:root {
  color-scheme: light;
  --bg: #f8fafc;
  --paper: #ffffff;
  --ink: #111827;
  --muted: #64748b;
  --line: #dbe3ef;
  --accent: #0f766e;
  --accent-strong: #115e59;
  --accent-soft: #ccfbf1;
  --warning-soft: #fef3c7;
  --danger-soft: #fee2e2;
  --shadow: 0 18px 45px rgba(15, 23, 42, 0.10);
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--bg);
  color: var(--ink);
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100%;
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  line-height: 1.72;
  background: var(--bg);
}

button,
input {
  font: inherit;
}

.app-shell {
  min-height: 100vh;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  min-height: 60px;
  padding: max(10px, env(safe-area-inset-top)) 14px 10px;
  border-bottom: 1px solid rgba(219, 227, 239, 0.95);
  background: rgba(248, 250, 252, 0.94);
  backdrop-filter: blur(16px);
}

.brand {
  min-width: 0;
  color: inherit;
  text-decoration: none;
}

.brand-title,
.brand-subtitle {
  display: block;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.brand-title {
  font-size: 17px;
  font-weight: 750;
  letter-spacing: 0;
}

.brand-subtitle {
  color: var(--muted);
  font-size: 12px;
  line-height: 1.2;
}

.topbar-button,
.nav-button,
.result-link {
  min-height: 40px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: var(--ink);
  cursor: pointer;
}

.topbar-button {
  padding: 0 12px;
  font-size: 14px;
}

.reader-layout {
  display: grid;
  grid-template-columns: 320px minmax(0, 1fr);
  gap: 0;
  max-width: 1180px;
  margin: 0 auto;
}

.sidebar {
  position: sticky;
  top: 61px;
  height: calc(100vh - 61px);
  overflow: auto;
  padding: 18px 14px 28px;
  border-right: 1px solid var(--line);
}

.sidebar-search {
  position: sticky;
  top: 0;
  z-index: 2;
  padding: 0 0 12px;
  background: var(--bg);
}

.search-label {
  display: block;
  margin-bottom: 6px;
  color: var(--muted);
  font-size: 13px;
}

.search-input {
  width: 100%;
  min-height: 44px;
  padding: 8px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: var(--ink);
  outline: none;
}

.search-input:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(15, 118, 110, 0.15);
}

.chapter-group {
  margin: 0 0 14px;
}

.chapter-heading {
  margin: 16px 0 8px;
  color: var(--accent-strong);
  font-size: 13px;
  font-weight: 800;
}

.chapter-link {
  display: block;
  padding: 8px 10px;
  border-radius: 7px;
  color: var(--ink);
  font-size: 14px;
  line-height: 1.35;
  text-decoration: none;
}

.chapter-link:hover,
.chapter-link.active {
  background: var(--accent-soft);
}

.chapter-link-level {
  display: block;
  margin-top: 2px;
  color: var(--muted);
  font-size: 12px;
}

.reader-main {
  min-width: 0;
  padding: 22px 20px 72px;
}

.article,
.search-results {
  width: min(100%, 780px);
  margin: 0 auto;
}

.article {
  padding: 28px 0 40px;
}

.article-home {
  padding: 18px 0 32px;
}

.hero {
  padding: 26px 0 18px;
  border-bottom: 1px solid var(--line);
}

.hero h1 {
  margin: 0 0 10px;
  font-size: clamp(30px, 7vw, 48px);
  line-height: 1.12;
  letter-spacing: 0;
}

.hero p {
  max-width: 680px;
  margin: 0;
  color: var(--muted);
  font-size: 16px;
}

.stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin: 18px 0 22px;
}

.stat {
  padding: 14px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
}

.stat-value {
  display: block;
  font-size: 22px;
  font-weight: 800;
  line-height: 1.2;
}

.stat-label {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.home-section-title {
  margin: 28px 0 12px;
  font-size: 18px;
}

