/* ============================================================
   header.css — Header · Nav · 語言切換
   ============================================================ */

/* ── Site Header ── */
.site-header {
  position: fixed;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  max-width: var(--max-width);
  height: var(--header-height);
  z-index: var(--z-header);

  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 var(--sp-5);

  /* 預設透明，捲動後加背景 */
  background: transparent;
  transition:
    background var(--dur-base) var(--ease-out),
    border-color var(--dur-base) var(--ease-out),
    backdrop-filter var(--dur-base) var(--ease-out);
  border-bottom: 1px solid transparent;
}

.site-header.is-scrolled {
  background: rgba(0, 7, 44, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom-color: var(--color-border);
}

/* ── Logo ── */
.site-logo {
  display: flex;
  align-items: center;
  text-decoration: none;
  flex-shrink: 0;
}

.site-logo__img {
  height: clamp(28px, 9vw, 36px);
  width: auto;
  display: block;
  image-rendering: pixelated;
}

/* ── Header Right Controls ── */
.header-controls {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
}

/* ── 語言切換 ── */
.lang-switcher {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--color-border);
  border-radius: var(--r-full);
  padding: 3px;
}

.lang-btn {
  height: 28px;
  padding: 0 var(--sp-3);
  border-radius: var(--r-full);
  font-size: var(--fs-xs);
  font-weight: var(--fw-bold);
  letter-spacing: var(--ls-wide);
  color: var(--color-text-muted);
  transition:
    background var(--dur-fast) var(--ease-out),
    color     var(--dur-fast) var(--ease-out);
}

.lang-btn:hover {
  color: var(--color-text-sub);
  background: rgba(255, 255, 255, 0.06);
}

.lang-btn.is-active {
  background: var(--token-btn-primary);
  color: #fff;
  box-shadow: 0 0 12px rgba(72, 54, 171, 0.45);
}

/* ── Menu 按鈕 ── */
.hamburger {
  position: relative;
  width: clamp(32px, 9.5vw, 40px);
  height: clamp(32px, 9.5vw, 40px);
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-md);
  transition: background var(--dur-fast) var(--ease-out);
  flex-shrink: 0;
}

.hamburger:hover {
  background: rgba(255, 255, 255, 0.06);
}

.hamburger__icon {
  display: block;
  width: clamp(20px, 6vw, 26px);
  height: clamp(20px, 6vw, 26px);
  image-rendering: pixelated;
  transition: opacity var(--dur-base) var(--ease-inout);
}

/* 開啟狀態 — 圖示淡出，顯示 ✕ */
.hamburger.is-open .hamburger__icon {
  opacity: 0;
}

.hamburger::after {
  content: '✕';
  position: absolute;
  font-size: 18px;
  font-weight: var(--fw-black);
  color: var(--color-text);
  opacity: 0;
  transition: opacity var(--dur-base) var(--ease-inout);
  pointer-events: none;
}

.hamburger.is-open::after {
  opacity: 1;
}

/* ── 全螢幕 Nav Menu ── */
.nav-menu {
  position: fixed;
  inset: 0;
  background: rgba(0, 7, 44, 0.97);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: calc(var(--z-header) - 1);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);

  /* 預設隱藏 */
  opacity: 0;
  pointer-events: none;
  transform: translateY(-8px);
  transition:
    opacity    var(--dur-base) var(--ease-out),
    transform  var(--dur-base) var(--ease-out);
}

.nav-menu.is-open {
  opacity: 1;
  pointer-events: auto;
  transform: translateY(0);
}

.nav-menu__list {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-2);
  width: 100%;
  max-width: var(--max-width);
  padding: 0 var(--sp-5);
}

.nav-menu__item {
  width: 100%;
}

.nav-menu__link {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: var(--sp-4) var(--sp-6);
  border-radius: var(--r-lg);
  font-size: var(--fs-xl);
  font-weight: var(--fw-black);
  letter-spacing: var(--ls-tight);
  color: var(--color-text-sub);
  transition:
    color      var(--dur-fast) var(--ease-out),
    background var(--dur-fast) var(--ease-out);
}

.nav-menu__link:hover,
.nav-menu__link.is-current {
  color: var(--color-text);
  background: rgba(255, 255, 255, 0.04);
}

.nav-menu__link.is-current {
  color: var(--color-red);
}

.nav-menu__link::after {
  content: '→';
  font-size: var(--fs-md);
  opacity: 0;
  transform: translateX(-8px);
  transition:
    opacity   var(--dur-fast) var(--ease-out),
    transform var(--dur-fast) var(--ease-out);
}

.nav-menu__link:hover::after {
  opacity: 1;
  transform: translateX(0);
}

.nav-menu__divider {
  width: 40px;
  height: 1px;
  background: var(--color-border);
  margin: var(--sp-4) 0;
}

.nav-menu__footer {
  display: flex;
  gap: var(--sp-6);
  margin-top: var(--sp-8);
}

.nav-social-link {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--r-full);
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
  font-size: var(--fs-md);
  transition:
    border-color var(--dur-fast) var(--ease-out),
    color        var(--dur-fast) var(--ease-out),
    background   var(--dur-fast) var(--ease-out);
}

.nav-social-link:hover {
  border-color: var(--color-red);
  color: var(--color-red);
  background: var(--color-red-glow);
}

/* ── Stagger animation for nav items ── */
.nav-menu.is-open .nav-menu__item {
  animation: navItemIn var(--dur-slow) var(--ease-spring) both;
}
.nav-menu.is-open .nav-menu__item:nth-child(1) { animation-delay: 60ms; }
.nav-menu.is-open .nav-menu__item:nth-child(2) { animation-delay: 120ms; }
.nav-menu.is-open .nav-menu__item:nth-child(3) { animation-delay: 180ms; }
.nav-menu.is-open .nav-menu__item:nth-child(4) { animation-delay: 240ms; }

@keyframes navItemIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}