/* ============================================================
   《操作系统》智慧学习网站 · 原创视觉系统
   风格：深邃夜空蓝 · 奥斯卡金 · 玻璃质感 · 活力光效
   ============================================================ */
:root {
  --navy: #ffe98a;         /* 标题用亮金（原深蓝变量位，保持标题醒目） */
  --navy-2: #f5c518;
  --blue: #f5c518;         /* 主操作 → 奥斯卡金 */
  --blue-soft: rgba(245,197,24,.14);  /* 金色半透填充 */
  --blue-line: rgba(245,197,24,.35);
  --ink: #eaf1ff;          /* 正文 */
  --muted: #9db4d8;        /* 次要文字 */
  --line: rgba(148,184,240,.16);
  --bg: #0b1c3d;           /* 页面底 */
  --surface: #112a52;      /* 卡片面 */
  --surface-2: #163563;
  --green: #35d48a;
  --amber: #f5c518;
  --red: #ff6b78;
  --cyan: #58b6ff;
  --gold: #f5c518;
  --gold-soft: #ffe98a;
  --radius: 12px;
  --shadow: 0 10px 30px rgba(3,12,30,.45);
  --glow-gold: 0 0 0 1px rgba(245,197,24,.28), 0 8px 26px rgba(245,197,24,.18);
  --font: "Noto Sans CJK SC","PingFang SC","Microsoft YaHei",system-ui,sans-serif;
}
* { box-sizing: border-box; margin: 0; padding: 0; }
html, body { height: 100%; }
body {
  font-family: var(--font);
  color: var(--ink);
  background:
    linear-gradient(var(--bg), var(--bg)),
    repeating-linear-gradient(0deg, transparent, transparent 23px, rgba(47,111,237,.05) 24px),
    repeating-linear-gradient(90deg, transparent, transparent 23px, rgba(47,111,237,.05) 24px);
  background-blend-mode: normal, multiply, multiply;
  -webkit-font-smoothing: antialiased;
  font-size: 14px;
  line-height: 1.55;
}
a { color: var(--blue); text-decoration: none; }
button { font-family: inherit; cursor: pointer; }
h1,h2,h3,h4 { color: var(--navy); font-weight: 700; }

/* ---------- App 框架 ---------- */
.app { display: flex; min-height: 100vh; }

/* 侧边导航（桌面） */
.sidebar {
  width: 232px; flex-shrink: 0; background: var(--surface);
  border-right: 1px solid var(--line);
  display: flex; flex-direction: column; position: sticky; top: 0; height: 100vh;
}
.brand { display: flex; align-items: center; gap: 10px; padding: 18px 18px 16px; border-bottom: 1px solid var(--line); }
.brand .logo {
  width: 34px; height: 34px; border-radius: 8px; background: var(--navy);
  color: #fff; display: grid; place-items: center; font-weight: 700; font-size: 15px;
}
.brand .t { font-weight: 700; color: var(--navy); font-size: 15px; line-height: 1.2; }
.brand .t small { display: block; color: var(--muted); font-weight: 400; font-size: 11px; }
.nav-scroll { flex: 1; overflow-y: auto; padding: 10px 10px 20px; }
.nav-group { margin-top: 12px; }
.nav-group .gtitle { font-size: 11px; color: var(--muted); padding: 6px 10px; letter-spacing: .5px; }
.nav-item {
  display: flex; align-items: center; gap: 10px; width: 100%;
  padding: 9px 10px; border-radius: 8px; color: var(--ink);
  background: transparent; border: none; font-size: 13.5px; text-align: left;
}
.nav-item .ico { width: 18px; text-align: center; opacity: .8; }
.nav-item:hover { background: var(--blue-soft); }
.nav-item.active { background: var(--navy); color: #fff; }
.nav-item.active .ico { opacity: 1; }
.side-foot { padding: 12px; border-top: 1px solid var(--line); }

