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

:root {
  --color-bg: #fafafa;
  --color-surface: #ffffff;
  --color-text: #1a1a2e;
  --color-text-secondary: #6b7280;
  --color-primary: #3b82f6;
  --color-primary-hover: #2563eb;
  --color-border: #e5e7eb;
  --color-tag-bg: #eff6ff;
  --color-tag-text: #3b82f6;
  --radius: 8px;
  --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --max-width: 720px;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans SC", sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.8;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== 头部 ===== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding: 16px 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
}

.site-nav {
  display: flex;
  gap: 20px;
}

.site-nav a {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
  font-weight: 500;
}

.site-nav a:hover {
  color: var(--color-primary);
}

/* ===== 文章列表 ===== */
.page-title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 40px 0 24px;
}

.post-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
  transition: box-shadow 0.2s, transform 0.2s;
  cursor: pointer;
}

.post-card:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
}

.post-card-title {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--color-text);
}

.post-card-meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 10px;
}

.post-card-excerpt {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.post-card-tags {
  margin-top: 12px;
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.tag {
  display: inline-block;
  background: var(--color-tag-bg);
  color: var(--color-tag-text);
  padding: 2px 10px;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 500;
}

/* ===== 文章详情 ===== */
.back-link {
  display: inline-block;
  margin: 32px 0 16px;
  font-size: 0.9rem;
  font-weight: 500;
}

#article-content {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 40px 32px;
  box-shadow: var(--shadow);
  margin-bottom: 40px;
}

#article-content h1 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 12px;
}

#article-content .article-meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-bottom: 24px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--color-border);
}

#article-content h2 {
  font-size: 1.4rem;
  font-weight: 600;
  margin: 28px 0 12px;
}

#article-content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin: 20px 0 10px;
}

#article-content p {
  margin-bottom: 16px;
}

#article-content ul, #article-content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

#article-content li {
  margin-bottom: 6px;
}

#article-content code {
  background: #f1f5f9;
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.88em;
}

#article-content pre {
  background: #1e293b;
  color: #e2e8f0;
  padding: 20px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 16px;
}

#article-content pre code {
  background: none;
  padding: 0;
  color: inherit;
}

#article-content blockquote {
  border-left: 3px solid var(--color-primary);
  padding: 8px 16px;
  margin-bottom: 16px;
  color: var(--color-text-secondary);
  background: var(--color-tag-bg);
  border-radius: 0 var(--radius) var(--radius) 0;
}

#article-content img {
  max-width: 100%;
  border-radius: var(--radius);
}

/* ===== 页脚 ===== */
.site-footer {
  border-top: 1px solid var(--color-border);
  padding: 24px 0;
  text-align: center;
  font-size: 0.85rem;
  color: var(--color-text-secondary);
  margin-top: 40px;
}

/* ===== 加载状态 ===== */
.loading {
  text-align: center;
  padding: 40px;
  color: var(--color-text-secondary);
}

/* ===== 空状态 ===== */
.empty-state {
  text-align: center;
  padding: 60px 20px;
  color: var(--color-text-secondary);
}

.empty-state h2 {
  font-size: 1.2rem;
  margin-bottom: 8px;
  color: var(--color-text);
}

/* ===== 响应式 ===== */
@media (max-width: 640px) {
  .container {
    padding: 0 16px;
  }

  #article-content {
    padding: 24px 16px;
  }

  .page-title {
    font-size: 1.25rem;
  }
}