.header {
    position: sticky;
    top: 0;
    z-index: 3000;
    background: rgba(255, 255, 255, 0.94);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--color-border);
  }
  
  .header-inner {
    position: relative;
  }
  
  .nav-list {
    list-style: none !important;
    display: flex;
    gap: 1rem;
    align-items: center;
    margin: 0;
    padding: 0;
  }
  
  .nav-list li {
    margin: 0;
  }
  
  .brand a {
    font-weight: 600;
    font-size: 1.1rem;
  }
  
  .nav-group {
    flex: 1;
  }
  
  .nav-left {
    justify-content: flex-start;
  }
  
  .nav-right {
    justify-content: flex-end;
  }
  
  .nav-group ul {
    justify-content: inherit;
  }
  
  .nav-toggle {
    display: none;
    width: 44px;
    height: 44px;
    flex: 0 0 44px;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    gap: 5px;
    border: 1px solid var(--color-border);
    border-radius: 12px;
    background: #fff;
    cursor: pointer;
    position: relative;
    z-index: 3002;
  }
  
  .nav-toggle span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--color-text);
    border-radius: 999px;
    transition: transform 0.25s ease, opacity 0.25s ease;
  }
  
  .nav-toggle[aria-expanded="true"] span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
  }
  
  .nav-toggle[aria-expanded="true"] span:nth-child(2) {
    opacity: 0;
  }
  
  .nav-toggle[aria-expanded="true"] span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
  }
  
  .mobile-menu {
    display: none;
  }
  
  .mobile-nav-list {
    list-style: none !important;
    display: flex;
    flex-direction: column;
    gap: 0;
    margin: 0;
    padding: 1rem;
  }
  
  .mobile-nav-list li {
    margin: 0;
  }
  
  .mobile-nav-list a {
    display: block;
    padding: 0.85rem 1rem;
    border-radius: 12px;
    font-weight: 500;
  }
  
  .mobile-nav-list a:hover {
    background: var(--color-muted);
  }
  
  @media (max-width: 768px) {
    .header-inner {
      min-height: 72px;
    }
  
    .nav-group {
      display: none;
    }
  
    .brand {
      flex: 1;
      text-align: left;
    }
  
    .brand a {
      font-size: 1rem;
    }
  
    .nav-toggle {
      display: flex;
    }
  
    .mobile-menu {
      position: absolute;
      top: 100%;
      left: 0;
      right: 0;
      width: 100%;
      max-height: 0;
      overflow: hidden;
      display: block;
      background: #fff;
      border-bottom: 1px solid var(--color-border);
      box-shadow: var(--shadow-md);
      opacity: 0;
      visibility: hidden;
      transform: translateY(-8px);
      transition: max-height 0.3s ease, opacity 0.25s ease, visibility 0.25s ease, transform 0.25s ease;
      z-index: 3001;
    }
  
    .mobile-menu.open {
      max-height: calc(100vh - 72px);
      overflow-y: auto;
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
    }
  }