:root {
  
  --bg: #ffffff;
  --fg: #2c3e50;
  --muted: #7f8c8d;
  --brand: #3498db;
  --brand-contrast: #ffffff;
  
  
  --font-sans: system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "SF Mono", Monaco, "Cascadia Code", monospace;
  --h1: 2.5rem;
  --h2: 2rem;
  --body: 1rem;
  
  
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-5: 3rem;
}


@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a202c;
    --fg: #41474f;
    --muted: #a0aec0;
    --brand: #4299e1;
    --brand-contrast: #1a202c;
  }
}


* {
  box-sizing: border-box;
}

body {
  font-family: var(--font-sans);
  font-size: var(--body);
  line-height: 1.6;
  color: var(--fg);
  background-color: var(--bg);
  margin: 0;
  padding: var(--space-2);
  max-width: 1200px;
  margin: 0 auto;
}


h1, h2, h3, h4, h5, h6,
p, ul, ol, dl, table, figure, blockquote, details {
  margin: 0 0 var(--space-2) 0;
}

h1 { font-size: var(--h1); }
h2 { font-size: var(--h2); }


header {
  margin-bottom: var(--space-4);
}

header h1 {
  margin-bottom: var(--space-1);
}


nav[aria-label="Primary"] ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1);
}

nav[aria-label="Primary"] a {
  display: block;
  padding: var(--space-1) var(--space-2);
  text-decoration: none;
  color: var(--fg);
  border: 1px solid var(--muted);
  border-radius: 4px;
  transition: all 0.2s ease;
}

nav[aria-label="Primary"] a:hover,
nav[aria-label="Primary"] a:focus {
  background-color: var(--brand);
  color: var(--brand-contrast);
  border-color: var(--brand);
}

nav[aria-label="Primary"] a[aria-current="page"] {
  background-color: var(--brand);
  color: var(--brand-contrast);
  border-color: var(--brand);
}


@media (max-width: 480px) {
  nav[aria-label="Primary"] ul {
    flex-direction: column;
  }
  
  nav[aria-label="Primary"] a {
    text-align: center;
  }
}


main {
  display: grid;
  gap: var(--space-3);
}


@media (min-width: 768px) {
  body {
    padding: var(--space-3);
  }
}

@media (min-width: 1024px) {
  main {
    grid-template-columns: 2fr 1fr;
    gap: var(--space-4);
  }
  
  aside {
    grid-column: 2;
    grid-row: 1;
  }
  
  article {
    grid-column: 1;
  }
}


body > footer {
  margin-top: var(--space-5);
  padding-top: var(--space-2);
  border-top: 1px solid var(--muted);
  color: var(--muted);
  font-size: 0.875rem;
  text-align: center;
}



code, kbd, samp, var {
  font-family: var(--font-mono);
  font-size: 0.875em;
  padding: 0.125em 0.25em;
  border-radius: 3px;
}

code {
  background-color: var(--muted);
  color: var(--bg);
}

kbd {
  background-color: var(--fg);
  color: var(--bg);
  border: 1px solid var(--muted);
  box-shadow: 0 1px 2px rgba(0,0,0,0.1);
}

samp {
  background-color: var(--bg);
  border: 1px solid var(--muted);
}

mark {
  background-color: #fff3cd;
  color: #856404;
  padding: 0.125em;
}


@media (prefers-color-scheme: dark) {
  mark {
    background-color: #856404;
    color: #fff3cd;
  }
  
  code {
    background-color: var(--muted);
    color: var(--bg);
  }
}


a {
  color: var(--brand);
  text-decoration: underline;
}

a:hover, a:focus {
  text-decoration-thickness: 2px;
}


.card {
  padding: var(--space-2);
  border-radius: 8px;
  border: 1px solid var(--muted);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
  background-color: var(--bg);
}

