/* ============================================
   HEADER & NAVIGATION
   ============================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  z-index: 1000;
  height: var(--header-height);
  background-color: rgba(46, 51, 41, 0.94);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.06);
  transition: background-color var(--transition-medium), backdrop-filter var(--transition-medium), box-shadow var(--transition-medium);
}

.site-header.scrolled {
  background-color: rgba(46, 51, 41, 0.98);
  backdrop-filter: blur(10px);
  box-shadow: 0 1px 0 rgba(255, 255, 255, 0.06);
}

.site-header__inner {
  display: flex;
  align-items: center;
  height: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 2rem;
}

@media (max-width: 768px) {
  .site-header__inner {
    padding: 0 1.25rem;
  }
}

/* Logo */
.site-header__logo {
  display: inline-flex;
  align-items: center;
  z-index: 1001;
  margin-right: 2rem;
}

.site-header__logo img {
  height: 28px;
  width: auto;
  display: block;
  filter: brightness(0) invert(1);
}

@media (max-width: 768px) {
  .site-header__logo img {
    height: 24px;
  }
}

/* Desktop Navigation */
.site-header__nav {
  display: flex;
  align-items: center;
  gap: 2.5rem;
  margin: 0 auto;
}

/* Header Right Group */
.site-header__right {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-left: auto;
}

.site-header__nav a {
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-white);
  transition: color var(--transition-fast);
  position: relative;
}

.site-header.scrolled .site-header__nav a {
  color: var(--color-white);
}

.site-header__nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background-color: currentColor;
  transition: width var(--transition-fast);
}

.site-header__nav a:hover::after,
.site-header__nav a.active::after {
  width: 100%;
  background-color: var(--color-olive);
}

.site-header__nav a:hover,
.site-header__nav a.active {
  color: var(--color-olive);
}

/* CTA Button in Header */
.site-header__cta {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border: 1px solid var(--color-olive);
  background-color: var(--color-olive);
  color: var(--color-white);
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.site-header__cta:hover {
  background-color: #6b7a64;
  border-color: #6b7a64;
  color: var(--color-white);
}

.site-header.scrolled .site-header__cta {
  border-color: var(--color-olive);
  background-color: var(--color-olive);
  color: var(--color-white);
}

.site-header.scrolled .site-header__cta:hover {
  background-color: #6b7a64;
  border-color: #6b7a64;
  color: var(--color-white);
}

/* Language Switcher */
.site-header__lang {
  position: relative;
  display: flex;
  align-items: center;
  z-index: 1001;
}

.site-header__lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.4rem 0.65rem;
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid rgba(255, 255, 255, 0.25);
  border-radius: 50px;
  color: var(--color-white);
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  line-height: 1;
  cursor: pointer;
  transition: background-color var(--transition-fast), border-color var(--transition-fast);
}

.site-header__lang-toggle:hover {
  background: rgba(255, 255, 255, 0.2);
  border-color: rgba(255, 255, 255, 0.4);
}

.site-header__lang-icon {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
}

.site-header__lang-current {
  min-width: 1.2em;
  text-align: center;
}

.site-header__lang-arrow {
  width: 10px;
  height: 10px;
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.site-header__lang.active .site-header__lang-arrow {
  transform: rotate(180deg);
}

.site-header__lang-menu {
  position: absolute;
  top: calc(100% + 0.5rem);
  right: 0;
  min-width: 150px;
  padding: 0.5rem;
  background: #E8EFE3;
  border-radius: 16px;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.15);
  list-style: none;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-5px);
  transition: opacity var(--transition-fast), visibility var(--transition-fast), transform var(--transition-fast);
}

.site-header__lang.active .site-header__lang-menu {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.site-header__lang-item {
  margin: 0;
}

.site-header__lang-item a {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  width: 100%;
  box-sizing: border-box;
  padding: 0.75rem 1rem;
  border-radius: 12px;
  color: var(--color-olive);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 500;
  text-decoration: none;
  transition: background-color var(--transition-fast), color var(--transition-fast);
}

.site-header__lang-item a:hover {
  background: rgba(255, 255, 255, 0.6);
}

.site-header__lang-item.is-active a {
  background: var(--color-white);
}

.site-header__lang-check {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  stroke: var(--color-olive);
  stroke-width: 2;
  fill: none;
}

@media (max-width: 1024px) {
  .site-header__lang {
    margin-left: auto;
    margin-right: 1rem;
  }
}

@media (max-width: 768px) {
  .site-header__lang-toggle {
    font-size: 0.7rem;
    padding: 0.35rem 0.55rem;
  }
}

/* Mobile Menu Toggle */
.menu-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  width: 32px;
  height: 32px;
  gap: 6px;
  z-index: 1001;
}

.menu-toggle span {
  display: block;
  width: 100%;
  height: 1.5px;
  background-color: var(--color-white);
  transition: transform var(--transition-fast), opacity var(--transition-fast), background-color var(--transition-fast);
}

.site-header.scrolled .menu-toggle span,
.site-header.menu-open .menu-toggle span {
  background-color: var(--color-white);
}

.menu-toggle.active span:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
  opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* Mobile Navigation */
.mobile-nav {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  min-height: 100vh;
  min-height: 100dvh;
  height: auto;
  background-color: rgba(46, 51, 41, 0.98);
  z-index: 999;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 2rem;
  padding: calc(var(--header-height-mobile) + 2rem) 2rem 2rem;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-medium), visibility var(--transition-medium);
  overflow-y: auto;
  box-sizing: border-box;
}

.mobile-nav.active {
  opacity: 1;
  visibility: visible;
}

.mobile-nav a {
  font-family: var(--font-serif);
  font-size: clamp(2rem, 8vw, 3.5rem);
  font-weight: 500;
  color: var(--color-white);
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease, color var(--transition-fast);
}

:lang(zh-CN) .mobile-nav a {
  font-family: var(--font-sans);
}

.mobile-nav.active a {
  opacity: 1;
  transform: translateY(0);
}

.mobile-nav a:nth-child(1) { transition-delay: 0.08s; }
.mobile-nav a:nth-child(2) { transition-delay: 0.14s; }
.mobile-nav a:nth-child(3) { transition-delay: 0.2s; }
.mobile-nav a:nth-child(4) { transition-delay: 0.26s; }
.mobile-nav a:nth-child(5) { transition-delay: 0.32s; }
.mobile-nav a:nth-child(6) { transition-delay: 0.38s; }

.mobile-nav a:hover,
.mobile-nav a.active {
  color: var(--color-olive);
}

.mobile-nav .mobile-nav__cta {
  margin-top: 1rem;
  font-family: var(--font-sans);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--color-white);
  white-space: nowrap;
  min-width: auto;
  height: auto;
  box-sizing: border-box;
  padding: 0.75rem 1.5rem;
  justify-content: center;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
  transition-delay: 0.44s;
}

.mobile-nav.active .mobile-nav__cta {
  opacity: 1;
  transform: translateY(0);
}

/* Responsive */
@media (max-width: 1024px) {
  .site-header__nav,
  .site-header__cta {
    display: none;
  }

  .menu-toggle {
    display: flex;
  }
}