```css

/* ---------- 全局变量与重置 ---------- */
:root {
    --bg-light: #f8fafc;
    --bg-card: #ffffff;
    --bg-deep: #111827;
    --bg-footer: #0f172a;
    --text-primary-light: #1f2937;
    --text-secondary-light: #374151;
    --text-muted-light: #4b5563;
    --text-link-light: #1d4ed8;
    --text-heading-light: #111827;
    --border-light: #e2e8f0;
    --brand-color: #2563eb;
    --brand-dark: #1e3a8a;
    --text-on-brand: #ffffff;

    --bg-dark: #0b1120;
    --bg-card-dark: #1e293b;
    --bg-footer-dark: #020617;
    --text-primary-dark: #e2e8f0;
    --text-secondary-dark: #cbd5e1;
    --text-muted-dark: #94a3b8;
    --text-link-dark: #93c5fd;
    --text-heading-dark: #f8fafc;
    --border-dark: #334155;

    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-banner: linear-gradient(135deg, #1e293b 0%, #334155 50%, #475569 100%);
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.06);
    --shadow-md: 0 4px 20px rgba(0,0,0,0.08);
    --shadow-lg: 0 12px 32px rgba(0,0,0,0.12);
    --radius-sm: 12px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, 'Noto Sans', sans-serif;
    background-color: var(--bg-light);
    color: var(--text-primary-light);
    line-height: 1.7;
    transition: background-color 0.3s ease, color 0.3s ease;
    background-image: radial-gradient(circle at 20% 50%, rgba(37, 99, 235, 0.03) 0%, transparent 50%),
                      radial-gradient(circle at 80% 20%, rgba(100, 116, 139, 0.03) 0%, transparent 50%);
    background-attachment: fixed;
}

body.dark-mode {
    background-color: var(--bg-dark);
    color: var(--text-primary-dark);
    background-image: radial-gradient(circle at 20% 50%, rgba(59, 130, 246, 0.05) 0%, transparent 50%),
                      radial-gradient(circle at 80% 20%, rgba(100, 116, 139, 0.05) 0%, transparent 50%);
}

/* 容器 */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
    width: 100%;
}

/* 链接 */
a {
    color: var(--text-link-light);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: color 0.2s, border-color 0.2s;
    position: relative;
}

a:hover {
    color: var(--brand-dark);
    text-decoration: none;
    border-bottom-color: var(--brand-color);
}

body.dark-mode a {
    color: var(--text-link-dark);
}

body.dark-mode a:hover {
    color: #bfdbfe;
    border-bottom-color: #3b82f6;
}

/* 标题层级 */
h1, h2, h3, h4 {
    color: var(--text-heading-light);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: 0.5rem;
    letter-spacing: -0.01em;
}

body.dark-mode h1, body.dark-mode h2, body.dark-mode h3, body.dark-mode h4 {
    color: var(--text-heading-dark);
}

h1 {
    font-size: clamp(2rem, 4vw, 2.8rem);
    letter-spacing: -0.02em;
    font-weight: 800;
}

h2 {
    font-size: clamp(1.5rem, 3vw, 2rem);
    border-left: 6px solid var(--brand-color);
    padding-left: 20px;
    margin: 2.5rem 0 1.25rem;
    position: relative;
    background: linear-gradient(to right, var(--brand-color), transparent);
    -webkit-background-clip: text;
    background-clip: text;
    border-image: linear-gradient(to bottom, var(--brand-color), var(--brand-dark)) 1;
    border-left: 6px solid;
    border-image-slice: 1;
}

h3 {
    font-size: 1.5rem;
    margin-top: 2rem;
    position: relative;
}

h4 {
    font-size: 1.2rem;
    color: var(--text-secondary-light);
    font-weight: 600;
}

body.dark-mode h4 {
    color: var(--text-secondary-dark);
}

/* 卡片网格 */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
    margin: 32px 0;
}

/* 卡片 */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-md);
    padding: 28px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border-light);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    background: rgba(255, 255, 255, 0.9);
}

body.dark-mode .card {
    background: rgba(30, 41, 59, 0.9);
    border-color: var(--border-dark);
    backdrop-filter: blur(10px);
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform 0.4s ease;
}

.card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
    border-color: var(--brand-color);
}

.card:hover::before {
    transform: scaleX(1);
}

.card h3 {
    margin-top: 0;
    color: var(--text-heading-light);
    font-size: 1.3rem;
}

body.dark-mode .card h3 {
    color: var(--text-heading-dark);
}

.card p {
    color: var(--text-secondary-light);
    margin-top: 8px;
}

body.dark-mode .card p {
    color: var(--text-secondary-dark);
}

/* 按钮 */
.btn {
    display: inline-block;
    background: var(--gradient-primary);
    color: var(--text-on-brand);
    padding: 12px 28px;
    border-radius: 50px;
