:root {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --primary-light: #eef2ff;
  --text: #111827;
  --text-secondary: #6b7280;
  --bg: #ffffff;
  --bg-secondary: #f9fafb;
  --border: #e5e7eb;
  --radius: 12px;
  --prose: 42rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --primary: #818cf8;
    --primary-hover: #6366f1;
    --primary-light: #1e1b4b;
    --text: #f9fafb;
    --text-secondary: #9ca3af;
    --bg: #111827;
    --bg-secondary: #1f2937;
    --border: #374151;
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 17px;
}

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

.blog-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: 68rem;
  margin: 0 auto;
  padding: 1.1rem 1.5rem;
  border-bottom: 1px solid var(--border);
}

.blog-nav .logo {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
}

.blog-nav .logo:hover { text-decoration: none; color: var(--primary); }
.blog-nav .logo img { width: 36px; height: 36px; }

.nav-links { display: flex; gap: 1.5rem; align-items: center; }
.nav-links a { color: var(--text-secondary); font-size: 0.95rem; font-weight: 500; text-decoration: none; }
.nav-links a:hover { color: var(--primary); }

.page-main {
  max-width: 68rem;
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

/* Index */
.blog-hero h1 {
  font-size: clamp(1.75rem, 4vw, 2.25rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.blog-hero p {
  color: var(--text-secondary);
  max-width: 40rem;
  margin-bottom: 2rem;
}

.post-list { list-style: none; }
.post-list li {
  border-bottom: 1px solid var(--border);
  padding: 1.25rem 0;
}
.post-list li:first-child { border-top: 1px solid var(--border); }

.post-list a.title {
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  display: block;
  margin-bottom: 0.35rem;
}
.post-list a.title:hover { color: var(--primary); }

.post-list .excerpt {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.5;
}

/* Article */
.blog-article { max-width: var(--prose); margin: 0 auto; }

.breadcrumb {
  font-size: 0.9rem;
  color: var(--text-secondary);
  margin-bottom: 1rem;
}

.blog-article header { margin-bottom: 2rem; }

.blog-article h1 {
  font-size: clamp(1.6rem, 4vw, 2rem);
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 0.75rem;
}

.meta {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.content h2 {
  font-size: 1.2rem;
  font-weight: 700;
  margin: 2rem 0 0.75rem;
  letter-spacing: -0.01em;
}

.content h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 1.5rem 0 0.5rem;
}

.content p { margin-bottom: 1rem; }
.content ul, .content ol { margin: 0 0 1rem 1.25rem; }
.content li { margin-bottom: 0.4rem; }

.content table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  margin: 1rem 0 1.5rem;
}

.content th, .content td {
  border: 1px solid var(--border);
  padding: 0.5rem 0.65rem;
  text-align: left;
}
.content th { background: var(--bg-secondary); font-weight: 600; }

.callout {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
  font-size: 0.95rem;
  color: var(--text-secondary);
}
.callout strong { color: var(--text); }

.article-footer {
  margin-top: 2.5rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  font-size: 0.95rem;
  color: var(--text-secondary);
}

.site-footer {
  text-align: center;
  padding: 2rem 1.5rem 2.5rem;
  color: var(--text-secondary);
  font-size: 0.9rem;
  border-top: 1px solid var(--border);
}

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

@media (max-width: 768px) {
  .nav-links { display: none; }
}