:root{--ink:#111;--muted:#666;--line:#d9d9d9;--bg:#f5f5f4;--panel:#fff;--accent:#111;--danger:#b00020}
*{box-sizing:border-box}
html,body{margin:0;height:100%}
body{font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Roboto,Helvetica,Arial,sans-serif;color:var(--ink);background:var(--bg);-webkit-text-size-adjust:100%}
a{color:var(--ink)}
.brand{display:flex;align-items:center;gap:10px;font-weight:700;letter-spacing:.02em}
.brand .mark{width:30px;height:30px;border:2px solid var(--ink);display:grid;place-items:center;font-family:Georgia,"Times New Roman",serif;font-size:18px}
.brand small{display:block;font-weight:400;color:var(--muted);font-size:12px;letter-spacing:0}
header.top{display:flex;align-items:center;justify-content:space-between;padding:10px 16px;background:var(--panel);border-bottom:1px solid var(--line);gap:10px}
footer.foot{text-align:center;color:var(--muted);font-size:12px;padding:12px 8px;border-top:1px solid var(--line);background:var(--panel)}
.page{min-height:100%;display:flex;flex-direction:column}
.center{flex:1;display:flex;align-items:flex-start;justify-content:center;padding:32px 16px}
.card{background:var(--panel);border:1px solid var(--line);border-radius:10px;padding:24px;width:100%;max-width:440px}
.card.wide{max-width:820px}
h1{font-size:22px;margin:0 0 6px}
h2{font-size:17px;margin:20px 0 10px}
p.lead{color:var(--muted);margin:0 0 18px;line-height:1.45}
label{display:block;font-size:13px;font-weight:600;margin:12px 0 6px}
input,select,textarea{font:inherit;font-size:16px;width:100%;padding:10px 12px;border:1px solid #bbb;border-radius:8px;background:#fff;color:var(--ink)}
input:focus,select:focus,textarea:focus{outline:2px solid var(--ink);outline-offset:-1px}
button,.btn{font:inherit;font-size:15px;border:1px solid var(--ink);background:var(--ink);color:#fff;padding:10px 16px;border-radius:8px;cursor:pointer;text-decoration:none;display:inline-flex;align-items:center;justify-content:center;gap:6px;white-space:nowrap}
button.ghost,.btn.ghost{background:#fff;color:var(--ink)}
button.danger{background:var(--danger);border-color:var(--danger)}
button:disabled{opacity:.45;cursor:default}
button.block{width:100%;margin-top:18px}
.err{color:var(--danger);font-size:14px;margin-top:10px;min-height:1em}
.row{display:flex;gap:10px;flex-wrap:wrap;align-items:center}
.muted{color:var(--muted)}
table.rooms{width:100%;border-collapse:collapse;font-size:14px}
table.rooms td,table.rooms th{border-bottom:1px solid var(--line);padding:10px 6px;text-align:left;vertical-align:middle}
.code{font-family:ui-monospace,Menlo,Consolas,monospace;font-size:16px;letter-spacing:.12em;font-weight:700}
.hidden{display:none!important}

/* ---------- Room ---------- */
body.room{overflow:hidden}
.app{height:100%;height:100dvh;display:flex;flex-direction:column}
.app header.top{padding:6px 12px}
.roomtitle{font-weight:700;font-size:15px;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.roomtitle small{display:block;font-weight:400;color:var(--muted);font-size:12px}
.main{flex:1;min-height:0;display:grid;grid-template-columns:minmax(0,1fr) 330px;gap:8px;padding:8px}
.left{display:flex;flex-direction:column;gap:8px;min-height:0}
.right{display:flex;flex-direction:column;gap:8px;min-height:0}
.panel{background:var(--panel);border:1px solid var(--line);border-radius:10px;display:flex;flex-direction:column;min-height:0;overflow:hidden}
.panel>.ph{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:6px 10px;border-bottom:1px solid var(--line);font-size:13px;font-weight:700;text-transform:uppercase;letter-spacing:.06em}
.panel>.ph .tools{display:flex;gap:6px;align-items:center;text-transform:none;letter-spacing:0;font-weight:400;flex-wrap:wrap}
.panel>.ph button,.panel>.ph select{padding:5px 10px;font-size:13px;width:auto}
.material{flex:3}
.board{flex:1.3;min-height:150px}
.pdfwrap{flex:1;overflow:auto;background:#e9e9e7;display:flex;justify-content:center;align-items:flex-start;padding:8px;-webkit-overflow-scrolling:touch}
