:root {
  color-scheme: light;
  --background: #ffffff;
  --text: #24292f;
  --muted: #57606a;
  --border: #d0d7de;
  --soft-background: #f6f8fa;
  --link: #0969da;
  --link-hover: #0550ae;
  --notice-background: #fff8c5;
  --notice-border: #d4a72c;
  --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --font-tech: "JetBrains Mono", "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  font-family: var(--font-body);
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: 7.5rem;
}

body {
  margin: 0;
  color: var(--text);
  background: var(--background);
  font-size: 16px;
  line-height: 1.65;
}

a {
  color: var(--link);
  text-underline-offset: 0.18em;
}

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

.skip-link {
  position: absolute;
  top: -4rem;
  left: 1rem;
  z-index: 10;
  padding: 0.5rem 0.75rem;
  color: #ffffff;
  background: var(--link);
}

.skip-link:focus { top: 0.5rem; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid var(--border);
  background: var(--background);
}

.header-content,
.footer-content {
  width: min(100% - 2rem, 1080px);
  margin: 0 auto;
}

.header-content {
  min-height: 104px;
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 2rem;
}

.product-logo {
  grid-column: 1;
  justify-self: start;
  display: flex;
}

.product-logo img {
  display: block;
  width: auto;
  height: 87px;
  aspect-ratio: 462 / 174;
}

.site-title {
  grid-column: 2;
  justify-self: center;
  color: var(--text);
  font-family: var(--font-tech);
  font-size: clamp(0.55rem, 2.7vw, 1.2rem);
  font-weight: 600;
  text-decoration: none;
  white-space: nowrap;
}

.site-header nav {
  grid-column: 3;
  justify-self: end;
  display: flex;
  align-items: center;
  gap: 1.5rem;
  font-size: 0.9rem;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 1.25rem;
}

.page-layout {
  width: min(100% - 2rem, 1180px);
  margin: 0 auto;
  padding: 4rem 0 6rem;
  display: grid;
  grid-template-columns: minmax(0, 840px) minmax(220px, 260px);
  gap: 3rem;
  align-items: start;
}

.document { min-width: 0; }

.category,
.platforms,
.caption {
  color: var(--muted);
  font-size: 0.875rem;
}

h1, h2, h3 {
  line-height: 1.25;
}

.document-header h1 {
  font-family: var(--font-tech);
}

h1 {
  margin: 0.5rem 0 1rem;
  font-size: clamp(0.75rem, 3.8vw, 2.35rem);
  letter-spacing: -0.025em;
  white-space: nowrap;
}

h2 {
  margin: 0 0 1rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--border);
  font-size: 1.65rem;
}

h3 {
  margin: 2rem 0 0.75rem;
  font-size: 1.15rem;
}

.lead {
  color: #343a40;
  font-size: 1.15rem;
}

p, ul, ol {
  margin-top: 0;
  margin-bottom: 1rem;
}

li + li { margin-top: 0.35rem; }

.primary-action {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.4rem 0.75rem;
  color: #ffffff;
  background: var(--link);
  border-radius: 6px;
  font-weight: 600;
  text-decoration: none;
}

.primary-action:hover {
  color: #ffffff;
  background: var(--link-hover);
}

.steam-logo {
  display: block;
  width: auto;
  height: 20px;
}

.important,
.contents {
  padding: 1.25rem 1.5rem;
  border: 1px solid var(--border);
  border-radius: 6px;
}

.important { margin: 2rem 0; }

.important {
  background: var(--notice-background);
  border-left: 4px solid var(--notice-border);
}

.important h2 {
  padding: 0;
  border: 0;
  font-size: 1.2rem;
}

.important p,
.contents ol {
  margin-bottom: 0;
}

.contents {
  position: sticky;
  top: 7.5rem;
  display: block;
  margin: 0;
  background: var(--soft-background);
  font-size: 0.875rem;
}

.contents ol {
  padding-left: 1.25rem;
}

section { margin-top: 3.5rem; }

.product-image {
  display: block;
  width: 100%;
  height: auto;
  margin-top: 2rem;
}

.site-footer {
  padding: 2rem 0;
  color: var(--muted);
  background: var(--soft-background);
  border-top: 1px solid var(--border);
  font-size: 0.85rem;
}

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

@media (max-width: 700px) {
  html { scroll-padding-top: 8rem; }

  .header-content {
    grid-template-columns: 1fr auto 1fr;
    padding: 0.8rem 0;
    gap: 0.5rem;
  }

  .product-logo {
    grid-column: 1;
    justify-self: start;
  }

  .product-logo img { height: 36px; }

  .site-title {
    grid-column: 2;
    justify-self: center;
    text-align: center;
  }

  .site-header nav {
    grid-column: 1 / -1;
    justify-self: center;
  }

  .header-actions { justify-content: center; }
  .footer-content { flex-direction: column; }
}

@media (max-width: 400px) {
  .product-logo img { height: 24px; }
}

@media (max-width: 1100px) {
  .page-layout {
    width: min(100% - 2rem, 840px);
    grid-template-columns: 1fr;
    gap: 0;
    padding-top: 2.5rem;
  }

  .contents {
    grid-row: 1;
    position: static;
    margin: 0 0 2rem;
  }

  .document { grid-row: 2; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}