.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-height);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-soft);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 var(--space-md);
  height: 100%;
}

.site-brand {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  flex-shrink: 0;
  text-decoration: none;
  color: var(--color-text);
}

.site-brand:hover {
  text-decoration: none;
}

.site-brand__logo {
  width: 40px;
  height: 40px;
}

.site-brand__text {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.site-brand__name {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-primary);
}

.site-brand__tag {
  font-size: 0.7rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.top-nav {
  display: none;
  flex: 1;
  justify-content: center;
}

.top-nav__list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-xs);
  list-style: none;
  margin: 0;
  padding: 0;
}

.top-nav__link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  white-space: nowrap;
}

.top-nav__link:hover {
  background: var(--color-bg-alt);
  text-decoration: none;
}

.top-nav__link.is-active {
  background: var(--color-primary);
  color: #fff;
}

.mobile-toggle {
  margin-left: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  cursor: pointer;
}

.mobile-toggle__bar {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  position: relative;
}

.mobile-toggle__bar::before,
.mobile-toggle__bar::after {
  content: "";
  position: absolute;
  left: 0;
  width: 20px;
  height: 2px;
  background: var(--color-text);
}

.mobile-toggle__bar::before { top: -6px; }
.mobile-toggle__bar::after { top: 6px; }

.site-layout {
  display: flex;
  max-width: 1400px;
  margin: 0 auto;
  min-height: calc(100vh - var(--header-height));
}

.site-sidenav {
  display: none;
  width: var(--sidenav-width);
  flex-shrink: 0;
  padding: var(--space-lg) var(--space-md);
  border-right: 1px solid var(--color-border);
  background: var(--color-surface);
  position: sticky;
  top: var(--header-height);
  align-self: flex-start;
  max-height: calc(100vh - var(--header-height));
  overflow-y: auto;
}

.site-sidenav__title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

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

.site-sidenav__link {
  display: block;
  padding: var(--space-sm) var(--space-md);
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: var(--color-text);
  text-decoration: none;
}

.site-sidenav__link:hover {
  background: var(--color-bg-alt);
  text-decoration: none;
}

.site-sidenav__link.is-active {
  background: var(--color-callout);
  color: var(--color-primary);
  font-weight: 600;
}

.site-main {
  flex: 1;
  padding: var(--space-lg) var(--space-md);
  min-width: 0;
}

.site-footer {
  border-top: 1px solid var(--color-border);
  background: var(--color-surface);
  padding: var(--space-lg) var(--space-md);
  text-align: center;
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

.mobile-drawer {
  position: fixed;
  inset: 0;
  z-index: 200;
  pointer-events: none;
  visibility: hidden;
}

.mobile-drawer.is-open {
  pointer-events: auto;
  visibility: visible;
}

.mobile-drawer__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.4);
  opacity: 0;
  transition: opacity var(--transition);
}

.mobile-drawer.is-open .mobile-drawer__backdrop {
  opacity: 1;
}

.mobile-drawer__panel {
  position: absolute;
  top: 0;
  right: 0;
  width: min(320px, 90vw);
  height: 100%;
  background: var(--color-surface);
  transform: translateX(100%);
  transition: transform var(--transition);
  overflow-y: auto;
  padding: var(--space-lg) var(--space-md);
}

.mobile-drawer.is-open .mobile-drawer__panel {
  transform: translateX(0);
}

.mobile-drawer__section {
  margin-bottom: var(--space-lg);
}

.mobile-drawer__heading {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
}

@media (min-width: 768px) {
  .mobile-toggle {
    display: none;
  }

  .top-nav {
    display: flex;
  }
}

@media (min-width: 1024px) {
  .site-sidenav {
    display: block;
  }
}