/* =========================================================
   中小学历史年代表 · 全局样式
   风格：莫兰迪低饱和 · 优雅克制 · 大量留白
   ========================================================= */

:root {
  /* —— 莫兰迪低饱和配色 —— */
  --c-primary: #54828c;      /* 主色 */
  --c-secondary: #6b7d9e;    /* 辅助色 */
  --c-accent: #ac536f;       /* 强调色 CTA/高亮 */
  --c-bg: #f8fbfb;           /* 页面背景 */
  --c-card: #ffffff;         /* 卡片/表面 */
  --c-text: #1b292c;         /* 正文文字 */
  --c-muted: #5c757a;        /* 次要文字 */
  --c-border: #dbe4e6;       /* 描边 */

  /* —— 由配色派生的柔和色阶 —— */
  --c-primary-soft: rgba(84, 130, 140, 0.09);
  --c-secondary-soft: rgba(107, 125, 158, 0.09);
  --c-accent-soft: rgba(172, 83, 111, 0.09);
  --c-primary-tint: rgba(84, 130, 140, 0.045);
  --c-ink-soft: rgba(27, 41, 44, 0.03);

  /* —— 字体 —— */
  --font-serif: 'Noto Serif SC', 'Songti SC', 'STSong', Georgia, 'Times New Roman', serif;
  --font-sans: system-ui, -apple-system, 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', 'Segoe UI', sans-serif;

  /* —— 圆角 / 阴影 / 间距 —— */
  --radius: 14px;
  --radius-sm: 10px;
  --shadow-soft: 0 12px 32px rgba(27, 41, 44, 0.07);
  --shadow-card: 0 2px 10px rgba(27, 41, 44, 0.05), 0 18px 40px rgba(27, 41, 44, 0.05);
  --shadow-sm: 0 2px 8px rgba(27, 41, 44, 0.05);
  --container: 1060px;
  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
}

/* ============ 基础 ============ */
* { box-sizing: border-box; margin: 0; padding: 0; }

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

body {
  font-family: var(--font-sans);
  background-color: var(--c-bg);
  color: var(--c-text);
  line-height: 1.75;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

/* 极淡噪点覆层 */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: .5;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)' opacity='0.05'/%3E%3C/svg%3E");
}

main, header, footer { position: relative; z-index: 1; }

::selection { background: var(--c-primary-soft); color: var(--c-text); }

img, svg { max-width: 100%; display: block; }

a { color: var(--c-primary); text-decoration: none; transition: color .25s var(--ease); }
a:hover { color: var(--c-accent); }

h1, h2, h3, h4, .serif { font-family: var(--font-serif); font-weight: 600; line-height: 1.35; letter-spacing: .01em; }

.container { max-width: var(--container); margin: 0 auto; padding: 0 28px; }

/* ============ 顶部导航 ============ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(248, 251, 251, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--c-border);
}
.nav-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 28px;
  height: 66px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--c-text);
}
.brand-mark {
  width: 36px; height: 36px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--c-primary), var(--c-secondary));
  color: #fff;
  display: grid;
  place-items: center;
  font-family: var(--font-serif);
  font-size: 19px;
  box-shadow: var(--shadow-sm);
  flex: none;
}
.brand-name { font-family: var(--font-serif); font-size: 17px; font-weight: 700; letter-spacing: .04em; }
.brand-sub { font-size: 11px; color: var(--c-muted); letter-spacing: .18em; margin-top: -2px; }

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links a {
  padding: 8px 16px;
  border-radius: 999px;
  color: var(--c-muted);
  font-size: 14px;
  transition: all .25s var(--ease);
}
.nav-links a:hover { color: var(--c-primary); background: var(--c-primary-soft); }
.nav-links a.active { color: var(--c-text); background: var(--c-ink-soft); font-weight: 600; }

/* ============ Hero ============ */
.hero { padding: 76px 0 48px; text-align: center; }
.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  letter-spacing: .28em;
  color: var(--c-secondary);
  text-transform: uppercase;
}
.hero-kicker::before, .hero-kicker::after {
  content: "";
  width: 26px; height: 1px;
  background: var(--c-border);
}
.hero h1 {
  font-size: clamp(34px, 6vw, 54px);
  font-weight: 700;
  margin: 22px auto 18px;
  max-width: 15em;
  color: var(--c-text);
}
.hero h1 .accent { color: var(--c-accent); font-weight: 400; font-style: italic; }
.hero p.lead {
  max-width: 560px;
  margin: 0 auto;
  color: var(--c-muted);
  font-size: 16px;
  line-height: 2;
}
.hero-stats {
  display: flex;
  justify-content: center;
  gap: 12px;
  margin-top: 30px;
  flex-wrap: wrap;
}
.stat {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: 999px;
  padding: 9px 20px;
  font-size: 13px;
  color: var(--c-muted);
  box-shadow: var(--shadow-sm);
}
.stat b { color: var(--c-primary); font-weight: 700; font-size: 15px; margin-right: 3px; }

