-weight:600}
/* Animind Player Styles */
.animind-player{background:#0d1b1e;border:1px solid #264348;border-radius:8px;padding:16px;margin:10px 0 22px;color:#fffdf8;box-shadow:0 12px 32px rgba(13,27,30,.22)}.animind-bar{display:flex;justify-content:space-between;align-items:center;flex-wrap:wrap;gap:10px;padding-bottom:12px;border-bottom:1px solid #1f393d}.animind-badge{display:flex;align-items:center;gap:10px;font-family:Mono,monospace;font-size:11px;color:#f4c95d}.animind-badge small{color:#9ebdb1;font-size:12px}.animind-controls{display:flex;gap:8px}.animind-btn{min-height:32px;padding:5px 12px;background:#162c30;border:1px solid #2e5258;color:#d6e5db;border-radius:4px;font-size:11.5px}.animind-btn:hover{border-color:#4ecdc4;color:#fff}.animind-btn.play{background:#0e6866;border-color:#4ecdc4;color:#fff;font-weight:600}.animind-stage{margin:12px 0;background:#091315;border-radius:6px;overflow:hidden}.animind-svg{display:block;width:100%;height:auto}.animind-tabs{display:flex;gap:6px;flex-wrap:wrap;padding-top:6px}.animind-tab{min-height:30px;padding:4px 10px;background:#132528;border:1px solid #243e42;color:#8faea9;border-radius:4px;font-size:11px;font-family:Mono,monospace}.animind-tab.active{background:#f4c95d22;border-color:#f4c95d;color:#f4c95d;font-weight:600}
.toast{position:fixed;left:50%;bottom:24px;transform:translateX(-50%);z-index:40;background:var(--ink);color:var(--white);padding:16px 24px;box-shadow:var(--shadow);max-width:90vw;font-size:13px;line-height:1.7;border-left:4px solid var(--yellow);border-radius:3px}dialog{border:1px solid var(--line);padding:32px;max-width:480px;width:calc(100% - 32px);background:var(--white);color:var(--ink);box-shadow:var(--shadow);border-radius:4px}dialog::backdrop{background:#173b3d99;backdrop-filter:blur(3px)}dialog h2{font-size:27px;margin:0 0 20px}dialog p{font-size:14px;line-height:1.9;color:#52675e}.dialog-actions{display:flex;justify-content:flex-end;gap:10px;margin-top:25px}.dialog-actions button{font-size:13px}.rule-grid{display:grid;grid-template-columns:1fr 1fr;gap:12px;margin:22px 0}.rule-grid>div{padding:18px;background:var(--cream)}.rule-grid b{font-size:22px;display:block}.rule-grid span{display:block;color:var(--muted);font-size:12px;margin-top:7px}footer{position:relative;z-index:1;border-top:1px solid var(--line);padding:24px max(20px,calc((100vw - 1200px)/2));display:flex;justify-content:space-between;gap:15px;font-size:11px;color:var(--muted)}.hidden{display:none!important}
@media(max-width:750px){.auth-layout,.hero,.exam-layout,.result-hero,.exam-grid{grid-template-columns:1fr}.score-big{text-align:left}}

#headerStatus.signed-in {
  font-family: "Songti SC", "STSong", "SimSun", "Noto Serif CJK SC", serif;
  font-size: 21px;
  font-weight: 600;
  letter-spacing: .045em;
  line-height: 1.4;
  overflow-wrap: anywhere;
}
#headerStatus .greeting-name {
  font-family: "Times New Roman", "Songti SC", "SimSun", serif;
  font-style: italic;
  font-size: 1.08em;
  color: var(--teal);
}
@media(max-width:600px) {
  #headerStatus.signed-in { font-size: 19px; }
}

