:root {
  --bg-primary: #0d1117;
  --bg-secondary: #161b22;
  --bg-tertiary: #21262d;
  --border-color: #30363d;
  --text-primary: #e6edf3;
  --text-secondary: #8b949e;
  --text-muted: #6e7681;
  --accent: #38bdf8;
  --accent-hover: #0ea5e9;
  --accent-glow: rgba(56, 189, 248, 0.15);
  --code-bg: #090d13;
  --code-border: #30363d;
  --badge-bg: rgba(56, 189, 248, 0.1);
  --badge-text: #38bdf8;
  --shadow: 0 4px 20px rgba(0, 0, 0, 0.35);
  --radius: 8px;
  --radius-lg: 12px;
  --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, "SF Mono", Consolas, "Liberation Mono", Menlo, monospace;
}

[data-theme="light"] {
  --bg-primary: #ffffff;
  --bg-secondary: #f6f8fa;
  --bg-tertiary: #eaeef2;
  --border-color: #d0d7de;
  --text-primary: #1f2328;
  --text-secondary: #57606a;
  --text-muted: #8c959f;
  --accent: #0284c7;
  --accent-hover: #0369a1;
  --accent-glow: rgba(2, 132, 199, 0.1);
  --code-bg: #f6f8fa;
  --code-border: #d0d7de;
  --badge-bg: #e0f2fe;
  --badge-text: #0284c7;
  --shadow: 0 4px 16px rgba(0, 0, 0, 0.08);
}

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

body {
  font-family: var(--font-main);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.65;
  font-size: 16px;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

a {
  color: var(--accent);
  text-decoration: none;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--accent-hover);
  text-decoration: underline;
}

.container {
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 0 20px;
}

/* Header */
.site-header {
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(8px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.brand {
  display: flex;
  align-items: baseline;
  gap: 12px;
}

.logo {
  font-size: 1.35rem;
  font-weight: 800;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.logo:hover {
  text-decoration: none;
}

.logo-accent {
  color: var(--accent);
}

.tagline {
  font-size: 0.8rem;
  color: var(--text-muted);
  display: none;
}

@media (min-width: 680px) {
  .tagline { display: inline-block; }
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 16px;
}

.main-nav a {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  padding: 6px 10px;
  border-radius: var(--radius);
  transition: all 0.15s ease;
}

.main-nav a:hover, .main-nav a.active {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
  text-decoration: none;
}

.icon-btn {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  cursor: pointer;
  padding: 7px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

.icon-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent);
  background-color: var(--bg-tertiary);
}

[data-theme="dark"] .sun-icon { display: block; }
[data-theme="dark"] .moon-icon { display: none; }
[data-theme="light"] .sun-icon { display: none; }
[data-theme="light"] .moon-icon { display: block; }

/* Main Content */
.main-content {
  flex: 1;
  padding: 32px 0 64px 0;
}

/* Hero Section */
.hero-section {
  padding: 40px 0 32px 0;
  border-bottom: 1px solid var(--border-color);
  margin-bottom: 36px;
}

.hero-inner {
  text-align: center;
  max-width: 760px;
}

.hero-badge {
  display: inline-block;
  padding: 4px 12px;
  background-color: var(--badge-bg);
  color: var(--badge-text);
  font-size: 0.8rem;
  font-weight: 600;
  border-radius: 999px;
  margin-bottom: 16px;
  border: 1px solid var(--border-color);
}

.hero-title {
  font-size: 2.2rem;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.5px;
  margin-bottom: 14px;
}

.hero-subtitle {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  line-height: 1.6;
}

.hero-actions {
  display: flex;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.btn {
  padding: 10px 20px;
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.15s ease;
  display: inline-block;
}

.btn-primary {
  background-color: var(--accent);
  color: #0b0f19;
  border: 1px solid var(--accent);
}

.btn-primary:hover {
  background-color: var(--accent-hover);
  color: #0b0f19;
  text-decoration: none;
}

.btn-secondary {
  background-color: var(--bg-secondary);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
}

.btn-secondary:hover {
  background-color: var(--bg-tertiary);
  border-color: var(--text-secondary);
  text-decoration: none;
}

