:root {
  color-scheme: light;

  --color-background: #ffffff;
  --color-surface: #f5f5f5;
  --color-surface-alt: #ededed;
  --color-text-primary: #111111;
  --color-text-secondary: #5c5c5c;
  --color-text-heading: #000000;
  --color-border-primary: #d6d6d6;
  --color-border-secondary: #e8e8e8;
  --color-accent: #111111;
  --color-accent-bg: rgba(17, 17, 17, 0.06);
  --color-code-bg: #f5f5f5;
  --color-link: #111111;
  --color-link-hover: #000000;
}

:root[data-theme='dark'] {
  color-scheme: dark;

  --color-background: #1e1e1e;
  --color-surface: #2d2d30;
  --color-surface-alt: #252526;
  --color-text-primary: #d4d4d4;
  --color-text-secondary: #9d9d9d;
  --color-text-heading: #ffffff;
  --color-border-primary: #3e3e42;
  --color-border-secondary: #333333;
  --color-accent: #3b82f6;
  --color-accent-bg: rgba(59, 130, 246, 0.12);
  --color-code-bg: #252526;
  --color-link: #7aa2ff;
  --color-link-hover: #a9c2ff;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  padding: 0;
  background: var(--color-background);
  color: var(--color-text-primary);
}

body {
  font-family: 'Open Sans', 'Roboto', sans-serif;
  font-size: 16px;
  line-height: 145%;
}

/* ---------- layout shell ---------- */

.page {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 16px 32px;
  border-bottom: 1px solid var(--color-border-primary);
  flex-wrap: wrap;
}

.wordmark {
  font-family: 'Roboto', 'Open Sans', sans-serif;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--color-text-heading);
  text-decoration: none;
}

.site-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.site-nav a {
  font-family: 'Lato', 'Open Sans', sans-serif;
  font-weight: 600;
  font-size: 14px;
  color: var(--color-link);
  text-decoration: none;
  padding: 6px 12px;
  border: 1px solid var(--color-border-primary);
  border-radius: 4px;
}

.site-nav a:hover {
  color: var(--color-link-hover);
  border-color: var(--color-link-hover);
}

#theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: 6px;
  border: 1px solid var(--color-border-primary);
  background: var(--color-surface);
  color: var(--color-text-primary);
  font-size: 18px;
  line-height: 1;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease;
}

#theme-toggle:hover {
  background: var(--color-surface-alt);
  border-color: var(--color-accent);
}

.hero {
  padding: 32px 32px 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-width: 860px;
}

.hero p {
  font-size: 16px;
  color: var(--color-text-secondary);
  line-height: 145%;
  margin: 0;
}

main.content {
  flex: 1;
  width: 100%;
  max-width: 860px;
  margin: 0 auto;
  padding: 32px;
  box-sizing: border-box;
}

.site-footer {
  border-top: 1px solid var(--color-border-primary);
  padding: 24px 32px 40px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: center;
  text-align: center;
}

.site-footer .quote {
  font-family: 'Open Sans', 'Roboto', sans-serif;
  font-style: italic;
  font-size: 14px;
  color: var(--color-text-secondary);
  max-width: 640px;
  margin: 0;
}

.site-footer .links {
  display: flex;
  gap: 16px;
  font-size: 14px;
}

.site-footer a {
  color: var(--color-link);
}

@media (max-width: 640px) {
  .site-header,
  .hero,
  main.content,
  .site-footer {
    padding-left: 16px;
    padding-right: 16px;
  }
}

/* ---------- list content ---------- */

.content h2 {
  font-family: 'Roboto', 'Open Sans', sans-serif;
  font-weight: 700;
  font-size: 24px;
  color: var(--color-text-heading);
  margin: 40px 0 12px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--color-border-secondary);
}

.content h3 {
  font-family: 'Roboto', 'Open Sans', sans-serif;
  font-weight: 600;
  font-size: 18px;
  color: var(--color-text-heading);
  margin: 28px 0 8px;
}

.content h4 {
  font-family: 'Lato', 'Open Sans', sans-serif;
  font-weight: 600;
  font-size: 15px;
  color: var(--color-text-heading);
  margin: 20px 0 6px;
}

.content p {
  margin: 0 0 16px;
  color: var(--color-text-primary);
}

.content ul,
.content ol {
  margin: 0 0 16px;
  padding-left: 24px;
}

.content li {
  margin-bottom: 8px;
  line-height: 145%;
}

.content a {
  color: var(--color-link);
  text-decoration: underline;
  text-decoration-color: var(--color-border-primary);
  text-underline-offset: 2px;
}

.content a:hover {
  color: var(--color-link-hover);
}

.content strong {
  color: var(--color-text-heading);
  font-weight: 700;
}

.content .logo {
  border-radius: 4px;
  object-fit: contain;
  vertical-align: middle;
  margin-right: 6px;
}

.content hr {
  border: none;
  border-top: 1px solid var(--color-border-secondary);
  margin: 32px 0;
}

.content img.badge {
  max-width: 100%;
}