/* ============ 设计变量 ============ */
:root {
  --bg: #f4f7fb;
  --bg-soft: #ffffff;
  --bg-elev: #ffffff;
  --sidebar: linear-gradient(180deg, #0e7c86 0%, #0b5d8a 100%);
  --text: #1d2733;
  --text-soft: #5a6b7b;
  --text-dim: #8a99a8;
  --border: #e4ebf2;
  --border-strong: #d3dde7;
  --primary: #0e9aa8;
  --primary-d: #0b7e8a;
  --primary-soft: #e2f4f6;
  --accent: #ff7a59;
  --accent-soft: #ffe9e2;
  --good: #2bb673;
  --warn: #f0a92b;
  --bad: #e25563;
  --shadow: 0 6px 22px rgba(20, 50, 80, 0.08);
  --shadow-lg: 0 16px 48px rgba(20, 50, 80, 0.16);
  --radius: 16px;
  --radius-sm: 10px;
  --cat-1: #ff8a80; --cat-2: #ffb74d; --cat-3: #4fc3f7; --cat-4: #a1887f;
  --cat-5: #80cbc4; --cat-6: #9ccc65; --cat-7: #64b5f6; --cat-8: #b39ddb;
  --cat-9: #f06292; --cat-10: #ba68c8;
}
[data-theme="dark"] {
  --bg: #0f1620;
  --bg-soft: #182230;
  --bg-elev: #1d2836;
  --sidebar: linear-gradient(180deg, #0a4a52 0%, #0a3a57 100%);
  --text: #e7eef5;
  --text-soft: #a9b8c7;
  --text-dim: #6f8295;
  --border: #283444;
  --border-strong: #38485a;
  --primary: #2bc4d4;
  --primary-d: #1aa3b3;
  --primary-soft: #123842;
  --accent: #ff8e6e;
  --accent-soft: #3a241c;
  --good: #46c98a;
  --warn: #f3bd4e;
  --bad: #f0737f;
  --shadow: 0 6px 22px rgba(0,0,0,0.35);
  --shadow-lg: 0 16px 48px rgba(0,0,0,0.5);
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}
.hidden { display: none !important; }
button { font-family: inherit; cursor: pointer; }
input, textarea, select { font-family: inherit; }

/* ============ 引导 ============ */
.onboard-overlay {
  position: fixed; inset: 0; z-index: 1000;
  display: flex; align-items: center; justify-content: center;
  background: radial-gradient(1200px 600px at 70% -10%, #0e9aa8 0%, transparent 60%),
              radial-gradient(900px 500px at 10% 110%, #0b5d8a 0%, transparent 55%), #0a1822;
}
.onboard-card {
  width: min(440px, 92vw); background: var(--bg-soft); color: var(--text);
  border-radius: 22px; padding: 36px 32px; box-shadow: var(--shadow-lg);
  text-align: center;
}
.onboard-logo { font-size: 56px; }
.onboard-card h1 { margin: 10px 0 6px; font-size: 24px; }
.onboard-sub { color: var(--text-soft); margin: 0 0 22px; font-size: 14px; line-height: 1.6; }
.onboard-label { display: block; text-align: left; font-size: 13px; color: var(--text-soft); margin-bottom: 8px; }
.onboard-tip { font-size: 12px; color: var(--text-dim); margin: 16px 0 0; line-height: 1.6; }

