/* ==========================================================================
   Header — hero üstünde şeffaf, scroll'da açık zemin + sticky.
   Mobilde drawer.
   ========================================================================== */
.header {
  position: fixed;
  inset: 0 0 auto;
  z-index: var(--z-header);
  height: var(--header-h);
  color: var(--color-white);
  transition: height var(--dur) var(--ease), background-color var(--dur) var(--ease),
              box-shadow var(--dur) var(--ease), color var(--dur) var(--ease);
}
.header::before {
  /* hero üzerinde okunabilirlik için hafif üst gölge */
  content: '';
  position: absolute;
  inset: 0 0 -40px;
  background: var(--gradient-header);
  pointer-events: none;
  transition: opacity var(--dur) var(--ease);
}

.header__inner {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-6);
  height: 100%;
}

.header__brand {
  position: relative;
  display: block;
  width: 168px;
  flex: none;
  transition: width var(--dur) var(--ease);
}
.header__logo { width: 100%; height: auto; transition: opacity var(--dur) var(--ease); }
.header__logo--dark { position: absolute; inset: 0; opacity: 0; }

/* Nav */
.nav { display: none; }
.nav__list { display: flex; gap: clamp(var(--space-5), 2.4vw, var(--space-7)); }
.nav__link {
  position: relative;
  display: inline-block;
  padding-block: var(--space-2);
  font-size: var(--fs-small);
  font-weight: 500;
  letter-spacing: .01em;
  color: inherit;
  opacity: .88;
}
.nav__link::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: -2px;
  height: 1px;
  background: var(--color-primary);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform var(--dur) var(--ease);
}
.nav__link:hover,
.nav__link.is-active { color: inherit; opacity: 1; }
.nav__link:hover::after,
.nav__link.is-active::after { transform: scaleX(1); transform-origin: left; }

.header__actions { display: flex; align-items: center; gap: var(--space-4); }

/* Teklif butonu — hero üstünde sade (ince çerçeve), scroll'da koyu grafit dolgu
   + altın ok. Dolgu geçişi animasyonlu olsun diye ::before katmanında. */
.header__cta {
  --btn-fg: var(--color-white);
  --btn-border: var(--color-line-on-dark-strong);
  position: relative;
  display: none;
  gap: 0;
  isolation: isolate;
  overflow: hidden;
  background: transparent;
  transition: color var(--dur) var(--ease), border-color var(--dur) var(--ease), box-shadow var(--dur) var(--ease), padding var(--dur) var(--ease);
}
.header__cta::before {
  content: '';
  position: absolute;
  inset: 0;
  z-index: -1;
  background: var(--color-dark);
  opacity: 0;
  transition: opacity var(--dur) var(--ease), background-color var(--dur-fast) var(--ease);
}
.header__cta svg {
  width: 0;
  margin-left: 0;
  opacity: 0;
  transition: width var(--dur) var(--ease), margin var(--dur) var(--ease), opacity var(--dur) var(--ease), transform var(--dur-fast) var(--ease);
}
.header__cta:hover { --btn-border: var(--color-white); color: var(--color-white); }

.header.is-scrolled .header__cta {
  --btn-fg: var(--color-white);
  --btn-border: transparent;
}
.header.is-scrolled .header__cta::before { opacity: 1; }
.header.is-scrolled .header__cta svg { width: 16px; margin-left: var(--space-2); opacity: 1; stroke: var(--color-primary); }
.header.is-scrolled .header__cta:hover { color: var(--color-white); box-shadow: var(--shadow-md); }
.header.is-scrolled .header__cta:hover::before { background: var(--color-dark-3); }

/* Hamburger */
.header__toggle {
  display: inline-flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-end;
  gap: 7px;
  width: 48px;
  height: 48px;
  padding: 0 var(--space-3);
  border: 1px solid var(--color-line-on-dark-strong);
  border-radius: var(--radius-pill);
  background: var(--color-glass-light);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
  color: inherit;
  cursor: pointer;
}
.header__toggle-bar { display: block; height: 1.5px; width: 22px; background: currentColor; border-radius: 2px; }
.header__toggle-bar + .header__toggle-bar { width: 14px; }

/* Scroll durumu */
.header.is-scrolled {
  height: var(--header-h-scrolled);
  color: var(--color-text);
  background: var(--color-header-scrolled);
  -webkit-backdrop-filter: saturate(160%) blur(14px);
  backdrop-filter: saturate(160%) blur(14px);
  box-shadow: 0 1px 0 var(--color-line);
}
.header.is-scrolled::before { opacity: 0; }
.header.is-scrolled .header__brand { width: 144px; }
.header.is-scrolled .header__logo--light { opacity: 0; }
.header.is-scrolled .header__logo--dark { opacity: 1; }
.header.is-scrolled .header__toggle { border-color: var(--color-line-strong); background: transparent; }

@media (min-width: 992px) {
  .nav { display: block; }
  .header__cta { display: inline-flex; }
  .header__toggle { display: none; }
}

/* ==========================================================================
   Drawer (mobil menü)
   ========================================================================== */
.drawer {
  position: fixed;
  inset: 0;
  z-index: var(--z-drawer);
}
.drawer[hidden] { display: none; }

.drawer__backdrop {
  position: absolute;
  inset: 0;
  background: var(--color-overlay);
  -webkit-backdrop-filter: blur(4px);
  backdrop-filter: blur(4px);
  opacity: 0;
  transition: opacity var(--dur) var(--ease);
}
.drawer__panel {
  position: absolute;
  inset: 0 0 0 auto;
  width: min(420px, 100%);
  display: flex;
  flex-direction: column;
  gap: var(--space-7);
  padding: var(--space-5) var(--gutter) var(--space-7);
  background: var(--gradient-dark);
  color: var(--color-on-dark);
  overflow-y: auto;
  transform: translateX(100%);
  transition: transform var(--dur) var(--ease-out);
}
.drawer__panel::after {
  content: '';
  position: absolute;
  width: 360px;
  height: 360px;
  right: -140px;
  bottom: -140px;
  background: var(--glow-gold-soft);
  pointer-events: none;
}
.drawer.is-open .drawer__backdrop { opacity: 1; }
.drawer.is-open .drawer__panel { transform: none; }

.drawer__top { display: flex; align-items: center; justify-content: space-between; }
.drawer__close {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border: 1px solid var(--color-line-on-dark-strong);
  border-radius: var(--radius-pill);
  background: transparent;
  color: inherit;
  cursor: pointer;
}
.drawer__close svg { width: 20px; height: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; }

.drawer__list { display: grid; }
.drawer__link {
  display: flex;
  align-items: baseline;
  gap: var(--space-4);
  padding: var(--space-4) 0;
  border-bottom: 1px solid var(--color-line-on-dark);
  font-size: clamp(1.5rem, 1.2rem + 1.5vw, 2rem);
  font-weight: 600;
  letter-spacing: var(--ls-heading);
  color: var(--color-on-dark);
}
.drawer__link span { font-size: var(--fs-xs); font-weight: 600; color: var(--color-primary); letter-spacing: .08em; }
.drawer__link:hover { color: var(--color-primary-bright); }

.drawer__foot { position: relative; z-index: 1; display: grid; gap: var(--space-3); margin-top: auto; }
.drawer__contact { color: var(--color-muted-on-dark); font-variant-numeric: tabular-nums; }
.drawer__contact:hover { color: var(--color-white); }