:root{--ink:#1c2430;--mute:#5d6877;--line:#d9dee5;--bg:#f6f7f9;--acc:#14586b;--acc-d:#0e4352;--tint:#e7f1f4;--ok:#1b7f4b;--okbg:#e3f3ea;--warn:#8a5a00;--warnbg:#fff3cf;--bad:#b42323;--badbg:#fde8e8}
*{box-sizing:border-box}
body{margin:0;font:16px/1.55 "Segoe UI",system-ui,-apple-system,sans-serif;color:var(--ink);background:var(--bg)}
h1{font-size:1.5rem;margin:0 0 4px}h2{font-size:1.1rem;margin:0 0 8px}
p{margin:0 0 10px}.h{color:var(--mute);font-size:.92rem}.err{color:var(--bad);min-height:1.4em;margin:8px 0 0}
:focus-visible{outline:3px solid #e0a100;outline-offset:2px}
[hidden]{display:none!important}

/* header */
.top{background:var(--acc);color:#fff;display:flex;align-items:center;gap:22px;padding:10px 24px;flex-wrap:wrap}
.brand{display:flex;align-items:center;gap:8px;color:#fff;text-decoration:none;font-weight:700;font-size:1.15rem}
.logo{display:inline-grid;place-items:center}
.top nav{display:flex;gap:4px;flex:1}
.top nav a{color:#d7e8ee;text-decoration:none;padding:6px 12px;border-radius:6px}
.top nav a:hover{background:rgba(255,255,255,.12)}
.top nav a.on{background:#fff;color:var(--acc);font-weight:600}
.who{margin-left:auto;display:flex;align-items:center;gap:12px;font-size:.95rem}
main{max-width:1100px;margin:26px auto;padding:0 20px;min-height:60vh}
footer{text-align:center;color:var(--mute);font-size:.85rem;padding:26px 0}

/* controls */
.btn{background:var(--acc);color:#fff;border:1px solid var(--acc);border-radius:6px;padding:9px 18px;font:inherit;cursor:pointer;text-decoration:none;display:inline-block}
.btn:hover:not(:disabled){background:var(--acc-d)}
.btn.alt{background:#fff;color:var(--acc)}.btn.alt:hover:not(:disabled){background:var(--tint)}
.btn.danger{background:#fff;color:var(--bad);border-color:var(--bad)}.btn.danger:hover:not(:disabled){background:var(--badbg)}
.btn.sm{padding:4px 10px;font-size:.88rem}
.btn:disabled{opacity:.5;cursor:not-allowed}
.btn.mk{background:var(--warnbg);border-color:#e0a100;color:var(--warn)}
label{display:block;font-weight:600;margin:12px 0 4px;font-size:.92rem}
label.chk{display:inline-flex;align-items:center;gap:8px;font-weight:500;margin:6px 18px 6px 0}
input,textarea,select{width:100%;padding:9px 10px;border:1px solid #b9c2cd;border-radius:6px;font:inherit;background:#fff;color:inherit}
input[type=checkbox]{width:auto;accent-color:var(--acc)}
textarea{font:14px/1.5 Consolas,"Courier New",monospace;resize:vertical}
.hint{color:var(--mute);font-size:.85rem;margin:4px 0 0}
.card{background:#fff;border:1px solid var(--line);border-radius:8px;padding:18px 22px;margin-bottom:14px}
.empty{text-align:center;color:var(--mute);padding:28px}
.auth{max-width:400px;margin:9vh auto 0}
.auth .btn{width:100%;margin-top:16px;padding:11px}
.row{display:flex;justify-content:space-between;align-items:flex-start;gap:12px;flex-wrap:wrap;margin-bottom:14px}
.acts{display:flex;gap:6px;flex-wrap:wrap}
.grid{display:grid;grid-template-columns:repeat(3,1fr);gap:0 18px}
.cols{display:grid;grid-template-columns:1.6fr 1fr;gap:22px;align-items:start}
.stack>.card{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap}
.stack h2{margin:0}
.sub{color:var(--mute);font-size:.9rem}
.back{background:none;border:0;color:var(--acc);cursor:pointer;font:inherit;padding:0;margin-bottom:10px}