/* Featured Topics Grid */
.featured-topics {
  margin-bottom: 48px;
}

.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
}

.topic-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 20px;
  border-radius: var(--radius-lg);
  transition: all 0.2s ease;
  display: block;
}

.topic-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent);
  text-decoration: none;
  box-shadow: var(--shadow);
}

.topic-icon {
  font-size: 1.8rem;
  margin-bottom: 8px;
}

.topic-card h3 {
  font-size: 1.05rem;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.topic-card p {
  font-size: 0.85rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

/* Section Header */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  margin-bottom: 20px;
  border-bottom: 1px solid var(--border-color);
  padding-bottom: 10px;
}

.section-header h2 {
  font-size: 1.4rem;
  font-weight: 700;
}

.view-all {
  font-size: 0.9rem;
  font-weight: 600;
}

/* Post Cards */
.post-cards-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.post-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 22px;
  border-radius: var(--radius-lg);
  transition: border-color 0.15s ease;
}

.post-card:hover {
  border-color: var(--accent);
}

.post-card-meta {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.badge {
  background-color: var(--badge-bg);
  color: var(--badge-text);
  padding: 2px 8px;
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.75rem;
}

.post-card-title {
  font-size: 1.25rem;
  margin-bottom: 8px;
  line-height: 1.35;
}

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

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

.post-card-desc {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.5;
  margin-bottom: 12px;
}

.read-more {
  font-size: 0.88rem;
  font-weight: 600;
}

.pagination-footer {
  text-align: center;
  margin-top: 36px;
}

/* Article Page */
.article-container {
  max-width: 820px;
}

.breadcrumb {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin-bottom: 16px;
}

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

.article-header {
  margin-bottom: 32px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border-color);
}

.article-title {
  font-size: 2.1rem;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -0.5px;
  margin-bottom: 14px;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  font-size: 0.88rem;
  color: var(--text-secondary);
  margin-bottom: 16px;
}

.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tag-pill {
  font-size: 0.8rem;
  padding: 3px 10px;
  background-color: var(--bg-tertiary);
  border: 1px solid var(--border-color);
  border-radius: 999px;
  color: var(--text-secondary);
}

.tag-pill:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
}

/* Article Body Typography */
.article-body {
  font-size: 1.05rem;
  line-height: 1.75;
  color: var(--text-primary);
}

.article-body p {
  margin-bottom: 20px;
}

.article-body h2 {
  font-size: 1.55rem;
  font-weight: 700;
  margin: 36px 0 16px 0;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border-color);
}

.article-body h3 {
  font-size: 1.25rem;
  font-weight: 600;
  margin: 28px 0 12px 0;
}

.article-body ul, .article-body ol {
  margin-bottom: 20px;
  padding-left: 24px;
}

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

.article-body blockquote {
  border-left: 4px solid var(--accent);
  padding: 12px 18px;
  background-color: var(--bg-secondary);
  border-radius: 0 var(--radius) var(--radius) 0;
  margin: 24px 0;
  font-style: italic;
  color: var(--text-secondary);
}

.post-figure {
  margin: 24px 0;
  text-align: center;
}

.post-figure img {
  max-width: 100%;
  height: auto;
  border-radius: var(--radius);
  border: 1px solid var(--border-color);
}

/* Code Blocks */
.code-container {
  background-color: var(--code-bg);
  border: 1px solid var(--code-border);
  border-radius: var(--radius);
  margin: 22px 0;
  overflow: hidden;
}

.code-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 6px 14px;
  background-color: var(--bg-secondary);
  border-bottom: 1px solid var(--border-color);
}

.code-lang {
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.copy-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-family: var(--font-main);
  padding: 3px 8px;
  border-radius: 4px;
  transition: all 0.15s ease;
}

.copy-btn:hover {
  color: var(--text-primary);
  background-color: var(--bg-tertiary);
}

.code-container pre {
  margin: 0;
  padding: 16px;
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 0.9rem;
  line-height: 1.5;
  color: #e6edf3;
}

