/* =========================================
   0. 字体引入 (Fonts)
   ========================================= */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* =========================================
   1. 核心变量与重置 (Core Variables & Reset)
   ========================================= */
:root {
    /* 品牌色 - 科技蓝紫系 (Tech Indigo) */
    --primary-hue: 225;
    --primary: hsl(var(--primary-hue), 70%, 55%);       /* 主色 */
    --primary-dark: hsl(var(--primary-hue), 75%, 45%);  /* Hover 深色 */
    --primary-light: hsl(var(--primary-hue), 90%, 96%); /* 浅色背景/标签 */
    
    /* 辅助色 - 活力青 (Cyan Accent) */
    --accent: #06b6d4;
    --accent-gradient: linear-gradient(135deg, #0ea5e9 0%, #06b6d4 100%);
    
    /* 中性色 (Neutrals) */
    --dark: #0f172a;       /* 深邃黑蓝 (标题色) */
    --text-main: #334155;  /* 正文灰 */
    --text-light: #64748b; /* 辅助灰 */
    --surface: #ffffff;    /* 纯白卡片背景 */
    --bg-body: #f8fafc;    /* 全局背景浅灰 */
    --border: #e2e8f0;     /* 边框色 */
    
    /* 布局与效果 (Effects) */
    --radius-sm: 6px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -2px rgba(0,0,0,0.05);
    
    --container-width: 1200px;
    --header-height: 72px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

html { scroll-behavior: smooth; font-size: 16px; }

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--bg-body);
    color: var(--text-main);
    line-height: 1.7;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

main { flex: 1; }

a { text-decoration: none; color: inherit; transition: color 0.2s ease; }
ul { list-style: none; }
img { max-width: 100%; height: auto; display: block; }
button { font-family: inherit; } /* 修正：让按钮继承字体 */

/* 容器 */
.container {
    max-width: var(--container-width);
    margin: 0 auto;
    padding: 0 24px;
    width: 100%;
}

/* 按钮样式 (SaaS 风格) */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 32px;
    background: var(--primary);
    color: #fff;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 1rem;
    letter-spacing: 0.5px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 1px solid transparent;
    box-shadow: 0 4px 6px rgba(79, 70, 229, 0.2);
    cursor: pointer;
}

.btn:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 8px 12px rgba(79, 70, 229, 0.3);
}

/* 标题样式 */
h1, h2, h3, h4 { color: var(--dark); font-weight: 700; line-height: 1.3; margin-bottom: 1rem; }

h2 {
    font-size: 2.25rem;
    text-align: center;
    margin-bottom: 3.5rem;
    position: relative;
    letter-spacing: -0.02em;
}

/* 标题下方的装饰条 */
h2::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent-gradient);
    margin: 16px auto 0;
    border-radius: 2px;
}

section { padding: 100px 0; position: relative; overflow: hidden; }

/* =========================================
   2. 头部导航 (Header) - 磨砂玻璃效果
   ========================================= */
.main-header {
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    height: var(--header-height);
    transition: all 0.3s ease;
}

.main-header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary);
    letter-spacing: -0.5px;
    display: flex;
    align-items: center;
}

/* Logo 图标装饰 */
.logo::before {
    content: '';
    display: inline-block;
    width: 24px;
    height: 24px;
    background: var(--accent-gradient);
    margin-right: 8px;
    border-radius: 6px;
    transform: rotate(45deg);
}

.main-nav ul { display: flex; gap: 32px; }

.main-nav ul li a {
    font-weight: 500;
    color: var(--text-main);
    font-size: 0.95rem;
    position: relative;
    padding: 8px 0;
}

/* 导航悬停动画 */
.main-nav ul li a::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 2px;
    background: var(--primary);
    transform: scaleX(0);
    transform-origin: right;
    transition: transform 0.3s ease;
}

.main-nav ul li a:hover,
.main-nav ul li a.active {
    color: var(--primary);
}

.main-nav ul li a:hover::before,
.main-nav ul li a.active::before {
    transform: scaleX(1);
    transform-origin: left;
}

.menu-toggle { display: none; background: none; border: none; font-size: 1.5rem; color: var(--dark); cursor: pointer; padding: 5px; }

