/* chat: left-rail list chrome + wide thread */
:root {
  --bg: #e8eef2;
  --bar: #1e3a5f;
  --card: #ffffff;
  --ink: #1e2937;
  --muted: #475569;
  --line: #cbd5e1;
  --rail: #dbe4ec;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: auto;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: Calibri, "Microsoft YaHei", sans-serif;
  line-height: 1.7;
}

a {
  color: #1d4ed8;
}

.topbar {
  background: var(--bar);
  color: #f8fafc;
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 12px 18px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  color: #f8fafc;
  text-decoration: none;
  font-weight: 700;
}

.desk {
  display: grid;
  grid-template-columns: 228px 1fr;
  min-height: calc(100vh - 56px);
}

.rail {
  background: var(--rail);
  border-right: 1px solid var(--line);
  padding: 16px 0;
}

.rail p {
  margin: 0 16px 10px;
  font-size: 0.8rem;
  color: var(--muted);
}

.rail a {
  display: block;
  padding: 10px 16px;
  color: var(--bar);
  text-decoration: none;
  border-left: 3px solid transparent;
}

.rail a:hover,
.rail a:focus {
  background: #cfd8e3;
  border-left-color: var(--bar);
}

.thread {
  padding: 22px 28px 48px;
}

.hero {
  background: var(--card);
  padding: 18px 20px;
  margin-bottom: 22px;
  border: 1px solid var(--line);
}

.hero h1 {
  margin: 0 0 10px;
  font-size: 1.75rem;
  color: var(--bar);
}

.hero p {
  margin: 0 0 8px;
  color: var(--muted);
}

.sec {
  margin: 0 0 28px;
}

.sec h2 {
  margin: 0 0 10px;
  color: var(--bar);
  font-size: 1.35rem;
}

.sec > p {
  margin: 0 0 12px;
}

.pain {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.pain article,
.caps article,
.switch article,
.mock,
.rhythm {
  background: var(--card);
  border: 1px solid var(--line);
  padding: 16px;
}

.pain h3,
.caps h3,
.switch h3 {
  margin: 8px 0;
}

.caps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
}

.mock {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 0;
  padding: 0;
  overflow: hidden;
}

.mock-list {
  background: #f1f5f9;
  padding: 12px;
  border-right: 1px solid var(--line);
}

.mock-list span {
  display: block;
  background: #fff;
  border: 1px solid var(--line);
  padding: 8px;
  margin: 0 0 8px;
  font-size: 0.85rem;
}

.mock-main {
  padding: 14px 16px;
}

.steps {
  display: flex;
  background: var(--card);
  border: 1px solid var(--line);
}

.steps div {
  flex: 1;
  padding: 12px;
  border-right: 1px solid var(--line);
}

.steps div:last-child {
  border-right: none;
}

.steps b {
  display: block;
  color: var(--bar);
  margin-bottom: 6px;
}

.place {
  width: 100%;
  border-collapse: collapse;
  background: var(--card);
}

.place th,
.place td {
  border: 1px solid var(--line);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}

.place th {
  background: #e2e8f0;
  color: var(--bar);
}

.switch {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

.dual {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.dual article {
  background: var(--card);
  border: 1px solid var(--line);
  padding: 16px;
}

.faq dt {
  background: var(--card);
  border: 1px solid var(--line);
  border-bottom: none;
  padding: 10px 14px;
  font-weight: 700;
  color: var(--bar);
}

.faq dd {
  margin: 0 0 8px;
  background: var(--card);
  border: 1px solid var(--line);
  padding: 10px 14px 14px;
  color: var(--muted);
}

.foot {
  background: var(--bar);
  color: #e2e8f0;
  padding: 22px 28px;
  grid-column: 1 / -1;
}

.foot p {
  margin: 0 0 8px;
}

.page {
  display: grid;
  grid-template-rows: auto 1fr auto;
}

@media (max-width: 900px) {
  .desk {
    grid-template-columns: 1fr;
  }

  .rail {
    border-right: none;
    border-bottom: 1px solid var(--line);
  }

  .pain,
  .caps,
  .dual,
  .switch,
  .mock {
    grid-template-columns: 1fr;
  }

  .steps {
    flex-direction: column;
  }

  .steps div {
    border-right: none;
    border-bottom: 1px solid var(--line);
  }
}