.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background-color: #fff;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    transition: all 0.3s ease;
}

.site-header.scrolled {
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.header-placeholder {
    height: 72px; /* 默认高度，将由JS动态调整 */
}

.top-bar {
    background: var(--color-primary);
    color: #fff;
    font-size: 0.875rem;
    padding: 0.5rem 0;
}

.top-bar-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.top-bar-text {
    flex: 1;
}

.top-bar-text a {
    color: #fff;
    text-decoration: underline;
}

.top-bar-text a:hover {
    color: var(--color-primary-light);
}

.top-bar-close {
    background: transparent;
    border: none;
    color: rgba(255, 255, 255, 0.7);
    cursor: pointer;
    padding: 0.25rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: color 0.3s ease;
}

.top-bar-close:hover {
    color: var(--color-primary-light);
}

.header-main {
    padding: 0.25rem 0; /* 再次降低高度 */
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.site-branding {
    flex-shrink: 0;
    max-width: 250px; /* 限制Logo区域最大宽度 */
}

.site-branding img {
    max-height: 50px; /* 限制Logo图片最大高度 */
    width: auto;
    display: block;
}

.site-logo-text {
    font-size: 1.5rem;
    font-weight: 700;
    text-decoration: none;
    color: var(--color-primary);
}

.logo-text {
    display: inline-block;
}

.main-navigation {
    flex: 1;
    display: flex;
    justify-content: center;
}

.nav-menu {
    display: flex;
    list-style: none;
    margin: 0;
    padding: 0;
    gap: 0.5rem;
}

.nav-menu > li {
    position: relative;
}

.nav-menu > li > a {
    display: block;
    padding: 0.75rem 1.25rem;
    color: var(--color-text);
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
}

.nav-menu > li > a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: width 0.3s ease;
}

.nav-menu > li > a:hover::after,
.nav-menu > li.current-menu-item > a::after {
    width: 80%;
}

.nav-menu > li > a:hover {
    color: var(--color-primary);
}

.nav-menu > li.current-menu-item > a {
    color: var(--color-primary);
}

.nav-menu ul {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 200px;
    background: #fff;
    box-shadow: 0 5px 20px rgba(0, 0, 0, 0.1);
    opacity: 0;
    visibility: hidden;
    transform: translateY(10px);
    transition: all 0.3s ease;
    list-style: none;
    margin: 0;
    padding: 0.5rem 0;
}

.nav-menu > li:hover > ul {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.nav-menu ul li a {
    display: block;
    padding: 0.75rem 1.25rem;
    color: var(--color-text);
    transition: all 0.3s ease;
}

.nav-menu ul li a:hover {
    background: var(--color-bg-light);
    color: var(--color-primary);
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.menu-icon {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    position: relative;
    transition: all 0.3s ease;
}

.menu-icon::before,
.menu-icon::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background: var(--color-text);
    left: 0;
    transition: all 0.3s ease;
}

.menu-icon::before {
    top: -8px;
}

.menu-icon::after {
    bottom: -8px;
}

.menu-toggle[aria-expanded="true"] .menu-icon {
    background: transparent;
}

.menu-toggle[aria-expanded="true"] .menu-icon::before {
    top: 0;
    transform: rotate(45deg);
}

.menu-toggle[aria-expanded="true"] .menu-icon::after {
    bottom: 0;
    transform: rotate(-45deg);
}

.header-actions {
    flex-shrink: 0;
}

@media (max-width: 992px) {
    .top-bar {
        display: none;
    }
    
    .header-placeholder {
        height: 70px;
    }
    
    .menu-toggle {
        display: block;
    }
    
    .main-navigation {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        bottom: 0;
        background: #fff;
        padding: 1rem;
        transform: translateX(-100%);
        transition: transform 0.3s ease;
        overflow-y: auto;
    }
    
    .main-navigation.active {
        transform: translateX(0);
    }
    
    .nav-menu {
        flex-direction: column;
        gap: 0;
    }
    
    .nav-menu > li > a {
        padding: 1rem;
        border-bottom: 1px solid var(--color-border);
    }
    
    .nav-menu > li > a::after {
        display: none;
    }
    
    .nav-menu ul {
        position: static;
        opacity: 1;
        visibility: visible;
        transform: none;
        box-shadow: none;
        padding-left: 1rem;
        display: none;
    }
    
    .nav-menu > li:hover > ul,
    .nav-menu > li.menu-item-has-children.open > ul {
        display: block;
    }
    
    .header-actions {
        display: none;
    }
}