/* ===== Header — KukuPDF ===== */
.header {
  position: sticky;
  top: 0;
  z-index: var(--z-sticky);
  background: rgba(13, 10, 26, 0.92);
  backdrop-filter: blur(20px) saturate(1.8);
  -webkit-backdrop-filter: blur(20px) saturate(1.8);
  border-bottom: 1px solid rgba(123, 47, 255, 0.2);
  height: var(--header-height);
  box-shadow: 0 1px 0 rgba(123, 47, 255, 0.3);
  transition: box-shadow var(--transition-base);
}

.header.scrolled {
  box-shadow: 0 1px 0 rgba(123, 47, 255, 0.3), 0 4px 20px rgba(0,0,0,0.4);
}

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

/* Logo */
.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.logo:hover .logo-icon {
  filter: drop-shadow(0 0 12px rgba(57, 255, 20, 0.6));
}

.logo-icon {
  width: 36px;
  height: 36px;
  position: relative;
  transition: filter var(--transition-base);
}

.logo-icon svg {
  width: 100%;
  height: 100%;
}

/* Fallback icon styling if SVG not loaded */
.logo-heart {
  display: none;
}

.logo-bird {
  width: 100%;
  height: 100%;
}

.logo-text {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-main);
  letter-spacing: -0.02em;
}

.logo-accent {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-weight: 700;
}

/* Desktop Nav */
.nav-desktop {
  display: flex;
  align-items: center;
  gap: 4px;
}

.nav-item {
  position: relative;
}

.nav-link {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 14px;
  border-radius: var(--radius-md);
  font-weight: 500;
  font-size: var(--fs-base);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  position: relative;
}

.nav-link::after {
  content: '';
  position: absolute;
  bottom: 2px;
  left: 14px;
  right: 14px;
  height: 2px;
  background: var(--primary);
  transform: scaleX(0);
  transform-origin: left;
  transition: transform var(--transition-base);
}

.nav-link:hover {
  color: var(--text-main);
}

.nav-link:hover::after, .nav-link.active::after {
  transform: scaleX(1);
}

.nav-link.active {
  color: var(--text-main);
}

.nav-chevron {
  width: 16px;
  height: 16px;
  transition: transform var(--transition-base);
}

.nav-item.open .nav-chevron {
  transform: rotate(180deg);
}

/* Mega Dropdown */
.mega-dropdown {
  position: absolute;
  top: calc(100% + 8px);
  left: 50%;
  transform: translateX(-50%) translateY(-8px) scale(0.97);
  background: #1E1540;
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.7),
              0 8px 24px rgba(0, 0, 0, 0.5),
              0 0 0 1px rgba(123, 47, 255, 0.25),
              inset 0 1px 0 rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(123, 47, 255, 0.4);
  padding: var(--space-lg);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  transition: all var(--transition-base);
  min-width: 700px;
  z-index: var(--z-dropdown);
  /* Prevent inheriting any parent backdrop-filter compositing */
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  isolation: isolate;
}

.mega-dropdown-sm {
  min-width: 480px;
}

.nav-item.open .mega-dropdown {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
  transform: translateX(-50%) translateY(0) scale(1);
}

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

.mega-category-title {
  font-family: var(--font-ui);
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-xs);
  border-bottom: 2px solid;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: 6px;
}

.mega-tool-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 6px 8px;
  border-radius: var(--radius-sm);
  font-size: var(--fs-sm);
  color: var(--text-secondary);
  transition: all var(--transition-fast);
  border-left: 2px solid transparent;
}

.mega-tool-link:hover {
  background: rgba(123, 47, 255, 0.12);
  color: var(--text-main);
  border-left-color: var(--primary);
}

.mega-tool-link i {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
}

/* Convert Columns */
.convert-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-xl);
}

.convert-col-title {
  font-size: 11px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--cat-convert);
  margin-bottom: var(--space-sm);
  padding-bottom: var(--space-xs);
  border-bottom: 2px solid var(--cat-convert);
}

/* Header Right */
.header-right {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.login-link {
  font-weight: 500;
  color: var(--text-secondary);
}

.login-link:hover {
  color: var(--text-main);
}

.signup-btn {
  border-radius: var(--radius-md);
  background: var(--accent) !important;
  color: var(--text-inverse) !important;
  box-shadow: var(--glow-btn);
  font-weight: 600 !important;
}

.signup-btn:hover {
  background: var(--accent-hover) !important;
  transform: translateY(-1px);
  box-shadow: 0 6px 28px rgba(57, 255, 20, 0.45);
}

/* Theme Toggle - hidden for KukuPDF (dark only) */
.theme-toggle {
  display: none;
}

/* Hamburger */
.hamburger {
  display: none;
  width: 36px;
  height: 36px;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 5px;
  padding: 4px;
  border-radius: var(--radius-md);
}

.hamburger span {
  width: 22px;
  height: 2px;
  background: var(--text-main);
  border-radius: 2px;
  transition: all var(--transition-base);
  transform-origin: center;
}

.hamburger.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
  transform: scaleX(0);
}

.hamburger.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile Drawer */
.mobile-drawer {
  position: fixed;
  top: var(--header-height);
  left: 0;
  width: 100%;
  height: calc(100vh - var(--header-height));
  background: var(--bg-base);
  z-index: var(--z-drawer);
  transform: translateX(-100%);
  transition: transform var(--transition-slow);
  overflow-y: auto;
  border-right: 1px solid var(--border);
}

.mobile-drawer.open {
  transform: translateX(0);
}

.drawer-content {
  padding: var(--space-lg);
}

.drawer-category {
  border-bottom: 1px solid var(--border-light);
}

.drawer-category-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-md) 0;
  font-weight: 600;
  font-size: var(--fs-md);
  color: var(--text-main);
}

.drawer-category-btn i {
  width: 20px;
  height: 20px;
  transition: transform var(--transition-base);
  color: var(--primary-light);
}

.drawer-category.open .drawer-category-btn i {
  transform: rotate(180deg);
}

.drawer-tools {
  display: none;
  padding: 0 0 var(--space-md) var(--space-md);
}

.drawer-category.open .drawer-tools {
  display: block;
}

.drawer-tool-link {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 0;
  color: var(--text-secondary);
  font-size: var(--fs-sm);
}

.drawer-tool-link:hover {
  color: var(--accent);
}

.drawer-footer {
  padding: var(--space-xl) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

@media (max-width: 768px) {
  .nav-desktop {
    display: none;
  }
  .login-link {
    display: none;
  }
  .hamburger {
    display: flex;
  }
}