/* ===== CSS Custom Properties ===== */
:root {
  --color-primary: #0e6e4e;
  --color-primary-dark: #0a5a3e;
  --color-primary-light: #12956a;
  --color-secondary: #1a6fa0;
  --color-secondary-dark: #145a82;
  --color-accent: #d4a017;
  --color-accent-light: #f0c040;
  --color-bg: #ffffff;
  --color-bg-alt: #f5f7f6;
  --color-bg-card: #ffffff;
  --color-text: #1a2e1a;
  --color-text-secondary: #4a5c4a;
  --color-text-muted: #6b7d6b;
  --color-border: #d0dcd0;
  --color-border-light: #e8ede8;
  --color-success: #22863a;
  --color-warning: #d4a017;
  --color-error: #cb2431;
  --color-footer-bg: #0f2318;
  --color-footer-text: #c8d8c8;
  --color-footer-heading: #ffffff;
  --color-footer-link: #7ec89e;
  --font-sans: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', monospace;
  --font-size-base: 16px;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  --font-size-3xl: 2.5rem;
  --line-height: 1.7;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,0.08), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
  --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
  --max-width: 1200px;
  --content-width: 800px;
  --transition: 0.2s ease;
}

/* Dark mode */
[data-theme="dark"],
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --color-bg: #0d1a12;
    --color-bg-alt: #142019;
    --color-bg-card: #1a2d20;
    --color-text: #e0ece0;
    --color-text-secondary: #a8c0a8;
    --color-text-muted: #7d9a7d;
    --color-border: #2d4a35;
    --color-border-light: #243828;
    --color-primary: #2ec47a;
    --color-primary-dark: #25a066;
    --color-primary-light: #3dd68a;
    --color-secondary: #4da8d4;
    --color-shadow: rgba(0,0,0,0.3);
    --shadow: 0 1px 3px rgba(0,0,0,0.2);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.25);
  }
}

/* ===== Reset & Base ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html {
  font-size: var(--font-size-base);
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  line-height: var(--line-height);
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

main { flex: 1; }

img { max-width: 100%; height: auto; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-primary-dark); text-decoration: underline; }

h1, h2, h3, h4 {
  color: var(--color-text);
  line-height: 1.3;
  margin-bottom: var(--spacing-sm);
  font-weight: 700;
}
h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
p { margin-bottom: var(--spacing-sm); }

/* ===== Container ===== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 var(--spacing-md); }
.content-container { max-width: var(--content-width); margin: 0 auto; padding: 0 var(--spacing-md); }

/* ===== Skip link ===== */
.skip-link {
  position: absolute; top: -100%; left: 50%; transform: translateX(-50%);
  background: var(--color-primary); color: #fff; padding: var(--spacing-xs) var(--spacing-sm);
  border-radius: var(--radius); z-index: 9999; font-weight: 600;
}
.skip-link:focus { top: var(--spacing-xs); }

/* ===== Header & Nav ===== */
.site-header {
  background: var(--color-bg);
  border-bottom: 2px solid var(--color-primary);
  position: sticky; top: 0; z-index: 100;
  box-shadow: var(--shadow);
}
.site-header .container {
  display: flex; align-items: center; justify-content: space-between;
  padding-top: var(--spacing-sm); padding-bottom: var(--spacing-sm);
}
.site-logo {
  font-size: 1.4rem; font-weight: 800; color: var(--color-primary);
  display: flex; align-items: center; gap: var(--spacing-xs);
}
.site-logo:hover { text-decoration: none; color: var(--color-primary-dark); }
.site-logo .logo-icon { font-size: 1.6rem; }

.nav-toggle {
  display: none; background: none; border: none; cursor: pointer;
  width: 44px; height: 44px; align-items: center; justify-content: center;
  color: var(--color-text); font-size: 1.5rem;
}

.main-nav ul { display: flex; list-style: none; gap: var(--spacing-xs); }
.main-nav a {
  display: block; padding: var(--spacing-xs) var(--spacing-sm);
  color: var(--color-text-secondary); font-weight: 500; border-radius: var(--radius);
  min-height: 44px; display: flex; align-items: center;
  transition: all var(--transition);
}
.main-nav a:hover, .main-nav a.active {
  color: var(--color-primary); background: var(--color-bg-alt); text-decoration: none;
}

