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

:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #e5e7eb;
  --max-width: 680px;
}

body {
  font-family: system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  margin: 0;
  padding: 0;
  line-height: 1.7;
  font-size: 1.0625rem;
}

/* Layout */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

/* Header / Nav */
header {
  border-bottom: 1px solid var(--border);
  margin-bottom: 3rem;
}

header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 1.25rem;
  padding-bottom: 1.25rem;
}

.site-title {
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  letter-spacing: -0.01em;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9375rem;
  margin-left: 1.5rem;
  transition: color 0.15s;
}

nav a:hover { color: var(--text); }

/* Post list */
.post-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

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

.post-list li:first-child { border-top: 1px solid var(--border); }

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

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

.post-title {
  font-size: 1.1875rem;
  font-weight: 600;
  margin: 0 0 0.25rem;
  letter-spacing: -0.01em;
  transition: color 0.15s;
}

.post-meta {
  font-size: 0.875rem;
  color: var(--muted);
  margin: 0 0 0.5rem;
}

.post-description {
  font-size: 0.9375rem;
  color: var(--muted);
  margin: 0;
}

/* Single post */
.post-header {
  margin-bottom: 2.5rem;
}

.post-header h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 0.5rem;
  line-height: 1.25;
}

.post-header .post-meta {
  font-size: 0.9375rem;
}

/* Prose / markdown content */
.prose h1, .prose h2, .prose h3, .prose h4 {
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.3;
  margin-top: 2em;
  margin-bottom: 0.5em;
}

.prose h2 { font-size: 1.375rem; }
.prose h3 { font-size: 1.125rem; }

.prose p { margin: 0 0 1.25em; }

.prose a { color: var(--accent); }

.prose code {
  font-family: 'Menlo', 'Monaco', 'Consolas', monospace;
  font-size: 0.875em;
  background: #f3f4f6;
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.prose pre {
  background: #f3f4f6;
  border-radius: 8px;
  padding: 1.25rem;
  overflow-x: auto;
  margin: 0 0 1.25em;
}

.prose pre code {
  background: none;
  padding: 0;
  font-size: 0.875rem;
}

.prose blockquote {
  border-left: 3px solid var(--border);
  margin: 0 0 1.25em;
  padding: 0.25em 0 0.25em 1.25em;
  color: var(--muted);
}

.prose ul, .prose ol {
  padding-left: 1.5em;
  margin: 0 0 1.25em;
}

.prose li { margin-bottom: 0.3em; }

.prose img {
  max-width: 100%;
  border-radius: 8px;
}

.prose hr {
  border: none;
  border-top: 1px solid var(--border);
  margin: 2em 0;
}

/* Back link */
.back-link {
  display: inline-block;
  font-size: 0.9375rem;
  color: var(--muted);
  text-decoration: none;
  margin-bottom: 2rem;
  transition: color 0.15s;
}

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

/* Page heading */
.page-heading {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 2.5rem;
}

/* Loading / error states */
.loading, .error {
  color: var(--muted);
  font-size: 0.9375rem;
}

/* Footer */
footer {
  border-top: 1px solid var(--border);
  margin-top: 4rem;
  padding: 2rem 0;
  text-align: center;
  font-size: 0.875rem;
  color: var(--muted);
}