@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700&family=Inter:wght@400;500;600;700&display=swap');

*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --color-primary: #1a56db;
  --color-primary-dark: #1e429f;
  --color-text: #111827;
  --color-text-secondary: #4b5563;
  --color-border: #e5e7eb;
  --color-bg: #ffffff;
  --color-bg-subtle: #f9fafb;
  --color-accent: #eff6ff;
  --max-width: 760px;
  --font-body: 'Inter', 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Helvetica Neue', sans-serif;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
  color: var(--color-primary-dark);
}

/* ─── Header ─── */
.site-header {
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.site-header__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.25rem;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.site-header__logo {
  display: flex;
  flex-direction: column;
  line-height: 1.2;
}

.site-header__jp {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-text);
}

.site-header__en {
  font-size: 0.7rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

/* ─── Main content wrapper ─── */
.page-wrapper {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2.5rem 1.25rem 4rem;
}

/* ─── Hero (index page) ─── */
.hero {
  text-align: center;
  padding: 3.5rem 1rem 3rem;
  background: var(--color-accent);
  border-radius: 12px;
  margin-bottom: 2.5rem;
}

.hero__icon {
  font-size: 3rem;
  margin-bottom: 1rem;
  line-height: 1;
}

.hero__title-jp {
  font-size: 2rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.25rem;
}

.hero__title-en {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  margin-bottom: 1.25rem;
}

.hero__description {
  font-size: 1rem;
  color: var(--color-text-secondary);
  max-width: 480px;
  margin: 0 auto 2rem;
  line-height: 1.6;
}

.btn-group {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  flex-wrap: wrap;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.65rem 1.25rem;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.15s, box-shadow 0.15s;
  border: none;
  text-decoration: none;
}

.btn-primary {
  background: var(--color-primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--color-primary-dark);
  color: #fff;
  text-decoration: none;
}

.btn-secondary {
  background: #fff;
  color: var(--color-primary);
  border: 1.5px solid var(--color-primary);
}

.btn-secondary:hover {
  background: var(--color-accent);
  text-decoration: none;
}

/* ─── Features grid ─── */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1rem;
  margin-bottom: 2.5rem;
}

.feature-card {
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: 10px;
  padding: 1.25rem;
}

.feature-card__title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text);
  margin-bottom: 0.3rem;
}

.feature-card__desc {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
  line-height: 1.5;
}

/* ─── Document pages ─── */
.doc-header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.5rem;
  border-bottom: 1px solid var(--color-border);
}

.doc-header__label {
  display: inline-block;
  background: var(--color-accent);
  color: var(--color-primary);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  padding: 0.3rem 0.75rem;
  border-radius: 100px;
  margin-bottom: 0.75rem;
}

.doc-header__title {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.doc-header__meta {
  font-size: 0.85rem;
  color: var(--color-text-secondary);
}

.doc-section {
  margin-bottom: 2.25rem;
}

.doc-section h2 {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--color-text);
  margin-bottom: 0.75rem;
  padding-bottom: 0.4rem;
  border-bottom: 2px solid var(--color-border);
}

.doc-section p {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.75rem;
}

.doc-section ul,
.doc-section ol {
  margin: 0.5rem 0 0.75rem 1.25rem;
}

.doc-section li {
  font-size: 0.95rem;
  color: var(--color-text-secondary);
  margin-bottom: 0.35rem;
}

.doc-section a {
  word-break: break-all;
}

.notice-box {
  background: #fefce8;
  border: 1px solid #fde68a;
  border-radius: 8px;
  padding: 0.9rem 1.1rem;
  margin-bottom: 1rem;
  font-size: 0.9rem;
  color: #92400e;
}

/* ─── Footer ─── */
.site-footer {
  background: var(--color-bg-subtle);
  border-top: 1px solid var(--color-border);
  margin-top: auto;
}

.site-footer__inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 1.75rem 1.25rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.85rem;
  text-align: center;
}

.site-footer__app {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--color-text);
}

.site-footer__links {
  display: flex;
  gap: 1.5rem;
  flex-wrap: wrap;
  justify-content: center;
  font-size: 0.875rem;
}

.site-footer__copy {
  font-size: 0.8rem;
  color: var(--color-text-secondary);
}

/* ─── Responsive ─── */
@media (max-width: 600px) {
  .hero__title-jp {
    font-size: 1.6rem;
  }
  .doc-header__title {
    font-size: 1.4rem;
  }
  .btn-group {
    flex-direction: column;
    align-items: center;
  }
}