.theme-toggle {
  background: none; border: 1px solid var(--color-border); cursor: pointer;
  width: 44px; height: 44px; border-radius: var(--radius);
  display: flex; align-items: center; justify-content: center;
  color: var(--color-text-secondary); font-size: 1.2rem;
  transition: all var(--transition);
}
.theme-toggle:hover { border-color: var(--color-primary); color: var(--color-primary); }

/* ===== Hero ===== */
.hero {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-secondary) 100%);
  color: #fff; padding: var(--spacing-2xl) 0; text-align: center;
}
.hero h1 { color: #fff; font-size: var(--font-size-3xl); margin-bottom: var(--spacing-sm); }
.hero p { font-size: var(--font-size-lg); opacity: 0.95; max-width: 700px; margin: 0 auto var(--spacing-lg); }

.hero-stats {
  display: flex; justify-content: center; gap: var(--spacing-xl);
  flex-wrap: wrap; margin-top: var(--spacing-lg);
}
.hero-stat { text-align: center; }
.hero-stat .stat-number { font-size: var(--font-size-2xl); font-weight: 800; display: block; }
.hero-stat .stat-label { font-size: var(--font-size-sm); opacity: 0.85; }

/* ===== Buttons ===== */
.btn {
  display: inline-flex; align-items: center; gap: var(--spacing-xs);
  padding: 0.75rem 1.5rem; border-radius: var(--radius); font-weight: 600;
  font-size: 1rem; border: none; cursor: pointer;
  min-height: 44px; min-width: 44px;
  transition: all var(--transition); text-decoration: none;
}
.btn-primary {
  background: var(--color-primary); color: #fff;
}
.btn-primary:hover { background: var(--color-primary-dark); color: #fff; text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-md); }
.btn-secondary {
  background: transparent; color: #fff; border: 2px solid rgba(255,255,255,0.6);
}
.btn-secondary:hover { border-color: #fff; color: #fff; text-decoration: none; background: rgba(255,255,255,0.1); }
.btn-accent {
  background: var(--color-accent); color: #1a1a1a;
}
.btn-accent:hover { background: var(--color-accent-light); text-decoration: none; transform: translateY(-1px); }

/* ===== Breadcrumbs ===== */
.breadcrumbs {
  padding: var(--spacing-sm) 0; font-size: var(--font-size-sm); color: var(--color-text-muted);
}
.breadcrumbs a { color: var(--color-text-secondary); }
.breadcrumbs a:hover { color: var(--color-primary); }
.breadcrumbs .separator { margin: 0 0.4rem; }

/* ===== Cards Grid ===== */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-md);
}

.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  transition: all var(--transition);
  display: flex; flex-direction: column;
}
.card:hover {
  box-shadow: var(--shadow-md);
  border-color: var(--color-primary);
  transform: translateY(-2px);
}
.card .card-icon { font-size: 2rem; margin-bottom: var(--spacing-sm); }
.card h3 { font-size: var(--font-size-lg); }
.card h3 a { color: var(--color-text); }
.card h3 a:hover { color: var(--color-primary); text-decoration: none; }
.card p { color: var(--color-text-secondary); font-size: var(--font-size-sm); flex: 1; }
.card .card-meta {
  display: flex; gap: var(--spacing-sm); font-size: var(--font-size-sm);
  color: var(--color-text-muted); margin-top: var(--spacing-sm);
  padding-top: var(--spacing-sm); border-top: 1px solid var(--color-border-light);
}
.card .card-tag {
  display: inline-block; background: var(--color-bg-alt); color: var(--color-primary);
  padding: 0.2rem 0.6rem; border-radius: 20px; font-size: 0.75rem; font-weight: 600;
}

/* ===== Section headings ===== */
.section { padding: var(--spacing-2xl) 0; }
.section-alt { background: var(--color-bg-alt); }
.section-title {
  font-size: var(--font-size-2xl); text-align: center; margin-bottom: var(--spacing-xs);
}
.section-subtitle {
  text-align: center; color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xl); max-width: 600px; margin-left: auto; margin-right: auto;
}

