/* ========================================
   闲笔 · 极简博客样式
   设计原则：黑白灰为主、衬线正文、大量留白
   ======================================== */

:root {
  --color-bg: #fafaf9;
  --color-text: #1c1c1a;
  --color-text-secondary: #6b6b66;
  --color-text-muted: #9c9c94;
  --color-border: #e8e8e3;
  --color-code-bg: #f0f0ec;

  --font-serif: "Songti SC", "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Helvetica Neue", sans-serif;
  --font-mono: "SF Mono", Menlo, Consolas, monospace;

  --content-width: 640px;
  --spacing-lg: 4rem;
  --spacing-md: 2rem;
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  background-color: var(--color-bg);
  color: var(--color-text);
  font-family: var(--font-serif);
  line-height: 1.75;
}

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

/* ============ 页面骨架 ============ */

.page { min-height: 100vh; display: flex; flex-direction: column; }

.container {
  width: 100%;
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  flex: 1;
}

/* ============ 页头 ============ */

.site-header { border-bottom: 1px solid var(--color-border); }

.site-header-inner {
  max-width: var(--content-width);
  margin: 0 auto;
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: baseline;
  justify-content: space-between;
}

.site-title {
  font-family: var(--font-serif);
  font-size: 1.125rem;
  font-weight: 600;
  letter-spacing: 0.05em;
}

.site-nav {
  display: flex;
  gap: 1.5rem;
  font-family: var(--font-sans);
  font-size: 0.875rem;
}

.site-nav a {
  color: var(--color-text-secondary);
  transition: color 0.2s ease;
}

.site-nav a:hover,
.site-nav a[aria-current="page"] { color: var(--color-text); }

/* ============ 首页简介区 ============ */

.intro { padding: var(--spacing-lg) 0 var(--spacing-md); }

.intro-title {
  font-size: 1.5rem;
  font-weight: 600;
  line-height: 1.5;
  letter-spacing: 0.02em;
  margin-bottom: 1rem;
}

.intro-sub {
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

/* ============ 分类筛选 ============ */

.filter-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  padding-bottom: var(--spacing-md);
  font-family: var(--font-sans);
}

.filter-btn {
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  padding: 0.25em 0.75em;
  border: 1px solid var(--color-border);
  border-radius: 2px;
  background: transparent;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: all 0.15s ease;
}

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

.filter-btn.active {
  background: var(--color-text);
  border-color: var(--color-text);
  color: var(--color-bg);
}

.filter-btn .count {
  margin-left: 0.35em;
  opacity: 0.6;
  font-size: 0.9em;
}

/* ============ 文章列表 ============ */

.post-list { padding-bottom: var(--spacing-lg); }

.post-item { border-top: 1px solid var(--color-border); }
.post-item:first-child { border-top: none; }

.post-link {
  display: block;
  padding: var(--spacing-md) 0;
}

.post-link:hover .post-title { color: var(--color-text-secondary); }

.post-meta {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  margin-bottom: 0.5rem;
}

.post-tag {
  padding: 0.1em 0.5em;
  border: 1px solid var(--color-border);
  border-radius: 2px;
  font-size: 0.75rem;
  color: var(--color-text-secondary);
}

.post-title {
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.5;
  margin-bottom: 0.5rem;
  transition: color 0.2s ease;
}

.post-excerpt {
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  line-height: 1.8;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.empty-tip {
  padding: 3rem 0;
  text-align: center;
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 0.9375rem;
}

/* ============ 文章详情 ============ */

.back-link {
  display: inline-block;
  margin: var(--spacing-md) 0 0;
  font-family: var(--font-sans);
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

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

.post-header { padding: var(--spacing-md) 0; }

.post-header h1 {
  font-size: 1.75rem;
  font-weight: 600;
  line-height: 1.4;
}

.post-body {
  padding-bottom: var(--spacing-lg);
  font-size: 1rem;
}

.post-body p { margin-bottom: 1.5em; color: #2a2a28; }

.post-body h2 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 2.5em 0 1em;
}

.post-body h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin: 2em 0 0.75em;
}

.post-body h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 1.75em 0 0.5em;
}

.post-body blockquote {
  margin: 1.5em 0;
  padding-left: 1em;
  border-left: 2px solid var(--color-border);
  color: var(--color-text-secondary);
}

.post-body blockquote p { margin-bottom: 0.75em; color: inherit; }
.post-body blockquote p:last-child { margin-bottom: 0; }

.post-body code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-code-bg);
  padding: 0.15em 0.4em;
  border-radius: 3px;
}

.post-body pre.code-block {
  margin: 1.5em 0;
  padding: 1em 1.25em;
  background: var(--color-code-bg);
  border-radius: 4px;
  overflow-x: auto;
  font-size: 0.875rem;
  line-height: 1.7;
}

.post-body pre.code-block code {
  background: transparent;
  padding: 0;
  font-size: inherit;
}

.post-body ul, .post-body ol {
  margin: 0 0 1.5em 1.5em;
  color: #2a2a28;
}

.post-body li { margin-bottom: 0.5em; }

.post-body hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 2.5em 0;
}

.post-body a {
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-color: var(--color-text-muted);
}

.post-body a:hover { text-decoration-color: var(--color-text); }

.post-body img {
  max-width: 100%;
  height: auto;
  border-radius: 4px;
  margin: 1em 0;
}

/* ============ 归档页 ============ */

.archive-year {
  margin-bottom: 2.5rem;
}

.archive-year-title {
  font-size: 1.125rem;
  font-weight: 600;
  margin-bottom: 1rem;
  color: var(--color-text-secondary);
  font-family: var(--font-sans);
}

.archive-list { list-style: none; }

.archive-item {
  display: flex;
  align-items: baseline;
  gap: 1rem;
  padding: 0.4rem 0;
}

.archive-item time {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  flex-shrink: 0;
  width: 5.5em;
}

.archive-item a {
  font-size: 1rem;
  flex: 1;
  min-width: 0;
}

.archive-item .post-tag { margin-left: auto; flex-shrink: 0; }

/* ============ 页脚 ============ */

.site-footer {
  padding: var(--spacing-md) 0 var(--spacing-lg);
  border-top: 1px solid var(--color-border);
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  text-align: center;
}

.site-footer a {
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ============ 错误提示 ============ */

.error-box {
  padding: var(--spacing-lg) 0;
  font-family: var(--font-sans);
  color: var(--color-text-secondary);
}

.error-box p { margin-bottom: 1em; }

/* ============ 加载中 ============ */

.loading {
  padding: var(--spacing-lg) 0;
  text-align: center;
  color: var(--color-text-muted);
  font-family: var(--font-sans);
  font-size: 0.875rem;
}

/* ============ 响应式 ============ */

@media (max-width: 640px) {
  .intro { padding-top: 2.5rem; }
  .intro-title { font-size: 1.25rem; }
  .post-title { font-size: 1.125rem; }
  .post-header h1 { font-size: 1.5rem; }
  .archive-item time { width: 4.5em; }
}