/* Teacher workspace follows the existing paper, ink, and teal palette. */
.teacher-heading { display:flex; align-items:flex-end; justify-content:space-between; gap:24px; padding:4px 0 24px; border-bottom:1px solid var(--line); }
.teacher-heading h1 { font-size:42px; margin:8px 0 12px; font-weight:500; }
.teacher-eyebrow { font-size:12px; letter-spacing:.16em; color:var(--teal); margin:0; }
.teacher-muted { color:var(--muted); font-size:13px; line-height:1.85; }
.teacher-heading .teacher-muted { margin:0; font-size:15px; }
.teacher-refresh { display:grid; gap:10px; justify-items:end; flex-shrink:0; }
.teacher-refresh span { font-size:12px; color:var(--muted); }
.teacher-note { margin:20px 0; padding:13px 17px; border-left:3px solid var(--teal); background:#eaf0e6; font-size:13px; line-height:1.9; }
.teacher-loading { padding:18px; background:var(--cream); color:var(--teal); }
.teacher-stats { display:grid; grid-template-columns:repeat(4,minmax(0,1fr)); gap:14px; margin:24px 0; }
.teacher-stat { padding:22px; background:var(--white); border:1px solid var(--line); min-width:0; }
.teacher-stat>span { display:block; font-size:13px; color:var(--muted); }
.teacher-stat strong { display:block; font-weight:500; color:var(--teal); font-size:40px; margin:12px 0; }
.teacher-stat small { display:block; color:var(--muted); font-size:12px; line-height:1.7; }
.teacher-toolbar { display:grid; grid-template-columns:minmax(200px,1fr) 150px 150px 170px; align-items:end; gap:16px; padding:4px 0 10px; }
.teacher-toolbar .field { margin:0; }
#teacherView select { font:inherit; font-size:14px; color:var(--ink); border:1px solid var(--line); border-radius:3px; padding:11px 13px; background:var(--white); min-height:45px; max-width:100%; }
#teacherView .section-head h2 { font-size:25px; }
.teacher-table-wrap { max-width:100%; overflow-x:auto; background:var(--white); border:1px solid var(--line); }
.teacher-mobile-hint { display:none; font-size:12px; color:var(--muted); line-height:1.8; }
.teacher-table { min-width:920px; font-size:14px; }
.teacher-table th,.teacher-table td { border:0; border-bottom:1px solid var(--line); padding:17px 16px; }
.teacher-table thead th { font-size:12px; color:var(--muted); background:var(--cream); }
.teacher-table tbody th { font-weight:500; background:transparent; }
.teacher-table tbody tr:hover { background:#f4f4e9; }
.teacher-table tbody tr:last-child>* { border-bottom:0; }
.teacher-table small { display:block; color:var(--muted); font-size:12px; margin-top:8px; }
.teacher-score { color:var(--teal); font-size:20px; }
.teacher-badge { display:inline-block; padding:5px 9px; border-radius:3px; background:#e5eee8; color:var(--teal); font-size:12px; white-space:nowrap; }
.teacher-badge.ongoing { color:#8a5f13; background:#f6eacb; }
.teacher-badge.wrong { color:#ae4d27; background:#fae6d9; }
.teacher-back { margin:8px 0 15px; }
.teacher-student-name { font-size:31px; font-weight:500; overflow-wrap:anywhere; }
.teacher-student-name span { color:var(--muted); font-size:15px; margin-left:18px; }
.teacher-topics { display:grid; grid-template-columns:repeat(3,minmax(0,1fr)); gap:12px; }
.teacher-topic { background:var(--white); border:1px solid var(--line); padding:18px; min-width:0; }
.teacher-topic>div { display:flex; justify-content:space-between; gap:10px; font-size:14px; }
.teacher-topic strong { font-weight:500; overflow-wrap:anywhere; }
.teacher-topic b { color:var(--teal); font-weight:500; white-space:nowrap; }
.teacher-topic progress { display:block; appearance:none; width:100%; height:5px; margin:15px 0 12px; border:none; background:var(--cream); }
.teacher-topic progress::-webkit-progress-bar { background:var(--cream); }
.teacher-topic progress::-webkit-progress-value { background:var(--teal); }
.teacher-topic progress::-moz-progress-bar { background:var(--teal); }
.teacher-topic small { color:var(--muted); font-size:12px; line-height:1.7; }
.teacher-more-topics { margin-top:16px; }
.teacher-more-topics summary { cursor:pointer; color:var(--teal); margin-bottom:16px; }
.teacher-record-filters { display:flex; align-items:center; gap:12px; flex-wrap:wrap; }
.teacher-record-filters label { font-size:13px; color:var(--muted); }
#teacherAttemptPanel { scroll-margin-top:24px; padding-top:12px; }
.teacher-attempt-meta { display:grid; gap:12px; padding:22px; background:var(--ink); color:var(--white); line-height:1.8; margin:20px 0; }
.teacher-attempt-meta strong { font-size:21px; font-weight:500; color:var(--yellow); }
.teacher-attempt-meta span { font-size:14px; }
.teacher-attempt-meta small { font-size:12px; color:#cfe0d5; }
.teacher-question { border:1px solid var(--line); background:var(--white); margin:12px 0; }
.teacher-question.incorrect { border-left:4px solid var(--orange); }
.teacher-question summary { display:flex; align-items:center; gap:20px; padding:18px 22px; cursor:pointer; line-height:1.8; font-size:14px; }
.teacher-question summary strong { font-weight:500; min-width:70px; }
.teacher-question summary .teacher-badge { margin-left:auto; }
.teacher-question-body { padding:0 24px 24px; overflow-wrap:anywhere; border-top:1px solid var(--line); }
.teacher-question-options { display:grid; gap:8px; }
.teacher-question-options p { border:1px solid var(--line); padding:12px; margin:0; font-size:16px; line-height:1.8; }
.teacher-question-options p.chosen { background:#eaf0e6; border-color:var(--teal); }
.teacher-question-options b { color:var(--teal); margin-right:12px; }
.teacher-question-options small { display:inline-block; color:var(--teal); font-size:12px; margin-left:12px; }
@media(max-width:900px) {
  .teacher-stats { grid-template-columns:repeat(2,minmax(0,1fr)); }
  .teacher-mobile-hint { display:block; }
  .teacher-topics { grid-template-columns:repeat(2,minmax(0,1fr)); }
  header { height:auto; min-height:76px; gap:15px; padding-top:16px; padding-bottom:16px; flex-wrap:wrap; }
  .header-actions { flex-wrap:wrap; gap:10px; }
}
@media(max-width:600px) {
  .teacher-heading { flex-direction:column; align-items:flex-start; gap:14px; }
  .teacher-heading h1 { font-size:34px; }
  .teacher-refresh { width:100%; display:flex; align-items:center; flex-wrap:wrap; }
  .teacher-toolbar { grid-template-columns:1fr 1fr; }
  .teacher-toolbar .field:first-child { grid-column:1/-1; }
  .teacher-stat { padding:16px; }
  .teacher-stat strong { font-size:32px; }
  .teacher-topics { grid-template-columns:1fr; }
  .teacher-student-name span { display:block; margin:10px 0 0; }
  .teacher-question summary { gap:10px; padding:14px 12px; flex-wrap:wrap; }
  .teacher-question-body { padding:0 14px 20px; }
  .teacher-question-body .review-question { font-size:18px; }
  .teacher-record-filters select { width:100%; }
  .teacher-record-filters { display:grid; grid-template-columns:36px minmax(0,1fr); }
  .header-actions .status { width:100%; font-size:14px; }
  .brand { font-size:18px; }
}

