/* ============================================================
   导航栏和页脚样式
   ============================================================ */

/* --- 导航栏 --- */
header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: var(--header-height);
    background-color: rgba(249, 250, 251, 0.95);
    border-bottom: 1px solid rgba(211, 217, 224, 0.6);
    z-index: 1000;
    transition: all var(--transition-normal);
    box-shadow: none;
    backdrop-filter: blur(12px);
}

header.scrolled {
    background-color: rgba(46, 58, 63, 0.95);
    border-bottom-color: transparent;
    box-shadow: var(--box-shadow-md);
}

header.scrolled .logo {
    color: white;
}

header.scrolled .logo:hover {
    color: var(--color-accent);
}

header.scrolled .logo-icon {
    background-color: var(--color-accent);
    color: #ffffff;
}

header.scrolled .nav-link {
    color: rgba(255, 255, 255, 0.85);
}

header.scrolled .nav-link:hover {
    color: var(--color-accent);
}

header.scrolled .nav-link::after {
    background-color: var(--color-accent);
}

header.scrolled .submenu {
    background-color: rgba(28, 36, 40, 0.96);
    border-color: rgba(35, 45, 50, 0.8);
}

header.scrolled .submenu a {
    color: rgba(255, 255, 255, 0.8);
}

header.scrolled .submenu a:hover {
    background-color: rgba(255, 107, 53, 0.15);
    color: #ffffff;
}

.header-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding: 0 var(--container-padding);
}

/* --- Logo --- */
.logo {
    display: flex;
    align-items: center;
    font-size: 1.25rem;
    font-weight: var(--font-weight-bold);
    color: var(--color-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.logo:hover {
    color: var(--color-accent);
}

.logo-icon {
    width: 40px;
    height: 40px;
    margin-right: var(--spacing-sm);
    background-color: var(--color-accent);
    border-radius: var(--border-radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: var(--font-weight-bold);
}

/* --- 导航菜单 --- */
nav {
    display: flex;
    align-items: center;
    height: 100%;
}

.nav-menu {
    display: flex;
    align-items: center;
    list-style: none;
    gap: var(--spacing-lg);
    margin: 0;
    padding: 0;
}

.nav-item {
    position: relative;
    display: flex;
    align-items: center;
}

.nav-link {
    color: var(--color-text);
    text-decoration: none;
    font-weight: var(--font-weight-medium);
    padding: var(--spacing-sm) 0;
    transition: color var(--transition-fast);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background-color: var(--color-accent);
    transition: width var(--transition-fast);
}

.nav-link:hover {
    color: var(--color-accent);
}

.nav-link:hover::after {
    width: 100%;
}

/* --- 二级下拉菜单 --- */
.submenu {
    position: absolute;
    top: 100%;
    left: 0;
    background-color: var(--color-background);
    border: 1px solid rgba(211, 217, 224, 0.7);
    border-top: none;
    border-radius: 0 0 var(--border-radius-lg) var(--border-radius-lg);
    min-width: 200px;
    display: none;
    list-style: none;
    box-shadow: var(--box-shadow-md);
    z-index: 999;
    margin-top: 0;
}

.submenu li {
    margin: 0;
}

.submenu a {
    display: block;
    padding: var(--spacing-md) var(--spacing-lg);
    color: var(--color-text);
    text-decoration: none;
    transition: all var(--transition-fast);
}

.submenu a:hover {
    background-color: rgba(78, 205, 196, 0.15);
    color: var(--color-primary);
    padding-left: calc(var(--spacing-lg) + 5px);
}

/* --- 菜单切换按钮（移动设备） --- */
.menu-toggle {
    display: none;
    flex-direction: column;
    background: none;
    border: none;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--color-accent);
    border-radius: 2px;
    transition: all var(--transition-fast);
}

.menu-toggle.active span:nth-child(1) {
    transform: rotate(45deg) translate(10px, 10px);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -7px);
}

/* --- 页脚 --- */
footer {
    background: linear-gradient(135deg, #12191D 0%, #182227 45%, var(--color-primary) 100%);
    color: white;
    padding: var(--spacing-xl) 0 var(--spacing-lg);
    margin-top: var(--spacing-xxl);
}

.footer-container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 var(--container-padding);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3 {
    color: white;
    margin-bottom: var(--spacing-md);
    font-size: 1.1rem;
}

.footer-section ul {
    list-style: none;
    margin: 0;
    padding: 0;
}

.footer-section li {
    margin-bottom: var(--spacing-sm);
}

.footer-section a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
    transition: color var(--transition-fast);
}

.footer-section a:hover {
    color: white;
    text-decoration: underline;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.2);
    padding-top: var(--spacing-lg);
    text-align: center;
    color: rgba(255, 255, 255, 0.7);
    font-size: 0.9rem;
}

/* --- 响应式导航栏 --- */
@media (max-width: 767px) {
    .menu-toggle {
        display: flex;
    }
    
    .nav-menu {
        position: absolute;
        top: var(--header-height);
        left: 0;
        right: 0;
        flex-direction: column;
        background-color: var(--color-background);
        border-top: 1px solid var(--color-border);
        gap: 0;
        max-height: 0;
        overflow: hidden;
        transition: max-height var(--transition-normal);
    }
    
    .nav-menu.active {
        max-height: 500px;
    }
    
    .nav-item {
        height: auto;
        border-bottom: 1px solid var(--color-border);
    }
    
    .nav-link {
        display: block;
        padding: var(--spacing-md) var(--container-padding);
    }
    
    .submenu {
        position: static;
        border: none;
        box-shadow: none;
        background-color: var(--color-light-bg);
        max-height: 0;
        overflow: hidden;
        transition: max-height var(--transition-normal);
    }
    
    .nav-item:hover .submenu {
        max-height: 500px;
    }
    
    .submenu a {
        padding-left: calc(var(--container-padding) * 2);
    }
}

@media (max-width: 1199px) {
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 767px) {
    .footer-content {
        grid-template-columns: 1fr;
    }
    
    .footer-section {
        text-align: center;
    }
    
    .footer-section ul {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--spacing-md);
    }
    
    .footer-section li {
        margin: 0;
    }
}