/* ============ 登录门禁 ============ */
.auth-overlay {
  position: fixed; inset: 0; z-index: 1000;
  display: flex; align-items: center; justify-content: center; padding: 20px;
  background: radial-gradient(1200px 600px at 70% -10%, #0e9aa8 0%, transparent 60%),
              radial-gradient(900px 500px at 10% 110%, #0b5d8a 0%, transparent 55%), #0a1822;
}
.auth-card {
  width: min(420px, 94vw); background: var(--bg-soft); color: var(--text);
  border-radius: 22px; padding: 34px 30px; box-shadow: var(--shadow-lg); text-align: center;
}
.auth-logo { font-size: 52px; }
.auth-card h1 { margin: 8px 0 6px; font-size: 22px; }
.auth-sub { color: var(--text-soft); margin: 0 0 18px; font-size: 14px; line-height: 1.6; }
.auth-tabs { display: flex; gap: 6px; background: var(--bg); border-radius: 12px; padding: 5px; margin-bottom: 18px; }
.auth-tab {
  flex: 1; border: none; background: transparent; color: var(--text-soft);
  padding: 9px 6px; border-radius: 9px; font-size: 13.5px; font-weight: 600; transition: .15s;
}
.auth-tab.active { background: var(--primary); color: #fff; }
.auth-panel { display: flex; flex-direction: column; gap: 12px; }
.auth-input { width: 100%; padding: 12px 14px; border: 1px solid var(--border-strong); border-radius: 12px; font-size: 14px; background: var(--bg); color: var(--text); }
.auth-input:focus { outline: none; border-color: var(--primary); }
.auth-error { background: var(--accent-soft); color: var(--bad); border-radius: 10px; padding: 9px 12px; font-size: 13px; margin-bottom: 14px; }
.auth-tip { font-size: 12px; color: var(--text-dim); margin: 16px 0 0; line-height: 1.6; }
.auth-local-warn { background: var(--accent-soft); color: var(--text); border-radius: 12px; padding: 12px 14px; font-size: 13px; line-height: 1.7; text-align: left; margin-bottom: 16px; }
.wx-login-box { width: 100%; min-height: 220px; display: flex; align-items: center; justify-content: center; background: var(--bg); border-radius: 14px; overflow: hidden; }
.wx-login-box iframe { border: none; }
.wx-disabled { color: var(--text-soft); font-size: 13px; line-height: 1.7; padding: 20px; }
.auth-wx-tip { color: var(--text-soft); font-size: 13px; margin: 12px 0 0; }

/* 找回密码 / 账号设置 弹窗内部样式 */
.auth-link { text-align: right; margin-top: 4px; }
.auth-link a { color: var(--primary); font-size: 13px; text-decoration: none; }
.auth-link a:hover { text-decoration: underline; }
.auth-form { display: flex; flex-direction: column; gap: 12px; text-align: left; }
.settings-form { display: flex; flex-direction: column; gap: 20px; text-align: left; }
.set-row { display: flex; flex-direction: column; gap: 8px; }
.set-row > label { font-size: 13px; font-weight: 600; color: var(--text-soft); }
.set-line { display: flex; gap: 10px; align-items: center; }
.set-line .auth-input { flex: 1; }
.set-wx { display: flex; align-items: center; gap: 12px; }
.set-wx-status { font-size: 14px; color: var(--text); font-weight: 600; }
.set-wx-status::before { content: "●"; margin-right: 6px; color: var(--text-dim); }
.set-wx .btn { min-width: 96px; }
.set-row .auth-error { margin-bottom: 0; }

/* ============ 布局 ============ */
.app { display: grid; grid-template-columns: 248px 1fr; height: 100vh; }
.sidebar {
  background: var(--sidebar); color: #eaf6f8; padding: 22px 16px;
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh;
}
.brand { display: flex; align-items: center; gap: 10px; padding: 4px 8px 18px; font-weight: 700; font-size: 17px; }
.brand-logo { font-size: 26px; }
.nav { display: flex; flex-direction: column; gap: 4px; flex: 1; }
.nav-item {
  display: flex; align-items: center; gap: 12px; padding: 12px 14px; border: none; background: transparent;
  color: #cfe9ec; border-radius: 12px; font-size: 15px; text-align: left; transition: background .15s, color .15s;
}
.nav-item:hover { background: rgba(255,255,255,.12); color: #fff; }
.nav-item.active { background: rgba(255,255,255,.18); color: #fff; font-weight: 600; }
.nav-ico { font-size: 18px; width: 22px; text-align: center; }
.sidebar-foot { border-top: 1px solid rgba(255,255,255,.14); padding-top: 14px; display: flex; align-items: center; gap: 10px; }
.teacher-chip { display: flex; align-items: center; gap: 10px; flex: 1; min-width: 0; cursor: pointer; border-radius: 8px; padding: 4px 6px; transition: background .15s; }
.teacher-chip:hover { background: rgba(255,255,255,.12); }
.avatar { width: 36px; height: 36px; border-radius: 50%; background: rgba(255,255,255,.2); display: grid; place-items: center; font-weight: 700; flex-shrink: 0; }
.teacher-meta { min-width: 0; }
.teacher-name { font-weight: 600; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.teacher-role { font-size: 12px; color: #bcd9dd; }