/* ============ 筛选控件 ============ */
.controls {
  margin: 26px 0 14px;
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 18px 20px 14px;
  box-shadow: var(--shadow-soft);
}
.controls-row {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}
.controls-label {
  font-size: 12px;
  letter-spacing: .12em;
  color: var(--c-muted);
  margin-right: 2px;
  flex: none;
}
.tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.tab-btn {
  border: 1px solid transparent;
  background: transparent;
  padding: 7px 18px;
  border-radius: 999px;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--c-muted);
  cursor: pointer;
  transition: all .25s var(--ease);
}
.tab-btn:hover { color: var(--c-text); background: var(--c-ink-soft); }
.tab-btn.active {
  background: var(--c-primary);
  color: #fff;
  box-shadow: 0 4px 14px rgba(84, 130, 140, 0.35);
}

.chips { display: flex; gap: 8px; flex-wrap: wrap; }
.chip {
  border: 1px solid var(--c-border);
  background: var(--c-bg);
  padding: 6px 14px;
  border-radius: 999px;
  font-size: 13px;
  color: var(--c-muted);
  cursor: pointer;
  transition: all .25s var(--ease);
}
.chip:hover { border-color: var(--c-primary); color: var(--c-primary); background: var(--c-primary-tint); }
.chip.active {
  border-color: var(--c-primary);
  background: var(--c-primary-soft);
  color: var(--c-primary);
  font-weight: 600;
}

.search-row { margin-top: 14px; display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.search-box {
  flex: 1;
  min-width: 220px;
  display: flex;
  align-items: center;
  gap: 10px;
  border: 1px solid var(--c-border);
  background: var(--c-bg);
  border-radius: 999px;
  padding: 0 18px;
  height: 44px;
  transition: border-color .25s var(--ease), box-shadow .25s var(--ease);
}
.search-box:focus-within { border-color: var(--c-primary); box-shadow: 0 0 0 4px var(--c-primary-soft); }
.search-box svg { width: 17px; height: 17px; color: var(--c-muted); flex: none; }
.search-box input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--c-text);
}
.search-box input::placeholder { color: var(--c-muted); opacity: .7; }
.result-count { font-size: 13px; color: var(--c-muted); letter-spacing: .04em; }
.result-count b { color: var(--c-primary); font-weight: 700; }

/* ============ 时间轴 ============ */
.timeline-wrap { position: relative; padding: 26px 0 10px; }
.timeline { position: relative; }
.timeline::before {
  content: "";
  position: absolute;
  top: 0; bottom: 0;
  left: 50%;
  width: 2px;
  background: var(--c-border);
  transform: translateX(-50%);
}
.tl-progress {
  position: absolute;
  top: 0;
  left: 50%;
  width: 2px;
  height: 0;
  transform: translateX(-50%);
  background: linear-gradient(180deg, var(--c-primary) 0%, var(--c-secondary) 55%, var(--c-accent) 100%);
  border-radius: 2px;
  box-shadow: 0 0 10px rgba(84, 130, 140, 0.25);
  transition: height .15s linear;
}

.tl-item {
  position: relative;
  width: calc(50% - 46px);
  margin: 40px 0;
  opacity: 0;
  transform: translateY(26px);
  transition: opacity .7s var(--ease), transform .7s var(--ease);
}
.tl-item.in { opacity: 1; transform: translateY(0); }
.tl-item.left { margin-right: auto; text-align: right; }
.tl-item.right { margin-left: auto; text-align: left; }

.tl-dot {
  position: absolute;
  top: 30px;
  left: calc(100% + 46px);
  width: 13px; height: 13px;
  border-radius: 50%;
  background: var(--c-card);
  border: 3px solid var(--c-primary);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 0 4px var(--c-primary-soft);
  transition: transform .3s var(--ease), box-shadow .3s var(--ease);
}
.tl-item.left .tl-dot { left: calc(100% + 46px); }
.tl-item.right .tl-dot { left: -46px; }
.tl-item:hover .tl-dot { transform: translate(-50%, -50%) scale(1.25); box-shadow: 0 0 0 6px var(--c-primary-soft); }

