:root {
  --color-bg: #fafaf9;
  --color-surface: #ffffff;
  --color-text: #1c1917;
  --color-text-secondary: #57534e;
  --color-text-muted: #a8a29e;
  --color-border: #e7e5e4;
  --color-border-strong: #d6d3d1;
  --color-accent: #44403c;
  --color-accent-hover: #1c1917;
  --color-info-bg: #f5f5f4;
  --color-info-border: #d6d3d1;
  --color-cta-bg: #292524;
  --color-cta-text: #fafaf9;
  --color-cta-hover: #1c1917;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --max-width: 780px;
  --nav-height: 64px;
}

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

body {
  font-family: var(--font);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

/* Navigation */
.blog-nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
}

.blog-nav-inner {
  width: 100%;
  max-width: var(--max-width);
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.blog-nav-brand {
  font-size: 0.875rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text);
  text-decoration: none;
}

.blog-nav-links {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.blog-nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

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

/* Layout */
.blog-content {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: calc(var(--nav-height) + 3rem) 1.5rem 4rem;
}

/* Article Index Grid */
.blog-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  margin-top: 2rem;
}

@media (min-width: 640px) {
  .blog-grid { grid-template-columns: repeat(2, 1fr); }
}

.blog-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s, box-shadow 0.15s;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.blog-card:hover {
  border-color: var(--color-border-strong);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.04);
}

.blog-card-tag {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.blog-card-title {
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.4;
  color: var(--color-text);
}

.blog-card-excerpt {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  line-height: 1.6;
}

.blog-card-meta {
  font-size: 0.75rem;
  color: var(--color-text-muted);
  margin-top: auto;
  padding-top: 0.5rem;
}

/* Page Header */
.blog-page-title {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 0.5rem;
}

.blog-page-subtitle {
  font-size: 1rem;
  color: var(--color-text-secondary);
  margin-bottom: 2rem;
}

/* Article */
.article-header {
  margin-bottom: 2.5rem;
}

.article-tag {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 0.75rem;
}

.article-title {
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin-bottom: 0.75rem;
}

.article-meta {
  font-size: 0.875rem;
  color: var(--color-text-muted);
}

@media (min-width: 640px) {
  .blog-page-title, .article-title { font-size: 2.5rem; }
}

/* Article Body */
.article-body h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 2.5rem;
  margin-bottom: 1rem;
  letter-spacing: -0.01em;
}

.article-body h3 {
  font-size: 1.125rem;
  font-weight: 600;
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.article-body p {
  margin-bottom: 1.25rem;
}

.article-body a {
  color: var(--color-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
  transition: color 0.15s;
}

.article-body a:hover {
  color: var(--color-accent-hover);
}

.article-body ul, .article-body ol {
  margin-bottom: 1.25rem;
  padding-left: 1.5rem;
}

.article-body li {
  margin-bottom: 0.5rem;
}

.article-body strong {
  font-weight: 600;
}

/* Tables */
.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
}

.article-body th, .article-body td {
  text-align: left;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--color-border);
}

.article-body th {
  font-weight: 600;
  font-size: 0.75rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-secondary);
  background: var(--color-info-bg);
}

.article-body td {
  color: var(--color-text);
}

.article-body tr:hover td {
  background: var(--color-info-bg);
}

/* Blockquote */
.article-body blockquote {
  border-left: 3px solid var(--color-border-strong);
  padding: 1rem 1.25rem;
  margin: 1.5rem 0;
  color: var(--color-text-secondary);
  font-style: italic;
}

/* Code */
.article-body code {
  font-family: 'JetBrains Mono', 'Fira Code', monospace;
  font-size: 0.875em;
  background: var(--color-info-bg);
  padding: 0.15em 0.4em;
  border-radius: 4px;
}

.article-body pre {
  background: var(--color-text);
  color: var(--color-bg);
  padding: 1.25rem 1.5rem;
  border-radius: 8px;
  overflow-x: auto;
  margin-bottom: 1.5rem;
  font-size: 0.875rem;
  line-height: 1.6;
}

.article-body pre code {
  background: none;
  padding: 0;
  color: inherit;
}

/* Info Box */
.info-box {
  background: var(--color-info-bg);
  border: 1px solid var(--color-info-border);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin: 1.5rem 0;
}

.info-box-title {
  font-weight: 600;
  font-size: 0.875rem;
  margin-bottom: 0.5rem;
}

.info-box p {
  font-size: 0.875rem;
  margin-bottom: 0;
}

/* CTA Box */
.cta-box {
  background: var(--color-cta-bg);
  color: var(--color-cta-text);
  border-radius: 8px;
  padding: 2rem;
  margin: 2rem 0;
  text-align: center;
}

.cta-box h3 {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
  color: var(--color-cta-text);
}

.cta-box p {
  font-size: 0.9375rem;
  margin-bottom: 1.25rem;
  opacity: 0.85;
}

.cta-button {
  display: inline-block;
  background: var(--color-cta-text);
  color: var(--color-cta-bg);
  font-size: 0.875rem;
  font-weight: 600;
  padding: 0.75rem 2rem;
  border-radius: 6px;
  text-decoration: none;
  transition: opacity 0.15s;
}

.cta-button:hover {
  opacity: 0.9;
}

/* Footer */
.blog-footer {
  border-top: 1px solid var(--color-border);
  padding: 2rem 1.5rem;
  text-align: center;
}

.blog-footer p {
  font-size: 0.75rem;
  font-weight: 500;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
}

.blog-footer a {
  color: var(--color-text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.blog-footer a:hover {
  color: var(--color-text-secondary);
}

/* Responsive */
@media (max-width: 639px) {
  .blog-content { padding-top: calc(var(--nav-height) + 2rem); }
  .article-body h2 { font-size: 1.25rem; }
  .article-body table { font-size: 0.8125rem; }
  .article-body th, .article-body td { padding: 0.5rem 0.75rem; }
  .cta-box { padding: 1.5rem; }
}