/* Typography Rules:
   - Chinese: Songti (宋体)
   - English Letters: Times New Roman, Italic
   - Numbers: Times New Roman, Upright */
var.math-var, .math-var {
  font-family: "Times New Roman", Times, serif !important;
  font-style: italic !important;
  font-weight: 400;
  padding: 0 1px;
}
.math-roman, sup.math-sup, sub.math-sub {
  font-family: "Times New Roman", Times, serif !important;
  font-style: normal !important;
}
sup.math-sup, sub.math-sub {
  font-size: 0.76em;
  line-height: 0;
}
.math-overline {
  text-decoration: overline;
}
.diagram-box { padding: 16px 20px; background: #fffdf8; border: 1px solid var(--line); border-left: 4px solid var(--orange); margin: 18px 0; }
.diagram-box h4 { margin: 0 0 12px; font-size: 14px; color: var(--ink); font-family: "Songti SC", "STSong", "SimSun", serif; }
.solution-diagram { display: block; width: 100%; max-width: 760px; height: auto; margin: 0 auto; border-radius: 6px; }
.video-explain-box { background: var(--white); border: 1px solid var(--line); border-radius: 3px; padding: 18px; margin: 12px 0 22px; color: var(--ink); box-shadow: none; }
.video-header { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; padding-bottom: 14px; border-bottom: 1px solid var(--line); }
.video-header > div:first-child { display: flex; align-items: center; gap: 14px; }
.video-header strong { font-size: 17px; font-weight: 500; }
.video-badge { display: inline-block; color: var(--teal); font: inherit; font-size: 14px; }
.video-actions { display: flex; gap: 8px; flex-wrap: wrap; }
.video-actions .download-link { min-height: 38px; padding: 8px 12px; border: 1px solid var(--line); border-radius: 3px; background: transparent; color: var(--teal); font: inherit; font-size: 14px; }
.video-actions .download-link:hover { background: var(--paper); border-color: var(--teal); }
.download-link { text-decoration: none; display: inline-flex; align-items: center; }
.video-canvas-wrap { margin-top: 12px; background: #071012; border-radius: 6px; overflow: hidden; border: 1px solid #1d3539; cursor: pointer; }
.video-canvas { display: block; width: 100%; height: auto; }
.video-timeline-bar { display: flex; align-items: center; gap: 12px; padding: 8px 14px; background: #102124; border-top: 1px solid #1f393d; }
.vtime, .vspeed { font-family: Mono, monospace; font-size: 11.5px; color: #9ebdb1; white-space: nowrap; }
.vspeed { padding: 2px 7px; background: #183136; border: 1px solid #2e5258; border-radius: 3px; color: #f4c95d; cursor: pointer; }
.vscrubber { flex: 1; min-height: 20px; accent-color: #4ecdc4; cursor: pointer; }
.mp4-fallback { margin-top: 10px; border-top: 1px solid #1f393d !important; }
.mp4-fallback summary { padding: 8px 0 !important; font-size: 12px !important; color: #8faea9 !important; }
.native-video { display: block; width: 100%; max-height: 420px; border-radius: 2px; background: var(--cream); margin-top: 14px; }
@media(max-width:600px) { .video-explain-box { padding: 12px; } .video-header { gap: 8px; } .video-header > div:first-child { gap: 10px; } }

