*{box-sizing:border-box}html,body{margin:0;height:100%;font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,sans-serif;background:#f3f5f9;color:#1d2433}
.hidden{display:none!important}.screen{height:100%}.center{display:flex;align-items:center;justify-content:center;padding:16px}
.card{background:#fff;border-radius:16px;box-shadow:0 8px 30px #0001;padding:28px;width:100%;max-width:400px;text-align:center}
h1{font-size:24px;margin:0 0 16px}label{display:block;text-align:left;margin:10px 0;font-size:14px;color:#555}
input,select{width:100%;padding:11px;border:1px solid #d5d9e2;border-radius:10px;font-size:16px;margin-top:4px}
button{font-size:15px;padding:10px 14px;border:0;border-radius:10px;background:#e8ebf2;cursor:pointer;color:#1d2433}button:hover{filter:brightness(.95)}
.primary{background:#2f6bff;color:#fff;width:100%;margin-top:8px}.danger{background:#ff3b30;color:#fff}.off{background:#ffd9d6!important}.on{background:#cfe0ff!important}
.tabs{display:flex;gap:6px;background:#eef1f6;padding:4px;border-radius:12px}.tab{flex:1;background:none}.tab.active{background:#fff;box-shadow:0 1px 4px #0002}
.err{color:#d70015;min-height:1em}.hint{color:#778;font-size:13px}
.spinner{width:42px;height:42px;border:4px solid #dde;border-top-color:#2f6bff;border-radius:50%;margin:0 auto 12px;animation:sp 1s linear infinite}@keyframes sp{to{transform:rotate(360deg)}}
#lobbyPreview{width:100%;border-radius:12px;background:#000;margin-top:10px;transform:scaleX(-1)}
#room{display:flex;flex-direction:column}header{display:flex;justify-content:space-between;align-items:center;padding:8px 14px;background:#fff;border-bottom:1px solid #e3e6ee;gap:8px;flex-wrap:wrap}
.rec{color:#ff3b30;font-weight:bold;margin-left:8px;animation:bl 1s infinite}@keyframes bl{50%{opacity:.3}}
main{flex:1;display:flex;min-height:0;gap:10px;padding:10px}#stageWrap{flex:1;display:flex;flex-direction:column;min-width:0;gap:6px}
#stage{position:relative;flex:1;background:#111;border-radius:14px;overflow:hidden;min-height:200px}
#stageVideo{position:absolute;inset:0;width:100%;height:100%;object-fit:contain}#draw{position:absolute;inset:0;width:100%;height:100%;touch-action:none}
#stageLabel{position:absolute;left:10px;top:10px;background:#0008;color:#fff;padding:3px 9px;border-radius:8px;font-size:13px;z-index:2}
#drawBar{display:flex;gap:6px;align-items:center;flex-wrap:wrap}#drawBar select{width:auto;margin:0;padding:6px}.tool.active{background:#cfe0ff}
.colors i{display:inline-block;width:24px;height:24px;border-radius:50%;border:2px solid #ccd;margin:0 2px;cursor:pointer;vertical-align:middle}.colors i.sel{outline:3px solid #2f6bff}
aside{width:320px;display:flex;flex-direction:column;gap:10px;min-height:0}
#grid{display:grid;grid-template-columns:1fr 1fr;gap:6px}.tile{position:relative;background:#222;border-radius:10px;overflow:hidden;aspect-ratio:4/3;cursor:pointer}
.tile video{width:100%;height:100%;object-fit:cover}.tile.self video{transform:scaleX(-1)}.tile span{position:absolute;left:5px;bottom:5px;background:#0008;color:#fff;font-size:12px;padding:2px 6px;border-radius:6px}
.panel{background:#fff;border-radius:12px;padding:10px}.panel h3{margin:4px 0 8px;font-size:14px}
