/**
 * layout.css — Structural Grid, Containers, Header, Footer, and Shell Layouts
 */

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.container-narrow {
  width: 100%;
  max-width: var(--container-narrow-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

/* Site Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background-color: var(--glass-surface);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border-subtle);
  transition: background-color var(--transition-normal), border-color var(--transition-normal);
}

.site-header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
  gap: var(--space-4);
}

.header-brand {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-bold);
  color: var(--color-text-primary);
  letter-spacing: -0.02em;
}

.brand-icon {
  width: 32px;
  height: 32px;
  fill: var(--color-brand-primary);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.nav-link {
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-secondary);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast), background-color var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
  color: var(--color-brand-primary);
  background-color: var(--color-bg-subtle);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

/* Grids */
.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
}

.grid-3-col {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-6);
}

.grid-2-col {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--space-6);
}

/* Tool Page Layout: Main Workstation + Side Reference */
.tool-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-8);
  margin-top: var(--space-6);
}

@media (min-width: 1024px) {
  .tool-layout {
    grid-template-columns: minmax(0, 1fr) 340px;
    align-items: start;
  }
}

.tool-sticky-sidebar {
  position: static;
}

@media (min-width: 1024px) {
  .tool-sticky-sidebar {
    position: sticky;
    top: calc(var(--header-height) + var(--space-4));
    display: flex;
    flex-direction: column;
    gap: var(--space-5);
  }
}

/* Site Footer */
.site-footer {
  margin-top: var(--space-20);
  background-color: var(--color-bg-surface);
  border-top: 1px solid var(--color-border-subtle);
  padding: var(--space-12) 0 var(--space-8);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr repeat(3, 1fr);
  gap: var(--space-8);
  margin-bottom: var(--space-10);
}

.footer-col h4 {
  font-size: var(--font-size-sm);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

.footer-col ul {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.footer-col a {
  font-size: var(--font-size-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.footer-col a:hover {
  color: var(--color-brand-primary);
}

.footer-bottom {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-6);
  border-top: 1px solid var(--color-border-subtle);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

/* Responsive Overrides */
@media (max-width: 768px) {
  .grid-3-col, .grid-2-col, .footer-grid {
    grid-template-columns: 1fr;
    gap: var(--space-6);
  }

  .header-nav {
    display: none; /* Managed via mobile drawer */
  }

  .footer-bottom {
    flex-direction: column;
    gap: var(--space-4);
    text-align: center;
  }
}