:root {
  --navy:#0b1020; --cyan:#20d9ff; --purple:#8b5cf6; --green:#36e6a5;
  --orange:#ff9f43; --red:#ff5a72; --ink:#172033; --muted:#657089;
  --line:#e6eaf1; --card:#fff; --lavender:#efeaff; --shadow:0 8px 26px rgba(34,45,80,.10);
}
*{box-sizing:border-box} html,body{margin:0;min-height:100%}
body{font-family:Inter,"Segoe UI",system-ui,sans-serif;color:var(--ink);background:radial-gradient(900px 600px at 50% -10%,#29395f,#070b16 66%);padding:22px 14px 32px}
button,select{font:inherit}.preview-shell{width:min(100%,470px);margin:auto}.preview-toolbar{position:relative;z-index:5;display:grid;grid-template-columns:1fr 1fr;gap:9px;padding:13px;margin-bottom:13px;background:rgba(16,24,45,.92);border:1px solid rgba(255,255,255,.12);border-radius:20px;box-shadow:0 18px 50px rgba(0,0,0,.35);backdrop-filter:blur(16px)}
.toolbar-mark{grid-column:1/-1;display:flex;align-items:center;gap:7px;color:#9aa8c8;font-size:10px;letter-spacing:1.8px}.pulse{width:7px;height:7px;border-radius:50%;background:var(--green);box-shadow:0 0 0 5px rgba(54,230,165,.12)}
.preview-toolbar label{display:flex;flex-direction:column;gap:4px;color:#8b98b8;font-size:9px;text-transform:uppercase;letter-spacing:.8px}.preview-toolbar label:nth-of-type(3){grid-column:1/-1}.preview-toolbar select{min-width:0;width:100%;height:38px;padding:0 30px 0 10px;color:#fff;background:#182241;border:1px solid #2b375d;border-radius:11px;outline:none}.preview-toolbar select:focus{border-color:var(--cyan)}
#refreshButton{grid-column:1/-1;height:40px;border:0;border-radius:11px;background:linear-gradient(135deg,var(--cyan),var(--purple));color:#fff;font-weight:750;cursor:pointer}#refreshButton:disabled{opacity:.55}.phone-frame{width:390px;max-width:100%;height:min(780px,calc(100vh - 245px));min-height:560px;margin:auto;padding:9px;background:#05070d;border:1px solid #252a36;border-radius:44px;box-shadow:0 35px 80px rgba(0,0,0,.56)}
.phone-screen{height:100%;overflow:hidden;border-radius:36px;background:var(--lavender);display:flex;flex-direction:column}.appbar{flex:none;display:flex;align-items:center;gap:10px;padding:18px 18px 13px;background:rgba(255,255,255,.83);border-bottom:1px solid rgba(139,92,246,.12);backdrop-filter:blur(12px)}.brand-orb{width:38px;height:38px;display:grid;place-items:center;border-radius:13px;background:linear-gradient(135deg,var(--cyan),var(--purple));box-shadow:0 7px 16px rgba(139,92,246,.25)}.appbar div:nth-child(2){min-width:0;display:flex;flex-direction:column}.appbar small{font-size:8px;letter-spacing:1.1px;color:#7b6bb6;font-weight:800}.appbar strong{font-size:14px;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.live-dot{margin-left:auto;padding:5px 8px;border-radius:99px;background:#dff8ea;color:#187453;font-size:9px;font-weight:800}.status-area{display:none;padding:8px 16px;background:#fff4d8;color:#8b5b00;font-size:11px;line-height:1.4}.status-area.show{display:block}.content-area{padding:17px 16px 45px;overflow-y:auto;scrollbar-width:thin;scrollbar-color:#c8bff0 transparent}.topic-hero{position:relative;overflow:hidden;padding:19px;border-radius:22px;color:#fff;background:linear-gradient(140deg,#17284e,var(--navy));box-shadow:0 12px 28px rgba(11,16,32,.20);margin-bottom:13px}.topic-hero:after{content:"";position:absolute;right:-38px;top:-55px;width:155px;height:155px;border-radius:50%;background:radial-gradient(circle,rgba(32,217,255,.38),transparent 