/* ============================================================
 * Ubuntu 学习营 —— 样式（移动优先 / Ubuntu 配色 / 支持暗色）
 * ============================================================ */

:root {
  --orange: #E95420;
  --orange-soft: rgba(233, 84, 32, 0.12);
  --purple: #772953;
  --green: #0E8420;
  --red: #C7162B;
  --bg: #F5F2EF;
  --card: #FFFFFF;
  --card-2: #FAF7F4;
  --text: #2B2B2B;
  --text-2: #6E6A66;
  --line: #EAE4DE;
  --code-bg: #2C001E;
  --code-fg: #F3E7EE;
  --shadow: 0 2px 10px rgba(60, 30, 20, 0.07);
  --radius: 16px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1B1719;
    --card: #262124;
    --card-2: #2E292B;
    --text: #F0EBE8;
    --text-2: #A79FA0;
    --line: #3A3335;
    --code-bg: #12020D;
    --code-fg: #F3E7EE;
    --orange-soft: rgba(233, 84, 32, 0.2);
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.35);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; -webkit-tap-highlight-color: transparent; }

html, body { height: 100%; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "HarmonyOS Sans SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  font-size: 15px;
  line-height: 1.65;
  padding-bottom: calc(78px + env(safe-area-inset-bottom));
}

code, pre, .mono { font-family: ui-monospace, "SF Mono", "JetBrains Mono", Consolas, "Courier New", monospace; }

#app { max-width: 560px; margin: 0 auto; padding: 14px 14px 20px; }

/* ---------- 顶栏 ---------- */
.topbar { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.topbar .logo {
  width: 38px; height: 38px; border-radius: 10px; flex: none;
  background: linear-gradient(135deg, var(--orange), #c33d10);
  color: #fff; font-weight: 800; font-size: 15px;
  display: flex; align-items: center; justify-content: center;
}
.topbar h1 { font-size: 19px; letter-spacing: 0.5px; flex: 1; }
.topbar h1 small { display: block; font-size: 11px; font-weight: 400; color: var(--text-2); letter-spacing: 1px; }

/* ---------- 通用卡片 ---------- */
.card {
  background: var(--card); border-radius: var(--radius);
  box-shadow: var(--shadow); padding: 16px; margin-bottom: 14px;
}

/* ---------- 欢迎总览 ---------- */
.hero { display: flex; align-items: center; gap: 16px; }
.hero .ring { flex: none; }
.hero .stats { flex: 1; display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }
.hero .stat { background: var(--card-2); border-radius: 12px; padding: 8px 10px; }
.hero .stat b { display: block; font-size: 17px; color: var(--orange); }
.hero .stat span { font-size: 11px; color: var(--text-2); }

/* ---------- 章节卡片 ---------- */
.ch-card { display: flex; gap: 12px; align-items: flex-start; cursor: pointer; position: relative; overflow: hidden; }
.ch-card:active { transform: scale(0.99); }
.ch-ico {
  width: 46px; height: 46px; border-radius: 13px; flex: none;
  background: var(--orange-soft); font-size: 24px;
  display: flex; align-items: center; justify-content: center;
}
.ch-main { flex: 1; min-width: 0; }
.ch-main h3 { font-size: 16px; margin-bottom: 2px; display: flex; align-items: center; gap: 8px; }
.ch-main p { font-size: 12.5px; color: var(--text-2); margin-bottom: 8px; }
.ch-arrow { color: var(--text-2); align-self: center; font-size: 18px; flex: none; }

.bar { height: 6px; border-radius: 4px; background: var(--line); overflow: hidden; }
.bar > i { display: block; height: 100%; border-radius: 4px; background: linear-gradient(90deg, var(--orange), #F0803C); transition: width 0.4s; }
.bar-meta { display: flex; justify-content: space-between; font-size: 11px; color: var(--text-2); margin-top: 4px; }

.badge {
  font-size: 10.5px; padding: 2px 8px; border-radius: 99px; font-weight: 600; flex: none;
  background: var(--orange-soft); color: var(--orange);
}
.badge.good { background: rgba(14, 132, 32, 0.14); color: var(--green); }
.badge.mid { background: rgba(233, 181, 32, 0.16); color: #A8770A; }
.badge.bad { background: rgba(199, 22, 43, 0.12); color: var(--red); }

