:root {
    --primary-color: #2196F3;  /* 主色调，使用更鲜明的蓝色 */
    --secondary-color: #42A5F5; /* 次要色调，稍浅的蓝色 */
    --accent-color: #1976D2;   /* 强调色，更深的蓝色 */
    --bg-color: #E3F2FD;      /* 浅蓝背景 */
    --text-color: #263238;     /* 深灰文字，保证可读性 */
    --header-footer-bg: #BBDEFB; /* 页眉页脚使用浅蓝背景 */
    /* 新增响应式断点 */
    --mobile-breakpoint: 768px;
    --tablet-breakpoint: 1024px;
}

body {
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    margin: 0;
    padding: 0;
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

header {
    background: linear-gradient(135deg, var(--header-footer-bg), #dfe6e9);
    color: var(--text-color);
    padding: 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: 0 2px 15px rgba(0,0,0,0.1);
    flex-wrap: wrap;
}

nav ul {
    display: flex;
    list-style: none;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
    background: rgba(255,255,255,0.7);
}

nav a:hover {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(74, 137, 220, 0.2);
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

nav a {
    color: var(--text-color);
    text-decoration: none;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border-radius: 4px;
    transition: all 0.3s ease;
}

nav a:hover {
    color: var(--primary-color);
    background-color: rgba(74, 137, 220, 0.1);
}

footer {
    background: linear-gradient(135deg, var(--header-footer-bg), #dfe6e9);
    color: var(--text-color);
    padding: 2rem 0;
    border-top: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 -2px 15px rgba(0,0,0,0.1);
    text-align: center;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.copyright {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--text-color);
}

.footer-contact {
    margin-top: 1rem;
    font-size: 0.95rem;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.footer-links, .footer-social {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-links a, .footer-social a {
    color: var(--light-color);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-links a:hover, .footer-social a:hover {
    color: var(--accent-color);
}

.social-icon {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    background: rgba(255,255,255,0.1);
    border-radius: 4px;
    margin-right: 0.5rem;
}

.copyright {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 0.9rem;
    color: rgba(255,255,255,0.6);
}

/* 移动端导航样式 */
@media (max-width: 768px) {
    header {
        flex-direction: column;
        padding: 0.5rem;
    }
    
    .logo {
        margin-bottom: 0.5rem;
    }
    
    nav ul {
        gap: 0.5rem;
    }
    
    nav a {
        padding: 0.3rem 0.6rem;
        font-size: 0.9rem;
    }
}

/* 内容区域响应式调整 */
main {
    flex: 1;
    padding: 1rem;
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
    box-sizing: border-box;
}

section {
    margin: 1rem auto;
    max-width: 100%;
}

/* 页脚响应式调整 */
footer {
    background: linear-gradient(135deg, var(--header-footer-bg), #dfe6e9);
    color: var(--text-color);
    padding: 2rem 0;
    border-top: 1px solid rgba(0,0,0,0.05);
    box-shadow: 0 -2px 15px rgba(0,0,0,0.1);
    text-align: center;
    padding: 1rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.copyright {
    margin-top: 1rem;
    font-size: 0.9rem;
    color: var(--text-color);
}

.footer-contact {
    margin-top: 1rem;
    font-size: 0.95rem;
}

.footer-logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--primary-color);
}

.footer-links, .footer-social {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-links a, .footer-social a {
    color: var(--light-color);
    text-decoration: none;
    transition: color 0.3s;
}

.footer-links a:hover, .footer-social a:hover {
    color: var(--accent-color);
}

.social-icon {
    display: inline-block;
    padding: 0.3rem 0.8rem;
    background: rgba(255,255,255,0.1);
    border-radius: 4px;
    margin-right: 0.5rem;
}

.copyright {
    text-align: center;
    margin-top: 2rem;
    padding-top: 1rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 0.9rem;
    color: rgba(255,255,255,0.6);
}

/* 平板设备调整 */
@media (max-width: 1024px) {
    .hero {
        padding: 2rem 1rem;
    }
    
    section {
        padding: 1.5rem;
    }
}


body {
    position: relative;
}

body::before {
    content: "";
    position: fixed;
    /* 适当增加页眉预留空间 */
    top: calc(1rem + 3rem); 
    /* 适当增加页脚预留空间 */
    bottom: calc(2rem + 3rem); 
    left: 0;
    right: 0;
    background-image: url('../images/pic_01.png');
    background-size: contain;
    background-position: center;
    background-repeat: no-repeat;
    opacity: 0.5;
    z-index: -1;
}