69%)}.eyebrow{font-size:9px;letter-spacing:1.25px;font-weight:800;color:var(--cyan);text-transform:uppercase}.topic-hero h1{position:relative;z-index:1;margin:6px 0 5px;font-size:24px;line-height:1.12;letter-spacing:-.5px}.topic-hero p{position:relative;z-index:1;margin:0;color:#bac5df;font-size:12px}.meta-row{display:flex;gap:7px;margin-top:13px}.meta-chip{padding:5px 9px;border-radius:99px;background:rgba(255,255,255,.10);font-size:10px;color:#e8edfb}.section-label{display:flex;align-items:center;gap:8px;margin:24px 2px 10px;font-size:14px}.section-label span{display:grid;place-items:center;width:28px;height:28px;border-radius:9px;background:#fff;box-shadow:var(--shadow)}
.content-card{position:relative;background:var(--card);border:1px solid var(--line);border-radius:17px;padding:16px;margin:10px 0;box-shadow:var(--shadow);overflow:hidden}.content-card:before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:#cfd7e7}.content-card .tag{display:inline-flex;padding:4px 8px;border-radius:99px;background:#f1f3f8;color:var(--muted);font-size:9px;font-weight:800;letter-spacing:.55px;text-transform:uppercase}.content-card h2{margin:9px 0 7px;font-size:16px;line-height:1.25}.rich{font-size:13px;line-height:1.68;color:#47526a}.rich p{margin:0 0 9px}.rich p:last-child{margin-bottom:0}.rich strong{color:#172033}.card-why:before{background:var(--purple)}.card-why .tag{background:#eee8ff;color:#6945c3}.card-warning{background:#fff7f4;border-color:#ffd7cc}.card-warning:before{background:var(--red)}.card-warning .tag{background:#ffe3dd;color:#b43f35}.card-life{background:#f5fffa;border-color:#cff2df}.card-life:before{background:#2fc58c}.card-life .tag{background:#dff8ea;color:#187453}.card-important{background:#fffaf0;border-color:#f7dfad}.card-important:before{background:var(--orange)}.card-important .tag{background:#ffedc8;color:#965e00}.card-summary{background:linear-gradient(145deg,#fff,#f6f3ff);border-color:#ded5ff}.card-summary:before{background:linear-gradient(var(--cyan),var(--purple))}.summary-list{display:grid;gap:8px;margin:10px 0 0;padding:0;list-style:none}.summary-list li{display:flex;gap:9px;font-size:12.5px;line-height:1.45}.summary-list li:before{content:"✓";flex:none;display:grid;place-items:center;width:20px;height:20px;border-radius:50%;background:#ddf8ec;color:#16815b;font-size:11px;font-weight:900}
.interactive{background:linear-gradient(145deg,#14203f,#0b1020);color:#fff;border-color:#25345d}.interactive:before{background:var(--cyan)}.interactive .tag{background:rgba(32,217,255,.14);color:var(--cyan)}.interactive h2{color:#fff}.interactive .rich{color:#b8c5df}.choice{width:100%;display:flex;align-items:center;gap:10px;text-align:left;padding:11px 12px;margin:8px 0;border-radius:12px;border:1px solid #35446b;background:#192545;color:#fff;cursor:pointer}.choice-key{width:25px;height:25px;border-radius:50%;display:grid;place-items:center;border:1px solid #516085;font-size:11px;font-weight:800}.choice.correct{border-color:var(--green);background:rgba(54,230,165,.12)}.choice.wrong{border-color:var(--red);background:rgba(255,90,114,.10)}.choice.correct .choice-key{background:var(--green);border-color:var(--green);color:#07301f}.feedback{margin-top:9px;padding:10px;border-radius:11px;background:rgba(54,230,165,.12);color:#bdf4dc;font-size:12px;line-height:1.5}.slider-wrap{padding:8px 0}.slider-wrap input{width:100%;accent-color:var(--cyan)}.slider-value{text-align:center;font-size:23px;font-weight:800;color:var(--cyan)}
