:root {
  color-scheme: light dark;
  --bg: #ffffff;
  --surface: #f6f7f9;
  --text: #1c1c1e;
  --muted: #5b5f66;
  --line: #e3e5e8;
  --pink: #f72585;
  --pink-text: #d70045;
  --cyan: #4cc9f0;
  --cyan-text: #007a9f;
  --yellow: #ffbe0b;
  --yellow-text: #8a6700;
  --on-accent: #2b000c;
  --radius: 16px;
  --max: 1080px;
  --prose: 760px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f0f11;
    --surface: #1a1a1e;
    --text: #f2f2f4;
    --muted: #a3a7ad;
    --line: #2c2d31;
    --pink-text: #ff5c9e;
    --cyan-text: #5ce1ff;
    --yellow-text: #ffd65a;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Helvetica Neue",
    "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Noto Sans JP", "Noto Sans KR",
    "Noto Sans SC", "Noto Sans TC", Arial, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--cyan-text); text-decoration: none; }
a:hover { text-decoration: underline; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 24px; }
.prose { max-width: var(--prose); margin: 0 auto; padding: 0 24px; }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
}
.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 60px;
  gap: 16px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  font-weight: 700;
  font-size: 18px;
  letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; }
.brand svg { width: 28px; height: 28px; }
.site-nav { display: flex; align-items: center; gap: 20px; font-size: 15px; }
.site-nav a { color: var(--muted); }
.site-nav a:hover { color: var(--text); text-decoration: none; }
.lang-switch {
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 4px 12px;
  color: var(--text) !important;
  font-size: 13px;
}
@media (max-width: 640px) {
  .site-nav a:not(.lang-switch) { display: none; }
}

/* Hero */
.hero {
  padding: 72px 0 56px;
  text-align: center;
  background:
    radial-gradient(60% 50% at 20% 0%, color-mix(in srgb, var(--pink) 14%, transparent), transparent 70%),
    radial-gradient(50% 50% at 85% 10%, color-mix(in srgb, var(--cyan) 18%, transparent), transparent 70%),
    radial-gradient(40% 40% at 60% 100%, color-mix(in srgb, var(--yellow) 14%, transparent), transparent 70%);
}
.hero .logo { width: 104px; height: 104px; margin: 0 auto 20px; }
.hero h1 {
  font-size: clamp(34px, 6vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 16px;
}
.hero .lead {
  font-size: clamp(17px, 2.2vw, 21px);
  color: var(--muted);
  max-width: 640px;
  margin: 0 auto 32px;
}
.badges {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-bottom: 12px;
}
.badge {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--text);
  color: var(--bg);
  border-radius: 12px;
  padding: 10px 18px;
  font-weight: 600;
  font-size: 15px;
  line-height: 1.2;
  text-align: left;
}
.badge small { display: block; font-weight: 400; font-size: 11px; opacity: 0.8; }
.badge:hover { text-decoration: none; opacity: 0.9; }
.badge svg { width: 22px; height: 22px; flex: none; }
.hero .note { font-size: 13px; color: var(--muted); margin: 0; }

/* Sections */
section { padding: 64px 0; }
section + section { border-top: 1px solid var(--line); }
.section-title {
  font-size: clamp(26px, 3.6vw, 36px);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 12px;
  text-align: center;
}
.section-lead {
  color: var(--muted);
  text-align: center;
  max-width: 640px;
  margin: 0 auto 40px;
}

.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  counter-reset: step;
}
.step {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 24px;
}
.step::before {
  counter-increment: step;
  content: counter(step);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--pink);
  color: var(--on-accent);
  font-weight: 700;
  margin-bottom: 14px;
}
.step h3 { margin: 0 0 8px; font-size: 19px; }
.step p { margin: 0; color: var(--muted); }

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}
.feature {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 24px;
}
.feature .icon {
  width: 40px;
  height: 40px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 14px;
  font-size: 20px;
}
.icon.pink { background: color-mix(in srgb, var(--pink) 18%, transparent); }
.icon.cyan { background: color-mix(in srgb, var(--cyan) 22%, transparent); }
.icon.yellow { background: color-mix(in srgb, var(--yellow) 22%, transparent); }
.feature h3 { margin: 0 0 8px; font-size: 19px; }
.feature p { margin: 0; color: var(--muted); font-size: 16px; }

.privacy-band {
  background: var(--surface);
}
.privacy-list {
  list-style: none;
  padding: 0;
  margin: 0 auto;
  max-width: 720px;
  display: grid;
  gap: 12px;
}
.privacy-list li {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 14px 16px;
}
.privacy-list .check {
  flex: none;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--cyan);
  color: #002b38;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: 700;
  margin-top: 2px;
}

.platforms {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 20px;
}
.platform {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 20px 24px;
}
.platform h3 { margin: 0 0 6px; font-size: 18px; }
.platform p { margin: 0; color: var(--muted); font-size: 15px; }

.faq { max-width: 760px; margin: 0 auto; }
.faq details {
  border-bottom: 1px solid var(--line);
  padding: 14px 0;
}
.faq summary {
  cursor: pointer;
  font-weight: 600;
  font-size: 17px;
  list-style: none;
  display: flex;
  justify-content: space-between;
  gap: 12px;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; color: var(--muted); }
.faq details[open] summary::after { content: "−"; }
.faq details p { margin: 10px 0 0; color: var(--muted); }

.cta {
  text-align: center;
  padding: 72px 0;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 32px 0;
  font-size: 14px;
  color: var(--muted);
}
.site-footer .container {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 12px 24px;
}
.site-footer nav { display: flex; flex-wrap: wrap; gap: 16px; }
.site-footer a { color: var(--muted); }

/* Legal documents */
.doc { padding: 48px 0 80px; }
.doc h1 {
  font-size: clamp(28px, 4vw, 38px);
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin: 0 0 8px;
}
.doc .meta { color: var(--muted); font-size: 15px; margin: 0 0 32px; }
.doc h2 {
  font-size: 22px;
  margin: 40px 0 12px;
  letter-spacing: -0.01em;
}
.doc h3 { font-size: 18px; margin: 24px 0 8px; }
.doc p, .doc li { font-size: 16px; }
.doc ul, .doc ol { padding-left: 24px; }
.doc li + li { margin-top: 6px; }
.doc .summary {
  background: var(--surface);
  border-left: 4px solid var(--cyan);
  border-radius: 8px;
  padding: 16px 20px;
  margin: 0 0 24px;
}
.doc .summary p:first-child { margin-top: 0; }
.doc .summary ul { margin-bottom: 0; }
.doc table {
  width: 100%;
  border-collapse: collapse;
  font-size: 15px;
  margin: 12px 0 20px;
}
.doc th, .doc td {
  text-align: left;
  vertical-align: top;
  padding: 10px 12px;
  border-bottom: 1px solid var(--line);
}
.doc th { color: var(--muted); font-weight: 600; white-space: nowrap; }
.doc .table-wrap { overflow-x: auto; }
.doc .toc {
  background: var(--surface);
  border-radius: 12px;
  padding: 16px 20px 16px 36px;
  margin: 0 0 24px;
  font-size: 15px;
  columns: 2;
  column-gap: 24px;
}
.doc .toc li { break-inside: avoid; margin: 4px 0; }
@media (max-width: 560px) { .doc .toc { columns: 1; } }