/* tables */
.tw{overflow-x:auto;background:#fff;border:1px solid var(--line);border-radius:8px;margin-bottom:14px}
table{width:100%;border-collapse:collapse;font-size:.93rem}
th{text-align:left;font-weight:600;color:var(--mute);font-size:.84rem;padding:9px 12px;border-bottom:1px solid var(--line);background:#fafbfc;white-space:nowrap}
td{padding:9px 12px;border-bottom:1px solid #eef0f3;vertical-align:middle}
tr:last-child td{border-bottom:0}
.pill{display:inline-block;padding:2px 10px;border-radius:99px;font-size:.8rem;font-weight:600;background:#eceff3;color:var(--mute);white-space:nowrap}
.pill.ok{background:var(--okbg);color:var(--ok)}.pill.warn{background:var(--warnbg);color:var(--warn)}
.pill.bad{background:var(--badbg);color:var(--bad)}.pill.live{background:var(--tint);color:var(--acc)}

/* alerts feed */
.feed{list-style:none;margin:0;padding:0;max-height:70vh;overflow:auto}
.feed li{background:#fff;border:1px solid var(--line);border-left:4px solid #e0a100;border-radius:6px;padding:9px 12px;margin-bottom:8px;font-size:.93rem}
.feed li.stop{border-left-color:var(--bad)}
.feed time{color:var(--mute);font-size:.82rem;margin-right:6px}
.feed .acts{margin-top:6px}

/* stats + bars */
.stats{display:grid;grid-template-columns:repeat(5,1fr);gap:12px;margin-bottom:16px}
.stat{background:#fff;border:1px solid var(--line);border-radius:8px;padding:12px 14px}
.stat b{display:block;font-size:1.5rem;line-height:1.2}.stat span{color:var(--mute);font-size:.85rem}
.qrow{display:grid;grid-template-columns:1fr 180px 90px;gap:14px;align-items:center;padding:8px 0;border-bottom:1px solid #eef0f3;font-size:.93rem}
.bar{height:10px;background:#e4e8ed;border-radius:9px;overflow:hidden}.bar i{display:block;height:100%;background:var(--acc)}
.bar.low i{background:var(--bad)}

/* dialogs + toasts */
dialog.dlg{border:0;border-radius:10px;padding:0;max-width:min(520px,92vw);width:100%;box-shadow:0 12px 40px rgba(0,0,0,.28);color:var(--ink)}
dialog.dlg.wide{max-width:min(640px,94vw)}
dialog.dlg::backdrop{background:rgba(20,30,40,.55)}
dialog.dlg h2{padding:16px 22px;margin:0;border-bottom:1px solid var(--line)}
.dbody{padding:16px 22px;max-height:65vh;overflow:auto}
.dact{display:flex;justify-content:flex-end;gap:10px;padding:12px 22px;border-top:1px solid var(--line);background:#fafbfc}
.dbody img{max-width:100%;border-radius:6px;display:block}
.rules{margin:8px 0 14px;padding-left:20px}.rules li{margin-bottom:4px}
.ins{background:var(--tint);border-radius:6px;padding:10px 12px;white-space:pre-wrap}
#toasts{position:fixed;right:16px;bottom:16px;display:flex;flex-direction:column;gap:8px;z-index:100;max-width:min(380px,90vw)}
.toast{background:var(--ink);color:#fff;padding:10px 16px;border-radius:8px;box-shadow:0 4px 14px rgba(0,0,0,.25)}
.toast.bad{background:var(--bad)}.toast.ok{background:var(--ok)}

