:root{--bg:#f5f7fb;--panel:#fff;--text:#162235;--muted:#677489;--border:#dfe5ee;--accent:#2563eb;--danger:#b42318;--ok:#067647;--warning:#b54708;--shadow:0 8px 26px rgba(16,24,40,.08)}
*{box-sizing:border-box}body{margin:0;background:var(--bg);color:var(--text);font:15px/1.5 system-ui,-apple-system,Segoe UI,Roboto,Arial,sans-serif}.topbar{background:#0f172a;color:#fff;padding:14px 24px;display:flex;align-items:center;justify-content:space-between;gap:20px;flex-wrap:wrap}.brand{font-weight:800;font-size:18px}.brand span{font-weight:500;color:#cbd5e1}.topbar nav{display:flex;gap:8px;flex-wrap:wrap}.topbar a{color:#dbe4f0;text-decoration:none;padding:8px 10px;border-radius:8px}.topbar a:hover,.topbar a.active{background:#1e293b;color:#fff}.container{max-width:1180px;margin:26px auto;padding:0 18px}.page-head{display:flex;align-items:flex-end;justify-content:space-between;gap:16px;margin-bottom:18px;flex-wrap:wrap}.page-head h1{margin:0;font-size:28px}.page-head p{margin:4px 0 0;color:var(--muted)}.card{background:var(--panel);border:1px solid var(--border);border-radius:14px;box-shadow:var(--shadow);padding:18px;margin-bottom:18px}.grid{display:grid;gap:16px}.grid-4{grid-template-columns:repeat(4,minmax(0,1fr))}.metric strong{display:block;font-size:28px}.metric span{color:var(--muted)}.btn{appearance:none;border:0;border-radius:9px;padding:10px 14px;font-weight:700;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:6px;background:var(--accent);color:#fff}.btn.secondary{background:#e8eefc;color:#1d4ed8}.btn.danger{background:#fee4e2;color:var(--danger)}.btn.ghost{background:#eef2f7;color:#344054}.btn.small{padding:7px 10px;font-size:13px}.btn:disabled{opacity:.55;cursor:not-allowed}.table-wrap{overflow:auto}.table{width:100%;border-collapse:collapse;min-width:760px}.table th,.table td{padding:12px;border-bottom:1px solid var(--border);text-align:left;vertical-align:top}.table th{font-size:12px;text-transform:uppercase;letter-spacing:.04em;color:var(--muted);background:#fafbfc}.name-link{border:0;background:none;padding:0;color:#1d4ed8;text-decoration:underline;font:inherit;font-weight:700;cursor:pointer}.badge{display:inline-block;padding:4px 8px;border-radius:999px;font-size:12px;font-weight:700;background:#eef2f6;color:#475467}.badge.ok{background:#dcfae6;color:var(--ok)}.badge.bad{background:#fee4e2;color:var(--danger)}.badge.wait{background:#fffaeb;color:var(--warning)}.form-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px}.field label{display:block;font-weight:700;margin-bottom:6px}.field input,.field select,.field textarea{width:100%;padding:11px 12px;border:1px solid #cbd5e1;border-radius:9px;background:#fff;color:#111827;font:inherit}.field textarea{min-height:110px;resize:vertical}.field.full{grid-column:1/-1}.options-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px}.alert{padding:12px 14px;border-radius:9px;margin-bottom:14px;background:#e8eefc}.alert.success{background:#dcfae6;color:#065f46}.alert.error{background:#fee4e2;color:#8a1c13}.muted{color:var(--muted)}.actions{display:flex;gap:8px;flex-wrap:wrap}.qr-box{display:flex;gap:22px;align-items:center;flex-wrap:wrap}.qr-box img{width:220px;height:220px;background:#fff;border:1px solid var(--border);padding:8px;border-radius:12px}.link-box{word-break:break-all;background:#f8fafc;border:1px solid var(--border);padding:10px;border-radius:9px}.modal[hidden]{display:none}.modal{position:fixed;inset:0;background:rgba(15,23,42,.58);display:flex;align-items:center;justify-content:center;padding:20px;z-index:50}.modal-panel{width:min(760px,100%);max-height:88vh;overflow:auto;background:#fff;border-radius:16px;box-shadow:0 22px 55px rgba(0,0,0,.22)}.modal-head{padding:16px 18px;border-bottom:1px solid var(--border);display:flex;justify-content:space-between;gap:12px;align-items:center}.modal-body{padding:18px}.modal-close{border:0;background:#eef2f7;border-radius:8px;padding:8px 10px;cursor:pointer}.answer-option{border:1px solid var(--border);border-radius:9px;padding:10px 12px;margin:8px 0}.answer-option.selected{border-color:#2563eb;background:#eff6ff}.answer-option.correct{border-color:#16a34a;background:#f0fdf4}.answer-option.wrong{border-color:#dc2626;background:#fef2f2}.login-shell,.student-shell{max-width:640px;margin:50px auto;padding:0 18px}.student-shell .card{padding:24px}.question-title{font-size:23px;line-height:1.4;margin:10px 0 18px}.choice{display:block;border:1px solid var(--border);border-radius:12px;padding:14px;margin:10px 0;cursor:pointer;background:#fff}.choice:hover{border-color:#94a3b8}.choice input{margin-right:10px}.timer{font-variant-numeric:tabular-nums;font-weight:800}.status-row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}.empty{padding:34px;text-align:center;color:var(--muted)}
@media(max-width:800px){.grid-4{grid-template-columns:repeat(2,minmax(0,1fr))}.form-grid,.options-grid{grid-template-columns:1fr}.field.full{grid-column:auto}.topbar{padding:12px 16px}.container{margin-top:18px}.page-head h1{font-size:24px}}
@media(max-width:480px){.grid-4{grid-template-columns:1fr}.btn{width:100%}.actions .btn{width:auto}.qr-box img{width:190px;height:190px}.student-shell{margin:22px auto}}

