:root {
  --color-primary: #2563eb;
  --color-primary-dark: #1e40af;
  --color-accent: #7c3aed;
  --color-text: #1f2937;
  --color-text-light: #6b7280;
  --color-bg: #ffffff;
  --color-bg-alt: #f9fafb;
  --color-bg-subtle: #f3f4f6;
  --color-border: #e5e7eb;
  --color-success: #10b981;
  --color-warning: #f59e0b;
  --max-content-width: 72ch;
  --max-page-width: 1200px;
  --spacing-unit: 1rem;
  --font-body: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-heading: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary);
  color: white;
  padding: 8px 16px;
  text-decoration: none;
  z-index: 1000;
}

.skip-link:focus {
  top: 0;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: var(--spacing-unit);
  color: var(--color-text);
}

h1 {
  font-size: 2.5rem;
  margin-bottom: 1.5rem;
}

h2 {
  font-size: 2rem;
  margin-top: 2rem;
  margin-bottom: 1rem;
}

h3 {
  font-size: 1.5rem;
  margin-top: 1.5rem;
  margin-bottom: 0.75rem;
}

h4 {
  font-size: 1.25rem;
  margin-top: 1rem;
}

p {
  margin-bottom: var(--spacing-unit);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: 2px;
}

.container {
  max-width: var(--max-page-width);
  margin: 0 auto;
  padding: 0 1rem;
}

.content-container {
  max-width: var(--max-content-width);
  margin: 0 auto;
  padding: 0 1rem;
}

.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  background-color: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(10px);
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
}

.logo-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
}

.logo-link:hover {
  text-decoration: none;
}

.logo-link img {
  height: 40px;
  width: auto;
}

.logo-text {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--color-text);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--color-border);
  padding: 0.5rem;
  cursor: pointer;
  font-size: 1.5rem;
  color: var(--color-text);
}

.nav-toggle:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.main-nav {
  display: flex;
  gap: 1.5rem;
  list-style: none;
  flex-wrap: wrap;
}

.main-nav a {
  color: var(--color-text);
  font-weight: 500;
  padding: 0.5rem 0;
  text-decoration: none;
}

.main-nav a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.main-nav a[aria-current="page"] {
  color: var(--color-primary);
  font-weight: 600;
}

.site-footer {
  background: var(--color-bg-alt);
  border-top: 1px solid var(--color-border);
  padding: 2rem 0;
  margin-top: 4rem;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-nav {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

.footer-nav a {
  color: var(--color-text-light);
  font-size: 0.9rem;
}

.breadcrumbs {
  margin: 1rem 0;
  font-size: 0.9rem;
  color: var(--color-text-light);
}

.breadcrumbs a {
  color: var(--color-text-light);
}

.breadcrumbs a:hover {
  color: var(--color-primary);
}

.breadcrumbs span {
  margin: 0 0.5rem;
  color: var(--color-text-light);
}

.card {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  transition: box-shadow 0.2s ease, transform 0.2s ease;
}

.card:hover {
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
  transform: translateY(-2px);
}

.card-link {
  text-decoration: none;
  display: block;
  color: inherit;
}

.card-link:hover {
  text-decoration: none;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.card-meta {
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-bottom: 0.75rem;
}

.card-excerpt {
  color: var(--color-text-light);
  line-height: 1.6;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1.5rem;
  margin: 2rem 0;
}

.btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  text-decoration: none;
  transition: background-color 0.2s ease;
}

.btn:hover {
  background: var(--color-primary-dark);
  text-decoration: none;
  color: white;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

.btn-secondary {
  background: var(--color-bg-subtle);
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  background: var(--color-border);
  color: var(--color-text);
}

.tag {
  display: inline-block;
  padding: 0.25rem 0.75rem;
  background: var(--color-bg-subtle);
  color: var(--color-text);
  border-radius: 4px;
  font-size: 0.85rem;
  margin-right: 0.5rem;
  margin-bottom: 0.5rem;
}

.tag-link {
  text-decoration: none;
  color: inherit;
}

.tag-link:hover {
  text-decoration: none;
  background: var(--color-border);
}

.prompt-block {
  background: var(--color-bg-alt);
  border-left: 4px solid var(--color-accent);
  padding: 1.5rem;
  margin: 1.5rem 0;
  border-radius: 4px;
}