/* 主内容 */
.main { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.topbar {
  height: 60px; background: rgba(255,255,255,.85); backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--line);
  display: flex; align-items: center; gap: 14px; padding: 0 24px; position: sticky; top: 0; z-index: 20;
}
.topbar .menu-btn { display: none; border: none; background: none; font-size: 20px; color: var(--navy); }
.class-switch {
  display: flex; align-items: center; gap: 8px; border: 1px solid var(--line);
  border-radius: 8px; padding: 6px 12px; background: #fff; font-size: 13px;
}
.class-switch b { color: var(--navy); }
.topbar .spacer { flex: 1; }
.role-toggle { display: flex; background: var(--blue-soft); border-radius: 8px; padding: 3px; }
.role-toggle button {
  border: none; background: transparent; padding: 6px 14px; border-radius: 6px;
  font-size: 13px; color: var(--navy-2);
}
.role-toggle button.active { background: var(--navy); color: #fff; }
.avatar { width: 34px; height: 34px; border-radius: 50%; background: var(--blue-soft); color: var(--navy); display: grid; place-items: center; font-weight: 700; }

.content { padding: 26px 28px 60px; max-width: 1280px; width: 100%; margin: 0 auto; }

/* 页面标题 */
.page-head { margin-bottom: 20px; }
.page-head h1 { font-size: 24px; display: flex; align-items: center; gap: 10px; }
.page-head p { color: var(--muted); margin-top: 4px; font-size: 13px; }

/* 卡片/网格通用 */
.grid { display: grid; gap: 16px; }
.g-4 { grid-template-columns: repeat(4, 1fr); }
.g-3 { grid-template-columns: repeat(3, 1fr); }
.g-2 { grid-template-columns: repeat(2, 1fr); }
.card {
  background: var(--surface); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 18px; box-shadow: var(--shadow);
}
.stat .k { color: var(--muted); font-size: 13px; display: flex; align-items: center; justify-content: space-between; }
.stat .v { font-size: 30px; font-weight: 700; color: var(--navy); margin-top: 6px; }
.stat .sub { font-size: 12px; color: var(--muted); margin-top: 2px; }
.badge { display: inline-block; font-size: 11px; padding: 2px 8px; border-radius: 20px; font-weight: 500; }
.badge.blue { background: var(--blue-soft); color: var(--blue); }
.badge.green { background: #e6f6ee; color: var(--green); }
.badge.amber { background: #fbf2df; color: var(--amber); }
.badge.gray { background: #eef1f6; color: var(--muted); }

.section-title { font-size: 15px; margin: 26px 0 12px; display: flex; align-items: center; justify-content: space-between; }
.section-title .more { font-size: 12px; color: var(--blue); font-weight: 400; }

/* 按钮 */
.btn { border: 1px solid var(--line); background: #fff; color: var(--ink); padding: 8px 16px; border-radius: 8px; font-size: 13px; }
.btn.primary { background: var(--blue); border-color: var(--blue); color: #fff; }
.btn.navy { background: var(--navy); border-color: var(--navy); color: #fff; }
.btn.ghost { background: var(--blue-soft); border-color: transparent; color: var(--blue); }
.btn.sm { padding: 5px 10px; font-size: 12px; }

/* 表格 */
table { width: 100%; border-collapse: collapse; font-size: 13px; }
th { text-align: left; color: var(--muted); font-weight: 500; font-size: 12px; padding: 10px 12px; border-bottom: 1px solid var(--line); }
td { padding: 11px 12px; border-bottom: 1px solid var(--line); }
tr:last-child td { border-bottom: none; }
.table-wrap { background: #fff; border: 1px solid var(--line); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow); }

/* 过滤栏 */
.toolbar { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.tabs { display: flex; gap: 4px; background: #eef2f9; border-radius: 8px; padding: 3px; }
.tabs button { border: none; background: transparent; padding: 6px 14px; border-radius: 6px; font-size: 13px; color: var(--muted); }
.tabs button.active { background: #fff; color: var(--navy); box-shadow: var(--shadow); }
.search { flex: 1; min-width: 180px; border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; font-size: 13px; background: #fff; }