.content { overflow-y: auto; padding: 0 28px 40px; }
.topbar {
  position: sticky; top: 0; z-index: 20; background: var(--bg);
  display: flex; align-items: center; justify-content: space-between;
  padding: 20px 0 14px; margin-bottom: 8px; border-bottom: 1px solid var(--border);
}
.topbar h2 { margin: 0; font-size: 22px; }
.page-sub { margin: 4px 0 0; color: var(--text-soft); font-size: 13px; }
.topbar-actions { display: flex; gap: 8px; }
.icon-btn {
  width: 40px; height: 40px; border-radius: 12px; border: 1px solid var(--border);
  background: var(--bg-soft); font-size: 18px; display: grid; place-items: center; transition: .15s;
}
.icon-btn:hover { border-color: var(--primary); }

/* ============ 通用组件 ============ */
.btn {
  border: 1px solid transparent; border-radius: 12px; padding: 10px 16px; font-size: 14px; font-weight: 600;
  display: inline-flex; align-items: center; gap: 8px; justify-content: center; transition: .15s;
}
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-d); }
.btn-ghost { background: transparent; border-color: var(--border-strong); color: var(--text); }
.btn-ghost:hover { border-color: var(--primary); color: var(--primary); }
.btn-danger { background: transparent; border-color: var(--bad); color: var(--bad); }
.btn-danger:hover { background: var(--bad); color: #fff; }
.btn-sm { padding: 7px 12px; font-size: 13px; border-radius: 10px; }
.btn-block { width: 100%; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); box-shadow: var(--shadow); }
.section-head { display: flex; align-items: center; justify-content: space-between; margin: 22px 0 14px; }
.section-head h3 { margin: 0; font-size: 17px; }

.field { margin-bottom: 14px; }
.field label { display: block; font-size: 13px; color: var(--text-soft); margin-bottom: 6px; }
.input, textarea.input, select.input {
  width: 100%; padding: 10px 12px; border: 1px solid var(--border-strong); border-radius: 10px;
  background: var(--bg-soft); color: var(--text); font-size: 14px; outline: none; transition: .15s;
}
.input:focus, textarea.input:focus, select.input:focus { border-color: var(--primary); box-shadow: 0 0 0 3px var(--primary-soft); }
textarea.input { resize: vertical; min-height: 80px; }
.row { display: flex; gap: 12px; flex-wrap: wrap; }
.row > * { flex: 1; min-width: 160px; }

.chip { display: inline-flex; align-items: center; gap: 6px; padding: 5px 11px; border-radius: 999px; font-size: 12px; background: var(--primary-soft); color: var(--primary-d); font-weight: 600; }
.chip.gray { background: var(--border); color: var(--text-soft); }
.chip.accent { background: var(--accent-soft); color: var(--accent); }

.empty { text-align: center; padding: 50px 20px; color: var(--text-dim); }
.empty .emoji { font-size: 46px; }
.empty p { margin: 10px 0 0; }

/* ============ 引导结束，开始视图 ============ */
.stat-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; margin-top: 6px; }
.stat-card { padding: 18px 20px; display: flex; align-items: center; gap: 14px; }
.stat-ico { width: 46px; height: 46px; border-radius: 14px; display: grid; place-items: center; font-size: 22px; background: var(--primary-soft); }
.stat-num { font-size: 26px; font-weight: 800; line-height: 1; }
.stat-label { font-size: 13px; color: var(--text-soft); margin-top: 4px; }

.quick-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 14px; }
.quick-card { padding: 18px; text-align: left; transition: .15s; }
.quick-card:hover { transform: translateY(-2px); border-color: var(--primary); }
.quick-card .qc-ico { font-size: 26px; }
.quick-card .qc-title { font-weight: 700; margin-top: 8px; }
.quick-card .qc-sub { font-size: 12px; color: var(--text-soft); margin-top: 2px; }

.list-card { padding: 14px 16px; display: flex; align-items: center; gap: 12px; margin-bottom: 10px; }
.list-card .lc-ico { width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center; font-size: 20px; background: var(--border); flex-shrink: 0; }
.list-card .lc-main { flex: 1; min-width: 0; }
.list-card .lc-title { font-weight: 600; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.list-card .lc-sub { font-size: 12px; color: var(--text-soft); margin-top: 2px; }

