/* 全局样式 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #4facfe;
    --text-color: #333;
    --text-light: #666;
    --text-muted: #999;
    --bg-color: #fff;
    --bg-light: #f8f9fa;
    --border-color: #e0e0e0;
    --shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-light);
}

/* 导航栏 */
.navbar {
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 70px;
}

.nav-logo a {
    color: white;
    text-decoration: none;
    font-size: 24px;
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: 10px;
}

.nav-logo i {
    font-size: 28px;
}

.nav-menu {
    display: flex;
    gap: 30px;
    align-items: center;
}

.nav-link {
    color: white;
    text-decoration: none;
    font-weight: 500;
    padding: 10px 15px;
    border-radius: var(--border-radius);
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link:hover,
.nav-link.active {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-2px);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.bar {
    width: 25px;
    height: 3px;
    background: white;
    margin: 3px 0;
    transition: var(--transition);
}

/* 主要内容 */
.main-content {
    min-height: calc(100vh - 70px - 200px);
    padding: 40px 0;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 卡片样式 */
.card {
    background: var(--bg-color);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    padding: 30px;
    margin-bottom: 30px;
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-5px);
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--border-radius);
    text-decoration: none;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    font-size: 14px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-color) 0%, #00f2fe 100%);
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
}

.btn-secondary {
    background: var(--bg-color);
    color: var(--text-color);
    border: 2px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
}

/* 页脚 */
.footer {
    background: var(--text-color);
    color: white;
    padding: 40px 0 20px;
    margin-top: 60px;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 30px;
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: 15px;
    color: var(--accent-color);
}

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

.footer-section ul li {
    margin-bottom: 8px;
}

.footer-section a {
    color: #ccc;
    text-decoration: none;
    transition: var(--transition);
}

.footer-section a:hover {
    color: var(--accent-color);
}

.social-links {
    display: flex;
    gap: 15px;
}

.social-links a {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--accent-color);
    transform: translateY(-3px);
}

.footer-bottom {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding-top: 20px;
    border-top: 1px solid #444;
    font-size: 14px;
    color: #999;
}

.icp-beian a {
    color: #999;
    text-decoration: none;
    transition: var(--transition);
}

.icp-beian a:hover {
    color: var(--accent-color);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        left: -100%;
        top: 70px;
        flex-direction: column;
        background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
        width: 100%;
        text-align: center;
        transition: 0.3s;
        box-shadow: var(--shadow);
        padding: 20px 0;
    }

    .nav-menu.active {
        left: 0;
    }

    .nav-link {
        margin: 10px 0;
        padding: 15px;
        width: 80%;
        justify-content: center;
    }

    .nav-toggle {
        display: flex;
    }

    .nav-toggle.active .bar:nth-child(2) {
        opacity: 0;
    }

    .nav-toggle.active .bar:nth-child(1) {
        transform: translateY(8px) rotate(45deg);
    }

    .nav-toggle.active .bar:nth-child(3) {
        transform: translateY(-8px) rotate(-45deg);
    }

    .main-content {
        padding: 20px 0;
    }

    .card {
        padding: 20px;
        margin-bottom: 20px;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
        text-align: center;
    }

    .footer-bottom {
        flex-direction: column;
        gap: 10px;
        text-align: center;
    }
}

/* 工具类 */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mb-1 { margin-bottom: 10px; }
.mb-2 { margin-bottom: 20px; }
.mb-3 { margin-bottom: 30px; }
.mb-4 { margin-bottom: 40px; }

.mt-1 { margin-top: 10px; }
.mt-2 { margin-top: 20px; }
.mt-3 { margin-top: 30px; }
.mt-4 { margin-top: 40px; }

.fade-in {
    animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 404页面样式 */
.error-page {
    text-align: center;
    padding: 100px 20px;
}

.error-page h1 {
    font-size: 72px;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.error-page h2 {
    font-size: 32px;
    margin-bottom: 20px;
}

.error-page p {
    font-size: 18px;
    color: var(--text-light);
    margin-bottom: 30px;
}