/* 远程学习站 — 移动优先样式，暗色适配，无外部依赖 */
:root {
  --bg: #f4f5f9;
  --surface: #ffffff;
  --surface-2: #eef0f7;
  --text: #1c2030;
  --text-2: #5b6172;
  --border: #e2e5ee;
  --primary: #4f6ef7;
  --primary-ink: #ffffff;
  --accent: #22a06b;
  --danger: #e05252;
  --warn: #d9912a;
  --shadow: 0 1px 3px rgba(20, 24, 40, .08);
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #131521;
    --surface: #1d2130;
    --surface-2: #262b3d;
    --text: #e8eaf2;
    --text-2: #9aa1b5;
    --border: #2e3348;
    --primary: #6b85ff;
    --primary-ink: #10132a;
    --accent: #3cc48a;
    --danger: #ff7a7a;
    --warn: #e8b45a;
    --shadow: 0 1px 3px rgba(0, 0, 0, .4);
  }
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei",
    "Noto Sans CJK SC", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
  font-size: 16px;
}

/* ---------- 头部 ---------- */
.site-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 10px;
  padding: 18px 16px 10px;
  max-width: 720px;
  margin: 0 auto;
}

.site-title {
  font-size: 1.2rem;
  margin: 0;
  line-height: 1.3;
}

.site-sub {
  margin: 2px 0 0;
  font-size: .8rem;
  color: var(--text-2);
}

.sync-pill {
  flex: none;
  font-size: .72rem;
  color: var(--text-2);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 10px;
  white-space: nowrap;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 6px 16px 48px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

/* ---------- 卡片 ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 14px 16px;
}

.card-title {
  font-size: .95rem;
  margin: 0 0 10px;
  color: var(--text-2);
  font-weight: 600;
  letter-spacing: .02em;
}

.sub-title {
  font-size: .85rem;
  color: var(--text-2);
  margin: 16px 0 6px;
}

/* ---------- 今日任务 ---------- */
.today-nums {
  display: flex;
  gap: 28px;
  margin-bottom: 14px;
}

.num-item { display: flex; flex-direction: column; }

.num-item b { font-size: 1.7rem; line-height: 1.1; }

.num-item span { font-size: .78rem; color: var(--text-2); }

/* ---------- 按钮 ---------- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 44px;
  padding: 10px 18px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  font-size: .95rem;
  font-family: inherit;
  text-decoration: none;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.btn:active { transform: scale(.98); }

.btn-primary {
  background: var(--primary);
  border-color: var(--primary);
  color: var(--primary-ink);
  font-weight: 600;
}

.btn-big {
  display: flex;
  width: 100%;
  font-size: 1.08rem;
  min-height: 52px;
}

/* ---------- 统计条 ---------- */
.stat-strip {
  display: flex;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 12px 4px;
}

.stat {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.stat b { font-size: 1.25rem; }

.stat span { font-size: .72rem; color: var(--text-2); }

/* ---------- 分册 ---------- */
.volume { border-top: 1px solid var(--border); }

.volume:first-child { border-top: 0; }

.volume summary {
  display: flex;
  justify-content: space-between;
  align-items: center;
  min-height: 48px;
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  padding: 4px 2px;
}

.volume summary::-webkit-details-marker { display: none; }

.volume summary::after {
  content: '›';
  color: var(--text-2);
  transition: transform .18s;
}

.volume[open] summary::after { transform: rotate(90deg); }

.volume-meta { font-size: .76rem; color: var(--text-2); font-weight: 400; margin-right: 8px; }

.article-list { padding-bottom: 6px; }

.article-row {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 44px;
  padding: 8px 6px;
  border-radius: 10px;
  text-decoration: none;
  color: var(--text);
}

.article-row:active { background: var(--surface-2); }

.article-num {
  flex: none;
  width: 26px;
  height: 26px;
  border-radius: 8px;
  background: var(--surface-2);
  color: var(--text-2);
  font-size: .78rem;
  display: flex;
  align-items: center;
  justify-content: center;
}

.article-title {
  flex: 1;
  min-width: 0;
  font-size: .86rem;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.article-meta {
  flex: none;
  font-size: .72rem;
  color: var(--text-2);
}

.chevron { color: var(--text-2); }

/* ---------- 设置 ---------- */
.settings summary { min-height: 48px; cursor: pointer; list-style: none; display: flex; align-items: center; }

.settings summary::-webkit-details-marker { display: none; }

.settings summary::after { content: '›'; margin-left: auto; color: var(--text-2); }

.settings[open] summary::after { transform: rotate(90deg); }

.settings-body { display: flex; flex-direction: column; gap: 12px; padding-top: 4px; }

.field { display: flex; flex-direction: column; gap: 4px; font-size: .82rem; color: var(--text-2); }

.field input {
  min-height: 44px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  padding: 8px 12px;
  font-size: .95rem;
  font-family: inherit;
}

.import-export { display: flex; gap: 10px; }

.import-export .btn { flex: 1; }

.nav-links { text-align: center; margin: 4px 0; }

.nav-links a { color: var(--primary); text-decoration: none; font-size: .9rem; }

/* ---------- Toast ---------- */
.toast {
  position: fixed;
  left: 50%;
  bottom: 32px;
  transform: translateX(-50%) translateY(20px);
  background: rgba(20, 24, 40, .88);
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: .85rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity .2s, transform .2s;
}

.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ================= 刷词页 ================= */
.review-page { display: flex; flex-direction: column; min-height: 100vh; }

.review-top {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px 6px;
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
}

