/* ==========================================================================
   header.css — common site header (site-branding.js injects the markup)
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 500;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-4);
  height: var(--header-height);
  padding: 0 clamp(14px, 4vw, 32px);
  background: var(--site-surface);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--site-border);
  font-family: var(--font-display);
  color: var(--site-text);
  animation: siteHeaderSlideDown 0.4s var(--transition-curve);
}

.site-header__brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  text-decoration: none;
  color: var(--site-text);
  font-weight: 800;
  font-size: 1.05rem;
  flex-shrink: 0;
}

.site-header__logo {
  width: 34px;
  height: 34px;
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  background: var(--brand-gradient);
  color: #fff;
  flex-shrink: 0;
}

.site-header__name {
  white-space: nowrap;
}

.site-header__name-full { display: inline; }
.site-header__name-short { display: none; }

.site-header__nav {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex: 1;
  justify-content: center;
  position: relative;
}

.site-header__nav-toggle {
  display: flex;
  align-items: center;
  gap: 6px;
  background: var(--site-surface-alt);
  border: 1px solid var(--site-border);
  color: var(--site-text);
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition-speed), transform 0.15s;
}
.site-header__nav-toggle:hover { transform: translateY(-1px); }
.site-header__nav-toggle i { font-size: 0.7rem; transition: transform 0.25s var(--transition-curve); }
.site-header__nav-toggle[aria-expanded="true"] i { transform: rotate(180deg); }

.site-header__menu {
  position: absolute;
  top: calc(100% + 10px);
  left: 50%;
  transform: translateX(-50%);
  width: min(720px, 92vw);
  max-height: min(70vh, 520px);
  overflow-y: auto;
  background: var(--site-surface);
  border: 1px solid var(--site-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  padding: var(--space-4);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-2) var(--space-4);
  animation: siteMenuReveal 0.18s var(--transition-curve);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}
.site-header__menu[hidden] { display: none; }

.site-header__menu-group h4 {
  margin: 0 0 6px;
  font-size: 0.68rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--site-text-muted);
  font-weight: 700;
}

.site-header__menu-link {
  display: block;
  padding: 6px 8px;
  margin: 0 -8px;
  border-radius: var(--radius-sm);
  text-decoration: none;
  color: var(--site-text);
  font-size: 0.86rem;
  font-weight: 500;
  transition: background var(--transition-speed);
}
.site-header__menu-link:hover,
.site-header__menu-link:focus-visible { background: var(--site-surface-alt); }
.site-header__menu-link.is-current {
  color: var(--brand-accent-2);
  font-weight: 700;
}

.site-header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
}

.site-header__icon-btn {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1px solid var(--site-border);
  background: var(--site-surface-alt);
  color: var(--site-text);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  text-decoration: none;
  transition: background var(--transition-speed), transform 0.15s;
}
.site-header__icon-btn:hover { transform: translateY(-1px); }

.site-header__hamburger {
  display: none;
  width: 38px;
  height: 38px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--site-border);
  background: var(--site-surface-alt);
  color: var(--site-text);
  align-items: center;
  justify-content: center;
  cursor: pointer;
}

/* Mobile menu behaves as a full drop panel under the header */
@media (max-width: 860px) {
  .site-header__name-full { display: none; }
  .site-header__name-short { display: inline; }
  .site-header__nav { display: none; }
  .site-header__hamburger { display: flex; }

  .site-header--menu-open .site-header__nav {
    display: block;
    position: fixed;
    inset: var(--header-height) 0 0 0;
    background: var(--site-bg);
    padding: var(--space-4);
    overflow-y: auto;
    z-index: 600;
  }
  .site-header--menu-open .site-header__menu {
    position: static;
    transform: none;
    width: 100%;
    max-height: none;
    grid-template-columns: 1fr;
    box-shadow: none;
    border: none;
    background: transparent;
    padding: 0;
  }
  .site-header--menu-open .site-header__nav-toggle { display: none; }
}

@media (max-width: 420px) {
  .site-header { padding: 0 12px; }
  .site-header__name { font-size: 0.95rem; }
}