/* ============================================
   Header & Navigation
   ============================================ */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--header-py) var(--header-px);
  background-color: var(--color-page-bg);
  position: relative;
  z-index: 100;
}

.site-logo {
  font-family: var(--font-condensed);
  font-size: var(--fs-logo);
  font-weight: 400;
  color: var(--color-logo);
  letter-spacing: var(--ls-logo);
  line-height: var(--lh-logo);
  text-decoration: none;
}

.site-logo:hover {
  opacity: 0.8;
  transition: opacity 0.2s ease;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 40px;
}

.site-nav a {
  font-family: var(--font-condensed);
  font-size: var(--fs-nav);
  font-weight: 400;
  color: var(--color-nav);
  letter-spacing: var(--ls-nav);
  line-height: var(--lh-nav);
  text-decoration: none;
  transition: opacity 0.2s ease;
}

.site-nav a:hover {
  opacity: 0.6;
}

/* Hamburger button — hidden on desktop */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  cursor: pointer;
  background: none;
  border: none;
  padding: 4px;
  z-index: 200;
}

.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background-color: var(--color-nav);
  border-radius: 1px;
  transition: transform 0.3s ease, opacity 0.3s ease;
}

.hamburger[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.hamburger[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.hamburger[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* Mobile nav overlay */
.mobile-nav-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background-color: var(--color-page-bg);
  z-index: 150;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 40px;
  opacity: 0;
  transition: opacity 0.3s ease;
}

.mobile-nav-overlay.is-open {
  display: flex;
  opacity: 1;
}

.mobile-nav-overlay a {
  font-family: var(--font-condensed);
  font-size: clamp(28px, 8vw, 48px);
  color: var(--color-nav);
  letter-spacing: var(--ls-nav);
  line-height: 1.2;
  transition: opacity 0.2s ease;
}

.mobile-nav-overlay a:hover {
  opacity: 0.6;
}

.mobile-nav-close {
  position: absolute;
  top: 20px;
  right: 24px;
  font-size: 20px;
  color: var(--color-nav);
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  line-height: 1;
  transition: opacity 0.2s ease;
}

.mobile-nav-close:hover {
  opacity: 0.5;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .site-header {
    padding: 20px 32px;
  }

  .site-logo {
    font-size: clamp(22px, 5vw, 28px);
  }

  .site-nav {
    display: none;
  }

  .hamburger {
    display: flex;
  }
}

@media (max-width: 480px) {
  .site-header {
    padding: 16px 24px;
  }
}