:root {
  --navy: #0c2b7a; --blue: #1d4fc4; --sky: #eaf1fd; --sky2: #d5e2fb; --line: #d3dcef;
  --red: #d6273c; --red2: #fdecef; --green: #138a64; --green2: #e6f6f0; --amber: #c77700; --amber2: #fff4dc;
  --ink: #1f2637; --mut: #5d6679; --bg: #f4f6fb; --card: #fff; --radius: 10px;
}
* { box-sizing: border-box; }
.connection-bar { display:flex; align-items:center; gap:12px; flex-wrap:wrap; padding:8px 20px; background:#fff; border-bottom:1px solid var(--line); font-size:12px; }
.join-link { display:flex; gap:12px; align-items:center; flex-wrap:wrap; padding:12px; background:var(--sky); margin:8px 0; border-radius:8px; }
.join-link > span { color:var(--navy); font-size:20px; font-weight:bold; overflow-wrap:anywhere; }
#password-form { max-width:420px; }
.classroom-wrap { max-width:1280px; margin:18px auto 0; padding:0 16px; }
.classroom-grid { display:grid; grid-template-columns:repeat(auto-fit,minmax(300px,1fr)); gap:16px; }
.new-class-form { display:flex; gap:10px; flex-wrap:wrap; align-items:center; }
.new-class-form input { flex:1; min-width:200px; }
.room-card-heading,.room-banner { display:flex; justify-content:space-between; gap:12px; flex-wrap:wrap; }
.room-card-heading h2 { max-width:80%; }
.room-stats { display:flex; justify-content:space-between; gap:8px; padding:12px 0; }
.room-stats span { font-size:12px; color:var(--mut); }
.room-stats b { display:block; font-size:25px; color:var(--navy); }
.room-actions { display:flex; align-items:center; gap:8px; flex-wrap:wrap; }
.room-banner p { margin:5px 0 0; }
html, body { margin: 0; }
body { font-family: "Microsoft YaHei", "PingFang SC", "Noto Sans SC", sans-serif; color: var(--ink); background: var(--bg); font-size: 15px; line-height: 1.6; }
button, input, select, textarea { font: inherit; }
.top { position: sticky; top: 0; z-index: 20; background: var(--navy); color: #fff; padding: 0 16px; height: 50px; display: flex; align-items: center; gap: 10px; box-shadow: 0 2px 8px rgba(0,0,0,.15); }
.top h1 { font-size: 17px; margin: 0; font-weight: 800; letter-spacing: 1px; display: flex; align-items: center; gap: 8px; }
.top .sp { flex: 1; }
.top .who { font-size: 13px; opacity: .9; }
.top button { background: rgba(255,255,255,.15); color: #fff; border: 1px solid rgba(255,255,255,.35); border-radius: 6px; padding: 3px 10px; cursor: pointer; font-size: 13px; }
.tabs { display: flex; gap: 4px; padding: 8px 16px 0; background: var(--card); border-bottom: 1px solid var(--line); position: sticky; top: 50px; z-index: 19; overflow-x: auto; }
.tabs button { border: 0; background: none; padding: 9px 14px; font-weight: 700; color: var(--mut); border-bottom: 3px solid transparent; cursor: pointer; white-space: nowrap; }
.tabs button.on { color: var(--navy); border-bottom-color: var(--red); }
main { max-width: 980px; margin: 0 auto; padding: 16px; }
.wide main { max-width: 1280px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 16px; margin-bottom: 14px; }
.card h2 { margin: 0 0 10px; font-size: 17px; color: var(--navy); display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.card h3 { margin: 12px 0 6px; font-size: 15px; color: var(--navy); }
.muted { color: var(--mut); font-size: 13px; }
.tag { display: inline-block; padding: 0 8px; border-radius: 10px; font-size: 12px; font-weight: 700; background: var(--sky); color: var(--navy); line-height: 20px; white-space: nowrap; }
.tag.red { background: var(--red2); color: var(--red); } .tag.green { background: var(--green2); color: var(--green); } .tag.amber { background: var(--amber2); color: var(--amber); } .tag.navy { background: var(--navy); color: #fff; }