/* ============ 资料库 ============ */
.toolbar { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-bottom: 16px; }
.toolbar .search { flex: 1; min-width: 200px; position: relative; }
.toolbar .search input { padding-left: 34px; }
.toolbar .search::before { content: "🔍"; position: absolute; left: 11px; top: 50%; transform: translateY(-50%); font-size: 13px; opacity: .6; }
.filter-tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.filter-tab { padding: 7px 13px; border-radius: 999px; border: 1px solid var(--border-strong); background: var(--bg-soft); font-size: 13px; color: var(--text-soft); }
.filter-tab.active { background: var(--primary); border-color: var(--primary); color: #fff; }

.dropzone {
  border: 2px dashed var(--border-strong); border-radius: var(--radius); padding: 30px; text-align: center;
  color: var(--text-soft); transition: .15s; background: var(--bg-soft); margin-bottom: 18px;
}
.dropzone.drag { border-color: var(--primary); background: var(--primary-soft); }
.dropzone .dz-ico { font-size: 40px; }
.dropzone .dz-title { font-weight: 700; color: var(--text); margin-top: 8px; }
.dropzone .dz-sub { font-size: 12px; margin-top: 4px; }

.mat-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); gap: 14px; }
.mat-card { padding: 0; overflow: hidden; cursor: pointer; transition: .15s; display: flex; flex-direction: column; }
.mat-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.mat-thumb { height: 104px; display: grid; place-items: center; font-size: 40px; color: #fff; position: relative; }
.mat-body { padding: 12px 14px; }
.mat-title { font-weight: 600; font-size: 14px; line-height: 1.35; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; min-height: 38px; }
.mat-meta { font-size: 12px; color: var(--text-soft); margin-top: 8px; display: flex; justify-content: space-between; gap: 8px; }
.mat-tags { margin-top: 8px; display: flex; gap: 5px; flex-wrap: wrap; }
.tag { font-size: 11px; padding: 2px 8px; border-radius: 999px; background: var(--border); color: var(--text-soft); }

/* ============ 班级 ============ */
.class-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(240px, 1fr)); gap: 16px; }
.class-card { padding: 18px; border-left: 5px solid var(--primary); transition: .15s; }
.class-card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.class-card .cc-head { display: flex; justify-content: space-between; align-items: flex-start; }
.class-card .cc-name { font-size: 18px; font-weight: 700; }
.class-card .cc-grade { font-size: 12px; color: var(--text-soft); }
.class-card .cc-stats { display: flex; gap: 16px; margin-top: 14px; }
.class-card .cc-stat .n { font-size: 20px; font-weight: 800; }
.class-card .cc-stat .l { font-size: 12px; color: var(--text-soft); }
.class-card .cc-actions { display: flex; gap: 8px; margin-top: 14px; }

/* ============ 备课 ============ */
.lesson-card { padding: 16px 18px; margin-bottom: 12px; }
.lesson-card .lc-top { display: flex; justify-content: space-between; gap: 12px; align-items: flex-start; }
.lesson-card .lc-title { font-size: 16px; font-weight: 700; }
.lesson-card .lc-sub { font-size: 12px; color: var(--text-soft); margin-top: 4px; }
.lesson-materials { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.lesson-mat { display: inline-flex; align-items: center; gap: 6px; font-size: 12px; padding: 5px 10px; border-radius: 8px; background: var(--border); }

/* ============ 元素周期表 ============ */
.ptable-wrap { overflow: auto; padding-bottom: 10px; }
.ptable { display: grid; grid-template-columns: repeat(18, minmax(46px, 1fr)); gap: 5px; min-width: 920px; }
.pe { aspect-ratio: 1; border-radius: 8px; padding: 4px; display: flex; flex-direction: column; justify-content: space-between; cursor: pointer; border: 1px solid rgba(0,0,0,.06); transition: .12s; position: relative; }
.pe:hover { transform: scale(1.12); z-index: 5; box-shadow: var(--shadow); }
.pe .pe-n { font-size: 9px; opacity: .8; }
.pe .pe-s { font-size: 18px; font-weight: 800; line-height: 1; }
.pe .pe-cn { font-size: 9px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.ptable-empty { height: 28px; }
.pt-legend { display: flex; gap: 10px; flex-wrap: wrap; margin: 12px 0 18px; }
.pt-legend .lg { display: flex; align-items: center; gap: 6px; font-size: 12px; color: var(--text-soft); }
.pt-legend .sw { width: 14px; height: 14px; border-radius: 4px; }