/* =========================================
   3. Hero 区域 - 科技感深色渐变
   ========================================= */
#hero {
    background: radial-gradient(circle at top right, #1e1b4b, #0f172a);
    color: #fff;
    height: auto;
    min-height: 600px;
    display: flex;
    align-items: center;
    text-align: center;
    padding: 120px 0 80px;
    position: relative;
    z-index: 1;
}

/* 背景抽象图形装饰 */
#hero::before {
    content: '';
    position: absolute;
    top: -100px;
    left: -100px;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(99, 102, 241, 0.15) 0%, rgba(0,0,0,0) 70%);
    border-radius: 50%;
    z-index: -1;
}

#hero::after {
    content: '';
    position: absolute;
    bottom: 0;
    right: 0;
    width: 100%;
    height: 100%;
    background-image: linear-gradient(rgba(255,255,255,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    z-index: -1;
    mask-image: linear-gradient(to bottom, rgba(0,0,0,1), rgba(0,0,0,0));
    -webkit-mask-image: linear-gradient(to bottom, rgba(0,0,0,1), rgba(0,0,0,0));
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    animation: fadeInUp 0.8s ease-out;
}

#hero h1 {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, #ffffff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    line-height: 1.2;
    letter-spacing: -1px;
}

#hero p {
    font-size: 1.25rem;
    color: #cbd5e1;
    margin-bottom: 2.5rem;
    max-width: 650px;
    margin-left: auto;
    margin-right: auto;
}

#hero .btn {
    background: var(--accent-gradient);
    border-radius: 50px;
    padding: 14px 40px;
    font-size: 1.1rem;
    box-shadow: 0 0 20px rgba(6, 182, 212, 0.4);
}

#hero .btn:hover {
    box-shadow: 0 0 30px rgba(6, 182, 212, 0.6);
    transform: translateY(-2px);
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

/* =========================================
   4. 解决方案 (Solutions)
   ========================================= */
#solutions { background-color: var(--surface); }

.solutions-grid {
    display: grid;
    /* 修正：使用 280px 避免小屏溢出 */
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.solution-card {
    background: #fff;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 40px 30px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.solution-card:hover {
    transform: translateY(-8px);
    border-color: var(--primary);
    box-shadow: var(--shadow-lg);
}

/* 卡片顶部装饰条 */
.solution-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--bg-body);
    transition: background 0.3s;
}

.solution-card:hover::before {
    background: var(--accent-gradient);
}

.solution-card h3 {
    font-size: 1.35rem;
    margin-bottom: 1rem;
    color: var(--dark);
}

.solution-card p {
    color: var(--text-light);
    font-size: 0.95rem;
    line-height: 1.6;
}

/* --- Abstract CSS Icons --- */
.solution-icon {
    width: 64px;
    height: 64px;
    background: var(--primary-light);
    border-radius: 16px;
    margin-bottom: 24px;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    transition: all 0.3s;
}

.solution-card:hover .solution-icon {
    background: var(--primary);
    color: #fff;
    transform: scale(1.1) rotate(5deg);
}

/* Icons Implementation */
.icon-cloud::after, .icon-cloud::before { content: ''; position: absolute; background: currentColor; }
.icon-cloud::before { width: 30px; height: 18px; border-radius: 10px; bottom: 18px; }
.icon-cloud::after { width: 14px; height: 14px; border-radius: 50%; top: 22px; right: 20px; box-shadow: -10px 4px 0 currentColor; }

.icon-data::before {
    content: ''; width: 24px; height: 24px;
    background: linear-gradient(to right, currentColor 6px, transparent 6px, transparent 9px, currentColor 9px, currentColor 15px, transparent 15px, transparent 18px, currentColor 18px);
    -webkit-mask: linear-gradient(to top, #000 0%, #000 50%, transparent 100%);
    mask: linear-gradient(to top, #000 0%, #000 100%);
    clip-path: polygon(0 40%, 30% 40%, 30% 100%, 70% 100%, 70% 20%, 100% 20%, 100% 100%, 0 100%);
}