.pool-status{padding:11px 12px;border-radius:9px;font-weight:700;border:1px solid var(--border)}.pool-status.pool-ok{background:#f0fdf4;color:var(--ok);border-color:#bbf7d0}.pool-status.pool-bad{background:#fef2f2;color:var(--danger);border-color:#fecaca}

.pool-status.pool-warn{background:#fffaeb;color:var(--warning);border-color:#fedf89}.picker-toolbar{display:flex;gap:8px;align-items:center;flex-wrap:wrap;margin:8px 0 12px}.picker-toolbar input[type=search]{min-width:240px;flex:1;padding:10px 12px;border:1px solid #cbd5e1;border-radius:9px;font:inherit}.question-picker{border:1px solid var(--border);border-radius:12px;max-height:420px;overflow:auto;background:#fff}.question-pick{display:flex;gap:10px;padding:12px 14px;border-bottom:1px solid var(--border);cursor:pointer;align-items:flex-start}.question-pick:last-child{border-bottom:0}.question-pick:hover{background:#f8fafc}.question-pick[hidden]{display:none}.question-pick input{width:18px;height:18px;margin-top:3px;flex:0 0 auto}.question-pick span{min-width:0}.question-pick strong,.question-pick small{display:block}.question-pick small{color:var(--muted);margin-top:3px}.question-pick:has(input:checked){background:#eff6ff}
.grid-5{display:grid;grid-template-columns:repeat(5,minmax(0,1fr));gap:16px}.grid-3{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:16px}.question-image{display:block;max-width:100%;max-height:480px;object-fit:contain;margin:14px auto;border:1px solid var(--border);border-radius:12px;background:#fff}.question-thumb{width:120px;max-height:90px;object-fit:contain;border:1px solid var(--border);border-radius:8px}.progress-track{height:8px;background:#e5e7eb;border-radius:999px;overflow:hidden;margin:14px 0}.progress-track span{display:block;height:100%;background:var(--accent)}.countdown{background:#fff1f2;color:#be123c;padding:6px 10px;border-radius:999px}.detail-question{border-top:1px solid var(--border);padding:18px 0}.detail-question:first-of-type{border-top:0}.compact{gap:10px;margin:12px 0}.preview-shell{margin:0 auto;max-width:720px}.stat-strip{display:flex;gap:12px;flex-wrap:wrap}.analytics-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.bar-row{display:grid;grid-template-columns:minmax(130px,1fr) 3fr 65px;gap:10px;align-items:center;margin:10px 0}.bar{height:12px;background:#e5e7eb;border-radius:999px;overflow:hidden}.bar>span{display:block;height:100%;background:#64748b}.qr-live-count{font-variant-numeric:tabular-nums}
@media(max-width:900px){.grid-5{grid-template-columns:repeat(2,minmax(0,1fr))}.analytics-grid{grid-template-columns:1fr}}@media(max-width:600px){.grid-5,.grid-3{grid-template-columns:1fr}.bar-row{grid-template-columns:1fr}.bar{height:10px}}
.option-with-media{overflow:hidden}.option-line{display:flex;align-items:flex-start;gap:8px;min-width:0}.option-line input{flex:0 0 auto;margin-top:4px}.option-image{display:block;max-width:min(100%,420px);max-height:300px;object-fit:contain;margin:12px 0 4px 28px;border:1px solid var(--border);border-radius:10px;background:#fff}.solution-image{display:block;max-width:100%;max-height:520px;object-fit:contain;margin:12px auto 0;border:1px solid var(--border);border-radius:12px;background:#fff}.solution-panel,.preview-solution,.feedback-answer{border:1px solid var(--border);border-radius:12px;padding:14px;margin:14px 0;background:#fafbfc}.solution-panel h3,.preview-solution h3{margin-top:0}.feedback-option-image{margin-left:0}.media-field{border:1px dashed #cbd5e1;border-radius:12px;padding:12px;background:#fafbfc}.media-preview-wrap{min-height:6px;margin-top:10px}.media-preview[hidden]{display:none}.media-preview{width:auto;max-width:180px;max-height:130px}.compact-choice{padding:8px 10px;margin:8px 0 0}.media-note{align-self:start}.option-editor>.media-field{margin-top:10px}.option-editor textarea{min-height:82px}
@media(max-width:600px){.option-image{margin-left:0;max-width:100%;max-height:260px}.media-preview{max-width:150px}}

/* v2.3 compact student result popup */
.simple-detail{padding:8px 0 18px;border-bottom:1px solid var(--border,#e5e7eb)}
.simple-detail:last-child{border-bottom:0;padding-bottom:0}
.simple-detail-row{margin-top:12px}
.simple-detail-row>strong,.simple-detail-grid>div>strong{display:block;margin-bottom:6px}
.simple-detail-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin-top:14px}
.simple-detail-grid>div{padding:12px;border:1px solid var(--border,#e5e7eb);border-radius:10px;min-width:0}
@media(max-width:640px){.simple-detail-grid{grid-template-columns:1fr}}

/* v2.4 live session feedback */
@keyframes liveResultPulse{0%{background:rgba(34,197,94,.18)}100%{background:transparent}}
tr.live-result-changed>td{animation:liveResultPulse .9s ease-out}
@media (prefers-reduced-motion:reduce){tr.live-result-changed>td{animation:none}}