    font-weight: 600;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    border-bottom: none;
    box-shadow: 0 4px 15px rgba(37, 99, 235, 0.3);
    position: relative;
    overflow: hidden;
    font-size: 1rem;
    letter-spacing: 0.02em;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.btn:hover {
    background: var(--brand-dark);
    color: #ffffff;
    text-decoration: none;
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(37, 99, 235, 0.4);
}

.btn:hover::before {
    left: 100%;
}

body.dark-mode .btn {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    color: white;
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

body.dark-mode .btn:hover {
    background: linear-gradient(135deg, #2563eb, #1d4ed8);
    box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
}

/* 导航栏 */
.navbar {
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-light);
    transition: var(--transition);
    box-shadow: 0 2px 20px rgba(0,0,0,0.05);
}

body.dark-mode .navbar {
    background: rgba(15, 23, 42, 0.9);
    border-bottom-color: var(--border-dark);
    box-shadow: 0 2px 20px rgba(0,0,0,0.3);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

.logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text-heading-light);
    letter-spacing: -0.5px;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    cursor: pointer;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

body.dark-mode .logo {
    background: linear-gradient(135deg, #93c5fd, #60a5fa);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.nav-links {
    display: flex;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    color: var(--text-primary-light);
    font-weight: 500;
    border-bottom: 2px solid transparent;
    padding: 8px 0;
    transition: var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--brand-color);
    transition: width 0.3s ease;
}

.nav-links a:hover {
    color: var(--brand-color);
    border-bottom-color: transparent;
}

.nav-links a:hover::after {
    width: 100%;
}

body.dark-mode .nav-links a {
    color: var(--text-primary-dark);
}

body.dark-mode .nav-links a:hover {
    color: var(--text-link-dark);
}

.nav-links .btn {
    border-bottom: none;
    padding: 10px 24px;
    margin-left: 8px;
}

.menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-primary-light);
    padding: 8px;
    transition: transform 0.3s;
    z-index: 1001;
}

.menu-toggle:hover {
    transform: scale(1.1);
}

body.dark-mode .menu-toggle {
    color: var(--text-primary-dark);
}

/* 移动菜单 */
.mobile-menu {
    display: none;
    flex-direction: column;
    background: rgba(255, 255, 255, 0.98);
    padding: 20px;
    border-radius: 0 0 var(--radius-md) var(--radius-md);
    box-shadow: 0 12px 30px rgba(0,0,0,0.1);
    backdrop-filter: blur(20px);
    position: absolute;
    top: 70px;
    left: 0;
    right: 0;
    z-index: 999;
    border-bottom: 1px solid var(--border-light);
}

body.dark-mode .mobile-menu {
    background: rgba(30, 41, 59, 0.98);
    border-bottom-color: var(--border-dark);
}

.mobile-menu a {
    padding: 14px 0;
    border-bottom: 1px solid var(--border-light);
    font-weight: 500;
    transition: padding-left 0.3s;
}

.mobile-menu a:hover {
    padding-left: 12px;
    color: var(--brand-color);
}

body.dark-mode .mobile-menu a {
    border-bottom-color: var(--border-dark);
}

.mobile-menu a:last-child {
    border-bottom: none;
}

/* Banner */
.banner {
    background: var(--gradient-banner);
    color: #ffffff;
    border-radius: var(--radius-lg);
    padding: 56px 48px;
    margin: 32px 0 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(255,255,255,0.1);
}

.banner::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 60%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    animation: float 6s ease-in-out infinite;
}

.banner::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 40%;
    height: 100%;
    background: radial-gradient(circle, rgba(37, 99, 235, 0.2) 0%, transparent 70%);
    animation: float 8s ease-in-out infinite reverse;
}

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

.banner > * {
    position: relative;
    z-index: 1;
}

.banner h1 {
    color: #ffffff;
    font-size: clamp(2rem, 4vw, 3rem);
    margin-bottom: 16px;
    text-shadow: 0 2px 20px rgba(0,0,0,0.3);
    font-weight: 800;
}

.banner p {
    font-size: 1.15rem;
    color: #e2e8f0;
    max-width: 600px;
    margin-bottom: 24px;
    line-height: 1.8;
}

.banner .btn {
    margin-top: 8px;
    background: #ffffff;
    color: #1e293b;
    box-shadow: 0 4px 20px rgba(0,0,0,0.2);
