/* ===== 我的学习笔记 · 基础样式 ===== */
:root {
  --bg: #fafafa;
  --surface: #ffffff;
  --text: #1f2328;
  --text-secondary: #57606a;
  --primary: #1f6feb;
  --border: #e5e7eb;
  --radius: 8px;
  --max-width: 760px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
}

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

html {
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
}

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

a:hover {
  text-decoration: underline;
}

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* ===== 头部 ===== */
.site-header {
  background: var(--surface);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
}

.site-title {
  font-size: 18px;
  font-weight: 600;
  color: var(--text);
}

.site-title:hover {
  text-decoration: none;
}

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

.site-nav a {
  color: var(--text-secondary);
  font-size: 15px;
}

.site-nav a:hover {
  color: var(--primary);
  text-decoration: none;
}

.site-nav a.active {
  color: var(--primary);
  font-weight: 600;
}

/* ===== 首屏 ===== */
.hero {
  padding: 48px 0 24px;
  text-align: center;
}

.hero h1 {
  font-size: 28px;
  margin-bottom: 12px;
}

.hero p {
  color: var(--text-secondary);
  font-size: 16px;
}

/* ===== 文章列表 ===== */
.post-list {
  padding: 8px 0 48px;
}

.post-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 16px;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}

.post-card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

.post-card h2 {
  font-size: 20px;
  margin-bottom: 8px;
}

.post-card h2 a {
  color: var(--text);
}

.post-card h2 a:hover {
  color: var(--primary);
  text-decoration: none;
}

.post-meta {
  color: var(--text-secondary);
  font-size: 13px;
  margin-bottom: 12px;
}

.post-excerpt {
  color: var(--text-secondary);
  font-size: 15px;
}

/* ===== 标签 ===== */
.tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 12px;
}

.tag {
  display: inline-block;
  background: #eef3fd;
  color: var(--primary);
  font-size: 13px;
  padding: 3px 10px;
  border-radius: 20px;
}

/* ===== 标签筛选栏 ===== */
.tag-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 8px 0 20px;
}

.filter-btn {
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text-secondary);
  font-size: 14px;
  padding: 5px 14px;
  border-radius: 20px;
  cursor: pointer;
  font-family: inherit;
  transition: all 0.15s ease;
}

.filter-btn:hover {
  color: var(--primary);
  border-color: var(--primary);
}

.filter-btn.active {
  background: var(--primary);
  color: #fff;
  border-color: var(--primary);
}

.empty-tip {
  color: var(--text-secondary);
  text-align: center;
  padding: 40px 0;
}

/* ===== 返回链接 ===== */
.back-link {
  display: inline-block;
  margin: 0 0 48px;
  font-size: 15px;
  color: var(--text-secondary);
}

.back-link:hover {
  color: var(--primary);
}

/* ===== 文章详情页 ===== */
.article-page {
  padding: 40px 0 48px;
}

.article-page .post-meta {
  margin-bottom: 24px;
}

.article-header h1 {
  font-size: 28px;
  margin-bottom: 12px;
}

.article-body {
  font-size: 16px;
}

.article-body h2 {
  font-size: 22px;
  margin: 32px 0 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
}

.article-body h3 {
  font-size: 18px;
  margin: 24px 0 10px;
}

.article-body p {
  margin-bottom: 16px;
}

.article-body ul,
.article-body ol {
  margin: 0 0 16px 24px;
}

.article-body li {
  margin-bottom: 6px;
}

.article-body code {
  background: #f0f2f5;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 14px;
}

.article-body pre {
  background: #1f2328;
  color: #e6e6e6;
  padding: 16px;
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 16px;
  line-height: 1.5;
}

.article-body pre code {
  background: transparent;
  color: inherit;
  padding: 0;
  font-size: 13px;
}

.article-body blockquote {
  border-left: 4px solid var(--primary);
  background: #f5f8fd;
  padding: 12px 16px;
  margin-bottom: 16px;
  color: var(--text-secondary);
  border-radius: 0 var(--radius) var(--radius) 0;
}

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

/* ===== 关于页 ===== */
.about-page {
  padding: 40px 0 48px;
}

.about-page h1 {
  font-size: 28px;
  margin-bottom: 16px;
}

.about-page h2 {
  font-size: 20px;
  margin: 32px 0 12px;
}

.about-page p {
  margin-bottom: 12px;
}

/* ===== 页脚 ===== */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 24px 0;
  text-align: center;
}

.site-footer p {
  color: var(--text-secondary);
  font-size: 13px;
}

.site-footer a {
  color: var(--text-secondary);
}

/* ===== 响应式（弹性，不用 @media 断点硬切） ===== */
.site-header .container,
.site-nav {
  flex-wrap: wrap;
}

@media (max-width: 480px) {
  .site-title {
    font-size: 16px;
  }
  .hero h1 {
    font-size: 24px;
  }
}