:root {
  --color-primary: #7BA19F;
  --color-primary-hover: #5B8A80;
  --color-primary-active: #3D6B63;
  --color-primary-dark: #2A4A44;
  --color-bg: #FAFAF8;
  --color-bg-card: #F5F4F0;
  --color-border: #E8E6E1;
  --color-text-muted: #7A7A72;
  --color-text: #4A4A46;
  --color-text-strong: #1A1A18;
  --color-danger: #B85A5A;
  --font-sans: "Noto Serif SC", "Source Han Serif SC", "Songti SC",
               "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei",
               Georgia, "Times New Roman", serif;
  --font-mono: "JetBrains Mono", "Fira Code", "Source Code Pro",
               Consolas, "Courier New", monospace;
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 40px;
  --space-2xl: 64px;
  --space-3xl: 96px;
  --layout-width: 1080px;
  --content-width: 720px;
  --sidebar-width: 260px;
  --sidebar-width-tablet: 220px;
  --column-gap: 48px;
  --nav-height: 56px;
}

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

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

body {
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.8;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a { color: var(--color-primary-hover); text-decoration: none; transition: color 150ms ease; }
a:hover { color: var(--color-primary-active); }

img { max-width: 100%; height: auto; }

/* NAV */
.nav {
  height: var(--nav-height);
  border-bottom: 1px solid var(--color-border);
  background: var(--color-bg);
  position: sticky;
  top: 0;
  z-index: 100;
}
.nav-inner {
  max-width: var(--layout-width);
  margin: 0 auto;
  padding: 0 var(--space-md);
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.nav-brand {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--color-primary-dark);
}
.nav-brand:hover { color: var(--color-primary-hover); }
.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--space-sm);
  flex-direction: column;
  gap: 4px;
  width: 32px;
  height: 32px;
  justify-content: center;
  align-items: center;
}
.nav-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background: var(--color-text);
  transition: all 200ms ease;
}
.nav-menu { display: flex; gap: var(--space-lg); }
.nav-link {
  font-size: 0.9375rem;
  color: var(--color-text);
  padding: var(--space-xs) 0;
  border-bottom: 2px solid transparent;
  transition: all 150ms ease;
}
.nav-link:hover { color: var(--color-primary-hover); border-bottom-color: var(--color-primary); }

/* MAIN */
.main {
  flex: 1;
  max-width: var(--layout-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md);
  width: 100%;
}

/* TWO COL LAYOUT */
.layout-two-col {
  display: flex;
  gap: var(--column-gap);
}
.content-col { flex: 1; min-width: 0; }

/* SIDEBAR */
.sidebar { width: var(--sidebar-width); flex-shrink: 0; }
.sidebar-module { margin-bottom: var(--space-lg); }
.sidebar-title {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-text-strong);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
  margin-bottom: var(--space-sm);
}
.sidebar-desc { font-size: 0.875rem; color: var(--color-text-muted); line-height: 1.6; }
.sidebar-list { list-style: none; }
.sidebar-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-xs) 0;
  font-size: 0.875rem;
}
.sidebar-item a { color: var(--color-text); }
.sidebar-item a:hover { color: var(--color-primary-hover); }
.sidebar-count { color: var(--color-text-muted); font-size: 0.8125rem; }

/* PAGE HEADING */
.page-heading {
  font-size: 1.5rem;
  color: var(--color-text-strong);
  margin-bottom: var(--space-lg);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}

/* POST CARD */
.post-card {
  padding: var(--space-lg) 0;
  border-bottom: 1px solid var(--color-border);
}
.post-card:first-child { padding-top: 0; }
.post-card-title {
  font-size: 1.25rem;
  line-height: 1.4;
  margin-bottom: var(--space-sm);
}
.post-card-title a { color: var(--color-text-strong); }
.post-card-title a:hover { color: var(--color-primary-hover); }
.post-card-summary {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin-bottom: var(--space-sm);
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}
.post-card-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.8125rem;
}
.post-card-category { color: var(--color-primary-hover); font-weight: 500; }
.post-card-date { color: var(--color-text-muted); margin-left: auto; }

/* TAG PILL */
.tag-pill {
  display: inline-block;
  background: var(--color-bg-card);
  color: var(--color-text-muted);
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 2px;
  transition: all 150ms ease;
}
.tag-pill:hover { background: var(--color-border); color: var(--color-primary-hover); }

/* PAGINATION */
.pagination {
  display: flex;
  justify-content: center;
  gap: var(--space-xs);
  padding: var(--space-xl) 0;
}
.pagination-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 32px;
  height: 32px;
  padding: 0 var(--space-sm);
  font-size: 0.875rem;
  color: var(--color-text-muted);
  border-radius: 2px;
  transition: all 150ms ease;
}
.pagination-link:hover { color: var(--color-primary-hover); }
.pagination-current { color: var(--color-primary-hover); font-weight: 700; }