/* 分类配色：古代=主色，近现代=辅助色，世界=强调色 */
.cat-ancient .tl-dot { border-color: var(--c-primary); box-shadow: 0 0 0 4px var(--c-primary-soft); }
.cat-modern .tl-dot { border-color: var(--c-secondary); box-shadow: 0 0 0 4px var(--c-secondary-soft); }
.cat-world .tl-dot { border-color: var(--c-accent); box-shadow: 0 0 0 4px var(--c-accent-soft); }
.cat-modern:hover .tl-dot { box-shadow: 0 0 0 6px var(--c-secondary-soft); }
.cat-world:hover .tl-dot { box-shadow: 0 0 0 6px var(--c-accent-soft); }

.tl-card {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 20px 24px 18px;
  box-shadow: var(--shadow-card);
  transition: transform .35s var(--ease), box-shadow .35s var(--ease), border-color .35s var(--ease);
  text-align: left;
  cursor: pointer;
  position: relative;
}
.tl-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 6px 16px rgba(27, 41, 44, 0.08), 0 26px 50px rgba(27, 41, 44, 0.10);
  border-color: rgba(84, 130, 140, 0.4);
}

.tl-year {
  font-family: var(--font-serif);
  font-size: 13px;
  color: var(--c-primary);
  letter-spacing: .14em;
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 8px;
}
.cat-modern .tl-year { color: var(--c-secondary); }
.cat-world .tl-year { color: var(--c-accent); }
.tl-year .line { width: 22px; height: 1px; background: currentColor; opacity: .5; flex: none; }
.tl-item.left .tl-year { flex-direction: row-reverse; }

.tl-title {
  font-size: 19px;
  font-weight: 700;
  color: var(--c-text);
  margin-bottom: 7px;
  line-height: 1.4;
}
.tl-summary { font-size: 14px; color: var(--c-muted); margin-bottom: 13px; line-height: 1.85; }

.tl-tags { display: flex; gap: 7px; flex-wrap: wrap; }
.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  font-size: 12px;
  padding: 3px 11px;
  border-radius: 999px;
  background: var(--c-primary-soft);
  color: var(--c-primary);
  letter-spacing: .03em;
}
.tag.is-cat { background: var(--c-primary-soft); color: var(--c-primary); }
.tag.is-period { background: var(--c-ink-soft); color: var(--c-muted); }
.cat-modern .tag.is-cat { background: var(--c-secondary-soft); color: var(--c-secondary); }
.cat-world .tag.is-cat { background: var(--c-accent-soft); color: var(--c-accent); }
.tag .dot { width: 5px; height: 5px; border-radius: 50%; background: currentColor; }

.tl-more {
  margin-top: 14px;
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  font-weight: 600;
  color: var(--c-accent);
}
.tl-more svg { width: 14px; height: 14px; transition: transform .25s var(--ease); }
.tl-card:hover .tl-more svg { transform: translateX(4px); }

.empty {
  text-align: center;
  padding: 70px 20px;
  color: var(--c-muted);
  font-size: 15px;
}
.empty .empty-mark {
  font-family: var(--font-serif);
  font-size: 40px;
  color: var(--c-border);
  margin-bottom: 10px;
}

/* ============ 详情页 ============ */
.crumb {
  padding: 26px 0 4px;
  font-size: 13px;
  color: var(--c-muted);
}
.crumb a { color: var(--c-muted); }
.crumb a:hover { color: var(--c-primary); }
.crumb .sep { margin: 0 8px; color: var(--c-border); }

.detail-hero {
  padding: 34px 0 30px;
  border-bottom: 1px solid var(--c-border);
  margin-bottom: 34px;
}
.detail-hero .d-cat {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  letter-spacing: .2em;
  color: var(--c-secondary);
  margin-bottom: 18px;
}
.detail-hero .d-cat::before { content: ""; width: 20px; height: 1px; background: currentColor; }
.detail-hero h1 { font-size: clamp(30px, 5vw, 44px); font-weight: 700; margin-bottom: 14px; }
.detail-hero .d-year {
  font-family: var(--font-serif);
  font-size: 17px;
  color: var(--c-accent);
  letter-spacing: .1em;
  margin-bottom: 16px;
}
.detail-hero .d-summary { max-width: 640px; font-size: 16px; color: var(--c-muted); line-height: 2; }