/* ---------- 章节详情 ---------- */
.backbar { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; position: sticky; top: 0; z-index: 5; padding: 4px 0; background: var(--bg); }
.backbar .btn-back {
  width: 34px; height: 34px; border-radius: 50%; border: none; flex: none;
  background: var(--card); color: var(--text); font-size: 17px; box-shadow: var(--shadow); cursor: pointer;
}
.backbar h2 { font-size: 17px; flex: 1; }

.lesson { overflow: hidden; }
.lesson + .lesson { margin-top: 10px; }
.lesson summary {
  list-style: none; cursor: pointer; display: flex; align-items: center; gap: 10px;
  font-weight: 600; font-size: 15px; padding: 14px 16px;
}
.lesson summary::-webkit-details-marker { display: none; }
.lesson summary .num {
  width: 24px; height: 24px; border-radius: 8px; flex: none; font-size: 12px;
  background: var(--orange-soft); color: var(--orange); font-weight: 700;
  display: flex; align-items: center; justify-content: center;
}
.lesson summary .dot { margin-left: auto; width: 8px; height: 8px; border-radius: 50%; background: var(--line); flex: none; }
.lesson summary .dot.read { background: var(--green); }
.lesson .l-body { padding: 0 16px 14px; font-size: 14px; color: var(--text); }
.lesson .l-body p { margin-bottom: 10px; }

.codebox { position: relative; background: var(--code-bg); color: var(--code-fg); border-radius: 12px; padding: 12px 12px; margin-bottom: 10px; overflow-x: auto; }
.codebox pre { font-size: 12.5px; line-height: 1.7; white-space: pre-wrap; word-break: break-all; }
.codebox .copy {
  position: absolute; top: 8px; right: 8px; border: none; cursor: pointer;
  background: rgba(255, 255, 255, 0.14); color: #fff; font-size: 11px;
  border-radius: 7px; padding: 4px 9px;
}
.tipbar {
  font-size: 12.5px; border-left: 3px solid var(--orange);
  background: var(--orange-soft); color: var(--text);
  padding: 8px 10px; border-radius: 0 10px 10px 0;
}
.tipbar b { color: var(--orange); }

/* ---------- 按钮 ---------- */
.cta-sticky { position: sticky; bottom: calc(72px + env(safe-area-inset-bottom)); z-index: 10; }
.btn {
  display: block; width: 100%; border: none; cursor: pointer;
  background: linear-gradient(135deg, var(--orange), #d64513); color: #fff;
  font-size: 15.5px; font-weight: 700; padding: 14px; border-radius: 14px;
  box-shadow: 0 4px 14px rgba(233, 84, 32, 0.35);
}
.btn:active { transform: scale(0.98); }
.btn.ghost {
  background: var(--card); color: var(--orange); box-shadow: var(--shadow);
  border: 1.5px solid var(--orange);
}
.btn.danger { background: var(--card); color: var(--red); border: 1.5px solid var(--red); box-shadow: none; }
.btn-sm { width: auto; padding: 8px 16px; font-size: 13px; border-radius: 10px; box-shadow: none; }

/* ---------- 测验列表 ---------- */
.qz-row { display: flex; align-items: center; gap: 12px; cursor: pointer; }
.qz-row:active { transform: scale(0.99); }
.qz-row .score { margin-left: auto; }

/* ---------- 测验进行 ---------- */
.q-progress { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; }
.q-progress .bar { flex: 1; }
.q-progress .cnt { font-size: 12px; color: var(--text-2); flex: none; }

.q-type { display: inline-block; font-size: 11px; font-weight: 700; padding: 3px 10px; border-radius: 99px; margin-bottom: 10px; }
.q-type.choice { background: var(--orange-soft); color: var(--orange); }
.q-type.input { background: rgba(119, 41, 83, 0.14); color: var(--purple); }
@media (prefers-color-scheme: dark) { .q-type.input { color: #E39AC8; } }

.q-title { font-size: 16.5px; font-weight: 700; margin-bottom: 16px; line-height: 1.55; }

.opt {
  display: block; width: 100%; text-align: left; cursor: pointer;
  background: var(--card-2); border: 1.5px solid var(--line); color: var(--text);
  border-radius: 13px; padding: 13px 14px; font-size: 14.5px; margin-bottom: 10px;
  transition: border-color 0.15s;
}
.opt .tag {
  display: inline-flex; width: 22px; height: 22px; border-radius: 7px; margin-right: 9px;
  background: var(--line); color: var(--text-2); font-size: 12px; font-weight: 700;
  align-items: center; justify-content: center;
}
.opt.correct { border-color: var(--green); background: rgba(14, 132, 32, 0.1); }
.opt.correct .tag { background: var(--green); color: #fff; }
.opt.wrong { border-color: var(--red); background: rgba(199, 22, 43, 0.08); }
.opt.wrong .tag { background: var(--red); color: #fff; }
.opt.dim { opacity: 0.55; }
.opt:disabled { cursor: default; }