.btn { background: var(--navy); color: #fff; border: 0; border-radius: 8px; padding: 9px 18px; font-weight: 700; cursor: pointer; }
.btn:hover { filter: brightness(1.1); } .btn:disabled { opacity: .5; cursor: default; }
.btn.red { background: var(--red); } .btn.ghost { background: #fff; color: var(--navy); border: 1px solid var(--navy); } .btn.sm { padding: 4px 10px; font-size: 13px; }
label.f { display: block; font-weight: 700; color: var(--navy); font-size: 13px; margin: 10px 0 4px; }
input[type=text], input[type=password], input[type=number], select, textarea { width: 100%; border: 1px solid var(--line); border-radius: 8px; padding: 8px 10px; background: #fff; color: var(--ink); }
textarea { min-height: 70px; resize: vertical; }
input:focus, textarea:focus, select:focus { outline: 2px solid var(--sky2); border-color: var(--blue); }
.row { display: flex; gap: 10px; flex-wrap: wrap; } .row > * { flex: 1; min-width: 140px; }
.opt { display: flex; gap: 8px; align-items: flex-start; padding: 7px 10px; border: 1px solid var(--line); border-radius: 8px; margin: 6px 0; cursor: pointer; background: #fff; }
.opt input { margin-top: 5px; } .opt:hover { border-color: var(--blue); }
.q { border-top: 1px dashed var(--line); padding-top: 12px; margin-top: 12px; } .q:first-of-type { border-top: 0; margin-top: 0; padding-top: 0; }
.qh { font-weight: 700; } .qh .tag { margin-right: 6px; }
.msg { border-radius: 8px; padding: 10px 12px; margin: 10px 0; font-size: 14px; }
.msg.ok { background: var(--green2); color: var(--green); } .msg.err { background: var(--red2); color: var(--red); } .msg.info { background: var(--sky); color: var(--navy); } .msg.warn { background: var(--amber2); color: var(--amber); }
.fb { display: grid; gap: 8px; margin: 10px 0; }
.fb > div { border-radius: 8px; padding: 9px 12px; }
.fb .ev { background: var(--green2); } .fb .mi { background: var(--red2); } .fb .qu { background: var(--navy); color: #fff; font-weight: 700; }
.fb b { display: block; font-size: 12px; opacity: .8; margin-bottom: 2px; }
.fb ul { margin: 0; padding-left: 18px; }
.case { background: var(--sky); border-radius: 8px; padding: 10px 12px; }
.case ul { margin: 4px 0; padding-left: 18px; }
.task { border: 1px solid var(--line); border-radius: 10px; margin: 10px 0; overflow: hidden; }
.task > summary { list-style: none; cursor: pointer; padding: 10px 12px; font-weight: 800; color: var(--navy); background: #fafcff; display: flex; gap: 8px; align-items: center; }
.task > summary::-webkit-details-marker { display: none; }
.task[open] > summary { border-bottom: 1px solid var(--line); }
.task .body { padding: 4px 12px 12px; }
.task.focus > summary { background: var(--red2); color: var(--red); }
.checks { display: flex; gap: 6px; flex-wrap: wrap; margin-top: 6px; }
.score { font-size: 34px; font-weight: 900; color: var(--navy); }
.grid { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 12px 14px; }
.stat b { display: block; font-size: 26px; color: var(--navy); } .stat span { color: var(--mut); font-size: 13px; }
table.t { width: 100%; border-collapse: collapse; font-size: 14px; background: #fff; }
.t th, .t td { border: 1px solid var(--line); padding: 6px 8px; text-align: left; vertical-align: top; }
.t th { background: var(--sky); color: var(--navy); white-space: nowrap; }
.t tr.click { cursor: pointer; } .t tr.click:hover td { background: #f7f9ff; }
.cell { display: inline-block; min-width: 38px; text-align: center; border-radius: 6px; padding: 0 4px; font-weight: 700; font-size: 13px; }
.c-hi { background: var(--green2); color: var(--green); } .c-mid { background: var(--amber2); color: var(--amber); } .c-lo { background: var(--red2); color: var(--red); } .c-na { background: #eef0f5; color: #999; }