.detail-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  margin-bottom: 22px;
}
.detail-block {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 26px 28px;
  box-shadow: var(--shadow-soft);
}
.detail-block.full { grid-column: 1 / -1; }
.detail-block h3 {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 17px;
  color: var(--c-text);
  margin-bottom: 14px;
}
.detail-block h3 .num {
  font-size: 12px;
  color: #fff;
  background: var(--c-primary);
  width: 26px; height: 26px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  flex: none;
}
.detail-block p { font-size: 15px; color: var(--c-muted); line-height: 2; }

.people-chips { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 6px; }
.people-chip {
  background: var(--c-secondary-soft);
  color: var(--c-secondary);
  border-radius: 999px;
  padding: 6px 16px;
  font-size: 14px;
  transition: all .25s var(--ease);
  border: 1px solid transparent;
}
.people-chip:hover { transform: translateY(-2px); background: var(--c-card); border-color: var(--c-secondary); box-shadow: var(--shadow-sm); }

.mnemonic-card {
  background: linear-gradient(135deg, rgba(172, 83, 111, 0.07), rgba(107, 125, 158, 0.06));
  border: 1px solid rgba(172, 83, 111, 0.22);
  border-radius: var(--radius);
  padding: 26px 28px;
  margin: 26px 0;
  display: flex;
  gap: 18px;
  align-items: flex-start;
}
.mnemonic-card .m-icon {
  flex: none;
  width: 44px; height: 44px;
  border-radius: 12px;
  background: var(--c-accent);
  color: #fff;
  display: grid;
  place-items: center;
  box-shadow: 0 8px 18px rgba(172, 83, 111, 0.3);
}
.mnemonic-card .m-icon svg { width: 22px; height: 22px; }
.mnemonic-card .m-label { font-size: 12px; letter-spacing: .2em; color: var(--c-accent); margin-bottom: 6px; font-weight: 700; }
.mnemonic-card .m-text { font-family: var(--font-serif); font-size: 16px; color: var(--c-text); line-height: 2; }

.detail-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 18px;
  margin: 30px 0 20px;
}
.d-nav {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 20px 24px;
  transition: all .3s var(--ease);
  color: var(--c-text);
}
.d-nav:hover { border-color: var(--c-primary); box-shadow: var(--shadow-soft); transform: translateY(-2px); }
.d-nav .dir { font-size: 12px; color: var(--c-muted); letter-spacing: .12em; margin-bottom: 6px; }
.d-nav.next { text-align: right; }
.d-nav .t { font-family: var(--font-serif); font-weight: 600; font-size: 16px; }
.d-nav .y { font-size: 12px; color: var(--c-primary); margin-top: 3px; }

/* ============ 记忆口诀页 ============ */
.mn-filter { margin: 26px 0 8px; }
.mn-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 22px;
  padding: 18px 0 40px;
}
.mn-card {
  background: var(--c-card);
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  padding: 28px 30px;
  box-shadow: var(--shadow-card);
  transition: transform .35s var(--ease), box-shadow .35s var(--ease);
  position: relative;
  opacity: 0;
  transform: translateY(22px);
  transition: opacity .6s var(--ease), transform .6s var(--ease), box-shadow .35s var(--ease);
}
.mn-card.in { opacity: 1; transform: translateY(0); }
.mn-card:hover { transform: translateY(-4px); box-shadow: 0 8px 20px rgba(27, 41, 44, 0.08), 0 24px 48px rgba(27, 41, 44, 0.09); }
.mn-card.flash { animation: mnFlash 1.6s var(--ease); }
@keyframes mnFlash {
  0%, 100% { box-shadow: var(--shadow-card); }
  25% { box-shadow: 0 0 0 5px var(--c-accent-soft), 0 8px 20px rgba(27, 41, 44, 0.08); }
}
.mn-card .mn-head { display: flex; align-items: center; gap: 10px; margin-bottom: 14px; flex-wrap: wrap; }
.mn-card .mn-title { font-family: var(--font-serif); font-size: 18px; font-weight: 700; }
.mn-card .mn-meta { margin-left: auto; display: flex; gap: 6px; }
.mn-card .mn-lines {
  font-family: var(--font-serif);
  font-size: 15.5px;
  line-height: 2.1;
  color: var(--c-text);
  border-left: 3px solid var(--c-border);
  padding-left: 18px;
}
.mn-card .mn-lines p + p { margin-top: 4px; }
.mn-card .mn-type {
  font-size: 11px;
  letter-spacing: .1em;
  padding: 2px 10px;
  border-radius: 999px;
  background: var(--c-accent-soft);
  color: var(--c-accent);
}
.random-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  justify-content: center;
  padding: 14px 0 6px;
  flex-wrap: wrap;
}
.random-bar .hint { font-size: 13px; color: var(--c-muted); }

