:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", "Noto Sans JP", sans-serif;
  color: #1c2430;
  background: #f6f8fb;
  line-height: 1.75;
}

* { box-sizing: border-box; }

body { margin: 0; }

a { color: #0b5cab; }
a:focus-visible { outline: 3px solid #ffbf47; outline-offset: 3px; }

.page {
  width: min(100% - 32px, 820px);
  margin: 0 auto;
  padding: 32px 0 56px;
}

header {
  margin-bottom: 30px;
  padding-bottom: 22px;
  border-bottom: 1px solid #d8dee9;
}

.brand { color: #52606d; font-weight: 700; text-decoration: none; }

nav { display: flex; flex-wrap: wrap; gap: 12px 20px; margin-top: 12px; }

main {
  padding: 32px;
  background: #fff;
  border: 1px solid #e1e6ed;
  border-radius: 12px;
  box-shadow: 0 8px 24px rgb(31 41 55 / 6%);
}

h1, h2, h3 { line-height: 1.35; color: #152238; }
h1 { margin-top: 0; font-size: clamp(1.65rem, 4vw, 2.15rem); }
h2 { margin-top: 2.25rem; font-size: 1.25rem; }
h3 { margin-top: 1.6rem; font-size: 1.05rem; }

.updated { margin: -12px 0 28px; color: #52606d; }
.notice { padding: 16px; border-left: 4px solid #c47f00; background: #fff8e8; }
.placeholder { color: #8b1e1e; font-weight: 700; }

footer { margin-top: 26px; color: #52606d; font-size: .9rem; }

@media (max-width: 600px) {
  .page { width: min(100% - 24px, 820px); padding-top: 20px; }
  main { padding: 24px 20px; }
}