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

section {
  margin-bottom: var(--space-3);
}


table {
  width: 100%;
  border-collapse: collapse;
  margin: var(--space-2) 0;
  font-size: 0.875rem;
}

th, td {
  padding: var(--space-1);
  text-align: left;
  border: 1px solid var(--muted);
}

th {
  background-color: var(--muted);
  color: var(--bg);
  font-weight: 600;
}


tbody tr:nth-child(even) {
  background-color: rgba(0,0,0,0.05);
}

@media (prefers-color-scheme: dark) {
  tbody tr:nth-child(even) {
    background-color: rgba(255,255,255,0.05);
  }
}


.table-wrapper {
  overflow-x: auto;
}

@media (max-width: 600px) {
  table {
    font-size: 0.75rem;
  }
  
  th, td {
    padding: var(--space-1) 0.25rem;
  }
}


img, video {
  max-width: 100%;
  height: auto;
}

figure {
  margin: var(--space-2) 0;
}

figcaption {
  font-size: 0.875rem;
  color: var(--muted);
  font-style: italic;
  margin-top: var(--space-1);
}

audio {
  width: 100%;
  max-width: 400px;
}

details {
  border: 1px solid var(--muted);
  border-radius: 4px;
  margin: var(--space-1) 0;
  padding: var(--space-1);
}

summary {
  cursor: pointer;
  font-weight: 600;
  padding: var(--space-1);
  background-color: var(--muted);
  color: var(--bg);
  margin: calc(-1 * var(--space-1));
  margin-bottom: var(--space-1);
  border-radius: 4px 4px 0 0;
  transition: background-color 0.2s ease;
}

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

details[open] summary {
  border-radius: 4px 4px 0 0;
}


dialog {
  border: 1px solid var(--muted);
  border-radius: 8px;
  padding: var(--space-2);
  background: var(--bg);
  color: var(--fg);
  box-shadow: 0 4px 8px rgba(0,0,0,0.2);
}


progress, meter {
  width: 100%;
  max-width: 300px;
  height: 20px;
  appearance: none;
  border: none;
  border-radius: 10px;
  background-color: var(--muted);
}

progress::-webkit-progress-bar {
  background-color: var(--muted);
  border-radius: 10px;
}

progress::-webkit-progress-value {
  background-color: var(--brand);
  border-radius: 10px;
}


.mt-2 { margin-top: var(--space-2); }
.mb-3 { margin-bottom: var(--space-3); }
.text-center { text-align: center; }
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}


a:focus,
button:focus,
summary:focus,
[tabindex]:focus {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}


a:hover {
  opacity: 0.8;
}


.card {
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.card:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}


@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}


@media (min-width: 480px) {
  /* Small tablets */
  body {
    padding: var(--space-3);
  }
}

@media (min-width: 768px) {
  /* Tablets */
  :root {
    --body: 1.125rem;
    --space-2: 1.25rem;
    --space-3: 2rem;
  }
}

@media (min-width: 1024px) {
  /* Desktop */
  body {
    padding: var(--space-4);
  }
  
  
  .content-grid {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: var(--space-4);
  }
}


@media (max-width: 375px) {
  /* Very narrow phones */
  :root {
    --space-1: 0.25rem;
    --space-2: 0.75rem;
    --h1: 2rem;
    --h2: 1.75rem;
  }
}

@media (min-width: 1280px) {
  /* Wide screens */
  body {
    max-width: 1400px;
  }
}


a[href="#main"] {
  position: absolute;
  top: -40px;
  left: 6px;
  background: var(--fg);
  color: var(--bg);
  padding: var(--space-1) var(--space-2);
  text-decoration: none;
  z-index: 1000;
  border-radius: 0 0 4px 4px;
  transition: top 0.3s;
}

a[href="#main"]:focus {
  top: 6px;
}


h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  font-weight: 600;
}


:focus-visible {
  outline: 2px solid var(--brand);
  outline-offset: 2px;
}


main {
  min-height: 60vh;
}