:root {
  color-scheme: light;
  --text: #1a1a1a;
  --text-muted: #666;
  --border: #e8e8e8;
  --accent: #111;
  --max-width: 42rem;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "Hiragino Sans", "Hiragino Kaku Gothic ProN", Meiryo, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  color: var(--text);
  background: #fff;
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 0.15em;
}

a:hover {
  opacity: 0.75;
}

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 1.25rem;
}

.site-header__inner,
.page,
.site-footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
}

.brand {
  margin: 0;
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.brand a {
  color: inherit;
  text-decoration: none;
}

.page {
  padding: 1.5rem 1.25rem 3rem;
}

.page h1 {
  margin: 0 0 0.5rem;
  font-size: 1.5rem;
  line-height: 1.35;
}

.page .meta {
  margin: 0 0 1.75rem;
  color: var(--text-muted);
  font-size: 0.875rem;
}

.page h2 {
  margin: 2rem 0 0.75rem;
  font-size: 1.0625rem;
  line-height: 1.4;
}

.page h3 {
  margin: 1.25rem 0 0.5rem;
  font-size: 1rem;
  line-height: 1.4;
  font-weight: 600;
}

.page p,
.page li {
  margin: 0 0 0.75rem;
}

.page ul,
.page ol {
  margin: 0 0 1rem;
  padding-left: 1.25rem;
}

.placeholder {
  padding: 1rem 1.125rem;
  border: 1px dashed var(--border);
  border-radius: 0.5rem;
  background: #fafafa;
  color: var(--text-muted);
  font-size: 0.9375rem;
}

.nav-list {
  list-style: none;
  margin: 1.5rem 0 0;
  padding: 0;
  border-top: 1px solid var(--border);
}

.nav-list li {
  margin: 0;
  border-bottom: 1px solid var(--border);
}

.nav-list a {
  display: block;
  padding: 0.875rem 0;
  text-decoration: none;
  color: var(--text);
  font-weight: 500;
}

.nav-list a:hover {
  opacity: 1;
  color: var(--accent);
}

.back-link {
  display: inline-block;
  margin-bottom: 1.25rem;
  font-size: 0.875rem;
  color: var(--text-muted);
  text-decoration: none;
}

.back-link:hover {
  color: var(--accent);
}

.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.25rem;
  color: var(--text-muted);
  font-size: 0.8125rem;
}

.site-footer p {
  margin: 0;
}