/**
 * 页眉增强样式
 */
 
.site-header {
    box-shadow: 0 2px 15px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

/* 导航栏品牌区域增强 */
.navbar-brand {
    display: flex;
    align-items: center;
}

.custom-logo {
    max-height: 50px;
    width: auto;
    margin-right: 10px;
    transition: transform 0.3s ease;
}

.custom-logo:hover {
    transform: scale(1.05);
}

/* 导航菜单动画和效果 */
.navbar-nav .nav-item {
    position: relative;
    margin: 0 2px;
}

.navbar-nav .nav-link {
    position: relative;
    z-index: 1;
    overflow: hidden;
}

.navbar-nav .nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 0;
    background-color: rgba(255, 255, 255, 0.1);
    transition: height 0.3s ease;
    z-index: -1;
}

.navbar-nav .nav-link:hover::before {
    height: 100%;
}

.navbar-nav .nav-item.active .nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background-color: #fff;
    transition: all 0.3s ease;
    transform: translateX(-50%);
    opacity: 0;
}

.navbar-nav .nav-item.active .nav-link:hover::after {
    width: 80%;
    opacity: 1;
}

/* 下拉菜单增强 */
.dropdown-menu {
    margin-top: 0;
    animation: fadeIn 0.3s ease;
    border-top: 3px solid var(--accent-color);
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.dropdown-item {
    padding: 0.6rem 1.5rem;
    position: relative;
    transition: all 0.2s ease;
}

.dropdown-item::before {
    content: '';
    position: absolute;
    left: 0.5rem;
    top: 50%;
    width: 0;
    height: 1px;
    background-color: var(--primary-color);
    transition: width 0.2s ease;
    transform: translateY(-50%);
}

.dropdown-item:hover::before {
    width: 0.5rem;
}

.dropdown-item:hover {
    padding-left: 1.8rem;
}

/* 用户登录/注册按钮 */
.navbar-nav .btn-outline-light {
    border-width: 2px;
    font-weight: 500;
    padding: 0.4rem 1rem;
    transition: all 0.3s ease;
}

.navbar-nav .btn-outline-light:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
}

/* 搜索按钮和表单 */
.navbar-search-form {
    position: relative;
}

.navbar-search-input {
    background-color: rgba(255, 255, 255, 0.1);
    border: none;
    border-radius: 50px;
    padding: 0.5rem 1rem;
    color: white;
    width: 200px;
    transition: all 0.3s ease;
}

.navbar-search-input::placeholder {
    color: rgba(255, 255, 255, 0.7);
}

.navbar-search-input:focus {
    background-color: rgba(255, 255, 255, 0.2);
    box-shadow: 0 0 0 0.2rem rgba(255, 255, 255, 0.1);
    width: 250px;
}

.navbar-search-button {
    background: transparent;
    border: none;
    color: white;
    position: absolute;
    right: 10px;
    top: 50%;
    transform: translateY(-50%);
}

/* 响应式调整 */
@media (max-width: 991.98px) {
    .navbar-collapse {
        backdrop-filter: blur(10px);
        background-color: rgba(52, 152, 219, 0.95);
    }
    
    .navbar-nav .nav-link::before {
        display: none;
    }
    
    .dropdown-menu {
        background-color: rgba(255, 255, 255, 0.1);
        border-top: none;
        animation: none;
    }
    
    .navbar-search-input,
    .navbar-search-input:focus {
        width: 100%;
        background-color: rgba(255, 255, 255, 0.2);
    }
}