/* ============================================================
   header.css — Üst menü
   Yarı saydam beyaz + bulanıklık; kaydırılınca netleşir, alt çizgisi
   kırmızıya döner (Bekkimya ile aynı davranış).
   ============================================================ */

.header {
  position: sticky;
  top: 0;
  z-index: var(--z-header);
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--color-line);
  transition: background var(--transition-normal), box-shadow var(--transition-normal), border-color var(--transition-normal);
}

.header.scrolled {
  background: rgba(255, 255, 255, 0.97);
  box-shadow: 0 2px 20px rgba(17, 17, 20, 0.08);
  border-bottom-color: rgba(var(--color-primary-rgb), 0.15);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-xl);
  height: 100%;
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-padding);
}

.logo {
  flex-shrink: 0;
}

.logo a {
  display: block;
}

.logo img {
  height: 40px;
  width: auto;
  transition: transform var(--transition-normal);
}

.logo a:hover img {
  transform: scale(1.03);
}

/* --- Masaüstü menü --- */
.nav-menu {
  display: none;
}

@media (min-width: 1024px) {
  .nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-xs);
    margin-left: auto;
  }
}

.nav-menu a {
  position: relative;
  padding: var(--space-sm) var(--space-md);
  font-family: var(--font-heading);
  font-size: 0.9rem;
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.02em;
  color: var(--color-text);
}

/* Kısa kırmızı alt çizgi: üzerine gelince ve aktif sayfada */
.nav-menu a::after {
  content: "";
  position: absolute;
  bottom: 0;
  left: 50%;
  width: 24px;
  height: 2px;
  background: var(--color-primary);
  border-radius: 1px;
  transform: translateX(-50%) scaleX(0);
  transition: transform var(--transition-normal);
}

.nav-menu a:hover,
.nav-menu a.active {
  color: var(--color-ink);
}

.nav-menu a:hover::after,
.nav-menu a.active::after {
  transform: translateX(-50%) scaleX(1);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.header-cta {
  display: none;
}

@media (min-width: 640px) {
  .header-cta {
    display: inline-flex;
  }
}

/* --- Hamburger --- */
.hamburger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 28px;
  height: 28px;
  /* Gorunen ikon 28 px; dokunma alani 44 px (WCAG 2.5.8) */
  box-sizing: content-box;
  padding: 8px;
  margin: -8px;
}

@media (min-width: 1024px) {
  .hamburger {
    display: none;
  }
}

.hamburger span {
  display: block;
  width: 100%;
  height: 2px;
  background-color: var(--color-ink);
  border-radius: 2px;
  transform-origin: center;
  transition: transform var(--transition-normal), opacity var(--transition-fast);
}

.hamburger.active span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.active span:nth-child(2) { opacity: 0; }
.hamburger.active span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* --- Mobil menü: tam ekran, ortalı bağlantılar --- */
.mobile-menu {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  z-index: var(--z-overlay);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--space-2xl);
  padding: var(--space-xl) var(--container-padding);
  background: rgba(255, 255, 255, 0.98);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  overflow-y: auto;
  visibility: hidden;
  opacity: 0;
  transition: opacity var(--transition-normal), visibility var(--transition-normal);
}

.mobile-menu.open {
  visibility: visible;
  opacity: 1;
}

@media (min-width: 1024px) {
  .mobile-menu {
    display: none;
  }
}

.mobile-nav {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-md);
}

.mobile-nav a {
  padding: var(--space-sm) var(--space-xl);
  font-family: var(--font-heading);
  font-size: 1.5rem;
  font-weight: var(--font-weight-semibold);
  color: var(--color-text);
  transition: color var(--transition-fast), transform var(--transition-fast);
}

.mobile-nav a:hover,
.mobile-nav a.active {
  color: var(--color-primary);
  transform: translateX(4px);
}