/* ============ 工具箱 ============ */
.tool-box { padding: 20px; }
.result-box { margin-top: 16px; padding: 16px; border-radius: 12px; background: var(--bg); border: 1px dashed var(--border-strong); }
.const-table { width: 100%; border-collapse: collapse; font-size: 13px; }
.const-table th, .const-table td { padding: 9px 10px; border-bottom: 1px solid var(--border); text-align: left; }
.const-table th { color: var(--text-soft); font-weight: 600; }
.formula-row { display: flex; gap: 10px; align-items: flex-end; flex-wrap: wrap; }
.breakdown { margin-top: 12px; font-size: 13px; }
.breakdown div { display: flex; justify-content: space-between; padding: 5px 0; border-bottom: 1px dashed var(--border); }

/* ============ 上课模式 ============ */
.classroom { position: fixed; inset: 0; z-index: 500; background: #0b0f14; color: #eef3f7; display: flex; flex-direction: column; }
.cr-top { display: flex; align-items: center; justify-content: space-between; padding: 10px 16px; background: #11161d; gap: 12px; }
.cr-title { font-weight: 700; font-size: 15px; }
.cr-class { font-size: 12px; color: #9fb0bf; }
.cr-tools { display: flex; gap: 8px; flex-wrap: wrap; }
.cr-btn { background: #1c2530; border: 1px solid #2a3644; color: #d6e2ec; border-radius: 10px; padding: 8px 12px; font-size: 13px; display: inline-flex; align-items: center; gap: 6px; }
.cr-btn:hover { background: #27323f; border-color: var(--primary); }
.cr-btn.active { background: var(--primary); border-color: var(--primary); color: #fff; }
.cr-body { flex: 1; display: flex; min-height: 0; }
.cr-list { width: 280px; background: #11161d; padding: 12px; overflow-y: auto; flex-shrink: 0; }
.cr-list h4 { margin: 0 0 10px; font-size: 13px; color: #9fb0bf; }
.cr-item { padding: 10px 12px; border-radius: 10px; margin-bottom: 6px; cursor: pointer; font-size: 13px; display: flex; gap: 8px; align-items: center; }
.cr-item:hover { background: #1c2530; }
.cr-item.active { background: var(--primary); color: #fff; }
.cr-item .ci-ico { font-size: 16px; }
.cr-stage { flex: 1; min-width: 0; position: relative; display: flex; align-items: center; justify-content: center; background: #0b0f14; }
.cr-stage iframe, .cr-stage img { max-width: 100%; max-height: 100%; border: none; }
.cr-stage video { max-width: 100%; max-height: 100%; }
.cr-stage .cr-placeholder { text-align: center; color: #6f8295; }
.cr-stage .cr-placeholder .big { font-size: 54px; }
/* 通用占位（资料库预览也复用） */
.cr-placeholder { text-align: center; color: #9fb0bf; padding: 30px; }
.cr-placeholder .big { font-size: 54px; margin-bottom: 8px; }
.cr-placeholder p { margin: 6px 0; line-height: 1.6; }
.cr-placeholder .btn { margin-top: 12px; }
.cr-audio { padding: 20px; text-align: center; }
.cr-audio audio { width: 80%; }

/* 板书 */
.cr-board { position: absolute; inset: 0; background: rgba(8,12,16,.96); display: none; flex-direction: column; }
.cr-board.show { display: flex; }
.cr-board canvas { flex: 1; touch-action: none; cursor: crosshair; background: #0d1117; }
.cr-board-bar { display: flex; gap: 8px; padding: 10px; align-items: center; background: #11161d; flex-wrap: wrap; }
.cr-color { width: 26px; height: 26px; border-radius: 50%; border: 2px solid #2a3644; cursor: pointer; }
.cr-color.active { border-color: #fff; transform: scale(1.12); }

/* 计时器 */
.cr-timer { position: absolute; top: 16px; right: 16px; background: #11161d; border: 1px solid #2a3644; border-radius: 14px; padding: 14px; width: 220px; display: none; box-shadow: var(--shadow-lg); }
.cr-timer.show { display: block; }
.cr-timer .t-display { font-size: 40px; font-weight: 800; text-align: center; font-variant-numeric: tabular-nums; }
.cr-timer .t-controls { display: flex; gap: 6px; margin-top: 10px; }
.cr-timer .t-set { display: flex; gap: 6px; margin-bottom: 10px; }
.cr-timer .t-set input { width: 100%; padding: 6px; border-radius: 8px; border: 1px solid #2a3644; background: #0b0f14; color: #eef3f7; text-align: center; }