.icon-ai { overflow: hidden; }
.icon-ai::before {
    content: ''; width: 24px; height: 24px; border: 2px solid currentColor; border-radius: 6px;
    box-shadow: 0 0 0 4px rgba(255,255,255,0.2);
}
.icon-ai::after { content: ''; position: absolute; width: 40px; height: 2px; background: currentColor; transform: rotate(45deg); }

.icon-security::before {
    content: ''; width: 22px; height: 26px; border: 2px solid currentColor; border-radius: 0 0 50% 50%; border-top: 0;
}
.icon-security::after { content: ''; position: absolute; top: 18px; width: 22px; height: 2px; background: currentColor; }

.icon-iot::before {
    content: ''; width: 8px; height: 8px; background: currentColor; border-radius: 50%;
    box-shadow: 15px -10px 0 currentColor, -15px -10px 0 currentColor;
}
.icon-iot::after {
    content: ''; position: absolute; width: 26px; height: 26px; border: 2px solid currentColor; border-radius: 50%; border-bottom-color: transparent; top: 12px;
}

.icon-consult::before { content: ''; width: 28px; height: 20px; border: 2px solid currentColor; border-radius: 4px; }
.icon-consult::after { content: ''; position: absolute; width: 0; height: 0; border: 6px solid transparent; border-top-color: currentColor; bottom: 16px; right: 20px; }


/* =========================================
   5. 关于我们 (About)
   ========================================= */
#about { background-color: var(--bg-body); }

#about .about-content {
    display: flex;
    align-items: stretch;
    gap: 60px;
}

.about-text { flex: 1; display: flex; flex-direction: column; justify-content: center; }

.about-text h3 { font-size: 1.75rem; color: var(--primary); margin-bottom: 1.5rem; }
.about-text p { margin-bottom: 1.25rem; color: var(--text-main); font-size: 1.05rem; }

.about-action { margin-top: 2rem; }
.about-action .btn {
    background: transparent; color: var(--primary); border: 2px solid var(--primary); box-shadow: none;
}
.about-action .btn:hover { background: var(--primary); color: #fff; }

.about-visual {
    flex: 1;
    min-height: 400px;
    background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

/* 毛玻璃浮层 */
.about-visual::before {
    content: '';
    position: absolute;
    width: 80%;
    height: 60%;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: var(--radius-md);
    transform: rotate(-5deg);
    z-index: 1;
}

.about-visual span {
    position: relative;
    z-index: 2;
    color: #fff;
    font-size: 2rem;
    font-weight: 800;
    text-shadow: 0 4px 10px rgba(0,0,0,0.2);
    letter-spacing: 2px;
}

/* =========================================
   6. 资讯中心 & 内容页 (News & Content)
   ========================================= */
#news, #content { background-color: var(--surface); }

/* 修正：内部页面容器，避免 Padding 冲突 */
.page-container {
    padding: 40px 0 80px !important; /* 优先级提升，覆盖 section 的 padding */
    background: #fff;
}

.news-grid {
    display: grid;
    /* 修正：小屏适应 */
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 40px;
}

.news-card {
    background: #fff;
    border-radius: var(--radius-md);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    border: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}

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

.news-cover {
    height: 220px;
    overflow: hidden;
    background: var(--primary-light);
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

.news-cover img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.news-card:hover .news-cover img { transform: scale(1.05); }

/* 缺省图兜底 */
.news-cover:empty::before {
    content: 'TECH NEWS';
    color: var(--primary);
    font-weight: bold;
    letter-spacing: 1px;
}

.news-content {
    padding: 24px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.news-content h4 { font-size: 1.25rem; margin-bottom: 0.75rem; line-height: 1.4; }
.news-content h4 a { color: var(--dark); font-weight: 700; transition: color 0.2s; }
.news-content h4 a:hover { color: var(--primary); }

.news-meta {
    font-size: 0.85rem;
    color: var(--text-light);
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.news-meta span a {
    color: var(--primary);
    background: var(--primary-light);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 600;
}

.news-content p {
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
    flex-grow: 1;
}

.read-more-link {
    font-size: 0.9rem;
    color: var(--primary);
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 5px;
}
.read-more-link:hover { gap: 8px; }