    font-weight: 700;
}

.banner .btn:hover {
    background: #e2e8f0;
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}

.banner svg {
    border-radius: 20px;
    background: rgba(45, 59, 80, 0.8);
    padding: 10px;
    box-shadow: 0 8px 32px rgba(0,0,0,0.3);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
}

/* 文章卡片 */
.article-item {
    border-bottom: 1px solid var(--border-light);
    padding: 24px 0;
    transition: var(--transition);
    position: relative;
    padding-left: 16px;
}

.article-item::before {
    content: '';
    position: absolute;
    left: 0;
    top: 24px;
    bottom: 24px;
    width: 3px;
    background: var(--gradient-primary);
    border-radius: 3px;
    opacity: 0;
    transition: opacity 0.3s;
}

.article-item:hover {
    padding-left: 24px;
}

.article-item:hover::before {
    opacity: 1;
}

body.dark-mode .article-item {
    border-bottom-color: var(--border-dark);
}

.article-item h4 {
    margin-bottom: 8px;
    font-size: 1.15rem;
    transition: color 0.3s;
}

.article-item:hover h4 {
    color: var(--brand-color);
}

body.dark-mode .article-item:hover h4 {
    color: var(--text-link-dark);
}

.article-meta {
    font-size: 0.9rem;
    color: var(--text-muted-light);
    margin-bottom: 8px;
    display: flex;
    gap: 16px;
    align-items: center;
}

body.dark-mode .article-meta {
    color: var(--text-muted-dark);
}

.article-item p {
    margin-bottom: 8px;
}

.article-item a {
    font-weight: 600;
    font-size: 0.95rem;
}

/* FAQ */
.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border-light);
    border-radius: var(--radius-sm);
    margin-bottom: 16px;
    padding: 0 24px;
    transition: var(--transition);
    overflow: hidden;
}

.faq-item:hover {
    border-color: var(--brand-color);
    box-shadow: var(--shadow-sm);
}

body.dark-mode .faq-item {
    background: var(--bg-card-dark);
    border-color: var(--border-dark);
}

.faq-question {
    font-weight: 600;
    padding: 20px 0;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text-heading-light);
    transition: color 0.3s;
    user-select: none;
}

.faq-question:hover {
    color: var(--brand-color);
}

body.dark-mode .faq-question {
    color: var(--text-heading-dark);
}

.faq-question span {
    font-size: 1.5rem;
    transition: transform 0.3s;
    color: var(--brand-color);
    font-weight: 300;
}

.faq-item.active .faq-question span {
    transform: rotate(180deg);
}

.faq-answer {
    padding-bottom: 20px;
    color: var(--text-secondary-light);
    line-height: 1.8;
    animation: fadeIn 0.3s ease;
}

body.dark-mode .faq-answer {
    color: var(--text-secondary-dark);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-10px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 表格 */
.info-table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
    border-radius: var(--radius-sm);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
}

.info-table th, .info-table td {
    border: 1px solid var(--border-light);
    padding: 14px 16px;
    text-align: left;
}

body.dark-mode .info-table th, body.dark-mode .info-table td {
    border-color: var(--border-dark);
}

.info-table th {
    background-color: #f1f5f9;
    color: var(--text-heading-light);
    font-weight: 600;
    text-transform: uppercase;
    font-size: 0.9rem;
    letter-spacing: 0.05em;
}

body.dark-mode .info-table th {
    background-color: #1e293b;
    color: var(--text-heading-dark);
}

.info-table tr:hover {
    background: rgba(37, 99, 235, 0.05);
}

/* Footer */
.footer {
    background-color: var(--bg-footer);
    color: #cbd5e1;
    padding: 56px 0 24px;
    margin-top: 80px;
    border-radius: 32px 32px 0 0;
    position: relative;
    overflow: hidden;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(to right, transparent, rgba(255,255,255,0.2), transparent);
}

body.dark-mode .footer {
    background-color: var(--bg-footer-dark);
}

.footer a {
    color: #cbd5e1;
    transition: color 0.3s;
}

.footer a:hover {
    color: #ffffff;
    text-decoration: none;
}

.footer h4 {
    color: #f8fafc;
    margin-bottom: 16px;
    font-size: 1.3rem;
}

.footer-bottom {
    border-top: 1px solid #334155;
    margin-top: 40px;
    padding-top: 24px;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    color: #94a3b8;
    gap: 16px;
}

/* 工具类 */
.text-center { text-align: center; }
.mt-4 { margin-top: 2rem; }
.mb-2 { margin-bottom: 1rem; }

.flex-between {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 16px;
}

.hidden { display: none; }