.pdfwrap canvas{background:#fff;box-shadow:0 1px 4px rgba(0,0,0,.2);max-width:none}
.pdfempty{margin:auto;color:var(--muted);text-align:center;padding:20px;font-size:14px}
.pageinfo{font-size:13px;min-width:70px;text-align:center}
.boardtext{flex:1;border:0;border-radius:0;resize:none;font-size:20px;line-height:1.45;padding:12px 14px;white-space:pre-wrap;overflow:auto;font-family:"Times New Roman",Times,serif}
.boardtext:focus{outline:none}
div.boardtext{color:var(--ink)}
.videos{display:grid;grid-template-columns:1fr 1fr;gap:6px;padding:6px;overflow:auto}
.tile{position:relative;background:#222;border-radius:8px;overflow:hidden;aspect-ratio:4/3}
.tile video{position:absolute;inset:0;width:100%;height:100%;object-fit:cover;display:block;background:#222}
#shareView{width:100%;height:100%;object-fit:contain;background:#111}
.pdfwrap.sharing{padding:0;background:#111;align-items:stretch}
.tile.screen video,.tile.local.screen video{object-fit:contain}
.tile.local:not(.screen) video{transform:scaleX(-1)}
.tile .nm{position:absolute;left:6px;bottom:6px;background:rgba(0,0,0,.65);color:#fff;font-size:12px;padding:2px 7px;border-radius:5px;max-width:calc(100% - 12px);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.tile .av{position:absolute;inset:0;display:none;place-items:center;color:#fff;font-size:30px;font-weight:700;background:#333}
.tile.novideo .av{display:grid}
.tile .acts{position:absolute;right:4px;top:4px;display:flex;gap:4px}
.tile .acts button{padding:3px 7px;font-size:11px;background:rgba(255,255,255,.92);color:#111;border-color:#fff}
.tile.teacher{grid-column:1/-1}
.tile .tap{position:absolute;inset:auto 6px 30px 6px;font-size:12px}
.chat{flex:1;min-height:160px}
.msgs{flex:1;overflow:auto;padding:8px 10px;font-size:14px;line-height:1.4}
.msgs .m{margin:0 0 6px}
.msgs .m b{font-weight:700}
.msgs .m.t b{text-decoration:underline}
.chatform{display:flex;gap:6px;padding:6px;border-top:1px solid var(--line)}
.chatform input{padding:8px 10px}
.chatform button{padding:8px 12px}
.controls{display:flex;justify-content:center;gap:8px;padding:8px;background:var(--panel);border-top:1px solid var(--line);flex-wrap:wrap}
.controls button{min-width:92px}
.controls button.off{background:#fff;color:var(--danger);border-color:var(--danger)}
.tabs{display:none}
.badge{display:inline-block;width:8px;height:8px;border-radius:50%;background:var(--danger);margin-left:4px;vertical-align:middle}
.toast{position:fixed;left:50%;top:60px;transform:translateX(-50%);background:#111;color:#fff;padding:10px 16px;border-radius:8px;font-size:14px;z-index:50;max-width:90vw;text-align:center}
.overlay{position:fixed;inset:0;background:rgba(0,0,0,.45);display:flex;align-items:center;justify-content:center;z-index:40;padding:16px}
.overlay .card{max-height:85vh;overflow:auto}
.hublist{max-height:50vh;overflow:auto;border:1px solid var(--line);border-radius:8px}
.hublist button{display:block;width:100%;text-align:left;background:#fff;color:#111;border:0;border-bottom:1px solid var(--line);border-radius:0;padding:9px 12px;font-size:14px;white-space:normal}
.hublist button:hover{background:#f0f0f0}
.hublist .wk{padding:8px 12px;background:#f3f3f3;font-weight:700;font-size:13px}

@media (max-width:820px){
  .main{grid-template-columns:1fr;grid-template-rows:auto auto minmax(0,1fr);padding:6px;gap:6px}
  .right,.left{display:contents}
  .vpanel{order:1}
  .tabs{order:2;display:flex;gap:4px}
  .tabs button{flex:1;padding:8px 4px;font-size:14px;background:#fff;color:#111}
  .tabs button.on{background:#111;color:#fff}
  .material,.board,.chat{order:3;display:none}
  .material.on,.board.on,.chat.on{display:flex}
  .board{min-height:0}
  .videos{display:flex;overflow-x:auto;padding:5px}
  .tile{flex:0 0 auto;width:112px;aspect-ratio:4/3}
  .tile.teacher{width:160px}
  .tile .nm{font-size:11px;left:4px;bottom:4px}
  .tile .av{font-size:22px}
  .vpanel>.ph{display:none}
  .controls{gap:6px;padding:6px}
  .controls button{min-width:0;flex:1;padding:9px 6px;font-size:14px}
  .boardtext{font-size:18px}
  .hide-sm{display:none!important}
}