/* POST DETAIL */
.post-detail { max-width: var(--content-width); margin: 0 auto; }
.post-header { margin-bottom: var(--space-xl); }
.post-title {
  font-size: 2rem;
  line-height: 1.4;
  color: var(--color-text-strong);
  margin-bottom: var(--space-md);
}
.post-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--space-sm);
  font-size: 0.875rem;
}
.post-category { color: var(--color-primary-hover); font-weight: 500; }
.post-date { color: var(--color-text-muted); }
.post-content { font-size: 1.0625rem; line-height: 1.8; }
.post-content h1, .post-content h2, .post-content h3 {
  color: var(--color-text-strong);
  margin-top: var(--space-xl);
  margin-bottom: var(--space-md);
}
.post-content h1 { font-size: 1.5rem; }
.post-content h2 { font-size: 1.25rem; }
.post-content h3 { font-size: 1.125rem; }
.post-content p { margin-bottom: var(--space-md); }
.post-content img { border-radius: 2px; margin: var(--space-lg) auto; display: block; }
.post-content blockquote {
  border-left: 3px solid var(--color-primary-hover);
  padding-left: var(--space-md);
  color: var(--color-text-muted);
  margin: var(--space-md) 0;
}
.post-content pre {
  background: var(--color-bg-card);
  border-radius: 2px;
  padding: var(--space-md);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
  margin: var(--space-md) 0;
}
.post-content code {
  font-family: var(--font-mono);
  font-size: 0.875em;
  background: var(--color-bg-card);
  padding: 2px 6px;
  border-radius: 2px;
}
.post-content pre code { background: none; padding: 0; }
.post-content ul, .post-content ol { padding-left: var(--space-lg); margin-bottom: var(--space-md); }
.post-content li { margin-bottom: var(--space-xs); }
.post-content table { width: 100%; border-collapse: collapse; margin: var(--space-md) 0; }
.post-content th, .post-content td {
  padding: var(--space-sm) var(--space-md);
  border: 1px solid var(--color-border);
  text-align: left;
}
.post-content th { background: var(--color-bg-card); font-weight: 700; }
.post-content hr {
  width: 60px;
  border: none;
  border-top: 2px solid var(--color-border);
  margin: var(--space-xl) auto;
}

/* POST NAV */
.post-nav {
  display: flex;
  justify-content: space-between;
  gap: var(--space-md);
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--color-border);
}
.post-nav-link {
  flex: 1;
  padding: var(--space-md);
  border: 1px solid var(--color-border);
  border-radius: 2px;
  transition: all 150ms ease;
}
.post-nav-link:hover { border-color: var(--color-primary); }
.post-nav-next { text-align: right; }
.post-nav-label { display: block; font-size: 0.75rem; color: var(--color-text-muted); margin-bottom: var(--space-xs); }
.post-nav-title { display: block; font-size: 0.9375rem; color: var(--color-text-strong); }

/* PAGE DETAIL */
.page-detail { max-width: var(--content-width); margin: 0 auto; }
.page-header { margin-bottom: var(--space-xl); }
.page-title { font-size: 2rem; line-height: 1.4; color: var(--color-text-strong); }
.page-content { font-size: 1.0625rem; line-height: 1.8; }
.page-content p { margin-bottom: var(--space-md); }
.page-content h2, .page-content h3 { color: var(--color-text-strong); margin-top: var(--space-xl); margin-bottom: var(--space-md); }
.page-content ul, .page-content ol { padding-left: var(--space-lg); margin-bottom: var(--space-md); }
.page-content blockquote { border-left: 3px solid var(--color-primary-hover); padding-left: var(--space-md); color: var(--color-text-muted); margin: var(--space-md) 0; }

/* CATEGORY GRID */
.category-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: var(--space-md);
}
.category-card {
  display: flex;
  flex-direction: column;
  padding: var(--space-lg);
  border: 1px solid var(--color-border);
  border-radius: 2px;
  transition: all 150ms ease;
}
.category-card:hover { border-color: var(--color-primary); }
.category-name { font-size: 1.0625rem; color: var(--color-text-strong); margin-bottom: var(--space-xs); }
.category-count { font-size: 0.8125rem; color: var(--color-text-muted); }

