:root {
  --bg: #f5f7fb;
  --surface: #ffffff;
  --text: #16202d;
  --muted: #5b6776;
  --brand: #1f4f8a;
  --brand-dark: #163a66;
  --brand-soft: #eaf1f9;
  --accent: #f59e0b;
  --accent-soft: #fff7e8;
  --line: rgba(31, 79, 138, 0.14);
  --shadow: 0 18px 52px rgba(29, 53, 87, 0.1);
  --container: 1080px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Noto Sans JP", sans-serif;
  line-height: 1.85;
  background:
    radial-gradient(circle at top left, rgba(31, 79, 138, 0.1), transparent 30rem),
    linear-gradient(180deg, #fbfdff, var(--bg));
}

a { color: var(--brand); }
img { max-width: 100%; }
.container { width: min(calc(100% - 32px), var(--container)); margin-inline: auto; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 20;
  border-bottom: 1px solid var(--line);
  background: rgba(251, 253, 255, 0.9);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
}
.topbar-inner {
  min-height: 68px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--brand);
  font-weight: 900;
  text-decoration: none;
}
.brand img { width: 36px; height: 36px; border-radius: 10px; }
.topnav { display: flex; align-items: center; gap: 8px; }
.topnav a {
  padding: 7px 12px;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.92rem;
  font-weight: 750;
  text-decoration: none;
}
.topnav a:hover { color: var(--brand); background: var(--brand-soft); }

.breadcrumb { padding-top: 26px; color: var(--muted); font-size: 0.88rem; }
.breadcrumb ol { display: flex; flex-wrap: wrap; gap: 7px; margin: 0; padding: 0; list-style: none; }
.breadcrumb li + li::before { content: "/"; margin-right: 7px; color: #9aa5b3; }
.breadcrumb a { color: inherit; }

.article-hero, .index-hero { padding: 38px 0 46px; }
.hero-panel {
  padding: clamp(28px, 5vw, 58px);
  border: 1px solid var(--line);
  border-radius: 30px;
  background: linear-gradient(135deg, rgba(255,255,255,.96), rgba(234,241,249,.94));
  box-shadow: var(--shadow);
}
.eyebrow {
  display: inline-flex;
  margin-bottom: 15px;
  padding: 6px 12px;
  border-radius: 999px;
  color: var(--brand);
  background: var(--brand-soft);
  font-size: 0.88rem;
  font-weight: 800;
}
h1, h2, h3 { line-height: 1.45; }
h1 { margin: 0; font-size: clamp(2rem, 5vw, 3.15rem); letter-spacing: -0.02em; }
.hero-lead { max-width: 780px; margin: 20px 0 0; color: var(--muted); font-size: 1.08rem; }
.article-meta { margin-top: 20px; color: var(--muted); font-size: 0.9rem; }

.article-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 280px;
  gap: 30px;
  align-items: start;
  padding-bottom: 76px;
}
.article-body, .side-card, .column-card {
  border: 1px solid var(--line);
  background: var(--surface);
  box-shadow: 0 12px 34px rgba(29, 53, 87, .06);
}
.article-body { padding: clamp(24px, 5vw, 52px); border-radius: 26px; }
.article-body > :first-child { margin-top: 0; }
.article-body h2 {
  margin: 2.7em 0 0.8em;
  padding-bottom: 0.45em;
  color: var(--brand-dark);
  font-size: clamp(1.45rem, 3vw, 1.85rem);
  border-bottom: 2px solid var(--brand-soft);
}
.article-body h3 { margin: 2em 0 0.55em; font-size: 1.2rem; }
.article-body p { margin: 0.9em 0; }
.article-body ul, .article-body ol { padding-left: 1.35em; }
.article-body li + li { margin-top: 0.45em; }
.article-body strong { color: var(--brand-dark); }

.summary-box, .note-box, .warning-box {
  margin: 24px 0;
  padding: 20px 22px;
  border-radius: 18px;
}
.summary-box { border: 1px solid rgba(31,79,138,.2); background: var(--brand-soft); }
.note-box { border-left: 4px solid var(--brand); background: #f7faff; }
.warning-box { border: 1px solid rgba(245,158,11,.3); background: var(--accent-soft); }
.summary-box > :first-child, .note-box > :first-child, .warning-box > :first-child { margin-top: 0; }
.summary-box > :last-child, .note-box > :last-child, .warning-box > :last-child { margin-bottom: 0; }

.comparison { width: 100%; margin: 22px 0; border-collapse: collapse; font-size: 0.95rem; }
.comparison th, .comparison td { padding: 13px 14px; border: 1px solid var(--line); text-align: left; vertical-align: top; }
.comparison th { color: var(--brand-dark); background: var(--brand-soft); }