.row{display:flex;justify-content:space-between;align-items:center;gap:6px;margin:4px 0;font-size:14px}.row button{padding:5px 9px;font-size:13px}
.chk{display:flex;gap:8px;align-items:center}.chk input{width:auto;margin:0}
.chat{flex:1;display:flex;flex-direction:column;min-height:180px}#msgs{flex:1;overflow:auto;font-size:14px}#msgs p{margin:4px 0}#msgs b.t{color:#2f6bff}
#chatForm{display:flex;gap:6px}#chatForm input{margin:0}
footer{display:flex;gap:8px;justify-content:center;padding:10px;background:#fff;border-top:1px solid #e3e6ee;flex-wrap:wrap}
#toast{position:fixed;left:50%;bottom:80px;transform:translateX(-50%);background:#1d2433;color:#fff;padding:10px 16px;border-radius:10px;opacity:0;transition:.3s;pointer-events:none;z-index:9}#toast.show{opacity:1}
@media(max-width:800px){main{flex-direction:column;overflow:auto}#stage{min-height:56vw;flex:none}aside{width:100%}#grid{grid-template-columns:repeat(3,1fr)}footer button{flex:1;padding:10px 6px;font-size:13px}}
/* v2 */
#draw,.fpreview canvas{position:absolute;left:0;top:0;width:100%;height:100%;touch-action:none}
.cbar{display:flex;gap:6px;align-items:center;flex-wrap:wrap}.cbar select{width:auto;margin:0;padding:6px}.cbar .sep{width:1px;height:26px;background:#d5d9e2;margin:0 2px}
.cbar button{padding:8px 10px}.drawtools{display:inline-flex;gap:6px;align-items:center;flex-wrap:wrap}
.modal{position:fixed;inset:0;background:#0006;display:flex;align-items:center;justify-content:center;z-index:20;padding:16px}.modal .card{text-align:left}
.ask{position:fixed;top:14px;left:50%;transform:translateX(-50%);background:#fff;box-shadow:0 6px 24px #0003;border-radius:12px;padding:10px 12px;display:flex;gap:8px;align-items:center;z-index:30;max-width:94vw}.ask .primary{width:auto;margin:0}
.ctl{padding:3px 7px!important;font-size:13px}.mut{background:#ffd9d6!important}
.float{position:fixed;right:16px;bottom:90px;width:340px;max-height:80vh;overflow:auto;background:#fff;border-radius:14px;box-shadow:0 10px 40px #0004;z-index:15;padding:8px;display:flex;flex-direction:column;gap:8px}
.float.inpip{position:static;width:auto;max-height:none;height:100vh;border-radius:0;box-shadow:none}
.fhead{display:flex;justify-content:space-between;align-items:center;cursor:move;user-select:none}.fhead button{padding:4px 8px}
.ftiles{display:grid;grid-template-columns:repeat(auto-fill,minmax(100px,1fr));gap:6px}
.ftile{background:#222;border-radius:8px;overflow:hidden;position:relative}.ftile video{width:100%;aspect-ratio:4/3;object-fit:cover;display:block}
.ftile .nm{position:absolute;left:4px;top:4px;background:#0008;color:#fff;font-size:11px;padding:1px 5px;border-radius:5px}
.ftile .fc{display:flex;gap:4px;padding:4px;background:#333;justify-content:center}
.fpreview{position:relative;background:#111;border-radius:8px;aspect-ratio:16/9;overflow:hidden}.fpreview video{position:absolute;inset:0;width:100%;height:100%;object-fit:contain}
body.pipbody{margin:0;background:#fff}
/* v3: tài khoản, thư viện lớp, ảnh đại diện, giơ tay */
.auto{width:auto!important;margin:0!important}.av{width:36px;height:36px;border-radius:50%;object-fit:cover;background:#dde3ee;flex:none}
.me{display:flex;gap:10px;align-items:center}.dashBody{max-width:1000px;margin:0 auto;padding:16px;overflow:auto;height:calc(100% - 60px)}