/* 课程章节 */
.chapter { display: flex; gap: 14px; padding: 16px; border: 1px solid var(--line); border-radius: var(--radius); background: #fff; margin-bottom: 12px; transition: .15s; }
.chapter:hover { border-color: var(--blue-line); box-shadow: var(--shadow); }
.chapter .num { width: 40px; height: 40px; border-radius: 9px; background: var(--blue-soft); color: var(--blue); display: grid; place-items: center; font-weight: 700; flex-shrink: 0; }
.chapter .info { flex: 1; }
.chapter .info h3 { font-size: 15px; margin-bottom: 4px; }
.chapter .meta { color: var(--muted); font-size: 12px; display: flex; gap: 14px; flex-wrap: wrap; }
.progress { height: 6px; background: var(--line); border-radius: 4px; overflow: hidden; margin-top: 10px; }
.progress > i { display: block; height: 100%; background: var(--blue); border-radius: 4px; }

/* 排行榜 */
.rank-row { display: flex; align-items: center; gap: 14px; padding: 12px 4px; border-bottom: 1px solid var(--line); }
.rank-row:last-child { border-bottom: none; }
.rank-no { width: 28px; height: 28px; border-radius: 7px; background: #eef2f9; color: var(--muted); display: grid; place-items: center; font-weight: 700; font-size: 13px; }
.rank-no.top1 { background: #fbe7c2; color: #b97e12; }
.rank-no.top2 { background: #e3e9f2; color: #5a6b85; }
.rank-no.top3 { background: #f3ddcf; color: #a85f34; }
.rank-row .nm { flex: 1; font-weight: 500; }
.rank-row .pts { font-weight: 700; color: var(--navy); }

/* 条形图（纯CSS） */
.bars { display: flex; align-items: flex-end; gap: 18px; height: 200px; padding: 10px 4px 0; }
.bars .bar { flex: 1; display: flex; flex-direction: column; align-items: center; gap: 8px; height: 100%; justify-content: flex-end; }
.bars .bar i { width: 60%; background: linear-gradient(180deg, var(--blue), var(--navy-2)); border-radius: 6px 6px 0 0; display: block; }
.bars .bar span { font-size: 12px; color: var(--muted); }
.bars .bar b { font-size: 12px; color: var(--navy); }

/* 大屏课堂 */
.stage { background: linear-gradient(135deg, #0a1f44, #113a7c); color: #fff; min-height: 100vh; padding: 40px; }
.stage h1 { color: #fff; font-size: 40px; }
.stage .qcard { background: rgba(255,255,255,.08); border: 1px solid rgba(255,255,255,.18); border-radius: 16px; padding: 30px; margin-top: 24px; }
.stage .opt { background: rgba(255,255,255,.1); border-radius: 10px; padding: 16px 20px; margin-top: 12px; display: flex; justify-content: space-between; }
.stage .livebar { height: 14px; background: rgba(255,255,255,.15); border-radius: 8px; overflow: hidden; flex: 1; margin: 0 16px; }
.stage .livebar i { display: block; height: 100%; background: linear-gradient(90deg,#5ab0ff,#8fd0ff); }

/* 空状态 */
.empty { text-align: center; padding: 50px 20px; color: var(--muted); }
.empty .e-ico { font-size: 40px; margin-bottom: 10px; }

/* 移动端底部 Tab */
.tabbar { display: none; }

/* ---------- 响应式 ---------- */
.sidebar-backdrop { display: none; }
@media (max-width: 960px) {
  .g-4 { grid-template-columns: repeat(2,1fr); }
  .g-3 { grid-template-columns: 1fr; }
  .g-2 { grid-template-columns: 1fr; }
}
@media (max-width: 760px) {
  .sidebar { position: fixed; left: 0; top: 0; z-index: 50; transform: translateX(-100%); transition: .2s; }
  .sidebar.open { transform: translateX(0); }
  .sidebar-backdrop.show { display: block; position: fixed; inset: 0; background: rgba(10,30,60,.4); z-index: 40; }
  .topbar .menu-btn { display: block; }
  .content { padding: 18px 16px 90px; }
  .role-toggle { display: none; }
  .g-4 { grid-template-columns: repeat(2,1fr); gap: 12px; }
  .stat .v { font-size: 24px; }
  /* 底部 Tab（学生移动优先） */
  .tabbar {
    display: flex; position: fixed; bottom: 0; left: 0; right: 0; z-index: 30;
    background: #fff; border-top: 1px solid var(--line); padding: 6px 4px calc(6px + env(safe-area-inset-bottom));
  }
  .tabbar button { flex: 1; border: none; background: none; color: var(--muted); font-size: 11px; display: flex; flex-direction: column; gap: 2px; align-items: center; }
  .tabbar button .ti { font-size: 19px; }
  .tabbar button.active { color: var(--blue); }
  .hide-mobile { display: none !important; }
}

