/**
 * Site header, navigation, mobile menu
 */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  transition: background 0.3s, box-shadow 0.3s, backdrop-filter 0.3s;
  background: rgba(0, 0, 0, 0.3);
  backdrop-filter: blur(2px);
}

.header.scrolled {
  background: rgba(0, 0, 0, 0.5);
  backdrop-filter: blur(20px);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 16px;
  height: 80px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
}

.header .nav-item {
  position: relative;
}

.nav-item > a {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 0;
  color: #aaaaaa;
  text-decoration: none;
  font-size: 16px;
  font-weight: 500;
  letter-spacing: 0.02em;
  transition: color 0.2s;
  white-space: nowrap;
  font-family: 'PT Serif', serif;
  cursor: pointer;
}

.nav-item > a:hover,
.nav-item > a.active {
  color: #ffffff;
}

.nav-item > a.dropdown-toggle {
  cursor: pointer;
}

.dropdown {
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(8px);
  min-width: 200px;
  padding: 8px 0;
  border-radius: 12px;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.2s, transform 0.2s, visibility 0.2s;
  background: rgba(15, 15, 15, 0.8);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid rgba(255, 255, 255, 0.08);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.5);
}

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

.dropdown a {
  display: block;
  padding: 8px 20px;
  color: #a3a3a3;
  text-decoration: none;
  font-size: 16px;
  transition: color 0.15s, background 0.15s;
  text-align: center;
  font-family: 'PT Serif', serif;
}

.dropdown a:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.05);
}
  .header-actions {
    display: flex;
    align-items: center;
    gap: 8px;
  }
  
  @media (min-width: 1025px) {
    .header-actions {
      margin-left: auto;
    }
  }
  
  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    border-radius: 10px;
    border: 1px solid rgba(255, 255, 255, 0.08);
    background: transparent;
    color: #a3a3a3;
    transition: color 0.2s, background 0.2s;
    cursor: pointer;
  }
  
  .mobile-menu-btn:hover {
    color: #ffffff;
    background: rgba(255, 255, 255, 0.03);
  }
.lang-switcher {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-shrink: 0;
}

.lang-btn {
  background: transparent;
  border: 1px solid transparent;
  color: #a3a3a3;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  padding: 8px 14px;
  border-radius: 4px;
  transition: all 0.3s;
  font-family: 'Inter', 'Noto Sans SC', sans-serif;
  white-space: nowrap;
  line-height: 1;
  flex-shrink: 0;
}

/* Keep the SAME font stack on every UI language.
   Neutralizes the `:lang(zh) .lang-btn` override (Noto Sans SC first) that the
   zh-only stylesheet applies, so the language buttons look identical on RU/EN/zh. */
.lang-switcher .lang-btn {
  font-family: 'Inter', 'Noto Sans SC', sans-serif;
}

.lang-btn.active {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.15);
}

.lang-btn:hover:not(.active) {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.1);
}

.lang-separator {
  color: #404040;
  font-size: 12px;
  padding: 0 2px;
}
.mobile-menu .lang-btn {
  font-size: 14px;
  padding: 12px 16px;
  border: 1px solid rgba(255, 255, 255, 0.08);
}

.mobile-menu .lang-separator {
  font-size: 14px;
  padding: 0 6px;
}
.mobile-menu .mobile-nav-link,
.mobile-menu .mobile-accordion-btn {
  font-family: 'PT Serif', serif;
  font-size: 1.2rem;
  line-height: 1.5rem;
}
.mobile-menu-inner {
  padding: 16px;
}

.mobile-menu-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 32px;
}

.mobile-menu-title {
  font-size: 14px;
  font-weight: 500;
}

.mobile-menu-close-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  border: 1px solid rgba(255, 255, 255, 0.08);
  background: transparent;
  color: #a3a3a3;
  transition: color 0.2s, background 0.2s;
  cursor: pointer;
}

.mobile-menu-close-btn:hover {
  color: #ffffff;
  background: rgba(255, 255, 255, 0.03);
}

.mobile-nav {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.mobile-nav-link {
  display: block;
  padding: 10px 0;
  color: #a3a3a3;
  text-decoration: none;
  font-family: 'PT Serif', serif;
  font-size: 1.2rem;
  line-height: 1.5rem;
  transition: color 0.2s;
}

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

.mobile-sub-link {
  padding-left: 16px;
  color: #737373;
  font-size: 1rem;
}

.mobile-sub-link:hover {
  color: #a3a3a3;
}

.mobile-accordion-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  padding: 10px 0;
  background: transparent;
  border: none;
  color: #a3a3a3;
  font-family: 'PT Serif', serif;
  font-size: 1.2rem;
  line-height: 1.5rem;
  cursor: pointer;
  transition: color 0.2s;
}

.mobile-accordion-btn:hover {
  color: #ffffff;
}

.mobile-accordion-icon {
  transition: transform 0.2s;
}

.mobile-accordion-btn[aria-expanded="true"] .mobile-accordion-icon,
.mobile-accordion.open .mobile-accordion-icon {
  transform: rotate(180deg);
}

.mobile-menu {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  max-width: 320px;
  background: rgba(10, 10, 10, 0.5);
  backdrop-filter: blur(30px);
  -webkit-backdrop-filter: blur(30px);
  z-index: 200;
  transform: translateX(100%);
  transition: transform 0.55s cubic-bezier(0.4, 0, 0.2, 1);
  overflow-y: auto;
  border-left: 1px solid rgba(255, 255, 255, 0.06);
}

.mobile-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.0);
  z-index: 199;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.5s, visibility 0.5s;
}

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

.mobile-menu.open {
  transform: translateX(0);
}

.mobile-accordion-content {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.9s ease;
}

.mobile-accordion-content.open {
  max-height: 500px;
}
.mobile-lang-row .lang-btn {
  flex: 1;
  text-align: center;
  font-size: 14px;
  padding: 10px 12px;
  border-radius: 8px;
  border: 1px solid transparent;
}

.mobile-lang-row .lang-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.1);
}

.mobile-lang-row .lang-separator {
  font-size: 14px;
  color: #404040;
}

/* Desktop / mobile nav visibility */
.nav-desktop {
  display: none;
}

@media (min-width: 1025px) {
  .nav-desktop {
    display: flex;
    align-items: center;
    gap: 32px;
    margin: 0 auto;
  }
}
.mobile-menu-btn {
  display: flex;
}

@media (min-width: 1025px) {
  .mobile-menu-btn {
    display: none;
  }
}

@media (max-width: 1024px) {
  .header-container {
    padding: 0 12px;
    justify-content: flex-end;
    height: 60px;
  }

  .header-actions {
    margin-left: 0;
  }
}

@media (max-width: 480px) {
  .header-container {
    padding: 0 12px;
  }

  .lang-switcher {
    gap: 6px;
  }

  .lang-btn {
    font-size: 12px;
    padding: 7px 12px;
    border-radius: 4px;
  }

  .lang-separator {
    font-size: 12px;
    padding: 0 2px;
  }
}

@media (max-width: 768px) {
  .lang-switcher {
    gap: 6px;
  }

  .lang-btn {
    padding: 7px 12px;
    font-size: 12px;
  }
}