/* ============================================================
   Header & Navigation
   ============================================================ */
.site-header {
  position: sticky;
  top: 0;
  z-index: 200;
  height: var(--header-height);
  background: var(--color-surface);
  border-bottom: 2px solid var(--color-border-light);
  box-shadow: 0 2px 12px var(--color-shadow);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* ---- Logo ---- */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  flex-shrink: 0;
}
.site-logo img, .site-logo svg {
  width: 40px;
  height: 40px;
}
.site-logo-text {
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-accent);
  line-height: 1.2;
  display: none;
}
@media (min-width: 480px) { .site-logo-text { display: block; } }

/* ---- Nav ---- */
.site-nav {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.45rem 0.85rem;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 500;
  color: var(--color-text);
  text-decoration: none;
  transition: background var(--transition-fast), color var(--transition-fast);
  white-space: nowrap;
}
.nav-link svg { width: 18px; height: 18px; flex-shrink: 0; }
.nav-link:hover { background: var(--color-surface-alt); color: var(--color-accent); }
.nav-link.active {
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
}
.nav-link.active:hover { background: var(--color-accent-hover); color: #fff; }

/* ---- Hamburger ---- */
.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
  border-radius: var(--radius-sm);
  transition: background var(--transition-fast);
}
.nav-toggle:hover { background: var(--color-surface-alt); }
.nav-toggle span {
  display: block;
  height: 2px;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-base), opacity var(--transition-base);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---- Mobile ---- */
@media (max-width: 768px) {
  .nav-toggle { display: flex; }

  .site-nav {
    display: none;
    position: absolute;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background: var(--color-surface);
    border-bottom: 2px solid var(--color-border-light);
    padding: var(--space-md);
    gap: var(--space-xs);
    box-shadow: 0 6px 16px var(--color-shadow);
  }
  .site-nav.open { display: flex; }
  .nav-link { padding: 0.75rem 1rem; font-size: 1rem; }
}

@media (min-width: 769px) {
  .site-nav { display: flex !important; }
}