.experiment-card{background:#f7fffb;border:1px solid #cceedd;border-radius:20px;padding:17px;margin:12px 0;box-shadow:var(--shadow)}.experiment-card h3{margin:5px 0;font-size:17px}.question-text{margin:7px 0 10px;font-size:16px;font-weight:750;line-height:1.4}.question-text p{margin:0}.experiment-sub{font-size:11px;color:#49806a}.detail-box{margin-top:11px;padding:12px;border-radius:13px;background:#fff;border:1px solid #dcefe5}.detail-box h4{margin:0 0 7px;font-size:11px;text-transform:uppercase;letter-spacing:.7px;color:#287a59}.detail-box p{margin:0;font-size:12.5px;line-height:1.55}.pill-list{display:flex;flex-wrap:wrap;gap:6px}.pill{padding:6px 9px;border-radius:99px;background:#e7f8ef;color:#216e50;font-size:11px}.simulation-placeholder{margin-top:11px;padding:13px;border:1px dashed #79c9a6;border-radius:13px;text-align:center;color:#34795c;font-size:12px}.teacher-brief{background:#fff4d8;border-color:#f0d494}.teacher-brief h4{color:#8b5b00}.prediction-options{display:grid;gap:6px;margin-top:8px}.prediction-option{padding:8px 10px;border-radius:10px;background:#f1f8f4;font-size:11px}.prediction-option.correct{outline:2px solid #6bd5aa}.result-summary{margin:8px 0 0;padding-left:18px;font-size:12px;line-height:1.55}
.question-card{background:#fffdf6;border:1px solid #f1dfaa;border-radius:20px;padding:17px;margin:12px 0;box-shadow:var(--shadow)}.question-code{font-size:9px;font-weight:850;letter-spacing:1px;color:#b4780a}.question-option{display:flex;gap:10px;align-items:center;padding:11px;margin-top:8px;border:1px solid #eadfbf;background:#fff;border-radius:12px;font-size:12px;line-height:1.4}.question-option .letter{flex:none;width:25px;height:25px;display:grid;place-items:center;border-radius:50%;border:1px solid #ddd0aa;color:#8e7842;font-weight:800}.question-option.answer{border-color:#53c99c;background:#effcf6}.question-option.answer .letter{background:var(--green);border-color:var(--green);color:#07301f}.solution{margin-top:10px;padding:11px;border-radius:12px;background:#fff3d4;color:#73520f;font-size:12px;line-height:1.55}.empty-state,.loading-card,.error-card{padding:28px 20px;text-align:center;background:#fff;border-radius:20px;box-shadow:var(--shadow);font-size:13px}.spinner{display:block;width:28px;height:28px;margin:0 auto 12px;border:3px solid #e6e2f6;border-top-color:var(--purple);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}.error-card{color:#a53c3c;background:#fff5f5}.environment-note{text-align:center;color:#75809b;font-size:10px;letter-spacing:.4px}
@media(max-width:430px){body{padding:0;background:var(--lavender)}.preview-shell{width:100%}.preview-toolbar{position:sticky;top:0;border-radius:0;margin:0;padding:9px 10px;grid-template-columns:1fr 1fr 82px}.toolbar-mark{display:none}.preview-toolbar label:nth-of-type(3){grid-column:auto}.preview-toolbar label span{display:none}.preview-toolbar select{height:36px;font-size:11px;padding-left:7px}#refreshButton{grid-column:auto;height:36px;font-size:11px}.phone-frame{width:100%;height:calc(100vh - 54px);min-height:500px;padding:0;border:0;border-radius:0;box-shadow:none}.phone-screen{border-radius:0}.environment-note{display:none}}