:root {
  --bg-color: #ffffff;
  --text-color: #333333;
  --primary-color: #2563eb;
  --border-color: #e5e7eb;
  --muted-color: #6b7280;
  --code-bg: #f3f4f6;
  --header-bg: #ffffff;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
  --bg-color: #111827;
  --text-color: #f9fafb;
  --primary-color: #3b82f6;
  --border-color: #374151;
  --muted-color: #9ca3af;
  --code-bg: #1f2937;
  --header-bg: #111827;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
}

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  line-height: 1.6;
  color: var(--text-color);
  background-color: var(--bg-color);
  transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 1rem;
}

/* Header */
.header {
  border-bottom: 1px solid var(--border-color);
  background-color: var(--header-bg);
  position: sticky;
  top: 0;
  z-index: 100;
  transition: background-color 0.3s ease;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 0;
  max-width: 720px;
  margin: 0 auto;
  padding: 1rem;
}

.nav-left {
  flex: 1;
}

.nav-center {
  flex: 1;
  display: flex;
  justify-content: center;
  gap: 2rem;
}

.nav-right {
  flex: 1;
  display: flex;
  justify-content: flex-end;
}

.site-title {
  font-size: 1.25rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--text-color);
}

.nav-link {
  text-decoration: none;
  color: var(--muted-color);
  font-weight: 500;
  transition: color 0.2s ease;
}

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

/* Dark Mode Toggle */
.dark-mode-toggle {
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 0.375rem;
  color: var(--text-color);
  transition: background-color 0.2s ease;
}

.dark-mode-toggle:hover {
  background-color: var(--code-bg);
}

/* Main Content */
.main {
  min-height: calc(100vh - 120px);
}

.content {
  max-width: 720px;
  margin: 0 auto;
  padding: 2rem 1rem;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.25;
  margin-bottom: 1rem;
  font-weight: 600;
}

h1 {
  font-size: 2.25rem;
  margin-bottom: 0.5rem;
}

h2 {
  font-size: 1.875rem;
  margin-top: 2rem;
}

h3 {
  font-size: 1.5rem;
  margin-top: 1.5rem;
}

p {
  margin-bottom: 1rem;
}

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

a:hover {
  text-decoration: underline;
}

/* Blog Posts */
.posts-list {
  margin-top: 2rem;
}

.post-preview {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border-color);
}

.post-preview:last-child {
  border-bottom: none;
}

.post-preview h2 {
  margin-top: 0;
  margin-bottom: 0.5rem;
}

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

.post-preview h2 a:hover {
  color: var(--primary-color);
  text-decoration: underline;
}

.post-meta {
  color: var(--muted-color);
  font-size: 0.875rem;
  margin-bottom: 1rem;
}

.reading-time {
  color: var(--muted-color);
}

.post-excerpt {
  color: var(--text-color);
  line-height: 1.6;
  margin-bottom: 0;
}

.post-header {
  margin-bottom: 2rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--border-color);
}

.post-content {
  line-height: 1.7;
  margin-bottom: 2rem;
}

.post-content h2,
.post-content h3 {
  margin-top: 2rem;
}

.post-content p {
  margin-bottom: 1.25rem;
}

.post-content ul,
.post-content ol {
  margin: 1.25rem 0;
  padding-left: 2rem;
}

.post-content li {
  margin-bottom: 0.5rem;
}

.post-content blockquote {
  border-left: 4px solid var(--primary-color);
  padding-left: 1rem;
  margin: 1.5rem 0;
  font-style: italic;
  color: var(--muted-color);
}

.post-content pre {
  background-color: var(--code-bg);
  padding: 1rem;
  border-radius: 0.5rem;
  overflow-x: auto;
  margin: 1.5rem 0;
}

.post-content code {
  background-color: var(--code-bg);
  padding: 0.125rem 0.25rem;
  border-radius: 0.25rem;
  font-size: 0.875rem;
}

.post-content pre code {
  background: none;
  padding: 0;
}

/* Tags */
.post-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

.tag {
  background-color: var(--code-bg);
  color: var(--muted-color);
  padding: 0.25rem 0.5rem;
  border-radius: 0.25rem;
  font-size: 0.875rem;
}

/* Table of Contents */
.toc {
  background-color: var(--code-bg);
  padding: 1rem;
  border-radius: 0.5rem;
  margin: 2rem 0;
}

.toc h3 {
  margin-top: 0;
  margin-bottom: 1rem;
  font-size: 1.125rem;
}

.toc ul {
  list-style: none;
  padding-left: 0;
}

.toc li {
  margin-bottom: 0.5rem;
}

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

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

/* Footer */
.footer {
  border-top: 1px solid var(--border-color);
  text-align: center;
  padding: 2rem 0;
  margin-top: 2rem;
  color: var(--muted-color);
  font-size: 0.875rem;
}

.footer a {
  color: var(--primary-color);
}

/* View All Posts */
.view-all {
  text-align: center;
  margin-top: 2rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border-color);
}

.view-all a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
}

.view-all a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
  .nav {
    flex-direction: column;
    gap: 1rem;
  }
  
  .nav-center {
    order: 3;
    gap: 1rem;
  }
  
  .nav-left,
  .nav-right {
    flex: none;
  }
  
  h1 {
    font-size: 2rem;
  }
  
  h2 {
    font-size: 1.5rem;
  }
  
  .content {
    padding: 1rem;
  }
}