.bar{display:flex;justify-content:space-between;align-items:center;gap:8px;flex-wrap:wrap}.bar h2{margin:8px 0}
.filters{display:flex;gap:6px;margin:8px 0;flex-wrap:wrap;background:#eef1f6;padding:4px;border-radius:12px}.filters input{flex:1;min-width:120px;margin:0;padding:7px}.filters .tab{flex:none}
.list .urow{display:flex;align-items:center;gap:10px;background:#fff;border-radius:12px;padding:8px 12px;margin:6px 0}.urow .grow{flex:1;min-width:0}.urow button{padding:6px 10px;font-size:13px}
.role{font-size:12px;padding:2px 8px;border-radius:20px;background:#eef1f6}.role.teacher{background:#e2f6e6}.role.admin{background:#ffe9c7}
.cards{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:12px}
.ccard{background:#fff;border-radius:14px;padding:14px;box-shadow:0 2px 10px #0001;display:flex;flex-direction:column;gap:6px}
.ccard h3{margin:0;font-size:17px}.ccard .topic{color:#2f6bff;font-weight:600;font-size:14px}.ccard .desc{font-size:14px;color:#445;white-space:pre-wrap}
.ccard .acts{display:flex;gap:6px;flex-wrap:wrap;margin-top:auto}.ccard .acts button{padding:7px 10px;font-size:13px}
.live{background:#ff3b30;color:#fff;font-size:12px;padding:2px 8px;border-radius:20px;font-weight:bold}.empty{color:#889;text-align:center;padding:40px 0;grid-column:1/-1}
.card.wide{max-width:520px;max-height:90vh;overflow:auto}textarea{width:100%;padding:11px;border:1px solid #d5d9e2;border-radius:10px;font-size:15px;margin-top:4px;font-family:inherit;min-height:70px}
.picks{max-height:240px;overflow:auto;border:1px solid #e3e6ee;border-radius:10px;padding:6px}.picks label{display:flex;gap:8px;align-items:center;margin:4px 0;color:#222}.picks input{width:auto;margin:0}
.avbig{width:120px;height:120px;border-radius:50%;object-fit:cover;background:#dde3ee;display:block;margin:6px auto}
.tile .avph,.ftile .avph{position:absolute;inset:0;display:flex;align-items:center;justify-content:center;background:#2a2f3a}.tile .avph img,.ftile .avph img{width:46%;aspect-ratio:1;border-radius:50%;object-fit:cover}
.avph .ini{width:46%;aspect-ratio:1;border-radius:50%;background:#2f6bff;color:#fff;display:flex;align-items:center;justify-content:center;font-size:24px;font-weight:bold}
.tile .hand,.ftile .hand{position:absolute;right:5px;top:5px;font-size:20px;animation:bl 1s infinite}
.badge{background:#ff9500;color:#fff;border-radius:20px;padding:1px 8px;font-size:12px}.handrow{background:#fff6e5;border-radius:8px;padding:4px 6px}
#msgs .cmsg{display:flex;gap:6px;align-items:flex-start}#msgs .cmsg .av{width:26px;height:26px;margin-top:4px}
.ccard .who{display:flex;gap:8px;align-items:center;font-size:13px;color:#556}.ccard .who .av{width:24px;height:24px}
.cbar button.hup{background:#ffe1a8}
.stabs{margin:6px 0 10px}.spane h3{margin:6px 0}.filebtn{display:inline-block;background:#e8ebf2;padding:9px 12px;border-radius:10px;cursor:pointer;color:#1d2433;margin:0;font-size:15px}
.logtbl{width:100%;border-collapse:collapse;font-size:13px}.logtbl th,.logtbl td{border-bottom:1px solid #eef0f4;padding:5px 4px;text-align:left;vertical-align:top}.logtbl input,.logtbl select{padding:5px;font-size:13px;margin:0}
.logtbl input.sc{width:64px}.card.xwide{max-width:960px;width:100%}.tblwrap{overflow:auto;max-height:60vh}.absent{color:#d70015}
