/* ============================================================
   RLB Steel — Navigation Styles
   固定顶栏 + Products下拉菜单 + 语言切换 + 汉堡菜单 + 移动端侧滑
   ============================================================ */

/* ── Slim Contact Bar — 全站顶部联系方式 ─────────────── */
.top-contact-bar {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: var(--top-contact-height);
  z-index: 1000;
  color: var(--color-white-80);
  background: var(--color-dark);
  border-bottom: 2px solid var(--color-primary);
}

.top-contact-bar .container {
  position: relative;
  display: flex;
  align-items: center;
  height: 100%;
  gap: var(--space-4);
}

.top-contact-bar__welcome {
  flex-shrink: 0;
  font-size: var(--font-size-xs);
  color: var(--color-white-50);
  white-space: nowrap;
}

.top-contact-bar__contacts,
.top-contact-bar__socials,
.top-contact-bar__contact,
.top-contact-bar__social {
  display: flex;
  align-items: center;
}

.top-contact-bar__center {
  display: contents;
}

.top-contact-bar__contacts {
  position: absolute;
  top: 50%;
  left: 50%;
  gap: var(--space-6);
  transform: translate(-50%, -50%);
}

.top-contact-bar__contact {
  gap: var(--space-2);
  font-size: var(--font-size-xs);
  color: var(--color-white-80);
  white-space: nowrap;
  transition: color var(--transition-fast);
}

.top-contact-bar__email {
  color: var(--color-white);
  font-weight: var(--font-weight-medium);
}

.top-contact-bar__contact:hover,
.top-contact-bar__social:hover {
  color: var(--color-white);
}

.top-contact-bar__contact svg {
  width: 14px;
  height: 14px;
  flex-shrink: 0;
  fill: var(--color-primary);
}

.top-contact-bar__socials {
  margin-left: auto;
}

.top-contact-bar__social {
  justify-content: center;
  width: 28px;
  height: 22px;
  color: var(--color-white-80);
  border-left: 1px solid var(--color-white-10);
  transition: color var(--transition-fast);
}

.top-contact-bar__social:first-child {
  border-left: 0;
}

.top-contact-bar__social svg {
  width: 14px;
  height: 14px;
  fill: currentColor;
}

/* ── Header Bar — 永久固定悬浮，滚动不缩小不消失 ──── */
.site-header {
  position: fixed;
  top: var(--top-contact-height);
  left: 0;
  width: 100%;
  height: var(--header-height);
  z-index: 999;
  background: var(--color-dark-90);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: 0 2px 20px rgba(0,0,0,0.3);
  transition: background var(--transition-base),
              box-shadow var(--transition-base);
}

.site-header.scrolled {
  background: var(--color-dark);
  box-shadow: 0 4px 24px rgba(0,0,0,0.4);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 100%;
}

/* ── Logo ────────────────────────────────────────────── */
.site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  flex-shrink: 0;
  text-decoration: none;
}

.site-logo img {
  width: 44px;
  height: 44px;
  object-fit: contain;
}

.site-logo span {
  font-size: var(--font-size-xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-white);
  letter-spacing: var(--letter-spacing-tight);
}

/* ── Desktop Navigation ──────────────────────────────── */
.main-nav {
  display: none;
}

.main-nav__list {
  display: flex;
  align-items: center;
  gap: var(--space-1);
}

.main-nav__item {
  position: relative;
}

.main-nav__link {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-white-80);
  border-radius: var(--radius-sm);
  transition: color var(--transition-fast),
              background var(--transition-fast);
  white-space: nowrap;
}

.main-nav__link:hover,
.main-nav__link.active {
  color: var(--color-white);
  background: var(--color-white-10);
}

/* 下拉箭头 */
.main-nav__arrow {
  font-size: 10px;
  transition: transform var(--transition-fast);
}

.main-nav__item:hover .main-nav__arrow,
.main-nav__item.open .main-nav__arrow {
  transform: rotate(180deg);
}

/* ── Products Mega Dropdown ──────────────────────────── */
.nav-dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(8px);
  min-width: 520px;
  background: var(--color-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-xl);
  padding: var(--space-6);
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast),
              visibility var(--transition-fast),
              transform var(--transition-fast);
  z-index: var(--z-dropdown);
}

.nav-dropdown::before {
  content: '';
  position: absolute;
  top: -8px;
  left: 0;
  right: 0;
  height: 8px;
}

.main-nav__item:hover .nav-dropdown,
.main-nav__item.open .nav-dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateX(-50%) translateY(0);
}

.nav-dropdown__grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-4);
}

.nav-dropdown__group-title {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-primary);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wider);
  margin-bottom: var(--space-2);
  padding-bottom: var(--space-2);
  border-bottom: 1px solid var(--color-gray);
}

.nav-dropdown__link {
  display: block;
  padding: var(--space-1) 0;
  font-size: var(--font-size-sm);
  color: var(--color-dark-light);
  transition: color var(--transition-fast),
              padding-left var(--transition-fast);
}

.nav-dropdown__link:hover {
  color: var(--color-primary);
  padding-left: var(--space-2);
}

/* ── Language Switcher (Desktop) ─────────────────────── */
.lang-switcher {
  display: none;
  position: relative;
}

.lang-switcher__btn {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-white-80);
  border: 1px solid var(--color-white-20);
  border-radius: var(--radius-sm);
  transition: all var(--transition-fast);
}

.lang-switcher__btn:hover {
  color: var(--color-white);
  border-color: var(--color-white-50);
}

.lang-switcher__arrow {
  font-size: var(--font-size-xs);
  transition: transform var(--transition-fast);
}

