:root {
  color-scheme: light dark;
  --background: #f4f6fb;
  --surface: #ffffff;
  --text: #0d1729;
  --muted: #667386;
  --accent: #2d68eb;
  --border: #dfe4ec;
  --shadow: 0 12px 36px rgb(27 41 70 / 8%);
}

@media (prefers-color-scheme: dark) {
  :root {
    --background: #0e1420;
    --surface: #171f2d;
    --text: #f3f6fc;
    --muted: #aab4c5;
    --accent: #78a3ff;
    --border: #2a3546;
    --shadow: 0 12px 36px rgb(0 0 0 / 28%);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  background: var(--background);
  color: var(--text);
  font-family:
    -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans JP", Helvetica,
    Arial, sans-serif;
  line-height: 1.75;
}

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem max(1.25rem, calc((100% - 880px) / 2));
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--background) 88%, transparent);
  backdrop-filter: blur(18px);
}

.brand {
  color: var(--text);
  font-size: 1.25rem;
  font-weight: 800;
  text-decoration: none;
}

nav {
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
}

nav a {
  font-size: 0.9rem;
  font-weight: 650;
  text-decoration: none;
}

main {
  width: min(100% - 2rem, 880px);
  margin: 0 auto;
}

.hero {
  padding: 5rem 0 3rem;
  text-align: center;
}

.hero h1 {
  margin: 0;
  font-size: clamp(2.8rem, 10vw, 5.5rem);
  letter-spacing: -0.06em;
  line-height: 1;
}

.hero p {
  color: var(--muted);
}

.eyebrow,
.language-label {
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.support-link {
  display: inline-block;
  margin-top: 0.75rem;
  font-weight: 700;
}

article {
  margin: 0 0 2rem;
  padding: clamp(1.5rem, 5vw, 3rem);
  scroll-margin-top: 5rem;
  border: 1px solid var(--border);
  border-radius: 1.5rem;
  background: var(--surface);
  box-shadow: var(--shadow);
}

article h2 {
  margin: 0 0 0.25rem;
  font-size: clamp(1.8rem, 6vw, 2.6rem);
  line-height: 1.2;
}

article h3 {
  margin: 2rem 0 0.4rem;
  font-size: 1.15rem;
}

article p {
  margin: 0 0 1rem;
}

.effective-date {
  color: var(--muted);
}

.contact-button {
  display: inline-block;
  padding: 0.75rem 1rem;
  border-radius: 0.75rem;
  background: var(--accent);
  color: #ffffff;
  font-weight: 750;
  text-decoration: none;
  overflow-wrap: anywhere;
}

footer {
  padding: 2rem 1rem 3rem;
  color: var(--muted);
  text-align: center;
}

@media (max-width: 560px) {
  .site-header {
    align-items: flex-start;
    flex-direction: column;
  }

  .hero {
    padding-top: 3.5rem;
  }
}