.ini{background:#2f6bff;color:#fff;display:flex;align-items:center;justify-content:center;font-weight:bold;border-radius:50%}.avph-s{display:inline-flex}
/* App máy tính (Electron): bảng điều khiển nổi không viền, kéo bằng thanh tiêu đề */
body.desktopfloat .fhead{-webkit-app-region:drag;background:#f3f5f9;margin:-8px -8px 0;padding:8px}
body.desktopfloat .fhead button,body.desktopfloat .fhead input{-webkit-app-region:no-drag}
.float .cbar{gap:4px}.float .cbar button{padding:6px 8px;font-size:13px}
/* v4 (XClass): bố cục phòng học cố định – thanh điều khiển luôn ở đáy, thanh bên cuộn riêng */
#room{height:100vh;height:100dvh;overflow:hidden}#room>header,#room>footer{flex:none}
#room main{overflow:hidden}#room aside{overflow-y:auto;overscroll-behavior:contain;padding-right:2px}
#room aside .chat{flex:none;min-height:240px;height:42vh;max-height:420px}
#room footer{position:relative;z-index:5}
@media(max-width:800px){#room{height:auto;min-height:100dvh;overflow:visible}#room main{overflow:visible}#room aside{overflow:visible}#room footer{position:sticky;bottom:0}}
.tile.self video{transform:none}.tile.mirror video,.ftile.mirror video,video.mirror{transform:scaleX(-1)}#lobbyPreview{transform:none}#lobbyPreview.mirror{transform:scaleX(-1)}
.fsbtn{position:absolute;right:10px;top:10px;z-index:3;background:#0008;color:#fff;padding:4px 10px;font-size:18px}
#stage:fullscreen{border-radius:0}#stage.pseudofull{position:fixed;inset:0;z-index:40;border-radius:0}
.netbanner{background:#ff9500;color:#fff;text-align:center;padding:6px;font-weight:600;flex:none}
.mrow{border-bottom:1px solid #f0f2f6;padding:2px 0}.volrow{display:flex;align-items:center;gap:6px;margin:0 0 4px;font-size:12px}.volrow input{margin:0;padding:0;height:18px}.volrow span{width:40px;text-align:right}
.fchat{display:flex;flex-direction:column;gap:4px;border:1px solid #e3e6ee;border-radius:8px;padding:4px}.fmsgs{max-height:200px;min-height:80px;overflow:auto;font-size:13px}.fmsgs .cmsg{display:flex;gap:4px}.fmsgs .cmsg p{margin:2px 0}.fmsgs .av{width:20px;height:20px}
.fchatForm{display:flex;gap:4px}.fchatForm input{margin:0;padding:6px;font-size:14px}.fchatForm button{padding:6px 10px}
.badgegrid{display:grid;grid-template-columns:repeat(auto-fill,minmax(150px,1fr));gap:10px;margin-bottom:20px}
.bcard{background:#fff;border-radius:14px;padding:12px;text-align:center;box-shadow:0 2px 10px #0001}.bcard .bi{font-size:36px}.bcard b{display:block;margin:4px 0}.bcard .hint{font-size:12px}
.pgrid{display:grid;grid-template-columns:1fr 1fr;gap:12px}@media(max-width:700px){.pgrid{grid-template-columns:1fr}}
.psec{background:#f7f8fb;border-radius:12px;padding:10px}.psec h3{margin:2px 0 8px;font-size:15px}.psec .row{font-size:13px}
.chip{display:inline-flex;align-items:center;gap:4px;background:#fff;border:1px solid #e3e6ee;border-radius:20px;padding:3px 9px;margin:3px;font-size:13px}
.chip button{padding:0 4px;background:none;font-size:12px}.sugg{background:#fff6e5;border-radius:8px;padding:6px;margin:6px 0;font-size:13px}
.audit td{font-size:12px}.invrow{display:flex;gap:6px;align-items:center;margin:6px 0}.invrow input{margin:0;font-size:13px;padding:7px}
code{background:#eef1f6;padding:4px 8px;border-radius:6px;font-size:12px;word-break:break-all}.grow{flex:1;min-width:0}