:root{
          --bg:#f4f7fb;
          --panel:#ffffff;
          --border:#2F3338;
          --soft:#ECEFF1;
          --soft2:#F7F8F9;
          --muted:#6B7280;
          --text:#2F3338;
          --ok:#37b34a;
          --line:#D1D5DB;
          --danger:#b00020;
          --brand:#2F3338;
          --warn:#f6c65b;
        }
        *{box-sizing:border-box;}
        body{margin:0;}
        .landing{background:var(--bg);min-height:100vh;color:var(--text);font-family:'OpenDyslexic', Arial, sans-serif;}
        .wrap{max-width:1200px;margin:0 auto;padding:0 18px 60px;}
        header{border-bottom:1px solid var(--line);background:#fff;position:sticky;top:0;z-index:10;}
        .nav{display:flex;justify-content:space-between;align-items:center;padding:14px 0;}
        .logo{font-weight:900;color:var(--border);letter-spacing:.4px;}
        .nav a{color:var(--brand);text-decoration:none;font-weight:900;}
        .nav-right{display:flex;gap:10px;align-items:center;}
        .nav-btn{border-radius:12px;padding:8px 12px;font-weight:900;border:1px solid var(--line);background:var(--soft);cursor:pointer;}
        .hero{display:grid;grid-template-columns:1.08fr .92fr;gap:24px;padding:24px 0 12px;}
        .hero h1{font-size:30px;margin:0 0 10px;color:var(--border);line-height:1.15;}
        .hero p{margin:0 0 14px;color:var(--muted);font-size:15px;line-height:1.45;}
        .hero-list{display:grid;gap:8px;margin:0 0 16px;padding:0;list-style:none;}
        .hero-list li{background:var(--soft);border:1px solid var(--line);padding:10px 12px;border-radius:12px;font-weight:900;}
        .cta-row{display:flex;gap:10px;flex-wrap:wrap;}
        .btn{border-radius:12px;padding:10px 16px;font-weight:900;border:1px solid var(--line);background:var(--soft);cursor:pointer;text-decoration:none;color:var(--text);display:inline-flex;align-items:center;gap:8px;}
        .btn-primary{background:var(--ok);border-color:var(--ok);color:#fff;}
        .btn-ghost{background:#fff;}
        .hero-card{border:2px solid var(--border);border-radius:16px;background:#fff;padding:16px;box-shadow:0 16px 40px rgba(13,42,54,.08);}
        .pill{display:inline-flex;align-items:center;gap:6px;border-radius:999px;padding:6px 10px;font-weight:900;font-size:12px;border:1px solid var(--line);background:#fff;}
        .mini-grid{display:grid;grid-template-columns:repeat(10, minmax(22px, 1fr));gap:6px;margin-top:12px;}
        .mini{height:24px;border-radius:8px;border:1px solid var(--line);display:grid;place-items:center;font-weight:900;font-size:12px;}
        .mini.ok{background:#dff3e2;color:#2F3338;}
        .mini.bad{background:#f9dde2;color:#7a0b1a;}
        .mini.partial{background:#fff2d6;color:#7a4a00;}

        .section{padding:14px 0;}
        .section-title{font-size:20px;color:var(--border);margin:0 0 10px;}
        .demo-note{padding:10px 12px;border:1px dashed var(--line);border-radius:12px;background:#fff;color:var(--muted);font-size:13px;}

        .teacher-list{display:grid;gap:14px;}
        .teacher-card{border:1px solid var(--line);border-radius:16px;background:#fff;overflow:hidden;}
        .teacher-row{display:grid;grid-template-columns:260px 1fr;gap:12px;padding:12px;}
        .teacher-meta{display:flex;flex-direction:column;gap:10px;}
        .teacher-title{font-weight:900;color:var(--border);font-size:16px;}
        .score-pill{border:2px solid var(--line);background:var(--soft2);border-radius:999px;padding:8px 10px;font-weight:900;width:max-content;}

        .qgrid-wrap{overflow-x:auto;padding-bottom:6px;}
        .qgrid{display:grid;grid-template-columns:repeat(20, minmax(36px, 1fr));gap:4px;min-width:760px;}
        .qcell{border:1px solid var(--line);border-radius:8px;background:#fff;min-height:44px;display:grid;place-items:center;font-weight:900;cursor:pointer;transition:transform .08s ease;}
        .qcell:hover{transform:translateY(-1px);}
        .qcell.ok{background:#dff3e2;color:#2F3338;}
        .qcell.bad{background:#f9dde2;color:#7a0b1a;}
        .qcell.partial{background:#fff2d6;color:#7a4a00;}
        .qcell.flash{outline:3px solid rgba(11,94,215,.35);}
        .qcell .qnum{font-size:11px;color:var(--border);}
        .qcell .qmark{font-size:14px;}

