:root{--primary:#2563EB;--bg:#F0F4FF;--text:#1E293B;--text-muted:#64748B;--accent:#F59E0B;--card:#fff;--radius:12px;--footer-h:72px;--safe:env(safe-area-inset-bottom,0)}
*,*::before,*::after{box-sizing:border-box}
html,body{margin:0;font-family:-apple-system,BlinkMacSystemFont,"PingFang SC",sans-serif;background:var(--bg);color:var(--text);line-height:1.5}
.hidden{display:none!important}
.panel{background:var(--card);border-radius:var(--radius);padding:16px;margin:12px;box-shadow:0 2px 8px rgba(0,0,0,.06)}
.form-input{width:100%;padding:10px 12px;border:1px solid #e2e8f0;border-radius:8px;margin:8px 0;font-size:.9rem}
.btn-primary,.btn-secondary,.btn-sm{display:inline-flex;align-items:center;justify-content:center;padding:10px 16px;border-radius:999px;border:none;cursor:pointer;font-size:.875rem;text-decoration:none}
.btn-primary{background:var(--primary);color:#fff}
.btn-secondary{background:var(--card);border:1px solid #e2e8f0;color:var(--text)}
.btn-sm{padding:6px 12px;font-size:.75rem}
.muted{color:var(--text-muted);font-size:.85rem}
.toast{position:fixed;bottom:calc(var(--footer-h) + 16px);left:50%;transform:translateX(-50%);background:rgba(0,0,0,.85);color:#fff;padding:10px 18px;border-radius:999px;opacity:0;transition:.3s;z-index:999;pointer-events:none}
.toast.show{opacity:1}
.top-bar{display:flex;justify-content:space-between;align-items:center;padding:12px 16px;background:var(--card);border-bottom:1px solid #e2e8f0}
.top-bar h1{margin:0;font-size:1.1rem}
.room-code{font-size:2.5rem;font-weight:800;letter-spacing:.2em;color:var(--primary)}
.room-header{display:flex;flex-wrap:wrap;gap:12px;align-items:center;padding:12px 16px;background:var(--card);margin:12px;border-radius:var(--radius)}
.room-qr{width:80px;height:80px;border-radius:8px}
.layout-grid{display:grid;grid-template-columns:200px 1fr 260px;gap:12px;padding:0 12px 100px}
@media(max-width:1023px){.layout-grid{grid-template-columns:1fr}}
.mode-bento{display:grid;grid-template-columns:1fr 1fr;gap:8px}
.mode-card{padding:14px 8px;border:1px solid #e2e8f0;border-radius:var(--radius);background:var(--card);cursor:pointer;font-size:.8rem;transition:.2s}
.mode-card:hover,.mode-card.active{transform:scale(1.03);border-color:var(--primary);box-shadow:0 4px 12px rgba(37,99,235,.15)}
.workspace,.data-panel,.sidebar{background:var(--card);border-radius:var(--radius);padding:12px;min-height:200px}
.workspace{align-self:start;width:100%}
.quiz-panel{display:flex;flex-direction:column;gap:12px}
.quiz-toolbar{display:flex;flex-wrap:wrap;align-items:center;gap:12px}
.quiz-toolbar #quiz-progress{flex:1;min-width:140px}
.quiz-ring{width:88px;height:88px;flex:0 0 88px;margin:0}
.quiz-phase{font-size:.75rem;padding:4px 10px;border-radius:999px;background:var(--bg);color:var(--text-muted);white-space:nowrap}
.quiz-phase.is-live{background:#DBEAFE;color:#1D4ED8}
.quiz-stage{flex:1;min-height:240px}
.quiz-projector{display:flex;flex-direction:column;gap:16px;height:100%}
.quiz-question{margin:0;font-size:clamp(1.25rem,3vw,2rem);font-weight:800;line-height:1.35;text-align:center;padding:8px 4px}
.quiz-options-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:12px;flex:1}
.quiz-options-grid.cols-2{grid-template-columns:repeat(2,1fr)}
.quiz-options-grid.cols-3{grid-template-columns:repeat(3,1fr)}
.quiz-options-grid.cols-4{grid-template-columns:repeat(2,1fr)}
@media(min-width:768px){.quiz-options-grid.cols-4{grid-template-columns:repeat(4,1fr)}}
.quiz-opt-card{position:relative;display:flex;flex-direction:column;justify-content:center;gap:8px;min-height:96px;padding:16px 14px 16px 52px;border-radius:var(--radius);background:var(--card);border:2px solid #e2e8f0;border-left:8px solid var(--opt-color,var(--primary));box-shadow:0 2px 8px rgba(0,0,0,.04);transition:.2s}
.quiz-opt-card.is-correct{border-color:#059669;background:#ECFDF5;box-shadow:0 0 0 2px rgba(5,150,105,.25)}
.quiz-opt-card.is-wrong{opacity:.55}