/* 随机点名 */
.cr-pick { position: absolute; inset: 0; background: rgba(8,12,16,.97); display: none; flex-direction: column; align-items: center; justify-content: center; }
.cr-pick.show { display: flex; }
.cr-pick .pick-name { font-size: 88px; font-weight: 800; color: var(--primary); }
.cr-pick .pick-label { color: #9fb0bf; margin-top: 10px; }

/* ============ 弹窗 ============ */
.modal-overlay { position: fixed; inset: 0; z-index: 600; background: rgba(10,20,30,.45); display: flex; align-items: center; justify-content: center; padding: 20px; }
.modal { width: min(560px, 96vw); max-height: 90vh; overflow-y: auto; background: var(--bg-soft); color: var(--text); border-radius: 18px; box-shadow: var(--shadow-lg); }
.modal.wide { width: min(820px, 96vw); }
.modal-head { display: flex; justify-content: space-between; align-items: center; padding: 18px 22px; border-bottom: 1px solid var(--border); position: sticky; top: 0; background: var(--bg-soft); z-index: 2; }
.modal-head h3 { margin: 0; font-size: 18px; }
.modal-body { padding: 20px 22px; }
.modal-foot { padding: 14px 22px; border-top: 1px solid var(--border); display: flex; justify-content: flex-end; gap: 10px; }
.close-x { background: transparent; border: none; font-size: 22px; color: var(--text-dim); line-height: 1; }

/* 预览 */
.preview-stage { min-height: 360px; border-radius: 12px; overflow: hidden; background: #0b0f14; display: flex; align-items: center; justify-content: center; }
.preview-stage iframe { width: 100%; height: 70vh; border: none; background: #fff; }
.preview-stage img { max-width: 100%; max-height: 70vh; }
.preview-stage video { max-width: 100%; max-height: 70vh; }
.preview-actions { display: flex; gap: 10px; margin-top: 14px; flex-wrap: wrap; }

/* 存储模式指示 */
.mode-badge { display: inline-flex; align-items: center; gap: 8px; margin: 10px 0 4px; padding: 6px 12px; border-radius: 999px; background: var(--bg); color: var(--text-soft); font-size: 13px; }
.mode-dot { width: 9px; height: 9px; border-radius: 50%; background: #b6c2cc; }
.mode-dot.on { background: #2bb673; box-shadow: 0 0 0 3px rgba(43,182,115,.18); }
.mode-dot.off { background: #f0a92b; box-shadow: 0 0 0 3px rgba(240,169,43,.18); }

/* Office 在线预览播放器 */
.office-viewer { width: 100%; height: 70vh; display: flex; flex-direction: column; background: #fff; border-radius: 12px; overflow: hidden; }
.office-viewer.fill { height: 100%; }
.office-viewer .ov-bar { display: flex; align-items: center; gap: 8px; padding: 8px 12px; background: #11161d; color: #eef3f7; flex: none; }
.office-viewer .ov-name { flex: 1; font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.office-viewer .ov-btn { font-size: 12px; padding: 6px 10px; border-radius: 8px; background: #1c2530; color: #eef3f7; text-decoration: none; border: none; cursor: pointer; }
.office-viewer .ov-btn:hover { background: var(--primary); color: #fff; }
.office-viewer iframe { flex: 1; width: 100%; border: none; background: #fff; }

/* 媒体（PDF/图片/音视频）包裹 + 全屏按钮 */
.media-viewer { position: relative; width: 100%; height: 70vh; display: flex; align-items: center; justify-content: center; background: #0b0f14; border-radius: 12px; overflow: hidden; }
.media-viewer.fill { height: 100%; }
.media-viewer iframe { width: 100%; height: 100%; border: none; background: #fff; }
.media-viewer img, .media-viewer video { max-width: 100%; max-height: 100%; }
.media-fs { position: absolute; top: 10px; right: 10px; z-index: 5; width: 36px; height: 36px; border: none; border-radius: 8px; background: rgba(0,0,0,.55); color: #fff; font-size: 16px; cursor: pointer; }
.media-fs:hover { background: var(--primary); }

