/* ========== 密度云科官网 前台样式（DeepSeek 极简风格） ========== */
:root {
    --color-text: #1a1a1a;
    --color-text-light: #666;
    --color-text-lighter: #999;
    --color-bg: #ffffff;
    --color-accent: #9cc1e7;
    --color-border: #eee;
    --color-border-dark: #ddd;
    --max-width: 1200px;
    --font-sans: -apple-system, BlinkMacSystemFont, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Source Han Sans CN", sans-serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
html { font-size: 16px; -webkit-font-smoothing: antialiased; }
body { font-family: var(--font-sans); color: var(--color-text); background: var(--color-bg); line-height: 1.75; }
a { color: inherit; text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--color-accent); }
img { max-width: 100%; height: auto; }
ul, ol { list-style: none; }

/* ========== 容器 ========== */
.front-container { max-width: var(--max-width); margin: 0 auto; padding: 0 24px; }

/* ========== 导航 ========== */
.front-nav { position: sticky; top: 0; z-index: 100; background: #fff; border-bottom: 1px solid var(--color-border); }
.front-nav-inner { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.front-logo { font-size: 1.3rem; font-weight: 700; color: var(--color-text); letter-spacing: 2px; }
.front-menu { display: flex; gap: 36px; }
.front-menu a { font-size: 0.95rem; color: var(--color-text-light); font-weight: 500; }
.front-menu a:hover { color: var(--color-text); }

/* ========== Hero ========== */
.front-hero { text-align: center; padding: 100px 24px 80px; }
.front-hero h1 { font-size: 2.8rem; font-weight: 700; color: var(--color-text); margin-bottom: 20px; letter-spacing: -0.5px; }
.front-hero p { font-size: 1.1rem; color: var(--color-text-light); max-width: 680px; margin: 0 auto 36px; }
.front-hero-btns { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
.front-btn { display: inline-block; padding: 12px 32px; border-radius: 8px; font-size: 0.95rem; font-weight: 600; transition: all 0.2s; cursor: pointer; border: none; }
.front-btn-primary { background: var(--color-text); color: #fff; }
.front-btn-primary:hover { background: #333; color: #fff; }
.front-btn-outline { background: transparent; color: var(--color-text); border: 1px solid var(--color-border-dark); }
.front-btn-outline:hover { border-color: var(--color-text); color: var(--color-text); }
.front-btn-accent { background: var(--color-accent); color: #fff; }
.front-btn-accent:hover { opacity: 0.85; color: #fff; }

/* ========== 通用区块 ========== */
.front-section { padding: 72px 0; }
.front-section-title { text-align: center; font-size: 2rem; font-weight: 700; margin-bottom: 12px; }
.front-section-subtitle { text-align: center; color: var(--color-text-light); font-size: 1rem; margin-bottom: 48px; }

/* ========== 功能卡片 ========== */
.front-cards { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.front-card { background: #fff; border: 1px solid var(--color-border); border-radius: 12px; padding: 32px; transition: box-shadow 0.2s; }
.front-card:hover { box-shadow: 0 4px 24px rgba(0,0,0,0.06); }
.front-card-icon { font-size: 2rem; color: var(--color-accent); margin-bottom: 16px; }
.front-card h3 { font-size: 1.25rem; font-weight: 600; margin-bottom: 8px; }
.front-card p { color: var(--color-text-light); font-size: 0.9rem; margin-bottom: 16px; }
.front-card ul { padding-left: 0; }
.front-card ul li { position: relative; padding-left: 20px; color: var(--color-text-light); font-size: 0.875rem; margin-bottom: 8px; }
.front-card ul li::before { content: ""; position: absolute; left: 0; top: 10px; width: 6px; height: 6px; border-radius: 50%; background: var(--color-accent); }

/* ========== 三步引导 ========== */
.front-steps { display: flex; justify-content: center; gap: 48px; flex-wrap: wrap; }
.front-step { text-align: center; max-width: 240px; }
.front-step-num { width: 48px; height: 48px; border-radius: 50%; background: var(--color-text); color: #fff; font-size: 1.2rem; font-weight: 700; display: flex; align-items: center; justify-content: center; margin: 0 auto 16px; }
.front-step h3 { font-size: 1.1rem; margin-bottom: 8px; }
.front-step p { color: var(--color-text-light); font-size: 0.875rem; }

/* ========== 最新动态 ========== */
.front-news-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.front-news-item { border: 1px solid var(--color-border); border-radius: 12px; overflow: hidden; transition: box-shadow 0.2s; }
.front-news-item:hover { box-shadow: 0 4px 24px rgba(0,0,0,0.06); }
.front-news-cover { width: 100%; height: 180px; object-fit: contain; background: #f5f5f5; }
.front-news-body { padding: 20px; }
.front-news-date { font-size: 0.8rem; color: var(--color-text-lighter); margin-bottom: 8px; }
.front-news-title { font-size: 1rem; font-weight: 600; margin-bottom: 8px; line-height: 1.5; }
.front-news-summary { font-size: 0.85rem; color: var(--color-text-light); line-height: 1.6; }
.front-more-link { text-align: center; margin-top: 40px; }
.front-more-link a { display: inline-block; color: var(--color-accent); font-weight: 600; }