.input-wrap { display: flex; gap: 8px; margin-bottom: 14px; }
.input-wrap input {
  flex: 1; min-width: 0; font-size: 14.5px; padding: 12px 13px;
  border: 1.5px solid var(--line); border-radius: 12px; background: var(--card-2); color: var(--text);
  outline: none; font-family: ui-monospace, Consolas, monospace;
}
.input-wrap input:focus { border-color: var(--orange); }
.input-wrap input:disabled { opacity: 0.6; }

.explain { border-radius: 12px; padding: 12px 14px; font-size: 13.5px; margin-top: 4px; margin-bottom: 14px; }
.explain.ok { background: rgba(14, 132, 32, 0.1); border: 1px solid rgba(14, 132, 32, 0.3); }
.explain.no { background: rgba(199, 22, 43, 0.08); border: 1px solid rgba(199, 22, 43, 0.3); }
.explain b { display: block; margin-bottom: 3px; }
.explain.ok b { color: var(--green); }
.explain.no b { color: var(--red); }

/* ---------- 结果页 ---------- */
.result-head { text-align: center; padding: 10px 0 4px; }
.result-head h2 { font-size: 20px; margin-bottom: 4px; }
.result-head p { color: var(--text-2); font-size: 13px; }
.result-ring-wrap { display: flex; justify-content: center; margin: 14px 0; }
.wrong-list h4 { font-size: 14px; margin-bottom: 8px; color: var(--text-2); }
.wrong-item { background: var(--card-2); border-radius: 12px; padding: 10px 12px; margin-bottom: 8px; font-size: 13px; }
.wrong-item .wq { font-weight: 600; margin-bottom: 2px; }
.wrong-item .wa { color: var(--green); font-family: ui-monospace, Consolas, monospace; font-size: 12.5px; }

/* ---------- 我的页 ---------- */
.profile-stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 14px; }
.profile-stats .stat { background: var(--card-2); border-radius: 12px; padding: 10px 6px; text-align: center; }
.profile-stats .stat b { display: block; font-size: 18px; color: var(--orange); }
.profile-stats .stat span { font-size: 11px; color: var(--text-2); }

.m-row { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.m-row:last-child { margin-bottom: 0; }
.m-row .m-name { width: 92px; font-size: 12.5px; flex: none; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.m-row .bar { flex: 1; }
.m-row .m-val { width: 40px; text-align: right; font-size: 12px; color: var(--text-2); flex: none; }

.about { text-align: center; font-size: 11.5px; color: var(--text-2); padding: 8px 0 4px; }

/* ---------- 底部导航 ---------- */
#tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 50;
  display: flex; justify-content: space-around; align-items: stretch;
  background: var(--card); border-top: 1px solid var(--line);
  padding: 6px 0 calc(6px + env(safe-area-inset-bottom));
  max-width: 560px; margin: 0 auto;
}
#tabbar button {
  border: none; background: none; cursor: pointer; flex: 1;
  display: flex; flex-direction: column; align-items: center; gap: 1px;
  color: var(--text-2); font-size: 10.5px; padding: 2px 0;
}
#tabbar button .t-ico { font-size: 21px; line-height: 1.2; }
#tabbar button.active { color: var(--orange); font-weight: 700; }

/* ---------- Toast ---------- */
#toast {
  position: fixed; left: 50%; bottom: 100px; transform: translateX(-50%) translateY(20px);
  background: rgba(30, 24, 26, 0.92); color: #fff; font-size: 13px;
  padding: 9px 18px; border-radius: 99px; z-index: 99;
  opacity: 0; pointer-events: none; transition: all 0.25s;
}
#toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

.section-title { font-size: 13px; font-weight: 700; color: var(--text-2); margin: 4px 2px 10px; letter-spacing: 1px; }

.empty { text-align: center; color: var(--text-2); font-size: 13px; padding: 26px 0; }

.fade-in { animation: fade 0.25s ease; }
@keyframes fade { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }