/* ===== ClaudeSkills Blog - Professional Design System ===== */

:root {
  --color-bg: #fafaf9;
  --color-surface: #ffffff;
  --color-surface-alt: #f5f5f4;
  --color-text: #1c1917;
  --color-text-muted: #57534e;
  --color-text-subtle: #78716c;
  --color-border: #e7e5e4;
  --color-border-strong: #d6d3d1;
  --color-primary: #b45309;
  --color-primary-dark: #92400e;
  --color-primary-light: #fef3c7;
  --color-accent: #0f766e;
  --color-code-bg: #292524;
  --color-code-text: #fafaf9;
  --color-success: #059669;
  --color-warning: #d97706;

  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-heading: 'Fraunces', Georgia, 'Times New Roman', serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;

  --container-max: 1200px;
  --container-narrow: 760px;
  --radius: 8px;
  --radius-lg: 14px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.06), 0 2px 4px -1px rgba(0,0,0,0.04);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -2px rgba(0,0,0,0.04);

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;
  --space-9: 96px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--font-body);
  font-size: 17px;
  line-height: 1.7;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.container-narrow {
  max-width: var(--container-narrow);
  margin: 0 auto;
  padding: 0 var(--space-5);
}

.skip-link {
  position: absolute; top: -40px; left: 0;
  background: var(--color-primary); color: #fff;
  padding: var(--space-3) var(--space-4);
  z-index: 100; text-decoration: none;
}
.skip-link:focus { top: 0; }

/* ===== Header ===== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(8px);
  background: rgba(255,255,255,0.92);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-4);
  padding-bottom: var(--space-4);
}

.logo {
  display: flex; align-items: center; gap: var(--space-3);
  text-decoration: none; color: var(--color-text);
  font-family: var(--font-heading);
  font-weight: 700; font-size: 20px;
  letter-spacing: -0.02em;
}

.logo svg {
  width: 32px; height: 32px;
}

nav ul.nav-links {
  list-style: none; margin: 0; padding: 0;
  display: flex; gap: var(--space-6);
  align-items: center;
}

nav ul.nav-links a {
  color: var(--color-text-muted);
  text-decoration: none;
  font-weight: 500;
  font-size: 15px;
  transition: color 0.15s;
}

nav ul.nav-links a:hover,
nav ul.nav-links a.active {
  color: var(--color-primary);
}

.lang-switch {
  display: inline-flex; align-items: center; gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius);
  color: var(--color-text-muted);
  text-decoration: none;
  font-size: 13px;
  font-weight: 600;
}

.lang-switch:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

.nav-toggle {
  display: none;
  background: none; border: none;
  cursor: pointer; color: var(--color-text);
}

/* ===== Hero ===== */
.hero {
  padding: var(--space-9) 0 var(--space-8);
  text-align: center;
  background: linear-gradient(180deg, var(--color-surface-alt), var(--color-bg));
  border-bottom: 1px solid var(--color-border);
}

.hero h1 {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: clamp(36px, 5vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin: 0 0 var(--space-5);
  color: var(--color-text);
}

.hero .subtitle {
  font-size: 20px;
  line-height: 1.6;
  color: var(--color-text-muted);
  max-width: 720px;
  margin: 0 auto var(--space-6);
}

.hero .tag {
  display: inline-block;
  padding: var(--space-2) var(--space-4);
  background: var(--color-primary-light);
  color: var(--color-primary-dark);
  border-radius: 999px;
  font-size: 13px;
  font-weight: 600;
  margin-bottom: var(--space-5);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* ===== Article Grid ===== */
.section {
  padding: var(--space-8) 0;
}

.section-title {
  font-family: var(--font-heading);
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-6);
  color: var(--color-text);
}

.section-subtitle {
  font-size: 17px;
  color: var(--color-text-muted);
  margin: -16px 0 var(--space-6);
}

.article-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: var(--space-6);
}

.article-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  transition: transform 0.2s, box-shadow 0.2s, border-color 0.2s;
  display: flex; flex-direction: column;
}

.article-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-lg);
  border-color: var(--color-border-strong);
}

.article-card a.card-link {
  color: inherit; text-decoration: none;
  padding: var(--space-6); display: flex; flex-direction: column; height: 100%;
}

.article-card .category {
  display: inline-block;
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  margin-bottom: var(--space-3);
}

.article-card h3 {
  font-family: var(--font-heading);
  font-size: 22px;
  font-weight: 600;
  line-height: 1.3;
  letter-spacing: -0.02em;
  margin: 0 0 var(--space-3);
  color: var(--color-text);
}

.article-card p {
  color: var(--color-text-muted);
  font-size: 15px;
  line-height: 1.6;
  margin: 0 0 var(--space-4);
  flex-grow: 1;
}

.article-card .meta {
  display: flex; align-items: center; gap: var(--space-3);
  font-size: 13px;
  color: var(--color-text-subtle);
  padding-top: var(--space-4);
  border-top: 1px solid var(--color-border);
}

.article-card .meta .read-more {
  color: var(--color-primary);
  font-weight: 600;
  margin-left: auto;
}

/* Featured card - larger */
.featured-card {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 320px;
}

.featured-card .featured-visual {
  background: linear-gradient(135deg, #92400e, #b45309, #d97706);
  padding: var(--space-8);
  display: flex; align-items: center; justify-content: center;
  color: #fff;
  font-family: var(--font-heading);
  font-size: 42px;
  font-weight: 700;
  text-align: center;
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.featured-card .featured-body {
  padding: var(--space-7);
  display: flex; flex-direction: column; justify-content: center;
}

.featured-card h2 {
  font-family: var(--font-heading);
  font-size: 30px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: var(--space-3) 0;
}

.featured-card p {
  color: var(--color-text-muted);
  font-size: 16px;
  line-height: 1.7;
  margin: 0 0 var(--space-5);
}

.featured-card a.btn-primary {
  align-self: flex-start;
}

/* ===== Article Page ===== */
.article-page {
  padding: var(--space-8) 0 var(--space-9);
}

.article-header {
  max-width: var(--container-narrow);
  margin: 0 auto var(--space-7);
  text-align: center;
}

.article-header .category {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  margin-bottom: var(--space-4);
}

.article-header h1 {
  font-family: var(--font-heading);
  font-size: clamp(32px, 4.5vw, 46px);
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin: 0 0 var(--space-5);
}

.article-header .lead {
  font-size: 20px;
  line-height: 1.6;
  color: var(--color-text-muted);
  margin: 0 0 var(--space-6);
}

.article-header .meta {
  display: flex; align-items: center; justify-content: center;
  gap: var(--space-4);
  font-size: 14px;
  color: var(--color-text-subtle);
}

.article-header .meta .author {
  color: var(--color-text);
  font-weight: 600;
}

.article-body {
  max-width: var(--container-narrow);
  margin: 0 auto;
  font-size: 18px;
  line-height: 1.8;
}

.article-body h2 {
  font-family: var(--font-heading);
  font-size: 30px;
  font-weight: 700;
  line-height: 1.2;
  letter-spacing: -0.02em;
  margin: var(--space-8) 0 var(--space-4);
  color: var(--color-text);
}

.article-body h3 {
  font-family: var(--font-heading);
  font-size: 24px;
  font-weight: 600;
  line-height: 1.3;
  margin: var(--space-6) 0 var(--space-3);
}

.article-body p {
  margin: 0 0 var(--space-5);
  color: var(--color-text);
}

.article-body a {
  color: var(--color-primary);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1.5px;
}

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

.article-body ul, .article-body ol {
  margin: 0 0 var(--space-5);
  padding-left: var(--space-6);
}

.article-body li {
  margin-bottom: var(--space-2);
}

.article-body strong { color: var(--color-text); font-weight: 700; }

.article-body blockquote {
  margin: var(--space-6) 0;
  padding: var(--space-5) var(--space-6);
  background: var(--color-surface-alt);
  border-left: 4px solid var(--color-primary);
  border-radius: var(--radius);
  font-style: italic;
  color: var(--color-text-muted);
}

.article-body code {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background: var(--color-surface-alt);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--color-primary-dark);
}

.article-body pre {
  background: var(--color-code-bg);
  color: var(--color-code-text);
  padding: var(--space-5);
  border-radius: var(--radius);
  overflow-x: auto;
  margin: var(--space-5) 0;
  font-size: 14px;
  line-height: 1.6;
}

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

.article-body table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-5) 0;
  font-size: 15px;
}

.article-body table th,
.article-body table td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--color-border);
}

.article-body table th {
  background: var(--color-surface-alt);
  font-weight: 700;
  color: var(--color-text);
}

.callout {
  padding: var(--space-5);
  border-radius: var(--radius);
  margin: var(--space-6) 0;
  border-left: 4px solid;
}

.callout-info {
  background: #eff6ff;
  border-color: #3b82f6;
}

.callout-tip {
  background: #f0fdf4;
  border-color: #10b981;
}

.callout-warning {
  background: #fffbeb;
  border-color: #f59e0b;
}

.callout p:last-child { margin-bottom: 0; }
.callout strong { display: block; margin-bottom: var(--space-2); }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; gap: var(--space-2);
  padding: var(--space-3) var(--space-5);
  border-radius: var(--radius);
  font-weight: 600;
  font-size: 15px;
  text-decoration: none;
  transition: all 0.15s;
  border: 2px solid transparent;
  cursor: pointer;
}

.btn-primary {
  background: var(--color-text);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border-color: var(--color-border-strong);
}

.btn-outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ===== Related articles ===== */
.related-section {
  margin-top: var(--space-9);
  padding-top: var(--space-7);
  border-top: 1px solid var(--color-border);
}

.related-section h2 {
  font-family: var(--font-heading);
  font-size: 26px;
  font-weight: 700;
  margin: 0 0 var(--space-5);
}

.related-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: var(--space-5);
}

/* ===== Ad slots ===== */
.ad-slot {
  background: var(--color-surface-alt);
  border: 1px dashed var(--color-border-strong);
  border-radius: var(--radius);
  padding: var(--space-6);
  text-align: center;
  color: var(--color-text-subtle);
  font-size: 13px;
  font-weight: 600;
  margin: var(--space-6) 0;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  min-height: 90px;
  display: flex; align-items: center; justify-content: center;
}

.ad-leaderboard { min-height: 90px; }
.ad-rectangle { min-height: 250px; max-width: 300px; margin-left: auto; margin-right: auto; }
.ad-in-article { max-width: 720px; margin-left: auto; margin-right: auto; min-height: 200px; }

/* ===== Footer ===== */
.site-footer {
  background: var(--color-text);
  color: #d6d3d1;
  padding: var(--space-8) 0 var(--space-5);
  margin-top: var(--space-9);
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: var(--space-6);
  margin-bottom: var(--space-7);
}

.footer-brand {
  color: #fff;
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: 20px;
  margin-bottom: var(--space-3);
}

.footer-tagline {
  color: #a8a29e;
  font-size: 14px;
  line-height: 1.6;
  margin: 0;
  max-width: 320px;
}

.footer-heading {
  color: #fafaf9;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin: 0 0 var(--space-4);
}

.footer-links {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-links li { margin-bottom: var(--space-2); }

.footer-links a {
  color: #a8a29e;
  text-decoration: none;
  font-size: 14px;
  transition: color 0.15s;
}

.footer-links a:hover { color: #fff; }

.footer-bottom {
  border-top: 1px solid #44403c;
  padding-top: var(--space-5);
  display: flex; justify-content: space-between; align-items: center;
  font-size: 13px;
  color: #78716c;
}

.footer-bottom p { margin: 0; }

.disclaimer {
  font-size: 12px;
  color: #78716c;
  margin-top: var(--space-4);
  line-height: 1.5;
}

/* ===== Legal / static pages ===== */
.legal-page {
  padding: var(--space-8) 0 var(--space-9);
}

.legal-page h1 {
  font-family: var(--font-heading);
  font-size: 42px;
  font-weight: 700;
  margin: 0 0 var(--space-3);
  letter-spacing: -0.02em;
}

.legal-page h2 {
  font-family: var(--font-heading);
  font-size: 26px;
  font-weight: 700;
  margin: var(--space-7) 0 var(--space-4);
  letter-spacing: -0.02em;
}

.legal-page .updated {
  color: var(--color-text-subtle);
  font-size: 14px;
  margin-bottom: var(--space-6);
}

.legal-page p, .legal-page li {
  color: var(--color-text);
  line-height: 1.75;
}

/* ===== Responsive ===== */
@media (max-width: 900px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
  .featured-card { grid-template-columns: 1fr; }
  .featured-card .featured-visual { padding: var(--space-6); font-size: 30px; min-height: 180px; }
}

@media (max-width: 720px) {
  body { font-size: 16px; }
  .article-body { font-size: 17px; }
  .article-body h2 { font-size: 26px; }
  .article-body h3 { font-size: 21px; }
  .hero { padding: var(--space-7) 0 var(--space-6); }
  .hero .subtitle { font-size: 17px; }
  .section { padding: var(--space-7) 0; }
  .section-title { font-size: 26px; }
  .footer-grid { grid-template-columns: 1fr; text-align: left; }
  .footer-bottom { flex-direction: column; gap: var(--space-3); }

  nav ul.nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0; right: 0;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
    border-bottom: 1px solid var(--color-border);
    padding: var(--space-4);
    flex-direction: column;
    gap: var(--space-3);
  }

  nav ul.nav-links.open { display: flex; }

  .nav-toggle { display: block; }
  .site-header .container { position: relative; }
}