/* 返回顶部 */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50%;
    width: 52px;
    height: 52px;
    font-size: 24px;
    cursor: pointer;
    z-index: 2000;
    box-shadow: 0 4px 20px rgba(0,0,0,0.3);
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px) scale(1.05);
    box-shadow: 0 8px 30px rgba(0,0,0,0.4);
}

body.dark-mode .back-to-top {
    background: linear-gradient(135deg, #3b82f6, #2563eb);
    box-shadow: 0 4px 20px rgba(59, 130, 246, 0.4);
}

/* 响应式 */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .menu-toggle { display: block; }
    
    .banner {
        padding: 40px 24px;
        flex-direction: column;
        text-align: center;
        gap: 24px;
    }
    
    .banner p {
        margin-left: auto;
        margin-right: auto;
    }
    
    .banner svg {
        width: 180px;
        height: 120px;
    }
    
    h1 { font-size: 2rem; }
    
    .card-grid {
        grid-template-columns: 1fr;
        gap: 16px;
    }
    
    .card {
        padding: 20px;
    }
    
    .footer {
        padding: 40px 0 20px;
        border-radius: 24px 24px 0 0;
    }
    
    .footer-bottom {
        flex-direction: column;
        text-align: center;
        gap: 8px;
    }
    
    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
        font-size: 20px;
    }
}

@media (max-width: 480px) {
    .container { padding: 0 16px; }
    
    .banner {
        padding: 32px 20px;
        margin: 16px 0 32px;
    }
    
    .banner h1 {
        font-size: 1.6rem;
    }
    
    .banner p {
        font-size: 1rem;
    }
    
    .card {
        padding: 16px;
    }
    
    .faq-item {
        padding: 0 16px;
    }
    
    .faq-question {
        font-size: 0.95rem;
        padding: 16px 0;
    }
    
    .btn {
        padding: 10px 20px;
        font-size: 0.95rem;
    }
    
    .logo {
        font-size: 1.5rem;
    }
    
    .nav-container {
        height: 60px;
    }
    
    .mobile-menu {
        top: 60px;
    }
}

/* 滚动动画 */
.fade-up {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s cubic-bezier(0.4, 0, 0.2, 1), transform 0.7s cubic-bezier(0.4, 0, 0.2, 1);
    will-change: opacity, transform;
}

.fade-up.visible {
    opacity: 1;
    transform: translateY(0);
}

/* 自定义滚动条 */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-light);
}

body.dark-mode ::-webkit-scrollbar-track {
    background: var(--bg-dark);
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(to bottom, var(--brand-color), var(--brand-dark));
    border-radius: 10px;
    border: 2px solid var(--bg-light);
}

body.dark-mode ::-webkit-scrollbar-thumb {
    border-color: var(--bg-dark);
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(to bottom, var(--brand-dark), var(--brand-color));
}

/* 选择文本样式 */
::selection {
    background: var(--brand-color);
    color: white;
}

/* 友情链接区域 */
.friend-links {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    background: var(--bg-card);
    padding: 24px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

body.dark-mode .friend-links {
    background: var(--bg-card-dark);
}

.friend-links a {
    padding: 8px 16px;
    background: var(--bg-light);
    border-radius: 20px;
    font-size: 0.9rem;
    transition: var(--transition);
    border: 1px solid var(--border-light);
}

body.dark-mode .friend-links a {
    background: var(--bg-dark);
    border-color: var(--border-dark);
}

.friend-links a:hover {
    background: var(--brand-color);
    color: white;
    border-color: var(--brand-color);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(37, 99, 235, 0.3);
}

/* 底部信息区域 */
.footer-info {
    padding: 24px;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    text-align: center;
    margin: 40px 0;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

body.dark-mode .footer-info {
    background: var(--bg-card-dark);
}

.footer-info a {
    margin: 0 12px;
    padding: 8px 16px;
    border-radius: 16px;
    transition: var(--transition);
    display: inline-block;
}

.footer-info a:hover {
    background: var(--brand-color);
    color: white;
    text-decoration: none;
    transform: translateY(-2px);
}

/* 动画延迟 */
.delay-1 { transition-delay: 0.1s; }
.delay-2 { transition-delay: 0.2s; }
.delay-3 { transition-delay: 0.3s; }
.delay-4 { transition-delay: 0.4s; }

/* 打印样式 */
@media print {
    .navbar, .mobile-menu, .back-to-top, .btn, .menu-toggle {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card, .faq-item, .banner {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}

```