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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  line-height: 1.7;
  color: #1a1a2e;
  background: #f8f9fa;
}

/* === SITE NAVIGATION === */
.site-nav {
  background: #fff;
  border-bottom: 1px solid #e9ecef;
  padding: 0 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 1000;
  height: 52px;
}
.site-nav .nav-brand {
  font-size: 1.2rem;
  font-weight: 700;
  color: #e63946;
  text-decoration: none;
  flex-shrink: 0;
}
.site-nav .nav-links {
  display: flex;
  align-items: center;
  gap: 0.3rem;
}
.site-nav .nav-links a {
  color: #495057;
  text-decoration: none;
  padding: 0.4rem 0.8rem;
  border-radius: 6px;
  font-size: 0.95rem;
  transition: background 0.15s, color 0.15s;
}
.site-nav .nav-links a:hover {
  color: #e63946;
  background: #f8f9fa;
}
.hamburger {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.4rem;
  border-radius: 6px;
}
.hamburger:hover { background: #f0f0f0; }
.hamburger svg { display: block; }

/* === PAGE NAV (article TOC) === */
.page-nav {
  background: #f8f9fa;
  border-bottom: 1px solid #e9ecef;
  padding: 0.6rem 1.5rem;
  overflow-x: auto;
  white-space: nowrap;
  -webkit-overflow-scrolling: touch;
}
.page-nav::-webkit-scrollbar { display: none; }
.page-nav a {
  color: #495057;
  text-decoration: none;
  padding: 0.3rem 0.6rem;
  font-size: 0.85rem;
  display: inline-block;
}
.page-nav a:hover { color: #e63946; }
.page-nav .sep { color: #ccc; margin: 0 0.1rem; }

/* === BLOG INDEX NAV (article list sections) === */
.blog-sections {
  max-width: 800px;
  margin: 0 auto;
  padding: 2rem 1.5rem 1rem;
}

/* === MAIN === */
main {
  max-width: 800px;
  margin: 2rem auto;
  padding: 0 1.5rem;
}

.page-header {
  text-align: center;
  margin-bottom: 2.5rem;
}
.page-header h1 { font-size: 2.2rem; margin-bottom: 0.5rem; }
.page-header p { color: #6c757d; font-size: 1.1rem; }

.articles { display: flex; flex-direction: column; gap: 1.5rem; }

.card {
  background: #fff;
  border-radius: 12px;
  padding: 1.5rem 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover {
  box-shadow: 0 4px 16px rgba(0,0,0,0.1);
  transform: translateY(-2px);
}
.card h2 { font-size: 1.4rem; margin-bottom: 0.3rem; }
.card h2 a { color: #1a1a2e; text-decoration: none; }
.card h2 a:hover { color: #e63946; }
.card .meta { color: #6c757d; font-size: 0.9rem; margin-bottom: 0.5rem; }
.card p { color: #495057; }

/* Article page */
.article-page { max-width: 720px; }

article header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid #e9ecef;
}
article header h1 { font-size: 2rem; line-height: 1.3; }
article header .meta { color: #6c757d; margin-top: 0.5rem; }

.article-body h2 {
  font-size: 1.5rem;
  margin: 2rem 0 0.8rem;
  color: #1a1a2e;
}
.article-body h3 {
  font-size: 1.25rem;
  margin: 1.5rem 0 0.6rem;
  color: #2d2d44;
}
.article-body h4 {
  font-size: 1.1rem;
  margin: 1.2rem 0 0.5rem;
}
.article-body p { margin-bottom: 1rem; color: #333; }
.article-body ul, .article-body ol {
  margin: 0.8rem 0 1rem 1.5rem;
  color: #333;
}
.article-body li { margin-bottom: 0.4rem; }
.article-body strong { color: #1a1a2e; }
.article-body code {
  background: #f1f3f5;
  padding: 0.15rem 0.4rem;
  border-radius: 4px;
  font-size: 0.9em;
  color: #d6336c;
}
.article-body pre {
  background: #212529;
  color: #f8f9fa;
  padding: 1.2rem;
  border-radius: 8px;
  overflow-x: auto;
  margin: 1rem 0;
}
.article-body pre code {
  background: none;
  color: inherit;
  padding: 0;
}
.article-body blockquote {
  border-left: 4px solid #e63946;
  padding: 0.8rem 1.2rem;
  margin: 1rem 0;
  background: #fff5f5;
  border-radius: 0 8px 8px 0;
  color: #495057;
}
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: 1rem 0;
  font-size: 0.92rem;
}
.article-body td, .article-body th {
  border: 1px solid #dee2e6;
  padding: 0.5rem 0.7rem;
  text-align: left;
}
.article-body th { background: #f8f9fa; font-weight: 600; }
.article-body a { color: #e63946; text-decoration: none; }
.article-body a:hover { text-decoration: underline; }
.article-body img { max-width: 100%; border-radius: 8px; margin: 1rem 0; }

.related-links {
  background: #fff;
  border-radius: 12px;
  padding: 1.5rem 2rem;
  margin-top: 2rem;
  box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}
.related-links h3 { margin-bottom: 0.8rem; color: #1a1a2e; }
.related-links ul { list-style: none; padding: 0; }
.related-links li { margin-bottom: 0.4rem; }
.related-links a { color: #e63946; text-decoration: none; }
.related-links a:hover { text-decoration: underline; }

footer {
  text-align: center;
  padding: 2rem;
  color: #6c757d;
  font-size: 0.9rem;
  border-top: 1px solid #e9ecef;
  margin-top: 3rem;
}
footer a { color: #e63946; text-decoration: none; }
footer a:hover { text-decoration: underline; }

/* === MOBILE (hamburger menu) === */
@media (max-width: 768px) {
  .site-nav { padding: 0 1rem; }
  .hamburger { display: block; }
  .site-nav .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 52px;
    left: 0;
    right: 0;
    background: #fff;
    border-bottom: 1px solid #e9ecef;
    box-shadow: 0 4px 12px rgba(0,0,0,0.08);
    padding: 0.5rem 0;
    gap: 0;
  }
  .site-nav .nav-links.open { display: flex; }
  .site-nav .nav-links a {
    padding: 0.8rem 1rem;
    border-radius: 0;
    font-size: 1rem;
    width: 100%;
    border-bottom: 1px solid #f0f0f0;
  }
  .site-nav .nav-links a:last-child { border-bottom: none; }
  main { padding: 0 1rem; }
  .card { padding: 1.2rem; }
  article header h1 { font-size: 1.5rem; }
  .page-nav { padding: 0.5rem 1rem; }
  .page-nav a { font-size: 0.8rem; padding: 0.25rem 0.4rem; }
  .blog-sections { padding: 1.5rem 1rem 0.5rem; }
}