/**
 * AIAppDrop — Header / Navigation (Linear-dense chrome)
 */

.aad-header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: var(--header-height);
  background: var(--glass-bg);
  backdrop-filter: blur(16px) saturate(1.2);
  -webkit-backdrop-filter: blur(16px) saturate(1.2);
  border-bottom: 1px solid transparent;
  transition:
    border-color var(--transition-base),
    background var(--transition-base);
}

.aad-header.is-scrolled {
  border-bottom-color: var(--bg-border);
  background: var(--glass-bg-strong);
}

.aad-header__inner {
  display: flex;
  align-items: center;
  gap: 10px;
  height: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--container-pad);
}

.aad-logo {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.0625rem;
  letter-spacing: -0.03em;
  line-height: 1;
  color: var(--text-primary);
  flex-shrink: 0;
}

.aad-logo:hover {
  color: var(--text-primary);
}

.aad-logo__icon {
  width: 28px;
  height: 28px;
  flex-shrink: 0;
  display: block;
  object-fit: contain;
  border-radius: 6px;
}

.aad-logo__text {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: -0.03em;
}

.aad-logo__text span {
  background: linear-gradient(135deg, var(--brand-accent), var(--brand-primary-hover));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}

.aad-nav {
  display: flex;
  align-items: center;
  gap: 1px;
  margin-left: var(--space-sm);
}

.aad-nav__link {
  position: relative;
  padding: 6px 10px;
  border-radius: var(--radius-sm);
  font-size: var(--text-small);
  font-weight: 500;
  color: var(--text-secondary);
  transition: color var(--transition-fast), background var(--transition-fast);
}

.aad-nav__link:hover {
  color: var(--text-primary);
  background: var(--bg-hover);
}

.aad-nav__link[aria-current="page"] {
  color: var(--text-primary);
  background: var(--wash-primary);
}

.aad-header__actions {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-left: auto;
}

.aad-header__search-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  min-width: 0;
  min-height: 32px;
  padding: 0 10px 0 12px;
  border: 1px solid var(--bg-border);
  border-radius: var(--radius-md);
  background: var(--bg-surface);
  color: var(--text-muted);
  font-size: var(--text-xs);
  transition:
    border-color var(--transition-fast),
    color var(--transition-fast),
    background var(--transition-fast);
}

.aad-header__search-btn:hover {
  border-color: var(--bg-border-strong);
  color: var(--text-secondary);
  background: var(--bg-elevated);
}

.aad-header__search-btn svg {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

.aad-header__search-label {
  display: none;
  white-space: nowrap;
}

@media (min-width: 960px) {
  .aad-header__search-label {
    display: inline;
  }

  .aad-header__search-btn {
    min-width: 180px;
  }
}

.aad-theme-toggle {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  border: 1px solid transparent;
  transition:
    background var(--transition-fast),
    color var(--transition-fast),
    border-color var(--transition-fast);
}

.aad-theme-toggle:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border-color: var(--bg-border);
}

.aad-theme-toggle svg {
  width: 16px;
  height: 16px;
  position: absolute;
  transition: opacity var(--transition-base), transform var(--transition-base);
}

.aad-theme-toggle .icon-sun {
  opacity: 0;
  transform: rotate(-45deg) scale(0.7);
}

.aad-theme-toggle .icon-moon {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="light"] .aad-theme-toggle .icon-sun {
  opacity: 1;
  transform: rotate(0) scale(1);
}

[data-theme="light"] .aad-theme-toggle .icon-moon {
  opacity: 0;
  transform: rotate(45deg) scale(0.7);
}

.aad-header__advertise {
  display: none;
  font-size: var(--text-xs);
  font-weight: 600;
  color: var(--brand-accent);
  padding: 6px 10px;
  border-radius: var(--radius-md);
  border: 1px solid rgba(34, 211, 238, 0.22);
}

.aad-header__advertise:hover {
  background: var(--wash-accent);
  color: var(--brand-accent);
}

@media (min-width: 1100px) {
  .aad-header__advertise {
    display: inline-flex;
  }
}

.aad-menu-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: var(--radius-md);
  color: var(--text-secondary);
  border: 1px solid transparent;
}

.aad-menu-toggle:hover {
  background: var(--bg-elevated);
  color: var(--text-primary);
  border-color: var(--bg-border);
}

.aad-menu-toggle svg {
  width: 18px;
  height: 18px;
}

@media (max-width: 860px) {
  .aad-nav {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 2px;
    margin: 0;
    padding: 10px;
    background: var(--glass-bg-strong);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--bg-border);
    box-shadow: var(--shadow-md);
    transform: translateY(-6px);
    opacity: 0;
    visibility: hidden;
    transition:
      opacity var(--transition-base),
      visibility var(--transition-base),
      transform var(--transition-base);
  }

  .aad-nav.is-open {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
  }

  .aad-nav__link {
    padding: 12px 14px;
    border-radius: var(--radius-md);
  }

  .aad-menu-toggle {
    display: inline-flex;
  }

  .aad-header__search-btn kbd {
    display: none;
  }
}