/* ============ 设计变量 ============ */
:root {
  --brand: #1d5f8a;
  --brand-2: #164a6c;
  --brand-soft: #e8f1f7;
  --gold: #d99a2b;
  --gold-soft: #fdf6e7;
  --ink: #1b2430;
  --ink-soft: #5d6a7a;
  --bg: #f3f5f8;
  --card: #ffffff;
  --line: #e5e9ef;
  --green: #1f9d63;
  --green-soft: #eaf7f0;
  --red: #c0392b;
  --red-soft: #fbecea;
  --radius: 16px;
  --radius-sm: 11px;
  --shadow: 0 1px 2px rgba(20, 28, 46, .04), 0 6px 18px rgba(20, 28, 46, .06);
  --topbar-h: 58px;
  --sidebar-w: 218px;
  --maxw: 1040px;
  --ease: cubic-bezier(.22, .61, .36, 1);
}
html[data-theme="dark"] {
  --ink: #e8ebf2; --ink-soft: #9aa4b6; --bg: #14171f; --card: #1c2029;
  --line: #2b3140; --brand-soft: #16303f; --gold-soft: #2a2415;
  --green-soft: #14291f; --red-soft: #2e1c1a;
  --shadow: 0 1px 2px rgba(0, 0, 0, .3), 0 8px 24px rgba(0, 0, 0, .35);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: var(--ink); background: var(--bg); line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3, h4 { margin: 0; font-weight: 800; letter-spacing: .2px; }
button { font: inherit; cursor: pointer; }
a { color: var(--brand); }
[hidden] { display: none !important; }

/* ============ 登录 / 申请 / 初始化 ============ */
.auth {
  min-height: 100vh; min-height: 100dvh;
  display: grid; grid-template-columns: 1.05fr .95fr;
  background: var(--bg);
}
.auth-side {
  position: relative; overflow: hidden;
  padding: 44px 48px;
  display: flex; flex-direction: column; justify-content: space-between;
  color: #fff;
  background: linear-gradient(145deg, #1d5f8a 0%, #123b57 55%, #0e2e44 100%);
}
.auth-side::after {
  content: ""; position: absolute; right: -120px; bottom: -140px;
  width: 380px; height: 380px; border-radius: 50%;
  background: radial-gradient(circle at 30% 30%, rgba(217, 154, 43, .45), transparent 62%);
}
.auth-side .logo { display: flex; align-items: center; gap: 12px; font-weight: 900; letter-spacing: 1px; }
.auth-side .logo i {
  width: 42px; height: 42px; border-radius: 12px; background: #fff; color: var(--brand);
  display: grid; place-items: center; font-style: normal; font-size: 22px; font-weight: 900;
}
.auth-side h2 { font-size: 34px; line-height: 1.35; margin: 0 0 14px; }
.auth-side p { color: rgba(255, 255, 255, .78); font-size: 14px; max-width: 30em; margin: 0; }
.auth-side ul { margin: 26px 0 0; padding: 0; list-style: none; display: grid; gap: 10px; font-size: 13.5px; color: rgba(255, 255, 255, .9); }
.auth-side li::before { content: "✓"; color: var(--gold); font-weight: 900; margin-right: 9px; }
.auth-foot { font-size: 11.5px; color: rgba(255, 255, 255, .55); position: relative; z-index: 1; }

.auth-main { display: flex; align-items: center; justify-content: center; padding: 30px 20px; }
.auth-card { width: 100%; max-width: 430px; background: var(--card); border: 1px solid var(--line); border-radius: 20px; padding: 30px 30px 26px; box-shadow: 0 20px 50px rgba(16, 34, 50, .10); }
.auth-card h3 { font-size: 22px; margin-bottom: 4px; }
.auth-card .sub { color: var(--ink-soft); font-size: 12.5px; margin: 0 0 20px; }
.auth-card .field { margin-bottom: 13px; }
.auth-card label { display: block; font-size: 12px; font-weight: 700; color: var(--ink-soft); margin-bottom: 5px; }
.auth-card input, .auth-card textarea, .auth-card select {
  width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px;
  background: var(--bg); color: var(--ink); font-size: 14px; outline: none;
}
.auth-card input:focus, .auth-card textarea:focus { border-color: var(--brand); background: var(--card); }
.auth-card textarea { min-height: 74px; resize: vertical; }
.auth-card .btn { width: 100%; margin-top: 4px; }
.auth-card .alt { margin: 14px 0 0; font-size: 12.5px; color: var(--ink-soft); text-align: center; }
.auth-card .alt button { border: 0; background: none; color: var(--brand); font-weight: 700; padding: 0 4px; }
.auth-card .err { margin: 10px 0 0; font-size: 12.5px; color: var(--red); min-height: 18px; }
.auth-card .ok { margin: 10px 0 0; font-size: 12.5px; color: var(--green); }
.auth-note { margin-top: 14px; padding: 10px 12px; border-radius: 10px; background: var(--gold-soft); font-size: 12px; color: #8a5a1e; }

