:root {
  --color-bg: #ffffff;
  --color-nav-bg: #f5f5f4;
  --color-border: #e2e2e0;
  --color-text: #262624;
  --color-text-muted: #6b6b68;
  --color-accent: #b45309;
  --color-accent-bg: #fdf0e0;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
}

.page {
  display: flex;
  min-height: 100vh;
}

.nav {
  flex: 0 0 280px;
  background: var(--color-nav-bg);
  border-right: 1px solid var(--color-border);
  padding: 1.5rem 1rem;
  overflow-y: auto;
}

.nav__logo {
  display: block;
  margin: 0 0 2.5rem 0;
  padding: 0 0.5rem;
}

.nav__logo img {
  display: block;
  max-width: 100%;
  height: auto;
}

.topbar {
  display: none;
}

.nav-toggle {
  display: none;
}

.page__title {
  margin: 0 0 1.5rem 0;
}

.nav__list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.nav__link {
  display: block;
  padding: 0.5rem 0.5rem;
  border-radius: 6px;
  color: var(--color-text);
  text-decoration: none;
  font-size: 0.92rem;
}

.nav__link:hover {
  background: var(--color-border);
}

.nav__link--active {
  background: var(--color-accent-bg);
  color: var(--color-accent);
  font-weight: 600;
}

.content {
  flex: 1;
  padding: 2rem 3rem;
  max-width: 760px;
}

.chapter__title {
  margin-top: 0;
}

.site-footer {
  margin-top: 3rem;
  padding-top: 1rem;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

.site-footer p {
  margin: 0 0 0.5rem 0;
}

.site-footer__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
}

.site-footer__links a {
  color: var(--color-accent);
}

.chapter__body h2 {
  margin-top: 2rem;
}

.chapter__body h3 {
  margin-top: 1.5rem;
}

.chapter__body blockquote {
  margin: 1rem 0;
  padding: 0.5rem 1rem;
  border-left: 3px solid var(--color-accent);
  background: var(--color-accent-bg);
  color: var(--color-text-muted);
}

.chapter__body .alert {
  margin: 1.5rem 0;
  padding: 1rem 1.25rem;
  border-radius: 8px;
  font-size: 1.15rem;
  font-weight: 700;
  text-align: center;
}

.chapter__body .alert p {
  margin: 0;
}

.chapter__body .alert--warning {
  border: 2px solid #b91c1c;
  background: #fee2e2;
  color: #7f1d1d;
}

.chapter__body table {
  border-collapse: collapse;
  width: 100%;
  margin: 1rem 0;
}

.chapter__body th,
.chapter__body td {
  border: 1px solid var(--color-border);
  padding: 0.4rem 0.75rem;
  text-align: left;
}

.chapter__body th {
  background: var(--color-nav-bg);
}

.chapter__body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 1.5rem 0;
}

.chapter__pagenav {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--color-border);
}

.chapter__pagenav-link {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  max-width: 48%;
  padding: 0.75rem 1rem;
  border: 1px solid var(--color-border);
  border-radius: 8px;
  text-decoration: none;
  color: var(--color-text);
}

.chapter__pagenav-link:hover {
  border-color: var(--color-accent);
  background: var(--color-accent-bg);
}

.chapter__pagenav-link--next {
  margin-left: auto;
  text-align: right;
}

.chapter__pagenav-label {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

.chapter__pagenav-title {
  font-weight: 600;
}

@media (max-width: 768px) {
  .page {
    flex-direction: column;
  }

  .topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.6rem 1rem;
    background: var(--color-nav-bg);
    border-bottom: 1px solid var(--color-border);
  }

  .topbar__logo img {
    display: block;
    height: 32px;
    width: auto;
  }

  .nav-toggle {
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 4px;
    width: 32px;
    height: 32px;
    padding: 0;
    border: none;
    background: transparent;
    cursor: pointer;
  }

  .nav-toggle__bar {
    display: block;
    height: 2px;
    width: 100%;
    background: var(--color-text);
    border-radius: 1px;
  }

  .nav__logo {
    display: none;
  }

  .nav {
    flex: none;
    border-right: none;
    border-bottom: 1px solid var(--color-border);
    max-height: 60vh;
    display: none;
  }

  .nav.nav--open {
    display: block;
  }

  .content {
    padding: 1.5rem;
    max-width: none;
  }

  .chapter__pagenav {
    flex-direction: column;
  }

  .chapter__pagenav-link {
    max-width: none;
  }

  .chapter__pagenav-link--next {
    margin-left: 0;
    text-align: left;
  }
}