/* ========== 产品列表 ========== */
.front-product-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
.front-product-card { border: 1px solid var(--color-border); border-radius: 12px; padding: 32px; text-align: center; transition: box-shadow 0.2s; }
.front-product-card:hover { box-shadow: 0 4px 24px rgba(0,0,0,0.06); }
.front-product-icon { font-size: 2.5rem; color: var(--color-accent); margin-bottom: 16px; height: 160px; display: flex; align-items: center; justify-content: center; background: #f5f5f5; border-radius: 8px; }
.front-product-cover { width: 100%; height: 160px; object-fit: contain; background: #f5f5f5; border-radius: 8px; margin-bottom: 16px; }
.front-product-name { font-size: 1.3rem; font-weight: 700; margin-bottom: 8px; }
.front-product-subtitle { color: var(--color-text-light); font-size: 0.9rem; margin-bottom: 16px; }
.front-product-tag { display: inline-block; padding: 4px 12px; border-radius: 4px; background: #f5f5f5; color: var(--color-text-light); font-size: 0.75rem; }

/* ========== 详情页 ========== */
.front-detail { max-width: 800px; margin: 0 auto; padding: 48px 24px; }
.front-detail h1 { font-size: 2.2rem; font-weight: 700; margin-bottom: 16px; }
.front-detail-meta { color: var(--color-text-lighter); font-size: 0.875rem; margin-bottom: 32px; }
.front-detail-content { font-size: 1rem; line-height: 1.8; }
.front-detail-content h2 { font-size: 1.5rem; font-weight: 600; margin: 32px 0 16px; }
.front-detail-content h3 { font-size: 1.2rem; font-weight: 600; margin: 24px 0 12px; }
.front-detail-content p { margin-bottom: 16px; color: var(--color-text); }
.front-detail-content ul { margin-bottom: 16px; padding-left: 0; }
.front-detail-content ul li { position: relative; padding-left: 20px; margin-bottom: 8px; }
.front-detail-content ul li::before { content: ""; position: absolute; left: 0; top: 10px; width: 6px; height: 6px; border-radius: 50%; background: var(--color-accent); }
.front-detail-content img { border-radius: 8px; margin: 16px 0; }

/* ========== 面包屑 ========== */
.front-breadcrumb { max-width: var(--max-width); margin: 0 auto; padding: 24px; color: var(--color-text-lighter); font-size: 0.85rem; }
.front-breadcrumb a { color: var(--color-text-light); }
.front-breadcrumb span { margin: 0 8px; }

/* ========== FAQ ========== */
.front-faq { max-width: 800px; margin: 0 auto; padding: 48px 24px; }
.front-faq h2 { text-align: center; font-size: 1.8rem; margin-bottom: 32px; }
.front-faq-item { border-bottom: 1px solid var(--color-border); padding: 20px 0; }
.front-faq-q { font-weight: 600; font-size: 1rem; margin-bottom: 8px; cursor: pointer; }
.front-faq-a { color: var(--color-text-light); font-size: 0.9rem; line-height: 1.7; }

/* ========== 反馈表单 ========== */
.front-form { max-width: 560px; margin: 0 auto; padding: 48px 24px; }
.front-form-group { margin-bottom: 24px; }
.front-form-label { display: block; font-weight: 600; margin-bottom: 8px; }
.front-form-input, .front-form-textarea { width: 100%; padding: 12px 16px; border: 1px solid var(--color-border-dark); border-radius: 8px; font-size: 0.95rem; font-family: var(--font-sans); transition: border-color 0.2s; }
.front-form-input:focus, .front-form-textarea:focus { outline: none; border-color: var(--color-accent); }
.front-form-textarea { resize: vertical; min-height: 120px; }
.front-form-tip { text-align: center; color: var(--color-text-light); margin-top: 16px; }

/* ========== 上一篇/下一篇 ========== */
.front-prev-next { display: flex; justify-content: space-between; gap: 24px; margin-top: 48px; padding-top: 32px; border-top: 1px solid var(--color-border); }
.front-prev-next a { color: var(--color-text-light); font-size: 0.9rem; }
.front-prev-next a:hover { color: var(--color-accent); }

/* ========== 分页 ========== */
.front-pagination { display: flex; justify-content: center; gap: 8px; margin-top: 48px; }
.front-pagination a, .front-pagination span { padding: 8px 16px; border: 1px solid var(--color-border); border-radius: 6px; font-size: 0.875rem; color: var(--color-text-light); }
.front-pagination .active { background: var(--color-text); color: #fff; border-color: var(--color-text); }