[data-theme="light"] .code-container pre {
  color: #24292f;
}

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  background-color: var(--bg-tertiary);
  padding: 2px 6px;
  border-radius: 4px;
  border: 1px solid var(--border-color);
}

/* Tables */
.table-container {
  overflow-x: auto;
  margin: 24px 0;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}

th, td {
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  text-align: left;
}

th {
  background-color: var(--bg-secondary);
  font-weight: 600;
}

/* Article Footer */
.article-footer {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.share-box {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.share-btn {
  padding: 6px 14px;
  border: 1px solid var(--border-color);
  background-color: var(--bg-secondary);
  color: var(--text-secondary);
  border-radius: var(--radius);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.share-btn:hover {
  color: var(--accent);
  border-color: var(--accent);
  text-decoration: none;
}

/* Archive List */
.archive-container {
  max-width: 820px;
}

.archive-header {
  margin-bottom: 32px;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border-color);
}

.page-title {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.page-subtitle {
  color: var(--text-secondary);
  font-size: 1rem;
}

.archive-year-group {
  margin-bottom: 36px;
}

.archive-year-title {
  font-size: 1.4rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.archive-year-title .count {
  font-size: 0.9rem;
  color: var(--text-muted);
  font-weight: 400;
}

.archive-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.archive-item {
  display: flex;
  align-items: baseline;
  gap: 16px;
  padding: 6px 0;
  border-bottom: 1px dashed var(--border-color);
}

.archive-date {
  font-size: 0.85rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
  min-width: 100px;
}

.archive-title {
  color: var(--text-primary);
  font-weight: 500;
  flex: 1;
}

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

.tag-badge {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* Tags Cloud */
.tags-cloud {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.tag-card {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  padding: 10px 16px;
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  gap: 10px;
  transition: all 0.15s ease;
}

.tag-card:hover {
  border-color: var(--accent);
  text-decoration: none;
  transform: translateY(-1px);
}

.tag-name {
  color: var(--text-primary);
  font-weight: 500;
}

.tag-count {
  background-color: var(--bg-tertiary);
  color: var(--text-secondary);
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 0.75rem;
  font-weight: 600;
}

/* Footer */
.site-footer {
  background-color: var(--bg-secondary);
  border-top: 1px solid var(--border-color);
  padding: 48px 0 24px 0;
  margin-top: auto;
}

.footer-inner {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 32px;
  margin-bottom: 32px;
}

.footer-logo {
  font-size: 1.15rem;
  margin-bottom: 8px;
}

.footer-bio {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.footer-author {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.footer-links h4, .footer-social h4 {
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  color: var(--text-muted);
  margin-bottom: 12px;
}

.footer-links ul, .footer-social ul {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.9rem;
}

.footer-links a, .footer-social a {
  color: var(--text-secondary);
}

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

.footer-bottom {
  border-top: 1px solid var(--border-color);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  font-size: 0.82rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 8px;
}

/* Modal Search */
.modal-overlay {
  position: fixed;
  inset: 0;
  background-color: rgba(0, 0, 0, 0.75);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding-top: 10vh;
  z-index: 1000;
  backdrop-filter: blur(4px);
}

.modal-overlay.hidden {
  display: none;
}

.modal-dialog {
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  width: 90%;
  max-width: 640px;
  box-shadow: var(--shadow);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  max-height: 75vh;
}

.search-input-wrapper {
  display: flex;
  align-items: center;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
  gap: 12px;
  color: var(--text-muted);
}

.search-input-wrapper input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  font-size: 1.05rem;
  color: var(--text-primary);
  font-family: var(--font-main);
}

.close-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.6rem;
  cursor: pointer;
  line-height: 1;
}

.close-btn:hover {
  color: var(--text-primary);
}

.search-results-list {
  overflow-y: auto;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.search-result-item {
  padding: 12px 14px;
  border-radius: var(--radius);
  background-color: var(--bg-primary);
  border: 1px solid transparent;
  display: block;
}

.search-result-item:hover {
  border-color: var(--accent);
  text-decoration: none;
}

.search-result-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.search-result-meta {
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  gap: 10px;
}