/* ============================================================
   HEADER — Sticky site header, primary nav, search overlay
   ============================================================ */

#site-header {
  position: sticky;
  top: 0;
  z-index: 500;
  height: var(--header-height);
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-light);
  box-shadow: var(--shadow-sm);
  transition: background var(--transition-normal), box-shadow var(--transition-normal);
}

#site-header .container {
  display: flex;
  align-items: center;
  height: 100%;
  gap: var(--space-8);
}

/* ---- Logo / Branding ---- */
.site-branding {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
  text-decoration: none;
}

.site-branding .logo-icon {
  width: 36px;
  height: 36px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
}

.site-branding .logo-icon svg { width: 20px; height: 20px; fill: #fff; }

.site-name {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.2rem;
  color: var(--text-primary);
  line-height: 1.2;
}
.site-name span { color: var(--color-primary); }

/* ---- Primary Nav ---- */
#primary-nav { flex: 1; }

#primary-nav ul {
  display: flex;
  gap: var(--space-1);
  align-items: center;
}

#primary-nav a {
  display: block;
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition-fast), background var(--transition-fast);
  text-decoration: none;
}
#primary-nav a:hover,
#primary-nav .current-menu-item > a {
  color: var(--color-primary);
  background: var(--bg-subtle);
}

/* ---- Header Actions ---- */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-shrink: 0;
  margin-left: auto;
}

/* Search toggle */
.btn-search {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
  color: var(--text-secondary);
  transition: color var(--transition-fast), background var(--transition-fast);
}
.btn-search:hover { background: var(--bg-subtle); color: var(--color-primary); }
.btn-search svg { width: 18px; height: 18px; stroke: currentColor; fill: none; }

/* Dark mode toggle */
.btn-darkmode {
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
  color: var(--text-secondary);
  transition: color var(--transition-fast), background var(--transition-fast);
  position: relative;
}
.btn-darkmode:hover { background: var(--bg-subtle); color: var(--color-primary); }
.btn-darkmode .icon-sun,
.btn-darkmode .icon-moon { width: 18px; height: 18px; stroke: currentColor; fill: none; position: absolute; transition: opacity var(--transition-fast), transform var(--transition-fast); }
[data-theme="light"] .icon-moon  { opacity: 1; transform: scale(1); }
[data-theme="light"] .icon-sun   { opacity: 0; transform: scale(0.5); }
[data-theme="dark"]  .icon-sun   { opacity: 1; transform: scale(1); }
[data-theme="dark"]  .icon-moon  { opacity: 0; transform: scale(0.5); }

/* Language selector */
.language-selector { position: relative; }
.language-selector select {
  appearance: none;
  background: var(--bg-subtle);
  border: 1px solid var(--border-light);
  border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-8) var(--space-2) var(--space-3);
  font-size: 0.82rem;
  font-family: var(--font-body);
  color: var(--text-secondary);
  cursor: pointer;
  transition: border-color var(--transition-fast);
}
.language-selector select:focus { outline: none; border-color: var(--color-primary); }
.language-selector::after {
  content: '';
  position: absolute;
  right: 10px; top: 50%;
  transform: translateY(-50%);
  border: 4px solid transparent;
  border-top-color: var(--text-muted);
  pointer-events: none;
}

/* Mobile menu toggle */
.btn-menu {
  display: none;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  place-items: center;
  color: var(--text-secondary);
}
/* Show X icon when menu is open */
.btn-menu svg { width: 22px; height: 22px; stroke: currentColor; fill: none; transition: transform 0.2s ease; }
body.menu-open .btn-menu svg { transform: rotate(45deg); }

/* Close-tap overlay when menu is open */
.menu-backdrop {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 498;
  background: rgba(0,0,0,0.4);
}
body.menu-open .menu-backdrop { display: block; }

/* ---- Search Overlay ---- */
#search-overlay {
  position: fixed;
  inset: 0;
  background: rgba(10,15,30,0.85);
  backdrop-filter: blur(8px);
  z-index: 1000;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding-top: 15vh;
  opacity: 0;
  pointer-events: none;
  transition: opacity var(--transition-normal);
}
#search-overlay.active { opacity: 1; pointer-events: all; }

#search-overlay .search-box {
  background: var(--bg-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-6);
  width: 100%;
  max-width: 600px;
  margin: 0 var(--space-6);
  box-shadow: var(--shadow-xl);
}
#search-overlay input[type="search"] {
  width: 100%;
  border: 2px solid var(--border-medium);
  border-radius: var(--radius-md);
  padding: var(--space-4) var(--space-5);
  font-size: 1.1rem;
  font-family: var(--font-body);
  background: var(--bg-subtle);
  color: var(--text-primary);
  transition: border-color var(--transition-fast);
}
#search-overlay input:focus { outline: none; border-color: var(--color-primary); }

.search-close {
  position: absolute;
  top: var(--space-6);
  right: var(--space-6);
  width: 42px; height: 42px;
  background: var(--bg-elevated);
  border-radius: var(--radius-full);
  display: grid;
  place-items: center;
  color: var(--text-secondary);
  font-size: 1.4rem;
  transition: background var(--transition-fast);
}
.search-close:hover { background: var(--bg-muted); }

/* ---- Tablet Responsive (769px – 1024px) ---- */
@media (max-width: 1024px) and (min-width: 769px) {
  #primary-nav { display: none; }
  .btn-menu { display: grid; }
  .language-selector { display: none; }

  #primary-nav.mobile-open {
    display: block;
    position: fixed;
    inset: var(--header-height) 0 0 0;
    background: var(--bg-surface);
    z-index: 499;
    padding: var(--space-6);
    overflow-y: auto;
  }
  #primary-nav.mobile-open ul { flex-direction: column; }
  #primary-nav.mobile-open a { font-size: 1.1rem; padding: var(--space-4); }
}

/* ---- Mobile Responsive ---- */
@media (max-width: 768px) {
  :root { --header-height: 60px; }

  #primary-nav { display: none; }
  #primary-nav.mobile-open {
    display: block;
    position: fixed;
    inset: var(--header-height) 0 0 0;
    background: var(--bg-surface);
    z-index: 499;
    padding: var(--space-6);
    overflow-y: auto;
  }
  #primary-nav.mobile-open ul { flex-direction: column; }
  #primary-nav.mobile-open a { font-size: 1.1rem; padding: var(--space-4); }

  .btn-menu { display: grid; }
  .language-selector { display: none; }
}