.alert { background: var(--red2); border: 1px solid #f2b6bf; border-left: 5px solid var(--red); border-radius: 8px; padding: 8px 12px; margin: 6px 0; display: flex; gap: 10px; align-items: center; }
.alert .sp { flex: 1; }
.chartbox { position: relative; }
.chartbox svg { width: 100%; height: auto; display: block; }
.chart-title { justify-content:space-between; align-items:flex-start !important; }
.chart-title span { flex:1; min-width:150px; }
.chart-title .dl { flex-shrink:0; }
.drawer { position: fixed; inset: 0; background: rgba(10,20,50,.45); z-index: 50; display: flex; justify-content: flex-end; }
.drawer .panel { width: min(760px, 100%); background: var(--bg); height: 100%; overflow: auto; padding: 16px; }
.hidden { display: none !important; }
.center { text-align: center; }
.login { max-width: 452px; margin: 24px auto; padding: 0 16px; }
.brand { text-align: center; margin: 30px 0 10px; color: var(--navy); }
.brand .t1 { font-size: 26px; font-weight: 900; letter-spacing: 2px; }
.brand .t2 { color: var(--red); font-weight: 700; letter-spacing: 3px; }
.ecg { display: block; margin: 6px auto; }
.pre { white-space: pre-wrap; }
.kv { display: grid; grid-template-columns: 90px 1fr; gap: 4px 10px; font-size: 14px; }
.kv > b { color: var(--navy); }
.toast { position: fixed; bottom: 20px; left: 50%; transform: translateX(-50%); background: var(--ink); color: #fff; padding: 8px 16px; border-radius: 8px; z-index: 99; font-size: 14px; }
.top button, .top .who { white-space: nowrap; }
@media (max-width: 600px) { main { padding: 10px; } .card { padding: 12px; } .top h1 { font-size: 15px; } .top h1 .sub { display: none; } .top .who { font-size: 12px; } }


.entry { max-width:920px; margin:0 auto; padding:48px 24px 28px; }
.entry-brand { text-align:center; margin:8px 0 32px; }
.entry-brand .eyebrow { font-size:13px; letter-spacing:3px; color:var(--red); font-weight:700; }
.entry-brand h1 { margin:8px 0; font-size:38px; color:var(--navy); }
.entry-brand p { color:var(--mut); margin:8px 0; }
.entry-roles { display:grid; grid-template-columns:1fr 1fr; gap:20px; }
.role-card { display:flex; flex-direction:column; padding:28px; background:#fff; border:1px solid var(--line); border-radius:16px; box-shadow:0 10px 28px rgba(12,43,122,.04); }
.role-card .role-icon { width:48px; height:48px; display:grid; place-items:center; background:var(--sky); color:var(--blue); border-radius:12px; font-size:22px; font-weight:800; }
.role-card.teacher .role-icon { background:var(--red2); color:var(--red); }
.role-card h2 { margin:16px 0 6px; font-size:23px; color:var(--navy); }
.role-card p { margin:0 0 18px; color:var(--mut); min-height:52px; }
.role-card .btn { display:block; text-align:center; text-decoration:none; margin-top:auto; }
.entry-note { margin:22px 0 0; font-size:13px; text-align:center; color:var(--mut); }
.entry-status { text-align:center; margin-top:24px; }
.top .role-switch { color:#fff; border:1px solid rgba(255,255,255,.35); border-radius:6px; padding:3px 8px; font-size:13px; text-decoration:none; white-space:nowrap; }
.top .who { overflow:hidden; text-overflow:ellipsis; }
@media(max-width:600px) { .entry { padding:26px 16px; } .entry-brand { margin-bottom:24px; } .entry-brand h1 { font-size:30px; } .entry-roles { grid-template-columns:1fr; gap:14px; } .role-card { padding:22px; } .role-card p { min-height:0; } .top { gap:6px; padding:0 10px; } .top h1 { letter-spacing:0; } .top .who { max-width:76px; } .role-teacher #badges,.role-teacher .top #student-join-top { display:none; } .top .role-switch { font-size:12px; padding:3px 6px; } }