:root {
  color-scheme: light;
  --background: #fefefe;
  --text: #232936;
  --muted: #6d7480;
  --border: #dfe5ed;
  --indigo: #06265f;
  --indigo-light: #dce7f7;
  --link: #174f91;
}

* {
  box-sizing: border-box;
}

body {
  position: relative;
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Yu Gothic", "YuGothic",
    "Noto Sans JP", sans-serif;
  font-size: 16px;
  line-height: 1.9;
}

body::after {
  position: fixed;
  z-index: 0;
  inset: auto 0 0;
  height: 72px;
  background-image: url("/assets/seigaiha-indigo.png");
  background-position: center top;
  background-size: 180px auto;
  content: "";
  opacity: 0.52;
  pointer-events: none;
}

main {
  position: relative;
  z-index: 1;
  width: min(100% - 48px, 780px);
  margin: 0 auto;
  padding: 76px 0 144px 28px;
  border-left: 2px solid var(--indigo);
}

main::after {
  position: fixed;
  z-index: 2;
  top: 0;
  right: 0;
  width: min(24vw, 320px);
  aspect-ratio: 1;
  background-image: url("/assets/seigaiha-indigo.png");
  background-position: left bottom;
  background-size: 160px auto;
  clip-path: polygon(100% 0, 100% 100%, 0 0);
  content: "";
  opacity: 0.68;
  pointer-events: none;
}

header {
  margin-bottom: 42px;
}

h1,
h2 {
  line-height: 1.4;
  letter-spacing: -0.02em;
}

h1 {
  margin: 0 0 12px;
  color: var(--indigo);
  font-size: clamp(2rem, 7vw, 2.8rem);
  font-weight: 700;
}

h2 {
  margin: 48px 0 12px;
  padding-left: 14px;
  border-left: 4px solid var(--indigo);
  color: var(--indigo);
  font-size: 1.25rem;
  font-weight: 700;
}

p,
ul {
  margin: 12px 0;
}

ul {
  padding-left: 1.4rem;
}

a {
  color: var(--link);
  text-underline-offset: 3px;
}

.eyebrow,
.updated {
  color: var(--muted);
  font-size: 0.9rem;
}

.eyebrow {
  margin-bottom: 8px;
  color: var(--indigo);
  font-weight: 700;
  letter-spacing: 0.16em;
}

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

.links {
  display: grid;
  gap: 12px;
  margin-top: 32px;
}

.links a {
  display: block;
  padding: 16px 18px;
  border: 1px solid var(--border);
  border-left: 4px solid var(--indigo);
  border-radius: 2px;
  color: var(--text);
  text-decoration: none;
  transition:
    border-color 160ms ease,
    color 160ms ease,
    background-color 160ms ease;
}

.links a:hover {
  border-color: var(--indigo);
  background: #f6f9fd;
  color: var(--indigo);
}

footer {
  margin-top: 64px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 520px) {
  main {
    width: min(100% - 28px, 720px);
    padding: 48px 0 120px 18px;
    border-left-width: 1px;
  }

  main::after {
    width: 180px;
    opacity: 0.38;
  }

  body::after {
    height: 52px;
    background-size: 140px auto;
    opacity: 0.4;
  }

  h2 {
    margin-top: 40px;
    padding-left: 11px;
    border-left-width: 3px;
  }
}