/* ============ 新增模块样式（原创浅色） ============ */
.empty { text-align:center; color:var(--muted); padding:40px; font-size:14px; }

/* 章节胶囊条 */
.chapter-strip { display:flex; gap:10px; flex-wrap:wrap; }
.ch-pill { border:1px solid var(--line); background:#fff; border-radius:20px; padding:8px 16px;
  font-size:13px; color:var(--navy-2); cursor:pointer; display:flex; flex-direction:column; align-items:center; line-height:1.3; }
.ch-pill small { color:var(--muted); font-size:11px; }
.ch-pill.on { background:var(--blue); color:#fff; border-color:var(--blue); }
.ch-pill.on small { color:rgba(255,255,255,.85); }

/* 视频卡 */
.video-card { padding:0 !important; overflow:hidden; }
.vc-cover { height:150px; background:linear-gradient(135deg,#dbe8fc,#eef4ff); display:grid; place-items:center;
  font-size:46px; position:relative; }
.vc-play { position:absolute; width:46px;height:46px;border-radius:50%;background:rgba(47,111,237,.9);
  color:#fff;display:grid;place-items:center;font-size:17px;padding-left:3px; }
.ai-tag { position:absolute; top:10px; left:10px; background:rgba(24,160,88,.92); color:#fff;
  font-size:11px; padding:3px 9px; border-radius:11px; }
.gnode { cursor:pointer; }
.gnode:hover circle { fill:#d4e4fb; }

/* 问答 */
.qa-stat { width:52px; text-align:center; flex-shrink:0; background:var(--bg); border-radius:8px; padding:8px 0; }
.qa-stat b { display:block; color:var(--blue); font-size:17px; }
.qa-stat span { font-size:11px; color:var(--muted); }

/* 小组答辩轮次 */
.round-grid { display:flex; gap:12px; flex-wrap:wrap; }
.round-item { flex:1; min-width:110px; border:1px solid var(--line); border-radius:10px; padding:14px;
  text-align:center; display:flex; flex-direction:column; gap:8px; align-items:center; }
.round-item .rno { font-weight:700; color:var(--navy); }
.round-item .rmeta { font-size:12px; color:var(--muted); }
.round-item.add { justify-content:center; color:var(--muted); border-style:dashed; cursor:pointer; min-height:96px; }

/* 成就 */
.honor { text-align:center; }
.honor .hico { font-size:40px; margin-bottom:8px; }
.honor.locked .hico { filter:grayscale(1); opacity:.45; }
.honor b { display:block; }
.honor .badge { margin-top:10px; display:inline-block; }

/* 词云 */
.wordcloud { min-height:240px; display:flex; flex-wrap:wrap; gap:8px 16px; align-items:center;
  justify-content:center; padding:16px; background:radial-gradient(circle at 50% 40%,#f5f9ff,#fff);
  border:1px solid var(--line); border-radius:10px; }
.wordcloud .w { font-weight:700; line-height:1; cursor:default; display:inline-flex; align-items:baseline; gap:2px; }
.wordcloud .wcnt { font-size:11px; font-weight:600; opacity:.7; }

/* 主题词云签到 */
.sign-topic-label { display:block; font-size:12.5px; color:var(--muted); margin:4px 0 6px; }
.sign-topic-input { flex:1; border:1px solid var(--line); border-radius:8px; padding:10px 12px;
  font-size:14px; color:var(--navy); background:#fff; }
.sign-topic-input:focus { outline:none; border-color:var(--blue); box-shadow:0 0 0 3px var(--blue-soft); }
.sign-banner { background:linear-gradient(135deg,#eaf2ff,#f6f9ff); border:1px solid var(--blue-line);
  border-radius:12px; padding:20px; text-align:center; }
.sb-topic { font-size:19px; font-weight:700; color:var(--navy); }
.sb-hint { font-size:12.5px; color:var(--muted); margin-top:8px; line-height:1.6; }
.sign-submit-row { display:flex; gap:10px; margin-top:16px; }
.sign-word-input { flex:1; border:1px solid var(--line); border-radius:10px; padding:12px 14px; font-size:15px; }
.sign-word-input:focus { outline:none; border-color:var(--blue); box-shadow:0 0 0 3px var(--blue-soft); }
.signed-ok { margin-top:16px; text-align:center; background:#e7f7ef; color:var(--green);
  border:1px solid #b7e6cd; border-radius:10px; padding:14px; font-weight:600; }


