*{box-sizing:border-box}body{margin:0;font-family:Arial,Microsoft YaHei,sans-serif;background:#f3f5f7;color:#202124}.page{min-height:100vh;padding:24px}.card{max-width:980px;margin:0 auto;background:#fff;border-radius:18px;padding:28px;box-shadow:0 10px 30px #00000014}h1{margin:0 0 8px}.sub{color:#666;margin-bottom:24px}input{width:100%;height:44px;border:1px solid #ddd;border-radius:10px;padding:0 14px;font-size:16px;margin:8px 0 12px}button{border:0;background:#1677ff;color:#fff;height:42px;padding:0 18px;border-radius:10px;font-size:15px;cursor:pointer}button.secondary{background:#6b7280}button.danger{background:#dc2626}.row{display:flex;gap:12px;flex-wrap:wrap;margin:12px 0}.hide{display:none!important}.msg{color:#dc2626}.meeting{margin-top:22px;padding:18px;border:1px dashed #1677ff;border-radius:14px;background:#f5f9ff}.room{margin-top:22px}.screen{background:#111;border-radius:16px;height:540px;display:flex;align-items:center;justify-content:center;overflow:hidden}.placeholder{color:#aaa;font-size:18px}.studentVideo{width:100%;height:100%;object-fit:contain;background:#111}.bottom{margin-top:14px;display:flex;gap:12px}.chat{position:fixed;right:24px;bottom:24px;width:360px;background:#fff;border-radius:16px;box-shadow:0 12px 40px #0003;padding:18px}.messages{height:260px;overflow:auto;background:#f7f7f7;border-radius:12px;padding:10px;margin-bottom:10px}.message{padding:6px 0;border-bottom:1px solid #e5e7eb}.chatInput{display:flex;gap:8px}.chatInput input{margin:0}@media(max-width:720px){.screen{height:360px}.chat{left:12px;right:12px;width:auto}}.apkBtn{display:inline-block;margin-left:10px;background:#16a34a;color:#fff;height:42px;line-height:42px;padding:0 18px;border-radius:10px;font-size:15px;text-decoration:none}.card.wide{max-width:1180px}.toolbar{display:grid;grid-template-columns:minmax(220px,1fr) auto auto auto;gap:12px;align-items:center;margin:14px 0 20px}.toolbar input{margin:0}.meetingList{margin-top:22px;padding:18px;border:1px solid #e5e7eb;border-radius:14px;background:#fafafa}.listBox{display:flex;flex-direction:column;gap:10px}.meetingItem{display:flex;justify-content:space-between;gap:16px;align-items:center;padding:14px;border:1px solid #e5e7eb;border-radius:12px;background:#fff}.meetingItem.active{border-color:#1677ff;background:#f5f9ff}.meetingItem .code{font-size:24px;font-weight:700;color:#111827;letter-spacing:1px}.meetingItem .meta{color:#6b7280;font-size:14px;margin-top:4px}.itemActions{display:flex;gap:8px;flex-wrap:wrap;justify-content:flex-end}.empty{color:#6b7280;padding:18px;background:#fff;border-radius:12px}.closeBtn{margin-top:10px}@media(max-width:900px){.toolbar{grid-template-columns:1fr}.meetingItem{flex-direction:column;align-items:flex-start}.itemActions{justify-content:flex-start}}