:root {
  --bg: #f3f3f2;
  --fg: #0f2350;
  --sub: #4a5878;
  --accent: #165e83;
  --line: #c9d3df;
  --card: #fbfbfa;
  --flow: url("images/flow-light.svg");
  --wave: url("images/seigaiha-light.svg");
  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b1838;
    --fg: #f3f3f2;
    --sub: #c3cad8;
    --accent: #80aba9;
    --line: #24447f;
    --card: #0f2350;
    --flow: url("images/flow-dark.svg");
    --wave: url("images/seigaiha-dark.svg");
  }
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: system-ui, -apple-system, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Noto Sans CJK JP", "Yu Gothic UI", "Yu Gothic", Meiryo, sans-serif;
  font-size: 1.0625rem;
  line-height: 1.85;
  letter-spacing: 0.02em;
  overflow-wrap: anywhere;
  word-break: auto-phrase;
  text-wrap: pretty;
}

.skip {
  position: absolute;
  left: -100vw;
}

.skip:focus {
  left: 1rem;
  top: 1rem;
  padding: 0.5rem 1rem;
  background: var(--card);
  border: 1px solid var(--accent);
}

.hero {
  padding: 3.5rem 1.25rem 2rem;
  text-align: center;
}

.hero img {
  width: min(420px, 88%);
  height: auto;
}

.lead {
  max-width: 28em;
  margin: 1.5rem auto 0;
  font-size: 1.15rem;
}

main {
  max-width: 40em;
  margin: 0 auto;
  padding: 0 1.25rem;
}

h1 {
  margin: 0;
}

h2 {
  margin: 3.25rem 0 1rem;
  padding-bottom: 1.4rem;
  background: var(--flow) left bottom / 120px 20px no-repeat;
  font-size: 1.35rem;
  letter-spacing: 0.06em;
  text-wrap: balance;
}

h3 {
  margin: 1.75rem 0 0.25rem;
  font-size: 1.05rem;
}

p,
li {
  margin: 0.75rem 0;
}

a {
  color: var(--accent);
  text-underline-offset: 0.2em;
}

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

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(15em, 100%), 1fr));
  gap: 1rem;
  margin: 1rem 0;
  padding: 0;
  list-style: none;
}

.cards li {
  margin: 0;
  padding: 1rem 1.1rem;
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 6px;
}

.cards h3 {
  margin: 0;
  text-wrap: balance;
}

.cards p {
  margin: 0.25rem 0 0;
  color: var(--sub);
  font-size: 0.95rem;
}

.note {
  padding-left: 0.8rem;
  border-left: 3px solid var(--accent);
}

.small {
  color: var(--sub);
  font-size: 0.95rem;
}

dl {
  margin: 1rem 0;
}

dt {
  margin-top: 1.25rem;
  font-weight: bold;
}

dd {
  margin: 0.25rem 0 0;
}

footer {
  margin-top: 4.5rem;
  padding: 5rem 1.25rem 2rem;
  background: var(--wave) center top / 48px auto repeat-x;
  color: var(--sub);
  font-size: 0.9rem;
  text-align: center;
}

footer p {
  margin: 0.25rem 0;
}

.notfound {
  padding-top: 1rem;
  text-align: center;
}

@media (min-width: 48em) {
  .hero {
    padding-top: 5rem;
  }
}

@media (max-height: 30em) {
  .hero {
    padding: 1rem 1rem 0.5rem;
  }

  .hero img {
    width: min(260px, 72%);
  }

  .lead {
    margin-top: 0.75rem;
    font-size: 1rem;
  }
}