/* ============ 主体布局 ============ */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; justify-content: space-between; gap: 12px;
  height: var(--topbar-h); padding: 0 18px; color: #fff;
  background: linear-gradient(120deg, var(--brand), var(--brand-2));
  box-shadow: 0 4px 18px rgba(13, 44, 64, .22);
}
.brand { display: flex; align-items: center; gap: 11px; min-width: 0; }
.brand-mark {
  width: 38px; height: 38px; flex: 0 0 38px; border-radius: 11px;
  background: #fff; color: var(--brand); font-weight: 900; font-size: 20px;
  display: grid; place-items: center;
}
.brand-text h1 { font-size: 16px; line-height: 1.15; }
.brand-text p { margin: 1px 0 0; font-size: 11px; opacity: .82; }
.top-actions { display: flex; align-items: center; gap: 9px; }
.avatar {
  width: 32px; height: 32px; flex: 0 0 auto; border-radius: 50%;
  display: inline-grid; place-items: center; overflow: hidden;
  background: rgba(255, 255, 255, .22); background-size: cover; background-position: center;
  color: #fff; font-weight: 800; font-size: 14px; line-height: 1;
}
.avatar.lg {
  width: 76px; height: 76px; font-size: 28px;
  background-color: var(--brand-soft); color: var(--brand);
  border: 1px solid var(--line);
}
.profile { display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
.profile .pinfo b { font-size: 17px; display: block; }
.profile .pinfo .mini { font-size: 12px; }
.who { font-size: 12.5px; opacity: .9; max-width: 20vw; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.icon-btn {
  min-width: 38px; height: 36px; padding: 0 12px; border: 0; border-radius: 10px;
  background: rgba(255, 255, 255, .16); color: #fff; font-size: 12.5px; font-weight: 700;
}
.icon-btn.dark { background: var(--bg); color: var(--ink); }
.menu-btn { display: none; }

.layout { display: grid; grid-template-columns: var(--sidebar-w) minmax(0, 1fr); max-width: 1440px; margin: 0 auto; }
.sidebar {
  position: sticky; top: var(--topbar-h); height: calc(100vh - var(--topbar-h));
  overflow-y: auto; padding: 16px 12px 28px;
  border-right: 1px solid var(--line); background: var(--card);
}
.navbtn {
  display: flex; align-items: center; gap: 9px; width: 100%; text-align: left;
  padding: 9px 10px; margin: 2px 0; border: 0; border-radius: 10px;
  background: transparent; color: var(--ink); font-size: 13.5px; font-weight: 600;
}
.navbtn:hover { background: var(--bg); }
.navbtn.active { background: var(--brand-soft); color: var(--brand); }
.navbtn .badge {
  margin-left: auto; min-width: 20px; padding: 0 6px; border-radius: 99px;
  background: var(--red); color: #fff; font-size: 11px; text-align: center;
}
.side-note { margin: 18px 8px 0; font-size: 11px; line-height: 1.65; color: var(--ink-soft); }
.content { min-width: 0; padding: 22px 22px 70px; }
#view { max-width: var(--maxw); margin: 0 auto; }