.lang-switcher.open .lang-switcher__arrow {
  transform: rotate(180deg);
}

.lang-switcher__dropdown {
  position: absolute;
  top: calc(100% + var(--space-1));
  right: 0;
  min-width: 160px;
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-8px);
  transition: all var(--transition-fast);
}

.lang-switcher.open .lang-switcher__dropdown {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
}

.lang-switcher__option {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--font-size-sm);
  color: var(--color-dark);
  transition: background var(--transition-fast);
  border: none;
  background: none;
  cursor: pointer;
  text-align: left;
}

.lang-switcher__option:hover {
  background: var(--color-primary-light);
  color: var(--color-primary);
}

.lang-switcher__option.active {
  color: var(--color-primary);
  font-weight: var(--font-weight-semibold);
}

/* ── Request A Quote (Desktop) ───────────────────────── */
.btn-inquiry--header {
  display: none;
  padding: var(--space-2) var(--space-5);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-white);
  background: var(--color-primary);
  border-radius: var(--radius-md);
  transition: background var(--transition-fast),
              transform var(--transition-fast);
  white-space: nowrap;
}

.btn-inquiry--header:hover {
  background: var(--color-primary-dark);
  transform: translateY(-1px);
}

/* ── Hamburger (Mobile) ──────────────────────────────── */
.hamburger {
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  width: 40px;
  height: 40px;
  gap: 5px;
  cursor: pointer;
  z-index: calc(var(--z-overlay) + 1);
}

.hamburger__line {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-white);
  border-radius: 2px;
  transition: all var(--transition-base);
}

.hamburger.open .hamburger__line:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}
.hamburger.open .hamburger__line:nth-child(2) {
  opacity: 0;
}
.hamburger.open .hamburger__line:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ── Mobile Slide-out Menu ───────────────────────────── */
.mobile-menu {
  position: fixed;
  top: 0;
  right: -100%;
  width: 85%;
  max-width: 360px;
  height: 100vh;
  background: var(--color-dark);
  box-shadow: var(--shadow-xl);
  z-index: var(--z-overlay);
  transition: right var(--transition-base);
  overflow-y: auto;
  padding: var(--space-20) var(--space-6) var(--space-6);
}

.mobile-menu.open { right: 0; }

.mobile-menu__link {
  display: block;
  padding: var(--space-4) 0;
  font-size: var(--font-size-lg);
  font-weight: var(--font-weight-medium);
  color: var(--color-white-80);
  border-bottom: 1px solid var(--color-white-10);
  transition: color var(--transition-fast);
}

.mobile-menu__link:hover,
.mobile-menu__link.active {
  color: var(--color-white);
}

/* Mobile submenu for Products */
.mobile-submenu {
  padding-left: var(--space-4);
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-base);
}

.mobile-submenu.open {
  max-height: 500px;
}

.mobile-submenu__link {
  display: block;
  padding: var(--space-2) 0;
  font-size: var(--font-size-sm);
  color: var(--color-white-50);
  transition: color var(--transition-fast);
}

.mobile-submenu__link:hover {
  color: var(--color-white);
}

.mobile-menu__lang {
  margin-top: var(--space-8);
}

.mobile-menu__lang-title {
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  color: var(--color-white-50);
  text-transform: uppercase;
  letter-spacing: var(--letter-spacing-wider);
  margin-bottom: var(--space-3);
}

.mobile-menu__lang-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-2);
}

.mobile-menu__lang-btn {
  padding: var(--space-2) var(--space-3);
  font-size: var(--font-size-sm);
  border: 1px solid var(--color-white-20);
  border-radius: var(--radius-sm);
  color: var(--color-white-80);
  background: transparent;
  transition: all var(--transition-fast);
}

.mobile-menu__lang-btn:hover,
.mobile-menu__lang-btn.active {
  border-color: var(--color-primary);
  color: var(--color-primary);
  background: var(--color-primary-light);
}

.mobile-menu__inquiry {
  margin-top: var(--space-6);
  width: 100%;
  padding: var(--space-3) var(--space-6);
  font-size: var(--font-size-md);
  font-weight: var(--font-weight-semibold);
  color: var(--color-white);
  background: var(--color-primary);
  border-radius: var(--radius-md);
  text-align: center;
  transition: background var(--transition-fast);
}

.mobile-menu__inquiry:hover {
  background: var(--color-primary-dark);
}

/* ── Overlay Backdrop ────────────────────────────────── */
.mobile-overlay {
  position: fixed;
  inset: 0;
  background: var(--color-overlay);
  z-index: calc(var(--z-overlay) - 1);
  opacity: 0;
  visibility: hidden;
  transition: all var(--transition-base);
}

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

@media (max-width: 1023px) {
  .top-contact-bar__welcome {
    display: none;
  }
}

@media (max-width: 640px) {
  .top-contact-bar .container {
    gap: var(--space-2);
  }

  .top-contact-bar__contacts {
    position: static;
    width: 100%;
    justify-content: space-between;
    gap: var(--space-2);
    transform: none;
  }

  .top-contact-bar__contact {
    gap: var(--space-1);
    font-size: 0.6875rem;
  }

  .top-contact-bar__socials {
    display: none;
  }
}

/* ── Desktop Breakpoint ──────────────────────────────── */
@media (min-width: 1024px) {
  .main-nav            { display: block; }
  .lang-switcher       { display: block; }
  .btn-inquiry--header { display: inline-flex; align-items: center; }
  .hamburger           { display: none; }
  .mobile-menu         { display: none; }
  .mobile-overlay      { display: none; }
}