.home-chapter-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.home-chapter {
  display: block;
  padding: 14px 14px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: var(--ink);
  text-decoration: none;
}

.home-chapter:hover {
  border-color: rgba(15, 118, 110, 0.45);
  box-shadow: var(--shadow);
}

.home-chapter-title {
  display: block;
  font-weight: 700;
  line-height: 1.4;
}

.home-chapter-count {
  display: block;
  margin-top: 4px;
  color: var(--muted);
  font-size: 13px;
}

.article-header {
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.article-kicker {
  margin: 0 0 8px;
  color: var(--accent-strong);
  font-size: 14px;
  font-weight: 700;
}

.article-title {
  margin: 0;
  font-size: clamp(28px, 6vw, 42px);
  line-height: 1.2;
  letter-spacing: 0;
}

.article-level {
  display: inline-flex;
  margin-top: 14px;
  padding: 4px 10px;
  border-radius: 999px;
  background: var(--warning-soft);
  color: #713f12;
  font-size: 13px;
  font-weight: 700;
}

.article-body {
  padding-top: 22px;
  font-size: 17px;
}

.article-body h1,
.article-body h2,
.article-body h3 {
  line-height: 1.28;
  letter-spacing: 0;
}

.article-body h1 {
  margin: 0 0 16px;
  font-size: 28px;
}

.article-body h2 {
  margin: 32px 0 12px;
  font-size: 22px;
}

.article-body h3 {
  margin: 24px 0 10px;
  font-size: 19px;
}

.article-body p {
  margin: 0 0 16px;
}

.article-body a {
  color: var(--accent-strong);
  font-weight: 700;
  overflow-wrap: anywhere;
}

.article-body ul {
  margin: 0 0 18px;
  padding-left: 1.3em;
}

.article-body li {
  margin: 0 0 8px;
}

.article-body svg {
  display: block;
  width: 100%;
  height: auto;
  margin: 16px auto 28px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  box-shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
}

.article-nav {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
  gap: 10px;
  margin-top: 34px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.nav-button {
  display: block;
  min-height: 56px;
  padding: 10px 12px;
  color: var(--ink);
  line-height: 1.35;
  text-decoration: none;
}

.nav-button span {
  display: block;
  color: var(--muted);
  font-size: 12px;
}

.search-results {
  padding: 18px 0 0;
}

.search-results h2 {
  margin: 0 0 12px;
  font-size: 20px;
}

.result-list {
  display: grid;
  gap: 10px;
  margin-bottom: 22px;
}

.result-link {
  display: block;
  padding: 12px;
  text-align: left;
  text-decoration: none;
}

.result-link strong {
  display: block;
}

.result-link span {
  display: block;
  color: var(--muted);
  font-size: 13px;
}

.empty-state {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--paper);
  color: var(--muted);
}

@media (max-width: 860px) {
  .reader-layout {
    display: block;
  }

  .sidebar {
    position: fixed;
    inset: 60px 0 0;
    z-index: 15;
    height: auto;
    max-height: calc(100vh - 60px);
    padding: 14px 14px 34px;
    border-right: 0;
    border-bottom: 1px solid var(--line);
    background: var(--bg);
    transform: translateY(-110%);
    transition: transform 180ms ease;
    box-shadow: var(--shadow);
  }

  .reader-layout.nav-open .sidebar {
    transform: translateY(0);
  }

  .reader-main {
    padding: 14px 16px 64px;
  }

  .article {
    padding-top: 18px;
  }

  .home-chapter-list {
    grid-template-columns: 1fr;
  }

  .stats {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 520px) {
  .topbar {
    min-height: 56px;
    padding-left: 10px;
    padding-right: 10px;
  }

  .topbar-button {
    min-height: 38px;
    padding: 0 10px;
  }

  .reader-main {
    padding-left: 14px;
    padding-right: 14px;
  }

  .article-body {
    font-size: 16px;
    line-height: 1.78;
  }

  .article-nav {
    grid-template-columns: 1fr;
  }
}