.prompt-title {
  font-weight: 600;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.prompt-instruction {
  color: var(--color-text-light);
  margin-bottom: 0.5rem;
}

.prompt-section {
  margin: 2rem 0;
}

.prompt-section h3 {
  margin-bottom: 1rem;
  color: var(--color-accent);
}

.article-header {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.article-meta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-bottom: 1rem;
}

.article-content {
  line-height: 1.8;
}

.article-content ul,
.article-content ol {
  margin-left: 1.5rem;
  margin-bottom: var(--spacing-unit);
}

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

.article-content blockquote {
  border-left: 4px solid var(--color-primary);
  padding-left: 1.5rem;
  margin: 1.5rem 0;
  color: var(--color-text-light);
  font-style: italic;
}

.article-content code {
  background: var(--color-bg-subtle);
  padding: 0.2rem 0.4rem;
  border-radius: 3px;
  font-size: 0.9em;
  font-family: "Courier New", monospace;
}

.article-content pre {
  background: var(--color-bg-subtle);
  padding: 1rem;
  border-radius: 6px;
  overflow-x: auto;
  margin: 1.5rem 0;
}

.article-content pre code {
  background: none;
  padding: 0;
}

.checklist {
  list-style: none;
  margin-left: 0;
}

.checklist li {
  position: relative;
  padding-left: 2rem;
  margin-bottom: 0.75rem;
}

.checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-success);
  font-weight: bold;
}

.faq-item {
  margin-bottom: 2rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.faq-question {
  font-size: 1.25rem;
  font-weight: 600;
  margin-bottom: 0.75rem;
  color: var(--color-text);
}

.faq-answer {
  color: var(--color-text-light);
  line-height: 1.7;
}

.toc {
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 2rem 0;
}

.toc-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 1rem;
}

.toc-list {
  list-style: none;
  margin-left: 0;
}

.toc-list li {
  margin-bottom: 0.5rem;
}

.toc-list a {
  color: var(--color-text);
  text-decoration: none;
}

.toc-list a:hover {
  color: var(--color-primary);
  text-decoration: underline;
}

.form-group {
  margin-bottom: 1.5rem;
}

.form-label {
  display: block;
  font-weight: 500;
  margin-bottom: 0.5rem;
  color: var(--color-text);
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--color-border);
  border-radius: 6px;
  font-family: var(--font-body);
  font-size: 1rem;
  transition: border-color 0.2s ease;
}

.form-input:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-textarea {
  min-height: 150px;
  resize: vertical;
}

.form-note {
  font-size: 0.9rem;
  color: var(--color-text-light);
  margin-top: 0.5rem;
}

.author-block {
  background: var(--color-bg-alt);
  border-radius: 8px;
  padding: 1.5rem;
  margin: 2rem 0;
}

.author-name {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.author-role {
  color: var(--color-text-light);
  font-size: 0.9rem;
}

.section {
  margin: 3rem 0;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 1.5rem;
}

.hero {
  text-align: center;
  padding: 3rem 0;
  margin-bottom: 3rem;
}

.hero h1 {
  margin-bottom: 1rem;
}

.hero p {
  font-size: 1.125rem;
  color: var(--color-text-light);
  max-width: 60ch;
  margin: 0 auto;
}

@media (max-width: 768px) {
  h1 {
    font-size: 2rem;
  }

  h2 {
    font-size: 1.75rem;
  }

  .nav-toggle {
    display: block;
  }

  .main-nav {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 0;
    margin-top: 1rem;
  }

  .main-nav.active {
    display: flex;
  }

  .main-nav li {
    border-top: 1px solid var(--color-border);
    padding: 0.75rem 0;
  }

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

  .footer-content {
    flex-direction: column;
    text-align: center;
  }

  .footer-nav {
    flex-direction: column;
    gap: 0.5rem;
  }

  .hero {
    padding: 2rem 0;
  }
}

@media (max-width: 480px) {
  html {
    font-size: 14px;
  }

  .container,
  .content-container {
    padding: 0 0.75rem;
  }
}