/* ===== Blog list ===== */
.post-list { display: flex; flex-direction: column; gap: var(--spacing-md); }
.post-item {
  background: var(--color-bg-card); border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg); padding: var(--spacing-md);
  transition: all var(--transition);
}
.post-item:hover { box-shadow: var(--shadow-md); border-color: var(--color-primary); }
.post-item h2 { font-size: var(--font-size-xl); margin-bottom: var(--spacing-xs); }
.post-item h2 a { color: var(--color-text); }
.post-item h2 a:hover { color: var(--color-primary); text-decoration: none; }
.post-meta {
  display: flex; flex-wrap: wrap; gap: var(--spacing-sm);
  font-size: var(--font-size-sm); color: var(--color-text-muted); margin-bottom: var(--spacing-sm);
}

/* ===== Single article ===== */
.article-header { margin-bottom: var(--spacing-xl); }
.article-header h1 { font-size: var(--font-size-2xl); }
.article-content { font-size: var(--font-size-lg); }
.article-content h2 { margin-top: var(--spacing-xl); font-size: var(--font-size-xl); }
.article-content h3 { margin-top: var(--spacing-lg); }
.article-content ul, .article-content ol {
  margin-bottom: var(--spacing-sm); padding-left: var(--spacing-lg);
}
.article-content li { margin-bottom: var(--spacing-xs); }
.article-content blockquote {
  border-left: 4px solid var(--color-primary); padding: var(--spacing-sm) var(--spacing-md);
  background: var(--color-bg-alt); margin: var(--spacing-md) 0; border-radius: 0 var(--radius) var(--radius) 0;
}
.article-content table {
  width: 100%; border-collapse: collapse; margin: var(--spacing-md) 0;
}
.article-content th, .article-content td {
  padding: var(--spacing-xs) var(--spacing-sm); border: 1px solid var(--color-border);
  text-align: left;
}
.article-content th { background: var(--color-bg-alt); font-weight: 600; }

/* ===== TOC ===== */
.toc {
  background: var(--color-bg-alt); border: 1px solid var(--color-border-light);
  border-radius: var(--radius-lg); padding: var(--spacing-md); margin-bottom: var(--spacing-lg);
}
.toc-title { font-size: 1rem; font-weight: 700; margin-bottom: var(--spacing-sm); }
.toc ul { list-style: none; padding-left: var(--spacing-sm); }
.toc li { margin-bottom: 0.3rem; }
.toc a { color: var(--color-text-secondary); font-size: var(--font-size-sm); }
.toc a:hover { color: var(--color-primary); }

/* ===== Glossary ===== */
.glossary-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--spacing-sm);
}
.glossary-item {
  background: var(--color-bg-card); border: 1px solid var(--color-border-light);
  border-radius: var(--radius); padding: var(--spacing-sm) var(--spacing-md);
  transition: all var(--transition);
}
.glossary-item:hover { border-color: var(--color-primary); box-shadow: var(--shadow); }
.glossary-item a { display: flex; align-items: center; gap: var(--spacing-xs); color: var(--color-text); font-weight: 500; min-height: 44px; }
.glossary-item a:hover { color: var(--color-primary); text-decoration: none; }
.glossary-item .glossary-arrow { color: var(--color-text-muted); transition: transform var(--transition); }
.glossary-item:hover .glossary-arrow { transform: translateX(4px); color: var(--color-primary); }

/* ===== FAQ ===== */
.faq-list { max-width: var(--content-width); margin: 0 auto; }
.faq-item {
  border: 1px solid var(--color-border-light); border-radius: var(--radius-lg);
  margin-bottom: var(--spacing-sm); overflow: hidden;
}
.faq-question {
  width: 100%; background: var(--color-bg-card); border: none; cursor: pointer;
  padding: var(--spacing-md); text-align: left; font-size: 1rem; font-weight: 600;
  color: var(--color-text); display: flex; justify-content: space-between; align-items: center;
  min-height: 44px; transition: background var(--transition);
}
.faq-question:hover { background: var(--color-bg-alt); }
.faq-question .faq-toggle { font-size: 1.2rem; color: var(--color-primary); transition: transform var(--transition); }
.faq-item.active .faq-toggle { transform: rotate(45deg); }
.faq-answer {
  padding: 0 var(--spacing-md) var(--spacing-md);
  color: var(--color-text-secondary); display: none;
}
.faq-item.active .faq-answer { display: block; }