/* 选资料（备课） */
.picker-list { max-height: 320px; overflow-y: auto; }
.picker-item { display: flex; align-items: center; gap: 10px; padding: 10px 12px; border-radius: 10px; }
.picker-item:hover { background: var(--bg); }
.picker-item .pi-ico { width: 36px; height: 36px; border-radius: 8px; display: grid; place-items: center; background: var(--border); font-size: 18px; }
.picker-item .pi-main { flex: 1; min-width: 0; }
.picker-item .pi-title { font-weight: 600; font-size: 14px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.picker-item .pi-sub { font-size: 12px; color: var(--text-soft); }

/* 提示 */
.toast-root { position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%); z-index: 900; display: flex; flex-direction: column; gap: 10px; align-items: center; }
.toast { background: #1d2836; color: #fff; padding: 12px 18px; border-radius: 12px; box-shadow: var(--shadow-lg); font-size: 14px; animation: toastIn .2s ease; }
.toast.good { background: var(--good); }
.toast.bad { background: var(--bad); }
.toast.warn { background: var(--warn); color: #1d2733; }
@keyframes toastIn { from { opacity: 0; transform: translateY(10px); } to { opacity: 1; transform: translateY(0); } }

/* 学生名单 */
.student-tags { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 10px; }
.student-tag { background: var(--primary-soft); color: var(--primary-d); padding: 6px 12px; border-radius: 999px; font-size: 13px; display: inline-flex; gap: 6px; align-items: center; }
.student-tag button { background: none; border: none; color: inherit; font-size: 14px; line-height: 1; opacity: .7; }
.student-tag button:hover { opacity: 1; }

/* 统计条 */
.bar-row { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.bar-label { width: 110px; font-size: 13px; color: var(--text-soft); text-align: right; flex-shrink: 0; }
.bar-track { flex: 1; background: var(--border); border-radius: 999px; height: 22px; overflow: hidden; }
.bar-fill { height: 100%; background: linear-gradient(90deg, var(--primary), var(--primary-d)); border-radius: 999px; transition: width .6s; }
.bar-num { width: 40px; font-size: 13px; font-weight: 700; text-align: left; }

@media (max-width: 880px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { position: fixed; bottom: 0; left: 0; right: 0; top: auto; height: auto; flex-direction: row; z-index: 50; padding: 8px; }
  .brand, .sidebar-foot { display: none; }
  .nav { flex-direction: row; overflow-x: auto; gap: 2px; }
  .nav-item { flex-direction: column; gap: 2px; font-size: 11px; padding: 6px 10px; }
  .nav-ico { font-size: 18px; }
  .content { padding: 0 16px 80px; }
  .stat-grid { grid-template-columns: repeat(2, 1fr); }
  .cr-list { width: 140px; }
}

/* ============ 后台管理 ============ */
.admin-wrap { max-width: 980px; margin: 0 auto; }
.admin-h { font-size: 20px; margin: 4px 0 18px; }
.stat-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 14px; margin-bottom: 22px; }
.stat-card { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 14px; text-align: center; box-shadow: var(--shadow); }
.stat-val { font-size: 28px; font-weight: 800; color: var(--primary); line-height: 1.1; }
.stat-label { font-size: 13px; color: var(--text-soft); margin-top: 6px; }
.admin-panel { background: var(--bg-soft); border: 1px solid var(--border); border-radius: var(--radius); padding: 18px 20px; box-shadow: var(--shadow); }
.admin-panel-h { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.admin-panel-h h4 { margin: 0; font-size: 16px; }
.admin-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.admin-table th, .admin-table td { text-align: left; padding: 11px 10px; border-bottom: 1px solid var(--border); }
.admin-table th { color: var(--text-soft); font-weight: 600; font-size: 13px; }
.admin-table .row-acts { display: flex; gap: 8px; flex-wrap: wrap; }
.badge { display: inline-block; padding: 2px 9px; border-radius: 999px; font-size: 12px; background: var(--bg); color: var(--text-soft); border: 1px solid var(--border); }
.badge-admin { background: var(--primary-soft); color: var(--primary-d); border-color: transparent; font-weight: 700; }
.empty-tip { color: var(--text-dim); padding: 18px 4px; text-align: center; }