/* 分页 */
.pagination {
    margin-top: 60px;
    display: flex;
    justify-content: center;
    gap: 8px;
    flex-wrap: wrap; /* 防止小屏溢出 */
}

.page-btn, .page-current {
    min-width: 44px;
    height: 44px;
    padding: 0 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all 0.2s;
}

.page-btn { background: #fff; border: 1px solid var(--border); color: var(--text-main); }
.page-btn:hover { border-color: var(--primary); color: var(--primary); }
.page-current { background: var(--primary); color: #fff; border: 1px solid var(--primary); }

/* =========================================
   7. 单页与文章 (Single Post & Page)
   ========================================= */
.single-post-wrapper { max-width: 800px; margin: 0 auto; }

.breadcrumb { font-size: 0.9rem; color: var(--text-light); margin-bottom: 2rem; }
.breadcrumb a:hover { color: var(--primary); }
.breadcrumb span { color: #cbd5e1; margin: 0 8px; }

.page-header h1 { font-size: 2.5rem; margin-bottom: 1rem; color: var(--dark); }
/* 修正：列表页头部居中 */
.center-header { text-align: center; margin-bottom: 60px; }
.center-header h1 { font-size: 2.5rem; margin-bottom: 1rem; }

.page-meta {
    padding-bottom: 2rem;
    border-bottom: 1px solid var(--border);
    margin-bottom: 2.5rem;
    color: var(--text-light);
}
.page-meta a { color: var(--primary); font-weight: 500; }

/* Markdown 内容样式 */
.markdown-body { font-size: 1.1rem; line-height: 1.8; color: var(--text-main); }

.markdown-body h2 {
    font-size: 1.8rem;
    margin-top: 3rem;
    margin-bottom: 1.5rem;
    color: var(--dark);
    border-left: 4px solid var(--primary);
    padding-left: 16px;
    background: linear-gradient(to right, var(--primary-light), transparent);
    border-radius: 0 4px 4px 0;
}

.markdown-body h3 { font-size: 1.4rem; margin-top: 2.5rem; color: var(--dark); font-weight: 700; }
.markdown-body p { margin-bottom: 1.5rem; }

/* 修正：文章内链接样式 */
.markdown-body a {
    color: var(--primary);
    text-decoration: underline;
    text-decoration-thickness: 2px;
    text-underline-offset: 3px;
    text-decoration-color: rgba(var(--primary-hue), 70%, 55%, 0.3);
}
.markdown-body a:hover { text-decoration-color: var(--primary); }

.markdown-body blockquote {
    background: var(--bg-body);
    border-left: 4px solid var(--accent);
    margin: 2rem 0;
    padding: 1.5rem;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    color: var(--text-main);
    font-style: italic;
}

.markdown-body code {
    background: #f1f5f9;
    color: #0ea5e9;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: Consolas, Monaco, monospace;
    font-size: 0.9em;
}

.markdown-body pre {
    background: #1e293b;
    padding: 20px;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    color: #e2e8f0;
    margin: 2rem 0;
}
.markdown-body pre code { background: transparent; color: inherit; padding: 0; }
.markdown-body img { border-radius: var(--radius-md); box-shadow: var(--shadow-md); margin: 2rem 0; }
.markdown-body ul, .markdown-body ol { margin-left: 20px; margin-bottom: 2rem; }
.markdown-body li { margin-bottom: 0.5rem; }

/* 标签与导航 */
.post-tags { margin-top: 3rem; }
.tag-pill {
    display: inline-block;
    background: #fff;
    border: 1px solid var(--border);
    color: var(--text-light);
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 0.85rem;
    margin-right: 8px;
    margin-bottom: 8px;
    transition: all 0.2s;
}
.tag-pill:hover { border-color: var(--primary); color: var(--primary); background: var(--primary-light); }

.post-navigation {
    display: flex;
    justify-content: space-between;
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.nav-prev, .nav-next {
    display: block;
    width: 48%; /* 修正宽度 */
    padding: 20px;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    transition: all 0.2s;
    background: #fff;
}

.nav-prev:hover, .nav-next:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

.nav-prev span, .nav-next span {
    display: block;
    font-size: 0.8rem;
    color: var(--text-light);
    margin-bottom: 5px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

