:root {
    --primary: #1e88e5;
    --primary-dark: #1565c0;
    --secondary: #43a047;
    --dark: #212121;
    --light: #f5f5f5;
    --gray: #757575;
}

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

body {
    color: var(--dark);
    line-height: 1.6;
    background-color: white;
}

/* 页脚 */
footer {
    background: #050c18;
    padding: 80px 0 30px;
    color: white;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 40px;
    margin-bottom: 60px;
    text-align: left;
}

.footer-column h4 {
    font-size: 1.3rem;
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
}

.footer-column h4::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 50px;
    height: 2px;
    background: var(--primary-color);
}

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

.footer-column ul li {
    margin-bottom: 10px;
}

.footer-column ul li a {
    color: white;
    text-decoration: none;
    opacity: 0.8;
    transition: opacity 0.3s ease;
}

.footer-column ul li a:hover {
    opacity: 1;
    color: var(--primary-color);
}

.social-links {
    display: flex;
    gap: 15px;
    margin-top: 20px;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    color: white;
    transition: all 0.3s ease;
}

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

.copyright {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    opacity: 0.7;
    font-size: 0.9rem;
}

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

.copyright a:hover {
    color: var(--primary-color);
}