/* student exam */
.exam{min-height:100vh;display:flex;flex-direction:column;user-select:none;-webkit-user-select:none}
.xbar{background:var(--acc);color:#fff;display:flex;align-items:center;gap:16px;padding:10px 24px;position:sticky;top:0;z-index:5}
.xbar b{flex:1;font-size:1.05rem;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.xbar .pill{background:rgba(255,255,255,.18);color:#fff}
.xbar .btn{background:#fff;color:var(--acc);border-color:#fff}
.timer{font-size:1.5rem;font-weight:700;font-variant-numeric:tabular-nums;min-width:5.5ch;text-align:center;padding:2px 12px;border-radius:6px;background:rgba(255,255,255,.14)}
.timer.warn{background:#e0a100;color:#1c2430}.timer.bad{background:var(--bad);color:#fff}
.offline{background:var(--warnbg);color:var(--warn);padding:8px 24px;font-weight:600;border-bottom:1px solid #e6d27a}
.xbody{flex:1;display:grid;grid-template-columns:1fr 280px;gap:24px;max-width:1180px;width:100%;margin:0 auto;padding:24px}
.qbox{background:#fff;border:1px solid var(--line);border-radius:10px;padding:24px 28px}
.qno{color:var(--mute);font-weight:600;margin-bottom:6px}
.qtext{font-size:1.28rem;line-height:1.5;white-space:pre-wrap;max-width:68ch;margin-bottom:18px}
.opts{display:grid;gap:10px;margin-bottom:22px}
.opt{display:flex;align-items:center;gap:14px;text-align:left;width:100%;background:#fff;border:1.5px solid #b9c2cd;border-radius:8px;padding:12px 14px;font:inherit;font-size:1.04rem;cursor:pointer;color:inherit}
.opt:hover{border-color:var(--acc)}
.opt .ltr{flex:none;display:grid;place-items:center;width:30px;height:30px;border-radius:50%;border:1.5px solid #8f9bab;font-weight:700;font-size:.9rem}
.opt.on{background:var(--tint);border-color:var(--acc)}.opt.on .ltr{background:var(--acc);border-color:var(--acc);color:#fff}
.qnav{display:flex;gap:10px;flex-wrap:wrap}.qnav .btn:nth-child(2){margin-right:auto}
.side{background:#fff;border:1px solid var(--line);border-radius:10px;padding:16px;align-self:start;position:sticky;top:76px}
.pal{display:grid;grid-template-columns:repeat(5,1fr);gap:6px;margin-bottom:12px}
.pb{height:38px;border:1px solid #b9c2cd;border-radius:6px;background:#fff;font:inherit;cursor:pointer;color:inherit}
.pb.ans{background:var(--acc);border-color:var(--acc);color:#fff}
.pb.mk{box-shadow:inset 0 0 0 3px #e0a100}
.pb.cur{outline:2px solid var(--ink);outline-offset:2px}
.legend{display:flex;flex-wrap:wrap;gap:4px 14px;font-size:.82rem;color:var(--mute);margin-bottom:14px}
.cam{width:100%;border-radius:8px;background:#222;aspect-ratio:4/3;object-fit:cover;transform:scaleX(-1)}
.camcap{font-size:.8rem;color:var(--mute);margin-top:4px}
.result{max-width:520px;margin:9vh auto 0;text-align:center}
.result .big{font-size:2.6rem;font-weight:700;margin:6px 0}

@media(max-width:900px){.cols,.xbody{grid-template-columns:1fr}.side{position:static}.stats{grid-template-columns:repeat(2,1fr)}.grid{grid-template-columns:1fr 1fr}.qrow{grid-template-columns:1fr}}
@media(max-width:560px){.grid{grid-template-columns:1fr}.top{padding:10px 14px}.xbar{padding:10px 14px;flex-wrap:wrap}.qbox{padding:18px}}
@media print{body *{visibility:hidden}#creds,#creds *{visibility:visible}#creds{position:absolute;left:0;top:0;width:100%}#creds .acts{display:none}}
@media(prefers-reduced-motion:reduce){*{transition:none!important;animation:none!important}}