:root {
  --color-bg: #F7F8FA;
  --color-surface: #FFFFFF;
  --color-text: #111827;
  --color-muted: #4B5563;
  --color-border: #D1D5DB;
  --color-primary: #1F6FEB;
  --color-secondary: #0E7C66;
  --color-accent: #E24A3B;
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --space: 1rem;
  --radius: 2px;
}

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

html {
  font-size: 100%;
  line-height: 1.6;
}

body {
  font-family: var(--font-sans);
  background-color: var(--color-bg);
  color: var(--color-text);
  text-align: left;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container {
  max-width: 90%;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space);
  padding-right: var(--space);
}

@media (min-width: 768px) {
  .container {
    max-width: 720px;
  }
}

@media (min-width: 1024px) {
  .container {
    max-width: 960px;
  }
}

.site-header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  padding-top: calc(var(--space) * 1.5);
  padding-bottom: calc(var(--space) * 1.5);
  margin-bottom: calc(var(--space) * 2);
}

.site-branding {
  font-size: 1.5rem;
  margin-bottom: calc(var(--space) * 0.5);
}

.utility-line {
  font-size: 0.875rem;
  color: var(--color-muted);
  margin-bottom: var(--space);
}

.site-header nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--space) * 1.5);
}

.site-header nav a {
  color: var(--color-text);
  text-decoration: none;
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
  transition: border-color 0.2s ease;
}

.site-header nav a:hover,
.site-header nav a:focus {
  border-bottom-color: var(--color-primary);
}

.site-header nav a[aria-current="page"] {
  border-bottom-color: var(--color-accent);
  font-weight: 600;
}

.site-header nav a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 4px;
}

@media (prefers-reduced-motion: reduce) {
  .site-header nav a {
    transition: none;
  }
}

main {
  margin-bottom: calc(var(--space) * 3);
}

h1, h2, h3, h4, h5, h6 {
  font-weight: 600;
  line-height: 1.2;
  margin-top: calc(var(--space) * 2);
  margin-bottom: var(--space);
}

h1 {
  font-size: 2rem;
  margin-top: 0;
}

h2 {
  font-size: 1.5rem;
  color: var(--color-text);
}

h3 {
  font-size: 1.25rem;
  color: var(--color-text);
}

p {
  margin-bottom: var(--space);
  max-width: 70ch;
}

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

a:hover {
  color: var(--color-secondary);
}

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

a[rel*="external"]::after {
  content: " ↗";
  font-size: 0.875em;
}

table {
  width: 100%;
  border-collapse: collapse;
  margin-top: calc(var(--space) * 1.5);
  margin-bottom: calc(var(--space) * 1.5);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
}

caption {
  font-weight: 600;
  text-align: left;
  padding: var(--space);
  background-color: var(--color-surface);
  border-bottom: 2px solid var(--color-border);
}

thead {
  background-color: var(--color-bg);
}

th {
  text-align: left;
  padding: calc(var(--space) * 0.75);
  font-weight: 600;
  border-bottom: 1px solid var(--color-border);
}

td {
  padding: calc(var(--space) * 0.75);
  border-bottom: 1px solid var(--color-border);
}

tbody tr:nth-child(even) {
  background-color: var(--color-bg);
}

tbody tr:hover {
  background-color: #E5E7EB;
}

details {
  margin-bottom: var(--space);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background-color: var(--color-surface);
}

summary {
  padding: var(--space);
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  transition: background-color 0.2s ease;
}

summary::-webkit-details-marker {
  display: none;
}

summary::before {
  content: "▸";
  margin-right: calc(var(--space) * 0.5);
  transition: transform 0.2s ease;
}

details[open] summary::before {
  transform: rotate(90deg);
}

summary:hover,
summary:focus {
  background-color: var(--color-bg);
}

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

details p {
  padding: 0 var(--space) var(--space) var(--space);
}

@media (prefers-reduced-motion: reduce) {
  summary,
  summary::before {
    transition: none;
  }
}

blockquote {
  margin: calc(var(--space) * 1.5) 0;
  padding: var(--space);
  border-left: 4px solid var(--color-accent);
  background-color: var(--color-surface);
  font-style: italic;
}

blockquote p:last-child {
  margin-bottom: 0;
}

aside {
  margin-top: calc(var(--space) * 2);
  margin-bottom: calc(var(--space) * 2);
  padding: var(--space);
  background-color: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
}

aside h2 {
  margin-top: 0;
  font-size: 1.125rem;
}

.breadcrumb {
  margin-bottom: calc(var(--space) * 1.5);
  font-size: 0.875rem;
}

.breadcrumb ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--space) * 0.5);
}

.breadcrumb li:not(:last-child)::after {
  content: ">";
  margin-left: calc(var(--space) * 0.5);
  color: var(--color-muted);
}

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

.site-footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding-top: calc(var(--space) * 2);
  padding-bottom: calc(var(--space) * 2);
  margin-top: calc(var(--space) * 3);
}

.site-footer p {
  margin-bottom: var(--space);
  color: var(--color-muted);
}

.site-footer nav ul {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: calc(var(--space) * 1.5);
}

.site-footer nav a {
  color: var(--color-text);
  text-decoration: none;
}

.site-footer nav a:hover {
  text-decoration: underline;
}

section {
  margin-top: calc(var(--space) * 2);
  margin-bottom: calc(var(--space) * 2);
}

article {
  background-color: var(--color-surface);
  padding: calc(var(--space) * 2);
  border-radius: var(--radius);
}

@media (min-width: 768px) {
  h1 {
    font-size: 2.5rem;
  }
  h2 {
    font-size: 1.75rem;
  }
  h3 {
    font-size: 1.375rem;
  }
  p {
    max-width: 75ch;
  }
}

@media (min-width: 1024px) {
  .container {
    display: grid;
    grid-template-columns: 1fr;
    gap: calc(var(--space) * 2);
  }
}