/* ============================================================
   登录 / 注册 门禁页
   ============================================================ */
.auth-wrap {
  min-height: 100vh;
  display: flex; align-items: center; justify-content: center;
  padding: 24px;
  background:
    radial-gradient(1200px 600px at 80% -10%, rgba(47,111,237,.10), transparent 60%),
    radial-gradient(900px 500px at -10% 110%, rgba(0,216,255,.10), transparent 60%),
    var(--bg);
}
.auth-card {
  width: 100%; max-width: 440px;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 34px 34px 28px;
  box-shadow: 0 20px 60px rgba(10,40,90,.08);
}
.auth-brand { text-align: center; margin-bottom: 20px; }
.auth-logo {
  width: 56px; height: 56px; margin: 0 auto 12px;
  border-radius: 14px;
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; font-size: 22px; color: #fff; letter-spacing: 1px;
  background: linear-gradient(135deg, var(--navy), var(--blue));
  box-shadow: 0 8px 20px rgba(47,111,237,.35);
}
.auth-brand h1 { font-size: 21px; color: var(--navy); margin: 0 0 6px; }
.auth-brand p { font-size: 13px; color: var(--muted); margin: 0; }

.auth-tabs {
  display: flex; background: var(--bg); border-radius: 10px; padding: 4px;
  margin-bottom: 20px;
}
.auth-tabs button {
  flex: 1; border: 0; background: transparent; padding: 9px 0;
  font-size: 14px; font-weight: 600; color: var(--muted);
  border-radius: 8px; cursor: pointer; transition: all .18s;
}
.auth-tabs button.active {
  background: #fff; color: var(--blue);
  box-shadow: 0 2px 8px rgba(10,40,90,.08);
}

.auth-form .af { display: block; margin-bottom: 14px; }
.auth-form .af span {
  display: block; font-size: 13px; color: var(--navy-2);
  font-weight: 600; margin-bottom: 6px;
}
.auth-form .af input {
  width: 100%; padding: 11px 13px; font-size: 14px;
  border: 1px solid var(--line); border-radius: 9px;
  background: #fff; color: var(--ink);
  transition: border-color .15s, box-shadow .15s;
}
.auth-form .af input:focus {
  outline: none; border-color: var(--blue-line);
  box-shadow: 0 0 0 3px rgba(47,111,237,.12);
}
.af-row { display: flex; gap: 12px; }
.af-row .af { flex: 1; }

.btn.block { width: 100%; padding: 12px 0; font-size: 15px; margin-top: 4px; }
.auth-msg { font-size: 13px; min-height: 18px; margin: 2px 0 10px; }
.auth-msg.err { color: var(--danger); }
.auth-msg.ok { color: var(--green); }
.auth-hint {
  margin-top: 16px; font-size: 12px; color: var(--muted);
  line-height: 1.7; text-align: center;
}
.auth-hint code {
  background: var(--bg); padding: 1px 6px; border-radius: 5px;
  color: var(--blue); font-size: 11.5px;
}
.auth-form.hidden { display: none; }

/* 顶栏真实用户 */
.user-chip { display: flex; align-items: center; gap: 8px; margin: 0 6px 0 4px; }
.user-chip .uc-info { display: flex; flex-direction: column; line-height: 1.25; }
.user-chip .uc-info b { font-size: 13.5px; color: var(--navy); }
.user-chip .uc-info span { font-size: 11.5px; color: var(--muted); }
.role-toggle .locked { opacity: .55; cursor: not-allowed; }

/* 用户管理表角色下拉 */
.um-role {
  padding: 5px 6px; font-size: 12.5px;
  border: 1px solid var(--line); border-radius: 7px; background: #fff;
}