        .cta-band{margin-top:18px;background:linear-gradient(120deg, #2F3338, #2F3338);color:#fff;border-radius:16px;padding:18px;border:2px solid #2F3338;}
        .cta-band h3{margin:0 0 8px;}

        .modal-bg{position:fixed;inset:0;background:rgba(0,0,0,.45);display:none;align-items:center;justify-content:center;z-index:70;padding:20px;}
        .modal-card{background:#fff;border:2px solid var(--border);border-radius:16px;width:min(980px, 96vw);max-height:92vh;overflow:auto;}
        .modal-head{display:flex;justify-content:space-between;align-items:center;padding:14px 18px;border-bottom:1px solid var(--line);background:#f6fbff;gap:10px;flex-wrap:wrap;}
        .modal-title{font-weight:900;color:var(--border);font-size:16px;display:flex;align-items:center;gap:10px;flex-wrap:wrap;}
        .tag{border-radius:999px;padding:6px 10px;font-weight:900;font-size:12px;border:1px solid var(--line);background:#fff;}
        .tag.ok{border-color:#bfe9c6;background:#eefaf0;color:#2F3338;}
        .tag.bad{border-color:#f1b7c0;background:#fff1f3;color:#7a0b1a;}
        .tag.partial{border-color:#f3db9a;background:#fff8e5;color:#7a4a00;}

        .modal-body{padding:18px;}
        .two-col{display:grid;grid-template-columns:1fr 340px;gap:14px;align-items:start;}
        .side{border:2px solid var(--line);border-radius:14px;padding:12px;background:#fff;}
        .side h4{margin:0 0 8px;color:var(--border);}
        .side p{margin:0;color:var(--muted);line-height:1.4;}
        .side .mini-stat{margin-top:8px;font-weight:900;}
        .q-title{font-weight:900;font-size:20px;margin:0 0 10px;color:var(--border);}
        .q-sub{color:var(--muted);margin-bottom:12px;white-space:pre-line;}
        .answer-box{border:2px solid var(--line);border-radius:12px;padding:12px;background:#fff;min-height:120px;}
        .answer-box textarea{width:100%;min-height:130px;border:0;resize:none;font-family:'OpenDyslexic', Arial, sans-serif;font-size:14px;background:transparent;}
        .ai-box{border:2px solid var(--line);border-radius:12px;padding:12px;background:#F7F8F9;margin-top:12px;}
        .ai-box h4{margin:0 0 8px;color:var(--border);}
        .ai-box ul{margin:6px 0 0 18px;}

        .option-list{display:grid;gap:10px;margin-top:10px;}
        .option{border:2px solid var(--line);border-radius:12px;padding:12px;font-weight:900;display:flex;gap:10px;align-items:center;background:#fff;}
        .option.selected{border-color:var(--border);background:#eef5fb;}
        .option.correct{border-color:var(--ok);background:#eefaf0;}
        .diagram{border:2px solid var(--line);border-radius:12px;background:#fff;padding:10px;display:grid;gap:10px;}
        .diagram img{max-width:100%;border-radius:10px;}
        .chip-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:10px;}
        .chip{border:2px dashed var(--border);border-radius:999px;padding:6px 12px;font-weight:900;background:#fff;}
        .pair-list{display:grid;gap:8px;margin-top:10px;}
        .pair{border:2px dashed var(--border);border-radius:12px;padding:10px;font-weight:900;background:#fff;}
        .gap-line{display:flex;flex-wrap:wrap;gap:8px;align-items:center;margin-top:8px;}
        .gap{border:2px dashed var(--border);border-radius:999px;padding:6px 14px;font-weight:900;background:#fff;}
.hero-sale{
  border:2px solid var(--border);
  border-radius:16px;
  background:#fff;
  padding:16px;
  box-shadow:0 16px 40px rgba(13,42,54,.08);
}
.hero-sale-pill{
  display:inline-block;
  font-weight:900;
  font-size:12px;
  border:1px solid var(--line);
  border-radius:999px;
  padding:6px 10px;
  background:#fff;
}
.hero-sale h2{
  margin:10px 0 8px;
  color:var(--border);
  font-size:20px;
}
.hero-sale p{margin:0;color:var(--muted);line-height:1.4;}

        @media (max-width:980px){
          .hero{grid-template-columns:1fr;}
          .teacher-row{grid-template-columns:1fr;}
          .qgrid{grid-template-columns:repeat(8, minmax(36px, 1fr));}
          .two-col{grid-template-columns:1fr;}
        }
      
        .modal-bg.open{display:flex;}

        .option-dot{width:18px;height:18px;border-radius:999px;border:2px solid var(--border);background:#fff;}