/* =========================================
   8. 常见问题 (FAQ)
   ========================================= */
#faq { background-color: var(--bg-body); }

.faq-accordion {
    max-width: 800px;
    margin: 0 auto;
    background: #fff;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.faq-item { border-bottom: 1px solid var(--border); }
.faq-item:last-child { border-bottom: none; }

.faq-question {
    width: 100%;
    background: none;
    border: none;
    text-align: left;
    padding: 24px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--dark);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.2s;
}

.faq-question:hover { background: #f8fafc; }

.faq-question::after {
    content: '+';
    font-size: 1.5rem;
    color: var(--primary);
    font-weight: 300;
    transition: transform 0.3s ease;
    margin-left: 16px;
}

.faq-item.active .faq-question { color: var(--primary); }
.faq-item.active .faq-question::after { transform: rotate(45deg); }

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.35s ease-out; /* 使用 JS 控制 max-height */
}

.faq-answer p {
    color: var(--text-light);
    font-size: 1rem;
    line-height: 1.6;
    padding: 0 24px 24px 24px; /* 修正 Padding 位置 */
}

/* =========================================
   9. 页脚 (Footer)
   ========================================= */
.main-footer {
    background-color: #0b1120;
    color: #94a3b8;
    padding: 80px 0 30px;
    font-size: 0.95rem;
    margin-top: auto; /* Sticky Footer */
}

.footer-content { display: flex; flex-wrap: wrap; gap: 40px; margin-bottom: 60px; }
.footer-column { flex: 1; min-width: 200px; }

.footer-column h4 { color: #fff; margin-bottom: 1.5rem; font-size: 1.1rem; letter-spacing: 0.5px; }
.footer-column ul li { margin-bottom: 12px; }

.footer-column ul li a { color: #94a3b8; transition: all 0.2s; }
.footer-column ul li a:hover { color: var(--accent); padding-left: 5px; }

.footer-bottom {
    border-top: 1px solid #1e293b;
    padding-top: 30px;
    text-align: center;
    font-size: 0.85rem;
}

/* =========================================
   10. 404 & Error
   ========================================= */
.error-page { text-align: center; padding: 120px 0; }
.error-page h1 {
    font-size: 8rem;
    line-height: 1;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 1rem;
}
.error-page p { font-size: 1.5rem; margin-bottom: 2rem; color: var(--text-light); }
.no-content { grid-column: 1 / -1; text-align: center; padding: 60px; background: #fff; border-radius: var(--radius-md); border: 2px dashed var(--border); color: var(--text-light); }

/* =========================================
   11. 响应式适配 (Responsive)
   ========================================= */
@media (max-width: 992px) {
    h2 { font-size: 2rem; }
    #hero h1 { font-size: 2.8rem; }
    .about-content { flex-direction: column; }
    .about-visual { min-height: 300px; width: 100%; }
}

@media (max-width: 768px) {
    :root { --header-height: 60px; }
    
    .menu-toggle { display: block; }
    
    .main-nav {
        position: absolute;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background-color: #fff;
        flex-direction: column;
        max-height: 0;
        overflow: hidden;
        transition: max-height 0.4s ease-in-out;
        box-shadow: 0 10px 20px rgba(0,0,0,0.1);
        border-bottom: 1px solid var(--border);
    }
    
    /* JS 会切换 .active 类 */
    .main-nav.active { max-height: 400px; }
    
    .main-nav ul { flex-direction: column; gap: 0; padding: 0; }
    
    .main-nav ul li a {
        display: block;
        padding: 16px 24px;
        border-bottom: 1px solid #f1f5f9;
        color: var(--dark);
    }
    
    .main-nav ul li a::before { display: none; } 
    
    #hero { padding: 80px 0 60px; min-height: auto; }
    #hero h1 { font-size: 2.2rem; }
    #hero p { font-size: 1rem; }
    
    .footer-content { flex-direction: column; }
    .nav-prev, .nav-next { width: 100%; margin-bottom: 10px; }
    .post-navigation { flex-direction: column; gap: 10px; }
    .nav-next { text-align: left !important; }
}