/* ============ 通用 ============ */
.hero {
  background: linear-gradient(135deg, var(--card), var(--brand-soft));
  border: 1px solid var(--line); border-radius: var(--radius);
  padding: 20px 22px; box-shadow: var(--shadow); margin-bottom: 16px;
}
.hero h2 { font-size: 20px; margin-bottom: 5px; }
.hero p { margin: 0; color: var(--ink-soft); font-size: 13px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px; box-shadow: var(--shadow); }
.card + .card { margin-top: 13px; }
.sec-title { display: flex; align-items: center; justify-content: space-between; gap: 10px; margin: 22px 0 10px; }
.sec-title h3 { font-size: 16px; }
.sec-title span { font-size: 12px; color: var(--ink-soft); }
.grid { display: grid; gap: 12px; }
.grid.c2 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
.grid.c3 { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.grid.c4 { grid-template-columns: repeat(4, minmax(0, 1fr)); }
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 40px; padding: 8px 16px; border: 1px solid var(--line); border-radius: 10px;
  background: var(--card); color: var(--ink); font-size: 13.5px; font-weight: 700;
}
.btn:hover { border-color: var(--brand); }
.btn.primary { background: var(--brand); border-color: var(--brand); color: #fff; }
.btn.primary:hover { background: var(--brand-2); }
.btn.ghost { background: transparent; }
.btn.sm { min-height: 32px; padding: 4px 10px; font-size: 12px; border-radius: 8px; }
.btn:disabled { opacity: .55; cursor: not-allowed; }
.tag { display: inline-block; padding: 2px 8px; border-radius: 99px; background: var(--gold-soft); color: #8a5a1e; font-size: 11px; font-weight: 700; }
.tag.green { background: var(--green-soft); color: var(--green); }
.tag.gray { background: var(--bg); color: var(--ink-soft); }
.bar { height: 8px; border-radius: 99px; background: var(--line); overflow: hidden; }
.bar > i { display: block; height: 100%; background: linear-gradient(90deg, var(--gold), #ecc06a); transition: width .4s var(--ease); }
.bar.green > i { background: linear-gradient(90deg, var(--green), #4cc28c); }
.empty { padding: 40px 16px; text-align: center; color: var(--ink-soft); background: var(--card); border: 1px dashed var(--line); border-radius: var(--radius); font-size: 13.5px; }
.stat { padding: 14px 16px; }
.stat b { display: block; font-size: 24px; line-height: 1.2; }
.stat span { font-size: 11.5px; color: var(--ink-soft); }
.field { margin-bottom: 12px; }
.field label { display: block; font-size: 12px; font-weight: 700; color: var(--ink-soft); margin-bottom: 5px; }
.field input, .field textarea, .field select {
  width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px;
  background: var(--bg); color: var(--ink); font-size: 14px; outline: none;
}
.field input:focus, .field textarea:focus { border-color: var(--brand); background: var(--card); }
.err { color: var(--red); font-size: 12.5px; min-height: 18px; margin: 8px 0 0; }
.ok { color: var(--green); font-size: 12.5px; margin: 8px 0 0; }

/* ============ 首页 ============ */
.dash { display: grid; grid-template-columns: 1.2fr .8fr; gap: 13px; }
.countdown { text-align: center; padding: 20px; }
.countdown .num { font-size: 48px; font-weight: 900; color: var(--brand); line-height: 1; }
.countdown .unit { font-size: 12px; color: var(--ink-soft); margin-top: 4px; }
.todo { display: flex; align-items: center; gap: 10px; padding: 8px 0; font-size: 13px; }
.todo i { width: 8px; height: 8px; border-radius: 50%; background: var(--gold); flex: 0 0 8px; }
.chapter-row { display: grid; grid-template-columns: 1fr 90px 52px; gap: 12px; align-items: center; padding: 8px 0; font-size: 12.5px; }
.chapter-row .nm { color: var(--ink); font-weight: 600; }
.chapter-row .n { text-align: right; color: var(--ink-soft); font-size: 11.5px; }
.quick { display: flex; flex-wrap: wrap; gap: 10px; }

/* ============ 听课 ============ */
.lesson {
  display: flex; align-items: center; gap: 14px; padding: 14px 16px; margin-bottom: 10px;
  background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm);
}
.lesson .no {
  flex: 0 0 38px; height: 38px; border-radius: 10px; display: grid; place-items: center;
  background: var(--brand-soft); color: var(--brand); font-weight: 900;
}
.lesson .info { flex: 1; min-width: 0; }
.lesson .info b { display: block; font-size: 14px; }
.lesson .info small { color: var(--ink-soft); font-size: 11.5px; }
.lesson .ops { display: flex; gap: 8px; flex-wrap: wrap; justify-content: flex-end; }
.lesson.done { border-color: rgba(31, 157, 99, .4); }
.lesson.done .no { background: var(--green-soft); color: var(--green); }

