/**
 * UL-ImGen 站点公共样式
 * 
 * 包含模块：
 * - 全局重置样式（universal reset）
 * - 页面基础样式（body base）
 * - 头部导航（.site-header 及子元素）
 * - 页脚（.site-footer）
 * - 头部导航响应式适配
 */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif; background: #f5f7fa; color: #333; }

.site-header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 12px rgba(0,0,0,0.15);
}
.site-header .header-inner {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 60px;
}
.site-header .logo {
    font-size: 22px;
    font-weight: 700;
    letter-spacing: 1px;
    text-decoration: none;
    color: white;
}
.site-header .logo i { margin-right: 8px; }
.site-header nav { display: flex; gap: 6px; }
.site-header nav a {
    color: rgba(255,255,255,0.85);
    text-decoration: none;
    padding: 8px 16px;
    border-radius: 6px;
    font-size: 14px;
    transition: all 0.3s;
}
.site-header nav a:hover { background: rgba(255,255,255,0.15); color: white; }
.site-header nav a.active { background: rgba(255,255,255,0.2); color: white; font-weight: 600; }

.site-footer {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: rgba(255,255,255,0.8);
    text-align: center;
    padding: 20px;
    font-size: 13px;
}
.site-footer a { color: white; text-decoration: none; }
.site-footer a:hover { text-decoration: underline; }

@media (max-width: 768px) {
    .site-header nav a { padding: 6px 10px; font-size: 13px; }
}