:root {
  color-scheme: light;
  --bg: #f7f5ef;
  --surface: #fffdf8;
  --surface-strong: #ffffff;
  --ink: #1f1b16;
  --muted: #655a4d;
  --border: #d9cfbf;
  --accent: #1c6e5f;
  --accent-2: #0f4f44;
  --code-bg: #efe8dc;
  --code-block-bg: #1e1c18;
  --code-block-ink: #f6eddc;
  --active-bg: #ece2cf;
  --topbar-bg: rgba(255, 253, 248, 0.95);
  --shadow: 0 8px 24px rgba(21, 17, 12, 0.08);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #111418;
  --surface: #171b20;
  --surface-strong: #20262d;
  --ink: #f4efe7;
  --muted: #b9aea1;
  --border: #333b42;
  --accent: #72d0bd;
  --accent-2: #a4eadc;
  --code-bg: #2b3339;
  --code-block-bg: #090b0d;
  --code-block-ink: #f4efe7;
  --active-bg: #263740;
  --topbar-bg: rgba(23, 27, 32, 0.95);
  --shadow: 0 10px 28px rgba(0, 0, 0, 0.28);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "IBM Plex Sans", "Avenir Next", "Segoe UI", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.6;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  display: grid;
  grid-template-columns: auto auto minmax(0, 1fr) auto;
  gap: 1rem;
  align-items: center;
  padding: 0.9rem 1rem;
  border-bottom: 1px solid var(--border);
  background: var(--topbar-bg);
  backdrop-filter: blur(6px);
}

.brand {
  text-decoration: none;
  color: var(--ink);
  font-weight: 700;
  letter-spacing: 0.01em;
}

.search-wrap {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.6rem;
  align-items: center;
  justify-self: end;
  width: min(28rem, 100%);
}

.nav-toggle {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--ink);
  padding: 0.45rem 0.7rem;
  border-radius: 0.5rem;
  cursor: pointer;
}

.theme-toggle {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--ink);
  padding: 0.45rem 0.65rem;
  border-radius: 0.5rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  min-height: 2.2rem;
}

.theme-toggle-icon {
  width: 0.85rem;
  height: 0.85rem;
  border-radius: 999px;
  border: 2px solid var(--accent);
  background: linear-gradient(90deg, var(--accent) 50%, transparent 50%);
}

.search-label {
  color: var(--muted);
  font-size: 0.9rem;
}

#search-input {
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  padding: 0.5rem 0.65rem;
  min-width: 16rem;
  background: var(--surface-strong);
  color: var(--ink);
}

.layout {
  display: grid;
  grid-template-columns: 18rem minmax(0, 1fr);
  min-height: calc(100vh - 61px);
}

.sidebar {
  border-right: 1px solid var(--border);
  background: var(--surface);
  padding: 1rem;
}

.chapter-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.3rem;
}

.chapter-list a {
  display: block;
  text-decoration: none;
  color: var(--muted);
  padding: 0.35rem 0.5rem;
  border-radius: 0.4rem;
}

.chapter-list a.active,
.chapter-list a:hover {
  color: var(--ink);
  background: var(--active-bg);
}

.search-results {
  margin-top: 1rem;
  border-top: 1px solid var(--border);
  padding-top: 0.75rem;
  display: grid;
  gap: 0.4rem;
}

.search-results-title {
  font-size: 0.8rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}

.search-results a {
  text-decoration: none;
  color: var(--accent-2);
  font-size: 0.95rem;
}

.content {
  padding: clamp(1rem, 2vw, 2.3rem);
  max-width: 58rem;
}

article h1,
article h2,
article h3 {
  font-family: "IBM Plex Serif", "Iowan Old Style", "Georgia", serif;
  line-height: 1.25;
}

article h1 {
  font-size: clamp(1.8rem, 2.7vw, 2.5rem);
}

article h2 {
  margin-top: 1.9rem;
  font-size: 1.4rem;
}

code {
  font-family: "JetBrains Mono", "SFMono-Regular", Menlo, monospace;
  background: var(--code-bg);
  padding: 0.08rem 0.32rem;
  border-radius: 0.3rem;
}

pre {
  background: var(--code-block-bg);
  color: var(--code-block-ink);
  padding: 0.9rem;
  border-radius: 0.6rem;
  overflow-x: auto;
  box-shadow: var(--shadow);
}

pre code {
  background: transparent;
  padding: 0;
}

.pager {
  margin-top: 2.5rem;
  border-top: 1px solid var(--border);
  padding-top: 1rem;
  display: flex;
  justify-content: space-between;
  gap: 1rem;
}

.pager-link {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
}

.pager-spacer {
  width: 1px;
}

@media (max-width: 860px) {
  .topbar {
    grid-template-columns: auto auto;
    grid-template-areas:
      "toggle brand"
      "search theme";
  }

  .nav-toggle {
    grid-area: toggle;
  }

  .brand {
    grid-area: brand;
    justify-self: end;
  }

  .search-wrap {
    grid-area: search;
  }

  .theme-toggle {
    grid-area: theme;
    justify-self: end;
  }

  #search-input {
    min-width: 0;
    width: 100%;
  }

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

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

  .sidebar.open {
    display: block;
  }

  .content {
    max-width: 100%;
  }
}