/* ---------- 基础变量 ---------- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-site: #f8fafc;
    --card-white: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --text-muted: #64748b;
    --accent: #3b82f6;
    --accent-dark: #2563eb;
    --border-light: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --radius-card: 1.25rem;
    --radius-md: 0.75rem;
    --transition: all 0.2s ease;
}

body {
    font-family: system-ui, -apple-system, 'Segoe UI', 'Roboto', 'Helvetica Neue', 'Noto Sans', sans-serif;
    background-color: var(--bg-site);
    color: var(--text-primary);
    line-height: 1.5;
    scroll-behavior: smooth;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition);
}

img {
    max-width: 100%;
    display: block;
}

/* 容器 */
.container {
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ---------- 头部 & 导航 ---------- */
.site-header {
    padding: 1.25rem 0;
    border-bottom: 1px solid var(--border-light);
    background: rgba(255,255,255,0.8);
    backdrop-filter: blur(8px);
    position: sticky;
    top: 0;
    z-index: 10;
}

.header-inner {
    display: flex;
    flex-wrap: wrap;
    align-items: baseline;
    justify-content: space-between;
    gap: 1rem;
}

.logo-area h1 {
    font-size: 1.8rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    background: linear-gradient(135deg, var(--accent), #1e40af);
    background-clip: text;
    -webkit-background-clip: text;
    color: transparent;
}

.logo-area p {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 0.2rem;
}

.nav-links {
    display: flex;
    gap: 2rem;
    flex-wrap: wrap;
}

.nav-links a {
    font-weight: 500;
    color: var(--text-secondary);
}

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

/* ---------- 主体布局 (网格 + 侧边栏) ---------- */
.content-grid {
    display: flex;
    gap: 2.5rem;
    margin: 3rem 0 4rem;
    flex-wrap: wrap;
}

/* 主内容区 — 文章列表 */
.main-blog {
    flex: 2.5;
    min-width: 0; /* 防止溢出 */
}

/* 侧边栏 */
.sidebar {
    flex: 1.2;
    min-width: 240px;
}

/* ---------- 文章卡片样式 ---------- */
.post-card {
    background: var(--card-white);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-sm);
    overflow: hidden;
    margin-bottom: 2rem;
    transition: var(--transition);
    border: 1px solid var(--border-light);
}

.post-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
    border-color: #cbd5e1;
}

.card-img {
    width: 100%;
    height: 220px;
    object-fit: cover;
    background-color: #e2e8f0;
}

.card-content {
    padding: 1.5rem;
}

.post-meta {
    display: flex;
    gap: 1rem;
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}

.post-meta span {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
}

.post-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 0.75rem;
    line-height: 1.3;
}

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

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

.post-excerpt {
    color: var(--text-secondary);
    margin: 0.75rem 0 1.25rem;
    display: -webkit-box;
    line-clamp: 3;
    -webkit-line-clamp: 3;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.read-more {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-weight: 600;
    color: var(--accent);
    border-bottom: 1.5px solid transparent;
}

.read-more:hover {
    gap: 0.7rem;
    border-bottom-color: var(--accent);
}

/* 标签样式 */
.post-tags {
    margin-top: 1rem;
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.tag {
    background: #eef2ff;
    color: var(--accent-dark);
    font-size: 0.7rem;
    padding: 0.25rem 0.75rem;
    border-radius: 40px;
    font-weight: 500;
    transition: var(--transition);
}

.tag:hover {
    background: var(--accent);
    color: white;
}

/* ---------- 侧边栏组件 ---------- */
.sidebar-widget {
    background: var(--card-white);
    border-radius: var(--radius-md);
    padding: 1.5rem;
    margin-bottom: 2rem;
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-sm);
}

.widget-title {
    font-size: 1.2rem;
    font-weight: 600;
    border-left: 4px solid var(--accent);
    padding-left: 0.75rem;
    margin-bottom: 1.25rem;
}

/* 作者简介 */
.author-avatar {
    width: 88px;
    height: 88px;
    border-radius: 50%;
    object-fit: cover;
    margin: 0 auto 1rem;
    border: 3px solid white;
    box-shadow: var(--shadow-sm);
}

.author-name {
    font-size: 1.2rem;
    font-weight: 700;
    text-align: center;
}

.author-bio {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin: 0.75rem 0;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1.25rem;
    margin-top: 1rem;
}

.social-links a {
    font-size: 0.9rem;
    background: #f1f5f9;
    padding: 0.3rem 0.8rem;
    border-radius: 40px;
    font-weight: 500;
}

.social-links a:hover {
    background: var(--accent);
    color: white;
}

/* 最近文章列表 */
.recent-posts-list {
    list-style: none;
}

.recent-posts-list li {
    margin-bottom: 1rem;
    border-bottom: 1px dashed var(--border-light);
    padding-bottom: 0.75rem;
}

.recent-posts-list li a {
    font-weight: 500;
    display: block;
    margin-bottom: 0.25rem;
}

.recent-posts-list li a:hover {
    color: var(--accent);
}

.recent-date {
    font-size: 0.7rem;
    color: var(--text-muted);
}

/* 分类列表 */
.category-list {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.category-item {
    background: #f1f5f9;
    padding: 0.3rem 1rem;
    border-radius: 30px;
    font-size: 0.8rem;
    font-weight: 500;
    transition: var(--transition);
}

.category-item:hover {
    background: var(--accent);
    color: white;
}

/* 搜索框 */
.search-form {
    display: flex;
    gap: 0.5rem;
}

.search-input {
    flex: 1;
    padding: 0.6rem 1rem;
    border: 1px solid var(--border-light);
    border-radius: 60px;
    font-size: 0.9rem;
    background: #f9fafb;
    transition: var(--transition);
}

.search-input:focus {
    outline: none;
    border-color: var(--accent);
    background: white;
}

.search-btn {
    background: var(--accent);
    border: none;
    color: white;
    padding: 0 1.2rem;
    border-radius: 60px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
}

.search-btn:hover {
    background: var(--accent-dark);
}

/* ---------- 页脚 ---------- */
.site-footer {
    border-top: 1px solid var(--border-light);
    padding: 2rem 0 2rem;
    background: white;
    margin-top: 2rem;
}

.footer-inner {
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
    align-items: center;
    color: var(--text-muted);
    font-size: 0.85rem;
}

.footer-links a {
    margin-left: 1.5rem;
}

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

/* ---------- 响应式设计 ---------- */
@media (max-width: 880px) {
    .content-grid {
        flex-direction: column;
    }
    .sidebar {
        order: 2;
    }
    .main-blog {
        order: 1;
    }
    .header-inner {
        flex-direction: column;
        align-items: center;
        text-align: center;
    }
    .nav-links {
        justify-content: center;
    }
}

@media (max-width: 640px) {
    .container {
        padding: 0 1rem;
    }
    .post-title {
        font-size: 1.3rem;
    }
    .card-img {
        height: 180px;
    }
    .footer-inner {
        flex-direction: column;
        text-align: center;
    }
    .footer-links a {
        margin: 0 0.75rem;
    }
}

/* 分隔装饰 */
.section-header {
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 1.8rem;
    letter-spacing: -0.3px;
    position: relative;
    display: inline-block;
}
.section-header:after {
    content: '';
    position: absolute;
    bottom: -8px;
    left: 0;
    width: 50px;
    height: 3px;
    background: var(--accent);
    border-radius: 3px;
}