/* ============ 背诵 ============ */
.toolbar { display: flex; flex-wrap: wrap; align-items: center; gap: 10px; padding: 12px 14px; margin-bottom: 14px; background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); }
.toolbar input[type="search"] { flex: 1 1 200px; min-width: 0; padding: 8px 12px; border: 1px solid var(--line); border-radius: 9px; background: var(--bg); color: var(--ink); font-size: 13px; }
.switch { display: inline-flex; align-items: center; gap: 6px; font-size: 12.5px; color: var(--ink-soft); }
.chapter-h {
  display: flex; align-items: center; gap: 8px; padding: 10px 14px; margin: 16px 0 8px;
  background: var(--card); border: 1px solid var(--line); border-left: 4px solid var(--gold);
  border-radius: 10px; font-size: 14px; font-weight: 800;
}
.chapter-h small { margin-left: auto; font-weight: 500; color: var(--ink-soft); font-size: 11.5px; }
.point { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius-sm); padding: 14px 16px; margin-bottom: 10px; }
.point.done { border-color: rgba(31, 157, 99, .45); background: linear-gradient(0deg, var(--green-soft), var(--card)); }
.point .pt-head { display: flex; align-items: flex-start; gap: 10px; }
.point .pt-title { font-size: 14.5px; font-weight: 800; flex: 1; }
.point .pt-body p { margin: 5px 0; font-size: 13.5px; }
.point .pt-req { margin-top: 8px; font-size: 11.5px; color: var(--ink-soft); }
.mark-btn { flex: 0 0 auto; padding: 5px 11px; border-radius: 9px; border: 1px solid var(--line); background: var(--bg); color: var(--ink-soft); font-size: 12px; font-weight: 700; }
.mark-btn.on { background: var(--green); border-color: var(--green); color: #fff; }
.k-blue { color: #1d6fa5; font-weight: 800; }
.k-red { color: var(--red); font-weight: 800; }

/* ============ 刷题 ============ */
.q-head { display: flex; align-items: center; justify-content: space-between; margin-bottom: 12px; }
.q-idx { font-size: 12px; color: var(--ink-soft); }
.q-text { font-size: 15.5px; font-weight: 700; line-height: 1.75; margin-bottom: 14px; }
.opts { display: grid; gap: 9px; }
.opt { display: flex; gap: 10px; align-items: flex-start; text-align: left; padding: 11px 14px; border: 1px solid var(--line); border-radius: 11px; background: var(--card); color: var(--ink); font-size: 13.5px; line-height: 1.65; }
.opt:hover { border-color: var(--brand); }
.opt .k { flex: 0 0 22px; font-weight: 900; color: var(--ink-soft); }
.opt.right { border-color: var(--green); background: var(--green-soft); }
.opt.right .k { color: var(--green); }
.opt.wrong { border-color: var(--red); background: var(--red-soft); }
.opt.wrong .k { color: var(--red); }
.opt:disabled { cursor: default; }
.exp { margin-top: 12px; padding: 12px 14px; border-radius: 10px; background: var(--gold-soft); font-size: 13px; line-height: 1.8; }
.quiz-nav { display: flex; gap: 10px; justify-content: flex-end; margin-top: 14px; }
.result-big { font-size: 36px; font-weight: 900; color: var(--brand); }
.mini { font-size: 12px; color: var(--ink-soft); }