.quiz-opt-label{position:absolute;left:14px;top:50%;transform:translateY(-50%);width:28px;height:28px;border-radius:50%;background:var(--opt-color,var(--primary));color:#fff;display:flex;align-items:center;justify-content:center;font-weight:800;font-size:.85rem}
.quiz-opt-text{margin:0;font-size:clamp(.95rem,2vw,1.15rem);font-weight:600;line-height:1.35}
.quiz-opt-count{font-size:.75rem;color:var(--text-muted)}
.student-grid{display:flex;flex-wrap:wrap;gap:8px;max-height:120px;overflow-y:auto}
.student-chip{display:flex;align-items:center;gap:6px;padding:4px 8px;background:var(--bg);border-radius:999px;font-size:.72rem}
.student-chip .avatar{width:28px;height:28px;border-radius:50%;background:var(--primary);color:#fff;display:flex;align-items:center;justify-content:center;font-weight:700}
.join-anim{animation:popIn .4s ease}
@keyframes popIn{from{transform:scale(0);opacity:0}to{transform:scale(1);opacity:1}}
.option-grid{display:grid;grid-template-columns:1fr;gap:10px;margin-top:12px}
.option-btn{min-height:56px;padding:12px;border:2px solid #e2e8f0;border-radius:var(--radius);background:var(--card);text-align:left;font-size:1rem;cursor:pointer;border-left:6px solid var(--opt-color,var(--primary))}
.option-btn:active,.option-btn.selected{transform:scale(.98);background:var(--primary-light,#DBEAFE)}
.buzzer-btn{width:100%;min-height:120px;font-size:1.5rem;font-weight:700;background:var(--accent);color:#fff;border:none;border-radius:var(--radius);cursor:pointer}
.viz-canvas{width:100%;display:block;margin:8px 0}
.progress-bar{height:8px;background:#e2e8f0;border-radius:999px;overflow:hidden}
.progress-fill{height:100%;background:var(--primary);transition:width .3s}
.ctrl-row{display:flex;flex-wrap:wrap;gap:8px;margin-top:12px}
.pick-result{font-size:2rem;font-weight:800;text-align:center;color:var(--primary);animation:popIn .5s}
.picker-wheel{max-width:280px;margin:0 auto}
.vote-bar{display:grid;grid-template-columns:80px 1fr 32px;gap:8px;align-items:center;margin:6px 0;font-size:.8rem}
.bar-track{height:10px;background:#e2e8f0;border-radius:999px;overflow:hidden}
.bar-fill{height:100%;background:var(--primary);transition:width .4s}
.leaderboard-list{list-style:none;padding:0;margin:0}
.leaderboard-list li{display:flex;gap:8px;padding:6px 0;border-bottom:1px solid #f1f5f9}
.dash-metrics{display:grid;grid-template-columns:repeat(2,1fr);gap:8px;margin-bottom:8px}
.metric{background:var(--bg);padding:8px;border-radius:8px;text-align:center}
.metric .val{display:block;font-size:1.1rem;font-weight:700;color:var(--primary)}
.timer-display{font-size:3rem;font-weight:800;text-align:center;padding:24px}
.countdown-big{font-size:4rem;text-align:center;font-weight:800;color:var(--primary)}
.offline-banner{position:fixed;top:0;left:0;right:0;background:#FEF3C7;color:#92400E;text-align:center;padding:8px;z-index:1000;transform:translateY(-100%);transition:.3s}
.offline-banner.show{transform:none}
.contact-footer{position:fixed;left:0;right:0;bottom:0;height:var(--footer-h);background:#fff;border-top:1px solid #e2e8f0;z-index:900;padding-bottom:var(--safe)}
body.has-contact-footer{padding-bottom:calc(var(--footer-h) + var(--safe))}
.contact-footer__btns{display:grid;grid-template-columns:repeat(3,minmax(0,88px));gap:6px;max-width:320px;margin:8px auto 4px;justify-content:center}
.contact-footer__cta,.contact-footer__btn{display:flex;align-items:center;justify-content:center;padding:.48rem .2rem;font-size:.72rem;border-radius:8px;text-decoration:none;border:1px solid #e2e8f0;background:var(--card);cursor:pointer}
.contact-footer__cta{background:#c41e1e!important;color:#fff!important;border:none}
.contact-footer__brand{text-align:center;font-size:.65rem;color:var(--text-muted);margin:0}
.dark{filter:invert(1) hue-rotate(180deg)}
.dark img,.dark .room-qr{filter:invert(1) hue-rotate(180deg)}
.student-points{display:flex;justify-content:space-between;padding:8px 12px;background:var(--card);border-radius:var(--radius);margin-top:8px;font-size:.85rem}
.group-battle{display:grid;grid-template-columns:repeat(2,1fr);gap:8px}
@media(max-width:567px){.layout-grid{grid-template-columns:1fr}.room-code{font-size:1.8rem}}