/* ============================================
   头部导航
   ============================================ */

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  height: var(--header-h);
  transition: background-color var(--t-normal), box-shadow var(--t-normal);
}

.site-header--scrolled {
  background-color: rgba(255, 255, 255, 0.95);
  box-shadow: 0 2px 20px rgba(0, 0, 0, 0.08);
  -webkit-backdrop-filter: blur(10px);
  backdrop-filter: blur(10px);
}

.header-container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
  height: 100%;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
}

/* --- Logo --- */
.logo {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--sp-sm);
  text-decoration: none;
  flex-shrink: 0;
}

.logo-icon-img {
  width: 42px;
  height: 42px;
  display: block;
  flex-shrink: 0;
}

.logo-text {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
}

.logo-cn {
  font-size: var(--fs-lg);
  font-weight: 700;
  color: #ffffff;
  letter-spacing: 2px;
  line-height: 1.2;
}

.site-header--scrolled .logo-cn {
  color: var(--color-white);
}

.logo-en {
  font-size: 10px;
  color: rgba(255, 255, 255, 0.8);
  letter-spacing: 3px;
  text-transform: uppercase;
  line-height: 1;
}

.site-header--scrolled .logo-en {
  color: var(--color-gold);
}

/* --- 桌面导航 --- */
.main-nav {
  display: none;
}

.nav-list {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--sp-xl);
}

.nav-link {
  font-size: 15px;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.85);
  letter-spacing: 0.5px;
  padding: 6px 0;
  position: relative;
  transition: color var(--t-fast);
}

.site-header--scrolled .nav-link {
  color: var(--color-text-secondary);
}

.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -2px;
  width: 0;
  height: 2px;
  background: var(--color-gold);
  transition: width var(--t-normal);
}

.nav-link:hover,
.nav-link.active {
  color: #ffffff;
}

.site-header--scrolled .nav-link:hover,
.site-header--scrolled .nav-link.active {
  color: var(--color-gold);
}

.nav-link.active::after,
.nav-link:hover::after {
  width: 100%;
}

/* --- 手机端菜单按钮 --- */
.mobile-toggle {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  gap: 5px;
  width: 32px;
  height: 32px;
  cursor: pointer;
  z-index: 1001;
}

.hamburger-line {
  display: block;
  width: 24px;
  height: 2px;
  background: #ffffff;
  border-radius: 1px;
  transition: all var(--t-normal);
}

.site-header--scrolled .hamburger-line {
  background: var(--color-white);
}

.mobile-toggle.is-active .hamburger-line {
  background: #ffffff;
}

.mobile-toggle.is-active .hamburger-line:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.mobile-toggle.is-active .hamburger-line:nth-child(2) {
  opacity: 0;
}

.mobile-toggle.is-active .hamburger-line:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* --- 手机端全屏导航 --- */
.mobile-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(26, 32, 44, 0.95);
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  z-index: 999;
  opacity: 0;
  visibility: hidden;
  transition: all var(--t-normal);
}

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

.mobile-nav-list {
  text-align: center;
}

.mobile-nav-link {
  display: block;
  font-size: var(--fs-2xl);
  font-weight: 600;
  color: rgba(255, 255, 255, 0.8);
  padding: var(--sp-md) 0;
  transition: color var(--t-fast);
  letter-spacing: 2px;
}

.mobile-nav-link:hover,
.mobile-nav-link.active {
  color: #ffffff;
}

/* --- 桌面端显示导航 --- */
@media (min-width: 1024px) {
  .main-nav { display: block; }
  .mobile-toggle { display: none; }
}