/* ============ 老师端 ============ */
.pending { border-left: 4px solid var(--gold); }
.pending + .pending { margin-top: 10px; }
.pending .line { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.pending .name { font-weight: 800; font-size: 15px; }
.pending .meta { font-size: 12px; color: var(--ink-soft); }
.pending .reason { margin: 8px 0; padding: 8px 11px; background: var(--bg); border-radius: 8px; font-size: 12.5px; }
.pending .ops { display: flex; gap: 8px; }
.tablehead, .trow { display: grid; grid-template-columns: 1.4fr 1fr .8fr .8fr 1fr; gap: 8px; align-items: center; padding: 9px 6px; font-size: 12.5px; }
.tablehead { color: var(--ink-soft); font-size: 11.5px; border-bottom: 1px solid var(--line); }
.trow { border-bottom: 1px solid var(--line); cursor: pointer; }
.trow:hover { background: var(--bg); }
.trow:last-child { border-bottom: 0; }
.trow .nm { font-weight: 700; }
.trow .num { text-align: right; }
.detail .prow { display: grid; grid-template-columns: 1fr 1fr 46px; gap: 10px; align-items: center; padding: 6px 0; font-size: 12.5px; }
.wrongq { padding: 9px 11px; border-radius: 9px; background: var(--bg); margin-bottom: 7px; font-size: 12.5px; }
.wrongq b { color: var(--green); }
.lesson-admin { display: flex; align-items: center; gap: 10px; padding: 9px 0; border-bottom: 1px solid var(--line); }
.lesson-admin:last-child { border-bottom: 0; }
.lesson-admin .t { flex: 0 0 210px; font-size: 13px; font-weight: 600; }
.lesson-admin input { flex: 1; min-width: 0; padding: 7px 10px; border: 1px solid var(--line); border-radius: 8px; background: var(--bg); color: var(--ink); font-size: 12px; }
.lcard { border: 1px solid var(--line); border-radius: 12px; padding: 12px 14px; margin-bottom: 10px; background: var(--card); }
.lcard .lhead { display: flex; align-items: center; justify-content: space-between; gap: 8px; margin-bottom: 8px; }
.lcard .lhead b { font-size: 13.5px; }
.lgrid, .ladd { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 10px; }
.lgrid label, .ladd label { display: block; font-size: 11px; color: var(--ink-soft); font-weight: 700; }
.lgrid input, .ladd input {
  width: 100%; margin-top: 4px; padding: 8px 10px; border: 1px solid var(--line);
  border-radius: 8px; background: var(--bg); color: var(--ink); font-size: 12.5px; box-sizing: border-box;
}
.lgrid input:focus, .ladd input:focus { border-color: var(--brand); background: var(--card); }
.lgrid .wide, .ladd .wide { grid-column: 1 / -1; }
.lfile { margin-top: 10px; border-top: 1px dashed var(--line); padding-top: 9px; }
.lfile-h { display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.lfile-h b { font-size: 11px; color: var(--ink-soft); letter-spacing: .5px; }
.lfile .file-row { padding: 8px 0; }
.lfile .file-row .fi b { font-size: 12.5px; }

/* ============ 弹窗 / 提示 ============ */
.modal { position: fixed; inset: 0; z-index: 80; display: block; padding: 0; background: #070b11; }
.modal-mask { display: none; }
.modal-box {
  position: relative; width: 100vw; height: 100vh; height: 100dvh;
  max-height: none; overflow: hidden; background: #0b0f16;
  display: flex; flex-direction: column;
}
.modal-box:fullscreen { width: 100vw; height: 100vh; }
.modal-box:-webkit-full-screen { width: 100vw; height: 100vh; }
.modal-head {
  flex: 0 0 auto; display: flex; align-items: center; justify-content: space-between;
  gap: 10px; padding: 10px 16px; border-bottom: 1px solid rgba(255, 255, 255, .1);
  background: #11161f; color: #eef2f8;
}
.modal-head b { font-size: 14px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.modal-head .icon-btn.dark { background: rgba(255, 255, 255, .12); color: #fff; }
.modal-body { flex: 1; min-height: 0; display: flex; flex-direction: column; padding: 0; background: #000; }
.player-shell { position: relative; flex: 1; min-height: 0; background: #000; }
.player-shell iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; background: #000; }
.player-shell video { width: 100%; height: 100%; object-fit: contain; background: #000; display: block; }
.player-bar {
  flex: 0 0 auto; display: flex; align-items: center; gap: 10px; flex-wrap: wrap;
  padding: 9px 16px calc(9px + env(safe-area-inset-bottom));
  background: #11161f; color: #9aa4b6; font-size: 12px;
}
.player-bar .spacer { flex: 1; }
.player-bar .btn { border-color: rgba(255, 255, 255, .18); background: rgba(255, 255, 255, .08); color: #fff; }
.player-bar .btn:hover { border-color: var(--gold); }
.player-bar a.btn { text-decoration: none; }
body.modal-open { overflow: hidden; }