.review-top-mid { flex: 1; min-width: 0; }

.review-progress { font-weight: 700; }

.review-article {
  font-size: .76rem;
  color: var(--text-2);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.back-link {
  flex: none;
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  text-decoration: none;
  color: var(--text);
  border-radius: 10px;
}

.loading { text-align: center; color: var(--text-2); padding: 40px 0; }

.review-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  max-width: 720px;
  margin: 0 auto;
  width: 100%;
  padding: 8px 16px 20px;
}

/* 卡片翻转 */
.card-flip {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 18px;
  box-shadow: var(--shadow);
  min-height: 340px;
  cursor: pointer;
  perspective: 900px;
  overflow: hidden;
}

.card-front, .card-back {
  padding: 24px 20px;
  transition: opacity .22s ease, transform .22s ease;
}

.card-back {
  position: absolute;
  inset: 0;
  overflow-y: auto;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
}

.card-flip.revealed .card-front {
  opacity: 0;
  transform: translateY(-12px);
  pointer-events: none;
}

.card-flip.revealed .card-back { opacity: 1; transform: none; pointer-events: auto; }

.word-row { display: flex; align-items: center; justify-content: center; gap: 10px; }

.word {
  font-size: 2.1rem;
  font-weight: 700;
  text-align: center;
  letter-spacing: .01em;
  margin-top: 56px;
}

.word.small { font-size: 1.3rem; margin: 0 0 10px; }

.reveal-hint {
  text-align: center;
  color: var(--text-2);
  font-size: .8rem;
  margin-top: 14px;
}

.icon-btn {
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  border-radius: 999px;
  width: 44px;
  height: 44px;
  font-size: 1.05rem;
  cursor: pointer;
  flex: none;
}

.icon-btn.inline {
  width: 34px;
  height: 34px;
  font-size: .85rem;
  vertical-align: middle;
}

.detail { margin: 0; display: flex; flex-direction: column; gap: 10px; }

.detail > div { display: flex; gap: 10px; }

.detail dt {
  flex: none;
  width: 62px;
  font-size: .74rem;
  color: var(--text-2);
  padding-top: 3px;
}

.detail dd { margin: 0; font-size: .92rem; flex: 1; min-width: 0; }

/* 评分按钮 */
.grade-bar {
  display: flex;
  gap: 10px;
  margin-top: 14px;
  opacity: .35;
  pointer-events: none;
  transition: opacity .2s;
}

.grade-bar.show { opacity: 1; pointer-events: auto; }

.grade-btn {
  flex: 1;
  min-height: 56px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  box-shadow: var(--shadow);
}

.grade-btn:active { transform: scale(.97); }

.grade-btn.g0 { color: var(--danger); }

.grade-btn.g1 { color: var(--warn); }

.grade-btn.g2 { color: var(--accent); }

/* 结束屏 */
.end-screen { display: none; text-align: center; padding: 48px 0; }

.end-screen.show { display: block; }

.end-stats { display: flex; justify-content: center; gap: 34px; margin: 22px 0 28px; }

.end-stats > div { display: flex; flex-direction: column; }

.end-stats b { font-size: 1.8rem; }

.end-stats span { font-size: .78rem; color: var(--text-2); }

.end-actions { display: flex; gap: 12px; justify-content: center; }

/* ================= 仪表盘 ================= */
.volume-bars { display: flex; flex-direction: column; gap: 8px; margin-top: 10px; }

.vol-bar-row { display: flex; align-items: center; gap: 10px; }

.vol-label { flex: none; width: 46px; font-size: .78rem; color: var(--text-2); }

.vol-pct { flex: none; width: 52px; text-align: right; font-size: .74rem; color: var(--text-2); }

.bar {
  flex: 1;
  height: 10px;
  border-radius: 999px;
  background: var(--surface-2);
  position: relative;
  overflow: hidden;
}

.bar-seen { position: absolute; left: 0; top: 0; bottom: 0; background: var(--primary); opacity: .35; border-radius: 999px; }

.bar-mastered { position: absolute; left: 0; top: 0; bottom: 0; background: var(--accent); border-radius: 999px; }

.due-forecast { display: flex; align-items: flex-end; gap: 8px; height: 120px; margin-top: 6px; }

.fc-col { flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: flex-end; height: 100%; }

.fc-count { font-size: .72rem; color: var(--text-2); min-height: 16px; }

.fc-bar { width: 70%; background: var(--primary); opacity: .55; border-radius: 6px 6px 0 0; }

.fc-bar.today { opacity: 1; background: var(--accent); }

.fc-label { font-size: .68rem; color: var(--text-2); margin-top: 4px; }

.snapshot-note { font-size: .74rem; color: var(--text-2); margin: 2px 2px 0; }

.board { margin-top: 14px; }

.board-name { font-size: 1.05rem; margin: 0 0 2px; }

.board-summary { font-size: .82rem; color: var(--text-2); margin: 0 0 10px; }

.board-section { margin-bottom: 14px; }

.board-section h3 { font-size: .88rem; margin: 0 0 6px; color: var(--text-2); }

.table-wrap {
  overflow-x: auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

table { border-collapse: collapse; width: 100%; font-size: .82rem; }

th, td {
  text-align: left;
  padding: 9px 12px;
  border-bottom: 1px solid var(--border);
  white-space: nowrap;
}

th { color: var(--text-2); font-weight: 600; font-size: .76rem; background: var(--surface-2); }

tr:last-child td { border-bottom: 0; }

@media (min-width: 640px) {
  body { font-size: 17px; }
  .word { font-size: 2.5rem; }
}