:root {
  --navy: #1f3f8f;
  --navy-tint: #e9edf7;
  --navy-ring: #c7d0e8;
  --bg: #f5f4f0;
  --card: #ffffff;
  --border: #e6e4dd;
  --text: #15203b;
  --text-2: #6a6e78;
  --text-3: #9a9da5;
  --amber: #c98a1b;
  --amber-tint: #fbf1dc;
  --amber-ring: #f0dcc0;
  color-scheme: light dark;
}
@media (prefers-color-scheme: dark) {
  :root {
    --navy: #6f8fe0;
    --navy-tint: #232c47;
    --navy-ring: #35406a;
    --bg: #121316;
    --card: #1c1d21;
    --border: #2c2e34;
    --text: #eceef3;
    --text-2: #9a9ea8;
    --text-3: #6e727c;
    --amber: #e0a93f;
    --amber-tint: #3a2f1a;
    --amber-ring: #5a4726;
  }
}

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

body {
  font-family: "Noto Sans JP", -apple-system, BlinkMacSystemFont, "Hiragino Sans", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.85;
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

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

.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
}
.site-header .inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 14px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 15px;
}
.brand img { width: 30px; height: 30px; border-radius: 7px; border: 1px solid var(--border); }
.site-nav { display: flex; gap: 16px; font-size: 14px; }
.site-nav a { color: var(--text-2); text-decoration: none; }
.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--navy); }

main {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 16px 64px;
}

.page-title { font-size: 28px; font-weight: 600; letter-spacing: 0.02em; line-height: 1.4; }
.page-lead { color: var(--text-2); margin-top: 8px; font-size: 15px; }
.meta { color: var(--text-3); font-size: 13px; margin-top: 12px; }

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 24px;
  margin-top: 24px;
}

.toc { margin-top: 28px; }
.toc h2 { font-size: 13px; color: var(--text-2); font-weight: 600; letter-spacing: 0.08em; margin-bottom: 8px; }
.toc ol { padding-left: 1.4em; columns: 2; column-gap: 24px; font-size: 14px; }
.toc li { break-inside: avoid; }
.toc a { text-decoration: none; }

article section { margin-top: 40px; scroll-margin-top: 16px; }
article h2 {
  font-size: 19px;
  font-weight: 600;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 14px;
}
article h3 { font-size: 16px; font-weight: 600; margin: 20px 0 6px; }
article p + p { margin-top: 10px; }
article ul, article ol { padding-left: 1.4em; margin-top: 8px; }
article li + li { margin-top: 4px; }
article p + ul, article p + ol { margin-top: 8px; }

.note {
  border: 1px solid var(--navy-ring);
  background: var(--navy-tint);
  border-radius: 12px;
  padding: 14px 16px;
  margin-top: 14px;
  font-size: 15px;
}
.warn {
  border: 1px solid var(--amber-ring);
  background: var(--amber-tint);
  border-radius: 12px;
  padding: 14px 16px;
  margin-top: 14px;
  font-size: 15px;
}

table { width: 100%; border-collapse: collapse; margin-top: 10px; font-size: 14px; }
th, td { text-align: left; padding: 10px 8px; border-bottom: 1px solid var(--border); vertical-align: top; }
th { color: var(--text-2); font-weight: 600; font-size: 13px; }
.table-wrap { overflow-x: auto; }

details {
  border-bottom: 1px solid var(--border);
  padding: 14px 0;
}
details summary {
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
details summary::-webkit-details-marker { display: none; }
details summary::after { content: "＋"; color: var(--text-3); font-weight: 400; }
details[open] summary::after { content: "−"; }
details .answer { margin-top: 10px; color: var(--text); }
details .answer p + p { margin-top: 8px; }
.faq-group { margin-top: 36px; }
.faq-group h2 { font-size: 13px; color: var(--text-2); letter-spacing: 0.08em; font-weight: 600; border: none; margin-bottom: 0; }

.hero { text-align: center; padding-top: 24px; }
.hero img { width: 104px; height: 104px; border-radius: 24px; border: 1px solid var(--border); }
.hero h1 { font-size: 26px; font-weight: 600; margin-top: 18px; line-height: 1.5; }
.hero p { color: var(--text-2); margin-top: 10px; }
.btn {
  display: inline-block;
  margin-top: 24px;
  padding: 12px 28px;
  border: 1.5px solid var(--navy);
  border-radius: 999px;
  color: var(--navy);
  text-decoration: none;
  font-weight: 600;
}
.btn:hover { background: var(--navy-tint); }

.features { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin-top: 40px; }
.feature { background: var(--card); border: 1px solid var(--border); border-radius: 16px; padding: 18px; }
.feature h2 { font-size: 15px; font-weight: 600; }
.feature p { font-size: 14px; color: var(--text-2); margin-top: 6px; line-height: 1.7; }

.links { margin-top: 40px; display: grid; gap: 0; }
.links a {
  display: flex; justify-content: space-between;
  padding: 16px 4px; border-bottom: 1px solid var(--border);
  color: var(--text); text-decoration: none;
}
.links a::after { content: "›"; color: var(--text-3); }

.site-footer {
  border-top: 1px solid var(--border);
  color: var(--text-3);
  font-size: 13px;
}
.site-footer .inner {
  max-width: 760px;
  margin: 0 auto;
  padding: 24px 16px 40px;
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  justify-content: space-between;
}
.site-footer nav { display: flex; gap: 16px; flex-wrap: wrap; }
.site-footer a { color: var(--text-2); text-decoration: none; }

@media (max-width: 560px) {
  main { padding-top: 28px; }
  .page-title { font-size: 24px; }
  .toc ol { columns: 1; }
  .features { grid-template-columns: 1fr; }
  .site-nav { gap: 12px; font-size: 13px; }
  .brand span { display: none; }
  .card { padding: 18px; }
}
.store-btns { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; margin-top: 24px; }
.store-btns .btn { margin-top: 0; }
.feature h3 { font-size: 15px; font-weight: 600; }
.lp-section { margin-top: 56px; }
.lp-section .features { margin-top: 16px; }
.lp-heading { font-size: 20px; font-weight: 600; text-align: center; letter-spacing: 0.02em; }
.lp-cta { text-align: center; border-top: 1px solid var(--border); padding-top: 48px; }
.lp-cta p { color: var(--text-2); margin-top: 10px; }