:root {
  --ink: #0B1624;
  --navy: #0F2A43;
  --line: #1F3350;
  --text: #E6EDF5;
  --muted: #93A6BA;
  --accent: #1E5EFF;
  --paper: #F7F9FC;
  --paper-line: #E3E8EF;
  --paper-text: #142033;
  --paper-muted: #5B6B80;
  --max: 1080px;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font: 16px/1.65 system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--paper-text);
  background: var(--paper);
}
a { color: inherit; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 24px; }

/* ヘッダー */
.top { background: var(--ink); color: var(--text); }
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.logo { display: flex; align-items: center; gap: 10px; font-weight: 700; letter-spacing: .01em; text-decoration: none; }
.logo img { width: 28px; height: 28px; border-radius: 6px; }
.nav-links { display: flex; gap: 22px; font-size: 14px; color: var(--muted); }
.nav-links a { text-decoration: none; }
.nav-links a:hover { color: var(--text); }

/* ヒーロー */
.hero { padding: 64px 0 72px; }
.eyebrow { font-size: 13px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; color: #7FA2FF; margin: 0 0 14px; }
.hero h1 { font-size: clamp(34px, 5.2vw, 56px); line-height: 1.08; letter-spacing: -.02em; margin: 0 0 18px; max-width: 14em; }
.hero p.lead { font-size: 19px; color: var(--muted); max-width: 36em; margin: 0 0 30px; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; }
.btn {
  display: inline-flex; align-items: center; justify-content: center; height: 46px; padding: 0 22px;
  border-radius: 8px; font-weight: 600; text-decoration: none; border: 1px solid transparent;
}
.btn.primary { background: var(--accent); color: #fff; }
.btn.primary:hover { background: #1747C8; }
.btn.ghost { border-color: var(--line); color: var(--text); }
.cta-note { font-size: 13px; color: var(--muted); }
.demo {
  margin-top: 48px; border-radius: 12px; overflow: hidden; border: 1px solid var(--line);
  background: #000; box-shadow: 0 30px 60px -20px rgba(0, 0, 0, .6);
}
.demo video { display: block; width: 100%; height: auto; aspect-ratio: 16 / 9; }

/* セクション */
section { padding: 72px 0; }
section + section { border-top: 1px solid var(--paper-line); }
h2 { font-size: clamp(26px, 3.4vw, 34px); letter-spacing: -.01em; line-height: 1.2; margin: 0 0 12px; }
.sub { color: var(--paper-muted); max-width: 40em; margin: 0 0 36px; }

.steps { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; counter-reset: s; }
.step { background: #fff; border: 1px solid var(--paper-line); border-radius: 10px; padding: 22px; }
.step::before {
  counter-increment: s; content: counter(s); display: inline-grid; place-items: center;
  width: 28px; height: 28px; border-radius: 50%; background: var(--navy); color: #fff; font-size: 14px; font-weight: 700; margin-bottom: 12px;
}
.step h3, .feature h3 { font-size: 17px; margin: 0 0 6px; }
.step p, .feature p { margin: 0; color: var(--paper-muted); font-size: 15px; }

.features { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px 32px; }
.feature { border-top: 2px solid var(--navy); padding-top: 14px; }

/* 料金 */
.plans { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; max-width: 820px; }
.plan { background: #fff; border: 1px solid var(--paper-line); border-radius: 12px; padding: 28px; display: flex; flex-direction: column; }
.plan.pro { border: 2px solid var(--accent); }
.plan h3 { margin: 0; font-size: 18px; }
.price { font-size: 40px; font-weight: 700; letter-spacing: -.02em; margin: 10px 0 2px; }
.price small { font-size: 15px; font-weight: 500; color: var(--paper-muted); letter-spacing: 0; }
.plan ul { list-style: none; padding: 0; margin: 18px 0 24px; flex: 1; }
.plan li { padding: 7px 0 7px 26px; position: relative; border-bottom: 1px solid var(--paper-line); font-size: 15px; }
.plan li::before { content: ""; position: absolute; left: 4px; top: 14px; width: 10px; height: 6px; border-left: 2px solid var(--accent); border-bottom: 2px solid var(--accent); transform: rotate(-45deg); }
.plan li.no::before { border-color: #B8C2CF; }
.plan li.no { color: var(--paper-muted); }
.plan .btn { width: 100%; }
.plan .btn.outline { border-color: var(--paper-line); color: var(--paper-text); background: #fff; cursor: default; }

/* FAQ */
.faq { max-width: 760px; }
.faq details { border-bottom: 1px solid var(--paper-line); padding: 16px 0; }
.faq summary { cursor: pointer; font-weight: 600; list-style: none; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; float: right; color: var(--paper-muted); font-weight: 400; }
.faq details[open] summary::after { content: "–"; }
.faq p { margin: 10px 0 0; color: var(--paper-muted); }

/* フッター */
footer { background: var(--ink); color: var(--muted); font-size: 14px; padding: 36px 0; }
.foot { display: flex; flex-wrap: wrap; gap: 12px 28px; justify-content: space-between; }
.foot nav { display: flex; gap: 20px; }
.foot a { text-decoration: none; }
.foot a:hover { color: var(--text); }

/* 規約ページ */
.doc { max-width: 760px; padding: 56px 0 80px; }
.doc h1 { font-size: 34px; margin: 0 0 6px; letter-spacing: -.01em; }
.doc .updated { color: var(--paper-muted); margin: 0 0 32px; font-size: 14px; }
.doc h2 { font-size: 20px; margin: 32px 0 8px; }
.doc p, .doc li { color: #2A3A50; }

@media (max-width: 820px) {
  .steps, .features, .plans { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .hero { padding: 40px 0 48px; }
  section { padding: 52px 0; }
}