@media (max-width: 720px) {
  .auth-card { padding: 26px 20px 22px; border-radius: 14px; }
  .auth-brand h1 { font-size: 19px; }
  .user-chip .uc-info { display: none; }
  .af-row { flex-direction: column; gap: 0; }
}

/* ============================================================
   深色主题 · 组件适配覆盖（原浅色硬编码白底 → 夜空蓝）
   ============================================================ */
body {
  background:
    radial-gradient(1100px 620px at 10% -10%, rgba(64,128,232,.38), transparent 60%),
    radial-gradient(820px 520px at 99% 4%, rgba(245,197,24,.12), transparent 56%),
    radial-gradient(1000px 720px at 50% 120%, rgba(40,100,200,.30), transparent 62%),
    linear-gradient(165deg,#0a1832 0%,#0d2148 48%,#09152e 100%);
  background-attachment: fixed;
}

/* 顶栏：深色玻璃 */
.topbar { background: rgba(11,26,56,.7); border-bottom: 1px solid var(--line); backdrop-filter: blur(10px); }
.topbar .menu-btn { color: var(--gold); }
.class-switch { background: var(--surface); border-color: var(--line); }
.class-switch b { color: var(--gold-soft); }
.role-toggle { background: rgba(10,24,52,.6); }
.role-toggle button { color: var(--muted); }
.role-toggle button.active { background: linear-gradient(135deg,#f5c518,#e0a800); color: #2a1c00; }
.avatar { background: rgba(245,197,24,.18); color: var(--gold); }

h1,h2,h3,h4 { color: #f3f7ff; }

/* 卡片表面更立体 */
.card { background: linear-gradient(180deg, rgba(25,52,99,.72), rgba(17,40,80,.72));
  border: 1px solid var(--line); backdrop-filter: blur(6px); }
.stat .v { color: var(--gold-soft); }

/* 徽章 */
.badge.green { background: rgba(53,212,138,.16); color: var(--green); }
.badge.amber { background: rgba(245,197,24,.16); color: var(--gold); }
.badge.gray { background: rgba(148,184,240,.14); color: var(--muted); }
.badge.blue { background: rgba(88,182,255,.16); color: var(--cyan); }

/* 按钮 */
.btn { background: var(--surface-2); color: var(--ink); border-color: var(--line); }
.btn.primary { background: linear-gradient(135deg,#f5c518,#e2a900); color:#2a1c00; border-color: transparent; }
.btn.navy { background: linear-gradient(135deg,#3f7fe0,#2f63c8); color:#fff; border-color: transparent; }
.btn.ghost { background: rgba(245,197,24,.12); color: var(--gold); }

/* 表格 */
.table-wrap { background: var(--surface); border-color: var(--line); }
tbody tr { transition: background .15s; }
tbody tr:hover { background: rgba(88,182,255,.07); }

/* 过滤/分段控制 */
.tabs { background: rgba(9,22,48,.6); }
.tabs button { color: var(--muted); }
.tabs button.active { background: var(--surface-2); color: var(--gold); box-shadow: none; }
.search { background: var(--surface); border-color: var(--line); color: var(--ink); }
.search::placeholder { color: var(--muted); }

/* 章节 */
.chapter { background: linear-gradient(180deg,rgba(25,52,99,.6),rgba(16,38,76,.6)); border-color: var(--line); }
.chapter:hover { border-color: var(--blue-line); box-shadow: var(--shadow); }
.chapter .num { background: rgba(245,197,24,.15); color: var(--gold); }
.progress { background: rgba(148,184,240,.18); }
.progress > i { background: linear-gradient(90deg,#ffe98a,#f5c518); }

/* 排行 */
.rank-no { background: rgba(148,184,240,.14); color: var(--muted); }
.rank-no.top1 { background: rgba(245,197,24,.22); color: var(--gold); }
.rank-no.top2 { background: rgba(186,205,235,.18); color: #d4e0f4; }
.rank-no.top3 { background: rgba(232,150,108,.2); color: #f3ab88; }
.rank-row .pts { color: var(--gold); }

/* 柱状图 */
.bars .bar i { background: linear-gradient(180deg,#ffe98a,#f0b400); }
.bars .bar b { color: var(--gold-soft); }

