/* ==================== CSS 变量 ==================== */
:root {
    /* 颜色 - 暗色主题 (默认) */
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #1c2128;
    --border-color: #30363d;
    --text-primary: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --accent-primary: #58a6ff;
    --accent-hover: #79c0ff;
    --accent-glow: rgba(88, 166, 255, 0.15);

    /* 字体 */
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body: 'Source Sans 3', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', Consolas, monospace;

    /* 间距 */
    --spacing-xs: 8px;
    --spacing-sm: 16px;
    --spacing-md: 24px;
    --spacing-lg: 32px;
    --spacing-xl: 48px;
    --spacing-2xl: 64px;

    /* 过渡 */
    --transition-fast: 0.15s ease;
    --transition-base: 0.25s ease;
    --transition-slow: 0.4s ease;

    /* 阴影 */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 8px 24px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 30px rgba(88, 166, 255, 0.1);
}

/* ==================== 重置 & 基础 ==================== */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-body);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
    overflow-x: hidden;
}

a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--accent-hover);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ==================== 导航栏 ==================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    height: 60px;
    background: rgba(13, 17, 23, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    z-index: 1000;
    transition: background var(--transition-base);
}

.nav-container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-primary);
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 600;
}

.nav-logo:hover {
    color: var(--accent-primary);
}

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

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--spacing-lg);
    list-style: none;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
    padding: var(--spacing-xs) 0;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-primary);
    transition: width var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

/* Hamburger 菜单 */
.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 28px;
    height: 28px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0;
}

.nav-toggle .bar {
    display: block;
    width: 100%;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-base);
}

.nav-toggle.active .bar:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.nav-toggle.active .bar:nth-child(2) {
    opacity: 0;
}

.nav-toggle.active .bar:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ==================== Hero 区域 ==================== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: calc(60px + var(--spacing-2xl)) var(--spacing-md) var(--spacing-2xl);
    text-align: center;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 80% 50% at 50% -20%, rgba(88, 166, 255, 0.15), transparent),
        radial-gradient(ellipse 60% 40% at 80% 60%, rgba(88, 166, 255, 0.08), transparent),
        radial-gradient(ellipse 50% 30% at 20% 80%, rgba(88, 166, 255, 0.05), transparent);
    pointer-events: none;
}

.hero-content {
    position: relative;
    max-width: 700px;
    animation: fadeInUp 0.8s ease-out;
}

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

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 6vw, 3rem);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.hero-title .highlight {
    background: linear-gradient(135deg, var(--accent-primary), #a371f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-weight: 400;
}

.hero-bio {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: var(--spacing-lg);
}

/* 分类卡片 */
.category-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-sm);
    width: 100%;
    margin-bottom: var(--spacing-xl);
}

.category-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    width: 140px;
    height: 100px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: all var(--transition-base);
}

.category-card:hover {
    border-color: var(--accent-primary);
    background: var(--accent-glow);
    transform: translateY(-5px);
}

.category-card-name {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-primary);
    margin-bottom: 6px;
}

.category-card-count {
    font-size: 0.875rem;
    color: var(--accent-primary);
    font-weight: 600;
}

.hero-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: var(--spacing-xs);
    margin-bottom: var(--spacing-lg);
}

.tag {
    padding: 6px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.tag:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--accent-glow);
}

.hero-social {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
}

.social-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border-radius: 12px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-secondary);
    transition: all var(--transition-base);
}

.social-btn:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--accent-glow);
    transform: translateY(-3px);
}

/* ==================== 分类页标题 ==================== */
.category-header {
    padding: calc(60px + var(--spacing-2xl)) 0 var(--spacing-xl);
    text-align: center;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border-color);
}

.category-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--accent-primary), #a371f7);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.category-subtitle {
    font-size: 1.15rem;
    color: var(--text-secondary);
}

/* ==================== 博客区域 ==================== */
.blog-section {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-secondary);
}

.section-header {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.section-title {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.section-subtitle {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

.blog-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

/* 文章卡片 */
.blog-card {
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: var(--spacing-lg);
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.blog-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--accent-primary), #a371f7);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-base);
}

.blog-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: var(--accent-primary);
}

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

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-sm);
}

.card-date {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.card-tags {
    display: flex;
    gap: 6px;
}

.card-tag {
    font-size: 0.75rem;
    padding: 3px 10px;
    background: var(--bg-tertiary);
    border-radius: 12px;
    color: var(--accent-primary);
}

.card-title {
    font-family: var(--font-display);
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: var(--spacing-sm);
    line-height: 1.4;
}

.card-title a {
    color: var(--text-primary);
}

.card-title a:hover {
    color: var(--accent-primary);
}

.card-excerpt {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
    display: -webkit-box;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.card-link {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--accent-primary);
}

.card-link:hover {
    color: var(--accent-hover);
    gap: 10px;
}

/* ==================== 文章详情页 ==================== */
.article-container {
    max-width: 800px;
    margin: 0 auto;
    padding: calc(60px + var(--spacing-2xl)) var(--spacing-md) var(--spacing-2xl);
}

