:root {
  color-scheme: light;
  --ink: #213141;
  --muted: #5c6c77;
  --panel: rgba(255, 255, 255, 0.72);
  --line: rgba(42, 62, 78, 0.14);
  --blue: #2f7aa7;
  --green: #5b9c8d;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  line-height: 1.75;
  color: var(--ink);
  background:
    linear-gradient(150deg, rgba(213, 238, 232, 0.92), rgba(244, 247, 224, 0.86) 45%, rgba(216, 231, 248, 0.95)),
    #f4f7ee;
}

a {
  color: var(--blue);
}

.page {
  width: min(920px, calc(100% - 32px));
  margin: 0 auto;
  padding: 48px 0 72px;
}

.hero {
  min-height: 72vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: flex-start;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--green);
  font-size: 0.9rem;
  font-weight: 700;
  letter-spacing: 0;
}

h1 {
  margin: 0;
  font-size: clamp(2.5rem, 8vw, 5.2rem);
  line-height: 1.08;
  letter-spacing: 0;
}

h2 {
  margin: 40px 0 10px;
  font-size: 1.35rem;
  line-height: 1.35;
}

h3 {
  margin: 28px 0 4px;
  font-size: 1.05rem;
}

p {
  margin: 0 0 16px;
}

.lead {
  margin-top: 18px;
  font-size: clamp(1.1rem, 3vw, 1.45rem);
  color: var(--muted);
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 32px;
}

.button {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 10px 18px;
  border-radius: 8px;
  background: var(--ink);
  color: #fff;
  text-decoration: none;
  font-weight: 700;
}

.button.secondary {
  background: rgba(255, 255, 255, 0.7);
  color: var(--ink);
  border: 1px solid var(--line);
}

.content {
  padding: 32px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  box-shadow: 0 18px 50px rgba(42, 62, 78, 0.10);
}

.document .content {
  margin-top: 28px;
}

.topnav {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 14px 0;
}

.topnav a {
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.updated {
  margin-top: 12px;
  color: var(--muted);
  font-size: 0.95rem;
}

@media (max-width: 640px) {
  .page {
    width: min(100% - 24px, 920px);
    padding-top: 28px;
  }

  .hero {
    min-height: 64vh;
  }

  .content {
    padding: 22px;
  }
}