.article-cta {
  margin: 34px 0 10px;
  padding: 26px;
  border-radius: 22px;
  color: #fff;
  background: linear-gradient(135deg, var(--brand), #356fae);
}
.article-cta h2, .article-cta h3 { margin: 0 0 8px; padding: 0; color: #fff; border: 0; }
.article-cta p { margin: 0 0 18px; color: rgba(255,255,255,.88); }
.article-cta .app-intro-link { display: inline-flex; margin-top: 14px; color: #fff; font-weight: 750; }
.button {
  display: inline-flex;
  min-height: 46px;
  align-items: center;
  justify-content: center;
  padding: 10px 18px;
  border-radius: 13px;
  color: var(--brand-dark);
  background: #fff;
  font-weight: 850;
  text-decoration: none;
}
.store-links { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.store-badge {
  display: inline-flex;
  min-height: 48px;
  align-items: center;
  text-decoration: none;
}
.store-badge img { display: block; width: auto; height: 48px; }
.store-badge-ios img { height: 48px; }
.store-badge-android img { height: 56px; }
.app-promo-section { padding: 0 0 72px; }
.app-promo {
  display: grid;
  grid-template-columns: 72px minmax(0, 1fr) auto;
  gap: 22px;
  align-items: center;
  padding: 28px 30px;
  border: 1px solid var(--line);
  border-radius: 24px;
  color: #fff;
  background: linear-gradient(135deg, var(--brand), #356fae);
  box-shadow: var(--shadow);
}
.app-promo-icon { width: 72px; height: 72px; border-radius: 18px; }
.app-promo-copy h2 { margin: 0 0 6px; font-size: 1.35rem; }
.app-promo-copy p { margin: 0; color: rgba(255,255,255,.88); }
.app-promo .store-links { justify-content: flex-end; }

.sidebar { position: sticky; top: 92px; display: grid; gap: 16px; }
.side-card { padding: 20px; border-radius: 20px; }
.side-card h2 { margin: 0 0 10px; color: var(--brand-dark); font-size: 1.05rem; }
.side-card ul { margin: 0; padding: 0; list-style: none; }
.side-card li + li { margin-top: 10px; }
.side-card a { font-size: 0.92rem; font-weight: 700; text-decoration: none; }
.side-card p { margin: 0; color: var(--muted); font-size: 0.9rem; }

.sources { margin-top: 42px; padding-top: 22px; border-top: 1px solid var(--line); }
.sources h2 { margin-top: 0; font-size: 1.2rem; }
.sources li { font-size: 0.9rem; }
.disclaimer { color: var(--muted); font-size: 0.86rem; }

.column-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  padding-bottom: 38px;
}
.column-card { display: flex; flex-direction: column; padding: 26px; border-radius: 22px; }
.column-card:first-child { grid-column: 1 / -1; }
.column-card .tag { color: var(--brand); font-size: 0.82rem; font-weight: 850; }
.column-card h2 { margin: 8px 0 10px; font-size: 1.3rem; }
.column-card p { margin: 0 0 20px; color: var(--muted); }
.column-card a { margin-top: auto; font-weight: 850; text-decoration: none; }

footer { padding: 24px 0 42px; color: var(--muted); font-size: 0.9rem; }
.footer-inner { display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; padding-top: 22px; border-top: 1px solid var(--line); }
.footer-links { display: flex; gap: 14px; flex-wrap: wrap; }
.footer-links a { color: inherit; }

a:focus-visible { outline: 3px solid #b66b00; outline-offset: 4px; }

@media (max-width: 820px) {
  .article-layout { grid-template-columns: 1fr; }
  .sidebar { position: static; }
  .column-grid { grid-template-columns: 1fr; }
  .column-card:first-child { grid-column: auto; }
  .app-promo { grid-template-columns: 58px minmax(0, 1fr); }
  .app-promo-icon { width: 58px; height: 58px; border-radius: 15px; }
  .app-promo .store-links { grid-column: 1 / -1; justify-content: flex-start; }
}

@media (max-width: 600px) {
  .container { width: min(calc(100% - 24px), var(--container)); }
  .topbar-inner { min-height: 0; flex-wrap: wrap; justify-content: center; gap: 4px; padding: 8px 0; }
  .brand { width: 100%; justify-content: center; }
  .brand span { font-size: 0.92rem; white-space: nowrap; }
  .topnav { width: 100%; justify-content: center; }
  .topnav a { padding: 6px 8px; font-size: 0.82rem; }
  .topnav .mobile-hide { display: none; }
  .article-hero, .index-hero { padding: 24px 0 30px; }
  .hero-panel { padding: 24px 20px; border-radius: 22px; }
  h1 { font-size: 1.75rem; }
  .hero-lead { font-size: 0.98rem; }
  .article-body { padding: 24px 20px; border-radius: 20px; }
  .comparison { display: block; overflow-x: auto; white-space: normal; }
  .store-badge img, .store-badge-ios img { height: 42px; }
  .store-badge-android img { height: 49px; }
  .app-promo { padding: 24px 20px; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}