/* TAG CLOUD */
.tag-cloud { display: flex; flex-wrap: wrap; gap: var(--space-sm); }
.tag-cloud-item {
  display: inline-block;
  background: var(--color-bg-card);
  color: var(--color-text);
  padding: var(--space-xs) var(--space-md);
  border-radius: 2px;
  font-size: 0.875rem;
  transition: all 150ms ease;
}
.tag-cloud-item:hover { background: var(--color-border); color: var(--color-primary-hover); }
.tag-cloud-count { font-size: 0.75rem; color: var(--color-text-muted); }

/* ARCHIVE */
.archive-page { max-width: var(--content-width); margin: 0 auto; }
.archive-year { margin-bottom: var(--space-xl); }
.archive-year-title {
  font-size: 1.25rem;
  color: var(--color-text-strong);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}
.archive-list { list-style: none; }
.archive-item {
  display: flex;
  align-items: baseline;
  gap: var(--space-md);
  padding: var(--space-sm) 0;
}
.archive-date { font-size: 0.875rem; color: var(--color-text-muted); white-space: nowrap; font-family: var(--font-mono); }
.archive-title { color: var(--color-text); }
.archive-title:hover { color: var(--color-primary-hover); }

/* SITEMAP */
.sitemap-page { max-width: var(--content-width); margin: 0 auto; }
.sitemap-section { margin-bottom: var(--space-xl); }
.sitemap-section-title {
  font-size: 1.125rem;
  color: var(--color-text-strong);
  margin-bottom: var(--space-md);
  padding-bottom: var(--space-sm);
  border-bottom: 1px solid var(--color-border);
}
.sitemap-list { list-style: none; }
.sitemap-list li { padding: var(--space-xs) 0; }
.sitemap-list time { font-size: 0.8125rem; color: var(--color-text-muted); margin-right: var(--space-sm); font-family: var(--font-mono); }

/* ERROR PAGE */
.error-page { text-align: center; padding: var(--space-3xl) 0; }
.error-code { font-size: 4rem; color: var(--color-border); margin-bottom: var(--space-md); }
.error-message { font-size: 1.125rem; color: var(--color-text-muted); margin-bottom: var(--space-xl); }

/* EMPTY STATE */
.empty-state { text-align: center; color: var(--color-text-muted); padding: var(--space-3xl) 0; }

/* BUTTONS */
.btn {
  display: inline-block;
  padding: 8px 20px;
  font-size: 0.875rem;
  font-family: inherit;
  border: 1px solid var(--color-border);
  border-radius: 2px;
  background: transparent;
  color: var(--color-text);
  cursor: pointer;
  transition: all 150ms ease;
  text-decoration: none;
}
.btn:hover { border-color: var(--color-primary); color: var(--color-primary-hover); }
.btn-primary { background: var(--color-primary-hover); color: #fff; border-color: var(--color-primary-hover); }
.btn-primary:hover { background: var(--color-primary-active); border-color: var(--color-primary-active); color: #fff; }
.btn-danger { color: var(--color-danger); border-color: var(--color-danger); }
.btn-danger:hover { background: var(--color-danger); color: #fff; }
.btn-sm { padding: 4px 12px; font-size: 0.8125rem; }
.btn-block { display: block; width: 100%; text-align: center; }

/* FOOTER */
.footer { border-top: 1px solid var(--color-border); padding: var(--space-xl) var(--space-md); text-align: center; }
.footer-inner { max-width: var(--layout-width); margin: 0 auto; font-size: 0.75rem; color: var(--color-text-muted); }

/* RESPONSIVE */
@media (max-width: 1024px) {
  .sidebar { width: var(--sidebar-width-tablet); }
  .layout-two-col { gap: var(--space-lg); }
}

@media (max-width: 768px) {
  .nav-toggle { display: flex; }
  .nav-menu {
    display: none;
    position: fixed;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--space-md);
    gap: 0;
    z-index: 99;
  }
  .nav-menu.active { display: flex; }
  .nav-link { padding: var(--space-sm) 0; border-bottom: none; }

  .layout-two-col { flex-direction: column; }
  .sidebar { width: 100%; border-top: 1px solid var(--color-border); padding-top: var(--space-lg); margin-top: var(--space-lg); }

  .main { padding: var(--space-lg) var(--space-md); }

  .post-title { font-size: 1.5rem; }
  .post-nav { flex-direction: column; }
  .post-nav-next { text-align: left; }

  .category-grid { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 480px) {
  .category-grid { grid-template-columns: 1fr; }
  .post-card-meta { flex-direction: column; align-items: flex-start; }
  .post-card-date { margin-left: 0; }
}

/* PRINT */
@media print {
  .nav, .sidebar, .footer, .post-nav { display: none; }
  .main { max-width: 100%; padding: 0; }
  .post-content { max-width: 100%; }
  a { text-decoration: underline; }
}