/* 空状态 */
.empty { color: var(--muted); }

/* 大屏 */
.stage { background: radial-gradient(900px 500px at 20% -10%,rgba(64,128,232,.4),transparent 60%),
  linear-gradient(135deg,#0a1c40,#0e2c60); }
.stage .livebar i { background: linear-gradient(90deg,#ffe98a,#f5c518); }

/* 章节胶囊 */
.ch-pill { background: var(--surface); border-color: var(--line); color: var(--ink); }
.ch-pill small { color: var(--muted); }
.ch-pill.on { background: linear-gradient(135deg,#f5c518,#e0a800); color:#2a1c00; border-color: transparent; }
.ch-pill.on small { color: rgba(42,28,0,.7); }

/* 视频卡 */
.vc-cover { background: linear-gradient(135deg,#17396b,#0f2447); }
.vc-play { background: rgba(245,197,24,.94); color:#2a1c00; }
.gnode:hover circle { fill: rgba(245,197,24,.22) !important; }

/* 问答 */
.qa-stat { background: rgba(9,22,48,.5); }
.qa-stat b { color: var(--gold); }

/* 小组轮次 */
.round-item { background: var(--surface); border-color: var(--line); }
.round-item .rno { color: var(--gold-soft); }
.round-item.add { background: transparent; }

/* 词云 */
.wordcloud { background: radial-gradient(circle at 50% 32%,rgba(34,66,124,.62),rgba(16,38,76,.45)); border-color: var(--line); }

/* 签到 */
.sign-topic-input { background: var(--surface); border-color: var(--line); color: var(--ink); }
.sign-banner { background: linear-gradient(135deg,rgba(30,60,114,.5),rgba(17,42,82,.5)); border-color: var(--line); }
.sb-topic { color: var(--gold-soft); }
.sign-word-input { background: var(--surface); border-color: var(--line); color: var(--ink); }
.sign-word-input::placeholder { color: var(--muted); }
.signed-ok { background: rgba(53,212,138,.14); color: var(--green); border-color: rgba(53,212,138,.32); }

/* 用户管理下拉 */
.um-role { background: var(--surface-2); border-color: var(--line); color: var(--ink); }

/* 移动端底部 tabbar 深色 */
.tabbar { background: rgba(10,23,50,.94); border-top: 1px solid var(--line); backdrop-filter: blur(10px); }
.tabbar button { color: var(--muted); }
.tabbar button.active { color: var(--gold); }


/* 邀请码 / 访问码 */
.inv-cell { display:flex; flex-direction:column; gap:3px; }
.inv-code {
  font-family: 'SFMono-Regular', Consolas, monospace;
  background: rgba(245,197,24,.13); color: var(--gold);
  border:1px solid rgba(245,197,24,.35); border-radius:6px;
  padding:2px 8px; font-size:13px; letter-spacing:1px;
  display:inline-block; width:fit-content;
}
.inv-code.off { background: rgba(160,174,200,.12); color: var(--muted); border-color: var(--line); text-decoration: line-through; }
.inv-state { font-size:11px; }
.inv-state.on { color: var(--green); }
.inv-state.off { color: var(--muted); }
.row-actions { white-space:nowrap; }
.row-actions .btn { margin-right:4px; }
.btn.danger { color:#ff7a7a; border-color:rgba(255,122,122,.35); }
.btn.danger:hover { background:rgba(255,122,122,.12); }

/* 新建访问码表单 */
.form-grid { display:grid; grid-template-columns:repeat(2,1fr); gap:14px 18px; }
.fg-item { display:flex; flex-direction:column; gap:5px; }
.fg-item label { font-size:12px; color:var(--muted); }
.fg-item input {
  background: var(--surface); border:1px solid var(--line); color:var(--ink);
  border-radius:8px; padding:8px 10px; font-size:13px;
}
.fg-full { grid-column:1 / -1; }
.check-row { display:flex; gap:18px; flex-wrap:wrap; }
.chk { font-size:13px; display:flex; align-items:center; gap:5px; cursor:pointer; }
@media (max-width:640px){ .form-grid { grid-template-columns:1fr; } }