/* 文言はindex.html、配色・余白は以下の変数で調整できます。 */
:root {
  color-scheme: light dark;
  --background: #f9f9f9;
  --text: #1c1c1e;
  --muted: #6e6e73;
  --link: #237a3b;
  --border: rgba(0, 0, 0, .14);
  --page-width: 44rem;
  --gutter: 1.25rem;
  --leading: 1.9;
}
@media (prefers-color-scheme: dark) {
  :root {
    --background: #1c1c1e;
    --text: #f5f5f7;
    --muted: #b0b0b8;
    --link: #81cf91;
    --border: rgba(255, 255, 255, .18);
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--background); color: var(--text); font-family: -apple-system, "Helvetica Neue", sans-serif; line-height: var(--leading); overflow-wrap: anywhere; }
.page { max-width: var(--page-width); margin: auto; padding: 0 var(--gutter); }
header { padding: 1rem 0; border-bottom: 1px solid var(--border); }
main { padding: 2rem 0; }
.app-name { color: var(--muted); font-size: .875rem; margin: 0 0 .75rem; }
h1 { font-size: clamp(1.5rem, 5vw, 2rem); line-height: 1.5; margin: 0 0 2rem; }
h2 { margin: 2rem 0 .5rem; font-size: 1.125rem; line-height: 1.6; }
p { margin: .75rem 0; }
a { color: var(--link); text-underline-offset: .2em; }
a:focus-visible { outline: 2px solid var(--link); outline-offset: 4px; border-radius: 2px; }
header a, nav a { display: inline-flex; align-items: center; min-height: 44px; }
footer { padding: 1rem 0 2rem; border-top: 1px solid var(--border); }
nav { display: flex; flex-wrap: wrap; gap: .25rem 1.5rem; margin-bottom: 1rem; font-size: .875rem; }
small { color: var(--muted); }
.skip-link { position: absolute; left: var(--gutter); top: .5rem; transform: translateY(-200%); padding: .5rem; background: var(--background); }
.skip-link:focus { transform: none; }