/* 讲义列表弹窗（白底小卡片） */
.modal.sheet-mode { background: rgba(8, 14, 22, .55); padding: 18px; display: grid; place-items: center; }
.modal-box.sheet { width: min(560px, 94vw); height: auto; max-height: 82vh; border-radius: 16px; background: var(--card); }
.modal-head.light { background: var(--card); color: var(--ink); border-bottom: 1px solid var(--line); }
.modal-head.light .icon-btn.dark { background: var(--bg); color: var(--ink); }
.sheet-body { padding: 8px 16px 16px; overflow: auto; }
.file-row { display: flex; align-items: center; gap: 8px; padding: 10px 0; border-bottom: 1px solid var(--line); }
.file-row:last-child { border-bottom: 0; }
.file-row .fi { flex: 1; min-width: 0; }
.file-row .fi b { display: block; font-size: 13px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.file-row .fi small { color: var(--ink-soft); font-size: 11px; }
.sheet-empty { padding: 22px 0; color: var(--ink-soft); font-size: 13px; text-align: center; }
.toast {
  position: fixed; left: 50%; bottom: 84px; transform: translateX(-50%); z-index: 99;
  background: rgba(16, 26, 38, .92); color: #fff; padding: 9px 16px; border-radius: 10px;
  font-size: 13px; box-shadow: 0 10px 26px rgba(0, 0, 0, .25);
}
.backdrop { display: none; }
.tabbar { display: none; }

/* ============ 响应式 ============ */
@media (max-width: 1024px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
  .menu-btn { display: inline-flex; align-items: center; justify-content: center; }
  .sidebar {
    position: fixed; top: var(--topbar-h); left: 0; z-index: 45; width: 252px;
    height: calc(100% - var(--topbar-h));
    padding-top: 16px; transform: translateX(-104%); transition: transform .26s var(--ease);
    box-shadow: 0 0 30px rgba(0, 0, 0, .2);
  }
  body.nav-open .sidebar { transform: none; }
  body.nav-open .backdrop { display: block; position: fixed; inset: 0; z-index: 44; background: rgba(8, 14, 22, .45); }
  body.nav-open { overflow: hidden; }
  .content { padding: 18px 15px calc(76px + env(safe-area-inset-bottom)); }
  .tabbar {
    position: fixed; left: 0; right: 0; bottom: 0; z-index: 40;
    display: grid; grid-auto-flow: column; grid-auto-columns: 1fr;
    padding: 6px 4px calc(6px + env(safe-area-inset-bottom));
    background: var(--card); border-top: 1px solid var(--line);
  }
  .tab {
    display: flex; flex-direction: column; align-items: center; gap: 2px;
    border: 0; background: transparent; color: var(--ink-soft);
    font-size: 10.5px; font-weight: 700; padding: 4px 0;
  }
  .tab span { font-size: 18px; line-height: 1.1; }
  .tab.active { color: var(--brand); }
}
@media (max-width: 820px) {
  .auth { grid-template-columns: minmax(0, 1fr); }
  .auth-side { display: none; }
  .auth-main { min-height: 100vh; min-height: 100dvh; }
  .dash { grid-template-columns: minmax(0, 1fr); }
  .grid.c3, .grid.c4 { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}
@media (max-width: 620px) {
  .grid.c2, .grid.c3, .grid.c4 { grid-template-columns: minmax(0, 1fr); }
  .who { display: none; }
  .lesson-admin { flex-wrap: wrap; }
  .lesson-admin .t { flex: 1 1 100%; }
  .tablehead, .trow { grid-template-columns: 1.3fr 1fr .8fr 1fr; }
  .tablehead span:nth-child(4), .trow span:nth-child(4) { display: none; }
  .chapter-row { grid-template-columns: 1fr 70px 44px; }
  .topbar { padding: 0 12px; }
}
@media (max-width: 720px) {
  .player-bar .hint { display: none; }
  .player-bar { justify-content: center; }
  .modal-head b { max-width: 68vw; }
  .lgrid, .ladd { grid-template-columns: 1fr 1fr; }
  .lgrid label:first-child, .ladd label:first-child { grid-column: 1 / -1; }
}
@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}