/* css/main.css */
:root {
    --color-primary: #0057B8;
    --color-secondary: #E6EFF7;
    --color-accent: #FFD100;
    --color-gray: #4A4A4A;
    --color-light: #F8F9FA;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: 'Segoe UI', system-ui, sans-serif;
}

html {
    overflow-x: hidden;
    touch-action: pan-y;
}

body {
    background: var(--color-light);
    min-width: 320px;
    -webkit-tap-highlight-color: transparent;
}

/* 桌面导航 */
.main-nav {
    background: var(--color-primary);
    padding: 1.2rem 2rem;
    display: flex;
    align-items: center;
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}

.nav-logo {
    color: white;
    font-size: 1.8rem;
    font-weight: 600;
    margin-right: auto;
}

.nav-items {
    display: flex;
    gap: 2.5rem;
    align-items: center;
    z-index: 1002;
}

.nav-item {
    color: rgba(255,255,255,0.9);
    cursor: pointer;
    padding: 0.8rem 1rem;
    border-radius: 8px;
    transition: all 0.3s ease;
}

.nav-item:hover {
    background: rgba(255,255,255,0.1);
}

/* 移动导航 */
.hamburger {
    display: none;
    color: white;
    font-size: 2rem;
    cursor: pointer;
    z-index: 1002;
}

/* 二级导航 */
.secondary-nav {
    background: var(--color-secondary);
    padding: 1rem;
    position: sticky;
    top: 0;
    z-index: 99;
    box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.secondary-nav-container {
    display: flex;
    gap: 1rem;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    -webkit-overflow-scrolling: touch;
}

.secondary-nav-item {
    padding: 0.6rem 1.2rem;
    border-radius: 2rem;
    background: white;
    color: var(--color-gray);
    white-space: nowrap;
    scroll-snap-align: start;
    flex-shrink: 0;
}

.secondary-nav-item.active {
    background: var(--color-accent);
    color: var(--color-primary);
}

/* 三级导航 */
.tertiary-nav {
    display: none;
    padding: 1rem;
    gap: 0.8rem;
    overflow-x: auto;
    background: white;
    border-bottom: 1px solid #eee;
    -webkit-overflow-scrolling: touch;
}

.tertiary-nav-item {
    padding: 0.6rem 1.2rem;
    border-radius: 2rem;
    background: var(--color-light);
    color: var(--color-gray);
    white-space: nowrap;
    flex-shrink: 0;
}

.tertiary-nav-item.active {
    background: var(--color-accent);
    color: var(--color-primary);
}

/* 页脚 */
footer {
    background: linear-gradient(135deg, #005bb5, #004893);
    color: white;
    text-align: center;
    padding: 30px 0;
    margin-top: 50px;
}

.footer-content {
    max-width: 800px;
    margin: 0 auto;
}

.footer-links {
    margin: 15px 0;
}

.footer-links a {
    color: white;
    margin: 0 10px;
    text-decoration: none;
}

.footer-links a:hover {
    text-decoration: underline;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .main-nav {
        padding: 1rem;
        position: sticky;
        top: 0;
        z-index: 1001;
    }

    .nav-items {
        display: flex;
        position: fixed;
        left: -100%;
        top: 0;
        height: 100%;
        width: 85%;
        background: var(--color-primary);
        padding: 5rem 1.5rem 1.5rem;
        flex-direction: column;
        transition: transform 0.3s ease;
        z-index: 1000;
        overflow-y: auto;
    }

    .nav-items.active {
        transform: translateX(100%);
    }

    .hamburger {
        display: block;
        transition: transform 0.3s ease;
    }

    .hamburger.active {
        transform: translateX(85%);
    }

    .secondary-nav {
        padding: 0.8rem 1rem;
        z-index: 99;
    }

    .tertiary-nav {
        padding: 0.8rem 1rem;
        display: flex;
    }

    .footer-content {
        padding: 0 10px;
    }
}