.article {
    animation: fadeInUp 0.6s ease-out;
}

.article-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.article-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-sm);
}

.article-date {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.article-tag {
    font-size: 0.8rem;
    padding: 4px 12px;
    background: var(--accent-glow);
    border-radius: 12px;
    color: var(--accent-primary);
}

.article-title {
    font-family: var(--font-display);
    font-size: clamp(1.75rem, 5vw, 2.5rem);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-sm);
}

.article-description {
    font-size: 1.15rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* 文章内容 */
.article-content {
    font-size: 1.125rem;
    line-height: 1.8;
}

.article-content h2 {
    font-family: var(--font-display);
    font-size: 1.75rem;
    font-weight: 600;
    margin: var(--spacing-xl) 0 var(--spacing-md);
    color: var(--text-primary);
    scroll-margin-top: 80px;
}

.article-content h3 {
    font-family: var(--font-display);
    font-size: 1.35rem;
    font-weight: 600;
    margin: var(--spacing-lg) 0 var(--spacing-sm);
    color: var(--text-primary);
    scroll-margin-top: 80px;
}

.article-content p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

.article-content ul,
.article-content ol {
    margin-bottom: var(--spacing-md);
    padding-left: var(--spacing-lg);
    color: var(--text-secondary);
}

.article-content li {
    margin-bottom: var(--spacing-xs);
}

.article-content strong {
    color: var(--text-primary);
    font-weight: 600;
}

.article-content a {
    color: var(--accent-primary);
    text-decoration: underline;
    text-underline-offset: 3px;
}

.article-content a:hover {
    color: var(--accent-hover);
}

/* 代码块 */
.code-block {
    margin: var(--spacing-lg) 0;
    border-radius: 12px;
    overflow: hidden;
    border: 1px solid var(--border-color);
    background: var(--bg-tertiary);
}

.code-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-xs) var(--spacing-sm);
    background: var(--bg-secondary);
    border-bottom: 1px solid var(--border-color);
}

.code-lang {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.code-copy {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    background: transparent;
    border: none;
    border-radius: 6px;
    color: var(--text-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}

.code-copy:hover {
    background: var(--bg-tertiary);
    color: var(--text-primary);
}

.code-copy.copied {
    color: #3fb950;
}

.code-block pre {
    margin: 0;
    padding: var(--spacing-md);
    overflow-x: auto;
}

.code-block code {
    font-family: var(--font-mono);
    font-size: 0.9rem;
    line-height: 1.6;
}

/* MathJax 样式 */
.math-inline {
    padding: 0 4px;
}

/* ==================== 文章页脚 ==================== */
.article-footer {
    margin-top: var(--spacing-2xl);
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--border-color);
}

.article-share {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
}

.share-label {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.share-btn {
    font-size: 0.85rem;
    padding: 6px 14px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    color: var(--text-secondary);
    transition: all var(--transition-fast);
}

.share-btn:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--accent-glow);
}

.article-nav {
    display: flex;
    justify-content: space-between;
    gap: var(--spacing-md);
}

.nav-prev,
.nav-next {
    flex: 1;
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    transition: all var(--transition-base);
}

.nav-prev:hover,
.nav-next:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: var(--accent-glow);
}

/* ==================== 页脚 ==================== */
.footer {
    padding: var(--spacing-lg) 0;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
    text-align: center;
}

.footer-text {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.footer-text:last-child {
    margin-bottom: 0;
}

/* ==================== 响应式设计 ==================== */
@media (max-width: 768px) {
    /* 导航栏 */
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 60px;
        left: 0;
        right: 0;
        flex-direction: column;
        gap: 0;
        background: var(--bg-secondary);
        border-bottom: 1px solid var(--border-color);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all var(--transition-base);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .nav-menu li {
        width: 100%;
    }

    .nav-link {
        display: block;
        padding: var(--spacing-sm) var(--spacing-md);
        border-bottom: 1px solid var(--border-color);
    }

    .nav-link::after {
        display: none;
    }

    /* Hero */
    .hero {
        padding-top: calc(60px + var(--spacing-xl));
    }

    .hero-bio {
        font-size: 1rem;
    }

    /* 博客网格 */
    .blog-grid {
        grid-template-columns: 1fr;
    }

    /* 文章导航 */
    .article-nav {
        flex-direction: column;
    }

    .nav-prev,
    .nav-next {
        text-align: center;
    }
}

@media (max-width: 480px) {
    :root {
        --spacing-lg: 24px;
        --spacing-xl: 36px;
        --spacing-2xl: 48px;
    }

    .hero-title {
        font-size: 1.75rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .article-title {
        font-size: 1.5rem;
    }

    .article-content {
        font-size: 1rem;
    }

    .code-block pre {
        padding: var(--spacing-sm);
        font-size: 0.85rem;
    }
}

/* ==================== 滚动条 ==================== */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ==================== 选中文字 ==================== */
::selection {
    background: var(--accent-primary);
    color: var(--bg-primary);
}