/* Scalable Mathematical Radical (Supports Single, Nested, and Fractional Radicands) */
.math-sqrt {
  display: inline-flex;
  align-items: stretch;
  white-space: nowrap;
  font-family: "Times New Roman", Times, serif !important;
  font-style: normal !important;
  margin: 2px 1.5px;
  vertical-align: middle;
  line-height: 1.15;
}
.math-root-idx {
  font-family: "Times New Roman", Times, serif !important;
  font-size: 0.65em;
  margin-right: -0.15em;
  align-self: flex-start;
  transform: translateY(0.1em);
}
.math-surd-svg {
  width: 0.56em;
  min-width: 0.56em;
  height: auto;
  align-self: stretch;
  display: block;
  margin-right: -0.03em;
  overflow: visible;
}
.math-radicand {
  border-top: 1.35px solid currentColor;
  padding: 0.08em 0.18em 0.02em 0.08em;
  font-family: "Times New Roman", Times, serif !important;
  line-height: 1.15;
  display: inline-flex;
  align-items: center;
}

/* Vertical Stacked Mathematical Fraction Formula (.math-frac) */
.math-frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  margin: 0 2.5px;
  font-family: "Times New Roman", Times, serif !important;
  font-style: normal !important;
  line-height: 1.05;
  text-align: center;
}
.math-frac > .math-num {
  border-bottom: 1.15px solid currentColor;
  padding: 0 3px 1px;
  font-size: 0.88em;
  display: block;
  width: 100%;
  white-space: nowrap;
}
.math-frac > .math-den {
  padding: 1px 3px 0;
  font-size: 0.88em;
  display: block;
  width: 100%;
  white-space: nowrap;
}

/* Enforce Songti for Chinese and Times New Roman for numbers/math across all containers */
body, h1, h2, h3, h4, .display, .lead, .question-text, .option-text,
.review-question, .answer-line, .explanation-content, .knowledge-box p,
.steps li, .after-box p, .pitfall, .q-num, .q-dot, .timer, .score, .score-big, .stat b {
  font-family: "Times New Roman", Times, "Songti SC", "STSong", "SimSun", "NSimSun", "Noto Serif CJK SC", serif !important;
}


/* Compact Multi-Column Option Layout (1 row / 2 rows based on option length) */
.options {
  display: grid;
  gap: 10px 12px;
  margin: 22px 0;
  align-items: stretch;
}
.options.options-cols-5 {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}
.options.options-cols-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}
.options.options-cols-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}
.options.options-cols-1 {
  grid-template-columns: 1fr;
}
.options .option {
  min-height: 48px;
  padding: 9px 13px;
  gap: 10px;
}
@media (max-width: 900px) {
  .options.options-cols-5 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}
@media (max-width: 600px) {
  .options.options-cols-5,
  .options.options-cols-3,
  .options.options-cols-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

.teacher-school-table .selected-school { background: #e5eee8; }
.teacher-school-table { min-width: 760px; }
@media(max-width:1050px) { .teacher-toolbar { grid-template-columns: 1fr 1fr; } }