/* ========== 页脚 ========== */
.front-footer { background: #fff; border-top: 1px solid var(--color-border); padding: 64px 0 32px; margin-top: 80px; }
.front-footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px; margin-bottom: 48px; }
.front-footer-brand { font-size: 1.3rem; font-weight: 700; margin-bottom: 8px; }
.front-footer-slogan { color: var(--color-text-light); font-size: 0.875rem; }
.front-footer-col h4 { font-size: 0.9rem; font-weight: 600; margin-bottom: 16px; }
.front-footer-col a, .front-footer-col span { display: block; color: var(--color-text-light); font-size: 0.85rem; margin-bottom: 10px; }
.front-footer-col a:hover { color: var(--color-accent); }
.front-footer-bottom { display: flex; justify-content: space-between; padding-top: 24px; border-top: 1px solid var(--color-border); color: var(--color-text-lighter); font-size: 0.8rem; }
.front-footer-bottom a { color: var(--color-text-lighter); }
.front-footer-bottom a:hover { color: var(--color-accent); }

/* ========== 404 ========== */
.front-404 { text-align: center; padding: 120px 24px; }
.front-404 h1 { font-size: 4rem; font-weight: 700; margin-bottom: 16px; }
.front-404 p { color: var(--color-text-light); margin-bottom: 32px; }

/* ========== 论坛 ========== */
.forum-toolbar { display: flex; justify-content: space-between; align-items: center; margin-bottom: 32px; flex-wrap: wrap; gap: 16px; }
.forum-categories { display: flex; gap: 8px; flex-wrap: wrap; }
.forum-categories a { display: inline-block; padding: 6px 16px; border-radius: 6px; font-size: 0.875rem; color: var(--color-text-light); border: 1px solid var(--color-border); transition: all 0.2s; }
.forum-categories a:hover { color: var(--color-text); border-color: var(--color-border-dark); }
.forum-categories a.active { background: var(--color-text); color: #fff; border-color: var(--color-text); }

.forum-topic-list { }
.forum-topic-item { border: 1px solid var(--color-border); border-radius: 12px; margin-bottom: 16px; transition: box-shadow 0.2s; }
.forum-topic-item:hover { box-shadow: 0 4px 24px rgba(0,0,0,0.06); }
.forum-topic-link { display: block; padding: 24px; }
.forum-topic-main { }
.forum-topic-tags { display: flex; gap: 8px; margin-bottom: 8px; }
.forum-tag { display: inline-block; padding: 2px 10px; border-radius: 4px; font-size: 0.75rem; font-weight: 600; }
.forum-tag-top { background: #e74c3c; color: #fff; }
.forum-tag-essence { background: #f39c12; color: #fff; }
.forum-tag-category { background: #f5f5f5; color: var(--color-text-light); }
.forum-topic-title { font-size: 1.15rem; font-weight: 600; margin-bottom: 8px; line-height: 1.5; }
.forum-topic-meta { display: flex; gap: 16px; color: var(--color-text-lighter); font-size: 0.8rem; flex-wrap: wrap; }
.forum-empty { text-align: center; padding: 64px 24px; }
.forum-empty p { color: var(--color-text-light); margin-bottom: 24px; }

.forum-detail-tags { display: flex; gap: 8px; margin-bottom: 12px; }
.forum-topic-content { white-space: pre-wrap; font-size: 1rem; line-height: 1.8; color: var(--color-text); margin-top: 16px; }

.forum-reply-list { margin-bottom: 48px; }
.forum-reply-item { display: flex; gap: 16px; padding: 24px 0; border-bottom: 1px solid var(--color-border); }
.forum-reply-avatar { flex-shrink: 0; width: 40px; height: 40px; border-radius: 50%; background: var(--color-accent); color: #fff; font-size: 1rem; font-weight: 700; display: flex; align-items: center; justify-content: center; }
.forum-reply-body { flex: 1; min-width: 0; }
.forum-reply-meta { display: flex; gap: 12px; align-items: center; margin-bottom: 8px; font-size: 0.8rem; color: var(--color-text-lighter); }
.forum-reply-nickname { font-weight: 600; color: var(--color-text-light); }
.forum-reply-floor { color: var(--color-accent); }
.forum-reply-content { white-space: pre-wrap; font-size: 0.95rem; line-height: 1.7; color: var(--color-text); }
.forum-reply-form { background: #fafafa; border-radius: 12px; padding: 32px; margin-top: 32px; }

/* ========== 响应式 ========== */
@media (max-width: 768px) {
    .front-menu { gap: 20px; }
    .front-menu a { font-size: 0.85rem; }
    .front-hero { padding: 60px 24px 48px; }
    .front-hero h1 { font-size: 2rem; }
    .front-hero p { font-size: 0.95rem; }
    .front-cards, .front-news-row, .front-product-grid { grid-template-columns: 1fr; }
    .front-steps { gap: 32px; }
    .front-section { padding: 48px 0; }
    .front-section-title { font-size: 1.5rem; }
    .front-footer-grid { grid-template-columns: 1fr; gap: 32px; }
    .front-footer-bottom { flex-direction: column; gap: 8px; text-align: center; }
    .front-prev-next { flex-direction: column; }
}