/* ===== Footer ===== */
.site-footer {
  background: var(--color-footer-bg); color: var(--color-footer-text);
  padding: var(--spacing-2xl) 0 var(--spacing-lg);
}
.footer-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--spacing-xl); margin-bottom: var(--spacing-xl);
}
.footer-col h3 { color: var(--color-footer-heading); font-size: 1rem; margin-bottom: var(--spacing-sm); }
.footer-col p { font-size: var(--font-size-sm); line-height: 1.6; }
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: var(--spacing-xs); }
.footer-col a {
  color: var(--color-footer-link); font-size: var(--font-size-sm);
  transition: color var(--transition); display: inline-flex; align-items: center; gap: 0.3rem;
  min-height: 44px;
}
.footer-col a:hover { color: #fff; text-decoration: none; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--spacing-md); text-align: center;
  font-size: var(--font-size-sm); color: var(--color-text-muted);
}

/* Portfolio footer section */
.portfolio-sites {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: var(--spacing-md); margin-top: var(--spacing-md);
}
.portfolio-sites h4 { color: var(--color-footer-heading); font-size: var(--font-size-sm); margin-bottom: var(--spacing-xs); }
.portfolio-sites a {
  color: var(--color-footer-link); font-size: var(--font-size-sm);
  margin-right: var(--spacing-sm);
}
.portfolio-sites a:hover { color: #fff; }

/* ===== Pagination ===== */
.pagination { display: flex; justify-content: center; gap: var(--spacing-xs); margin-top: var(--spacing-xl); flex-wrap: wrap; }
.pagination a, .pagination .current {
  display: inline-flex; align-items: center; justify-content: center;
  min-width: 44px; min-height: 44px; padding: var(--spacing-xs);
  border: 1px solid var(--color-border); border-radius: var(--radius);
  font-weight: 500; transition: all var(--transition);
}
.pagination a { color: var(--color-text-secondary); }
.pagination a:hover { border-color: var(--color-primary); color: var(--color-primary); text-decoration: none; }
.pagination .current { background: var(--color-primary); color: #fff; border-color: var(--color-primary); }

/* ===== Reading time & meta ===== */
.reading-time { display: inline-flex; align-items: center; gap: 0.3rem; }

/* ===== Search page ===== */
.search-input {
  width: 100%; padding: var(--spacing-sm) var(--spacing-md);
  border: 2px solid var(--color-border); border-radius: var(--radius-lg);
  font-size: var(--font-size-lg); background: var(--color-bg);
  color: var(--color-text); transition: border-color var(--transition);
  min-height: 44px;
}
.search-input:focus { border-color: var(--color-primary); outline: none; }
#search-results { margin-top: var(--spacing-lg); }

/* ===== Responsive ===== */
@media (max-width: 768px) {
  :root {
    --font-size-3xl: 1.8rem;
    --font-size-2xl: 1.5rem;
    --font-size-xl: 1.25rem;
  }

  .nav-toggle { display: flex; }

  .main-nav {
    display: none; position: absolute; top: 100%; left: 0; right: 0;
    background: var(--color-bg); border-bottom: 2px solid var(--color-primary);
    box-shadow: var(--shadow-lg); z-index: 99;
  }
  .main-nav.active { display: block; }
  .main-nav ul { flex-direction: column; padding: var(--spacing-sm); }
  .main-nav a { padding: var(--spacing-sm); }

  .hero { padding: var(--spacing-xl) 0; }
  .hero-stats { gap: var(--spacing-md); }

  .footer-grid { grid-template-columns: 1fr 1fr; }

  .card-grid { grid-template-columns: 1fr; }
}

@media (max-width: 375px) {
  .container, .content-container { padding: 0 var(--spacing-sm); }
  .footer-grid { grid-template-columns: 1fr; }
  .hero-stats { flex-direction: column; gap: var(--spacing-sm); }
}

@media (min-width: 1440px) {
  :root { --max-width: 1320px; }
}

/* ===== Utility ===== */
.text-center { text-align: center; }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); border: 0;
}