/* ============ 按钮 ============ */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  border: none;
  cursor: pointer;
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 600;
  padding: 11px 24px;
  border-radius: 999px;
  background: var(--c-accent);
  color: #fff;
  box-shadow: 0 8px 20px rgba(172, 83, 111, 0.32);
  transition: all .3s var(--ease);
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 12px 26px rgba(172, 83, 111, 0.4); }
.btn:active { transform: translateY(0); }
.btn.ghost {
  background: transparent;
  color: var(--c-muted);
  box-shadow: none;
  border: 1px solid var(--c-border);
}
.btn.ghost:hover { color: var(--c-primary); border-color: var(--c-primary); background: var(--c-primary-tint); box-shadow: none; }
.btn svg { width: 16px; height: 16px; }

/* ============ 页脚 ============ */
.site-footer {
  border-top: 1px solid var(--c-border);
  margin-top: 30px;
  padding: 40px 0 46px;
  background: var(--c-card);
}
.footer-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 24px;
  flex-wrap: wrap;
}
.footer-brand { display: flex; align-items: center; gap: 10px; color: var(--c-text); }
.footer-brand .brand-name { font-size: 15px; }
.footer-note { font-size: 13px; color: var(--c-muted); margin-top: 10px; max-width: 420px; line-height: 1.9; }
.footer-links { display: flex; gap: 8px; flex-wrap: wrap; }
.footer-links a {
  font-size: 13px;
  color: var(--c-muted);
  padding: 6px 12px;
  border-radius: 999px;
}
.footer-links a:hover { color: var(--c-primary); background: var(--c-primary-soft); }

/* ============ 回到顶部 ============ */
.back-top {
  position: fixed;
  right: 26px;
  bottom: 26px;
  width: 44px; height: 44px;
  border-radius: 50%;
  border: 1px solid var(--c-border);
  background: var(--c-card);
  color: var(--c-primary);
  box-shadow: var(--shadow-soft);
  cursor: pointer;
  display: grid;
  place-items: center;
  opacity: 0;
  visibility: hidden;
  transform: translateY(10px);
  transition: all .35s var(--ease);
  z-index: 40;
}
.back-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-top:hover { color: var(--c-accent); border-color: var(--c-accent); transform: translateY(-3px); }
.back-top svg { width: 18px; height: 18px; }

/* ============ 加载提示 ============ */
.loading { text-align: center; padding: 70px 0; color: var(--c-muted); font-size: 14px; letter-spacing: .1em; }
.loading::after {
  content: "";
  display: block;
  width: 26px; height: 26px;
  margin: 14px auto 0;
  border-radius: 50%;
  border: 3px solid var(--c-border);
  border-top-color: var(--c-primary);
  animation: spin 1s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ============ 响应式 ============ */
@media (max-width: 860px) {
  .nav-links a { padding: 8px 11px; font-size: 13px; }
  .brand-sub { display: none; }

  /* 时间轴改为左侧线 */
  .timeline::before { left: 14px; }
  .tl-progress { left: 14px; }
  .tl-item, .tl-item.left, .tl-item.right {
    width: calc(100% - 46px);
    margin-left: 46px;
    margin-right: 0;
    text-align: left;
  }
  .tl-dot,
  .tl-item.left .tl-dot,
  .tl-item.right .tl-dot { left: -32px; }
  .tl-year, .tl-item.left .tl-year { flex-direction: row; }

  .detail-grid, .mn-grid { grid-template-columns: 1fr; }
  .detail-nav { grid-template-columns: 1fr; }
}

@media (max-width: 520px) {
  .container, .nav-inner, .footer-inner { padding-left: 18px; padding-right: 18px; }
  .hero { padding-top: 52px; }
  .controls { padding: 16px 14px 12px; }
  .tl-card { padding: 17px 18px 15px; }
  .tl-item { margin: 34px 0; }
  .detail-block, .mnemonic-card { padding: 22px 20px; }
  .back-top { right: 16px; bottom: 16px; }
}