:root {
  color-scheme: light;
  --bg: #eef6f4;
  --surface: #ffffff;
  --surface-tint: #f7fbfa;
  --text: #173431;
  --muted: #54716d;
  --accent: #0d7669;
  --accent-strong: #07554c;
  --border: rgba(13, 118, 105, 0.16);
  --shadow: 0 18px 50px rgba(26, 85, 77, 0.1);
  --max-width: 920px;
}

* { box-sizing: border-box; }

html {
  min-height: 100%;
  background:
    radial-gradient(circle at top right, rgba(99, 198, 179, 0.22), transparent 30%),
    linear-gradient(180deg, #f8fcfb 0%, var(--bg) 100%);
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--text);
  font-family: "Hiragino Sans", "Noto Sans JP", system-ui, sans-serif;
  line-height: 1.8;
}

a { color: var(--accent-strong); }

.page-shell {
  width: min(calc(100% - 32px), var(--max-width));
  margin: 0 auto;
  padding: 40px 0 72px;
}

.hero,
.subhero,
.card {
  border: 1px solid var(--border);
  border-radius: 26px;
  box-shadow: var(--shadow);
}

.hero,
.subhero {
  position: relative;
  overflow: hidden;
  padding: 34px 30px;
  background: linear-gradient(140deg, rgba(255, 255, 255, 0.96), rgba(230, 247, 242, 0.92));
}

.hero::after,
.subhero::after {
  position: absolute;
  right: -88px;
  bottom: -120px;
  width: 310px;
  height: 310px;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(29, 166, 145, 0.24), rgba(29, 166, 145, 0));
  content: "";
  pointer-events: none;
}

.brand,
.meta,
.lead { position: relative; z-index: 1; }

.brand {
  margin: 0 0 10px;
  color: var(--accent);
  font-size: 1.05rem;
  font-weight: 800;
  letter-spacing: 0.04em;
}

h1 {
  margin: 0;
  font-size: clamp(2rem, 5vw, 3.35rem);
  line-height: 1.18;
  letter-spacing: -0.03em;
}

.lead {
  max-width: 43rem;
  margin: 18px 0 0;
  color: var(--muted);
  font-size: 1.05rem;
}

.meta {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 0.95rem;
}

.button-row {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 24px;
}

.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 48px;
  padding: 0 18px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.76);
  color: var(--accent-strong);
  font-weight: 800;
  text-decoration: none;
}

.button.primary {
  border-color: transparent;
  background: linear-gradient(135deg, #169080, #087064);
  color: white;
}

.content-grid,
.stack { margin-top: 24px; }

.content-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(245px, 1fr));
  gap: 18px;
}

.stack { display: grid; gap: 18px; }

.card {
  padding: 24px 22px;
  background: var(--surface);
}

.card.tint { background: var(--surface-tint); }

.card h2,
.card h3 { margin-top: 0; }

.prose h2 {
  margin-top: 36px;
  font-size: 1.35rem;
}

.prose h2:first-child { margin-top: 0; }

.prose h3 {
  margin-top: 28px;
  font-size: 1.08rem;
}

ul { padding-left: 1.3rem; }

@media (max-width: 640px) {
  .page-shell {
    width: min(calc(100% - 20px), var(--max-width));
    padding: 18px 0 48px;
  }

  .hero,
  .subhero,
  .card { padding: 22px 18px; }

  .button-row { flex-direction: column; }
  .button { width: 100%; }
}