/* Site chrome: header, nav, footer. */
.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}
.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 58px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
}
.brand:hover {
  text-decoration: none;
}
.brand-logo {
  width: 28px;
  height: 28px;
  border-radius: 8px;
}
.site-nav {
  display: flex;
  align-items: center;
  gap: 1.2rem;
}
.site-nav a {
  color: var(--muted);
  font-weight: 500;
}
.site-nav a:hover {
  color: var(--text);
  text-decoration: none;
}
.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  cursor: pointer;
  width: 32px;
  height: 32px;
  font-size: 1rem;
  line-height: 1;
}
.theme-toggle:hover {
  border-color: var(--brand);
}
.lang-switch {
  display: inline-flex;
  align-items: center;
  gap: 0.15rem;
  font-size: 0.82rem;
}
.lang-switch a {
  color: var(--muted);
  font-weight: 600;
  padding: 0.1rem 0.35rem;
  border-radius: 6px;
}
.lang-switch a:hover {
  color: var(--text);
  text-decoration: none;
}
.lang-switch a.active {
  color: var(--brand);
  background: var(--surface-2);
}

.nav-toggle {
  display: none;
}

.site-footer {
  margin-top: 3rem;
  padding: 2.2rem 0 3rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.92rem;
  text-align: center;
}

/* Mobile: collapse the nav behind a hamburger toggle (desktop layout is untouched above). */
@media (max-width: 760px) {
  .site-header-inner {
    flex-wrap: wrap;
    height: auto;
    min-height: 58px;
    padding-top: 0.7rem;
    padding-bottom: 0.7rem;
  }
  .nav-toggle {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    order: 2;
    width: 36px;
    height: 36px;
    background: none;
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text);
    font-size: 1.1rem;
    line-height: 1;
    cursor: pointer;
  }
  .nav-toggle:hover {
    border-color: var(--brand);
  }
  .site-nav {
    display: none;
    order: 3;
    flex-basis: 100%;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin-top: 0.8rem;
    padding-top: 0.6rem;
    border-top: 1px solid var(--border);
  }
  .nav-toggle-cb:checked ~ .site-nav {
    display: flex;
  }
  .site-nav a {
    padding: 0.65rem 0.1rem;
    border-bottom: 1px solid var(--border);
  }
  .lang-switch,
  .theme-toggle {
    margin-top: 0.7rem;
  }
}