:root {
  --bg: #f6f4ef;
  --surface: #ffffff;
  --ink: #1f1d1a;
  --muted: #6b665e;
  --line: #e2ddd2;
  --accent: #3a4a7c;
  --accent-ink: #ffffff;
  --accent-soft: #dfe4f3;
  --cell: #ebe7dc;
  --cell-soft: #e1e5f0;
  --serif: ui-serif, "Hiragino Mincho ProN", "Yu Mincho", Georgia, serif;
  --sans: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Segoe UI", sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121315;
    --surface: #1b1c1f;
    --ink: #ece9e2;
    --muted: #9b968c;
    --line: #2b2c30;
    --accent: #a9b8ee;
    --accent-ink: #14172a;
    --accent-soft: #2a3150;
    --cell: #26272b;
    --cell-soft: #252a3d;
  }
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.75 var(--sans);
  -webkit-text-size-adjust: 100%;
}
a { color: var(--accent); }
h1, h2, h3, p { margin: 0; }

.skip {
  position: absolute; left: 16px; top: -48px; padding: 8px 14px;
  background: var(--surface); border-radius: 8px; z-index: 20;
}
.skip:focus { top: 12px; }

.lang-hint { text-align: center; padding: 8px 16px; background: var(--accent-soft); font-size: 14px; }

.topbar {
  position: sticky; top: 0; z-index: 10;
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 14px max(16px, calc((100vw - 1080px) / 2));
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--line);
}
.wordmark, .footer-brand {
  font: 600 19px/1 var(--serif); letter-spacing: 0.02em;
  color: var(--ink); text-decoration: none;
}
.wordmark span, .wordmark-xl span, .footer-brand span { color: var(--accent); font-weight: 400; }
.topnav { display: flex; align-items: center; gap: 22px; font-size: 14px; }
.topnav a { color: var(--muted); text-decoration: none; }
.topnav a:hover { color: var(--ink); }
.topnav .lang-toggle { padding: 4px 12px; border: 1px solid var(--line); border-radius: 999px; }

.hero {
  max-width: 1080px; margin: 0 auto; padding: 72px 16px 56px;
  display: grid; grid-template-columns: 1.15fr 0.85fr; gap: 56px; align-items: center;
}
.wordmark-xl { font: 600 clamp(40px, 7vw, 68px)/1.05 var(--serif); letter-spacing: 0.01em; }
.tagline { margin-top: 20px; font: 500 clamp(20px, 3vw, 26px)/1.4 var(--serif); }
.lead { margin-top: 16px; color: var(--muted); max-width: 34em; }
.cta { margin-top: 32px; }
.btn {
  display: inline-block; padding: 14px 28px; border-radius: 999px;
  background: var(--accent); color: var(--accent-ink);
  font-weight: 600; text-decoration: none;
  transition: transform .15s ease, opacity .15s ease;
}
.btn:hover { opacity: .9; transform: translateY(-1px); }
.btn:focus-visible, a:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }
.meta { margin-top: 12px; font-size: 14px; color: var(--muted); }

.panel { width: 100%; max-width: 360px; justify-self: center; height: auto; }
.panel-bg { fill: var(--surface); stroke: var(--line); stroke-width: 2; }
.cell { fill: var(--cell); }
.cell-soft { fill: var(--cell-soft); }
.cell-accent { fill: var(--accent); }
.cell-wide { fill: var(--surface); stroke: var(--line); stroke-width: 2; }
.dot { fill: var(--accent-ink); }
.stroke { fill: none; stroke: var(--accent); stroke-width: 6; stroke-linecap: round; }

.section { max-width: 1080px; margin: 0 auto; padding: 64px 16px; border-top: 1px solid var(--line); }
.section h2 { font: 600 clamp(26px, 4vw, 34px)/1.3 var(--serif); }
.section-lead { margin-top: 10px; color: var(--muted); }

.features { margin-top: 36px; display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.feature { background: var(--surface); border: 1px solid var(--line); border-radius: 20px; padding: 28px; }
.feature h3 { font: 600 19px/1.5 var(--serif); }
.feature p { margin-top: 10px; color: var(--muted); font-size: 15px; }

.steps { list-style: none; margin: 36px 0 0; padding: 0; display: grid; gap: 18px; }
.step { display: flex; gap: 18px; align-items: flex-start; }
.num {
  flex: none; width: 36px; height: 36px; border-radius: 50%;
  display: grid; place-items: center;
  background: var(--accent-soft); color: var(--accent);
  font: 600 16px/1 var(--serif);
}
.step h3 { font-size: 17px; font-weight: 600; line-height: 1.5; }
.step p { margin-top: 2px; color: var(--muted); font-size: 15px; }
.app-note { margin-top: 32px; padding: 14px 18px; border-radius: 14px; background: var(--accent-soft); font-size: 15px; }

.footer { text-align: center; padding: 48px 16px 56px; border-top: 1px solid var(--line); color: var(--muted); font-size: 14px; }
.footer-brand { display: block; color: var(--ink); }
.footer-tagline { margin-top: 8px; }
.footer-links { margin-top: 16px; }
.footer-note { margin-top: 16px; font-size: 13px; }

@media (max-width: 760px) {
  .hero { grid-template-columns: 1fr; gap: 40px; padding-top: 48px; }
  .features { grid-template-columns: 1fr; }
  .topnav { gap: 14px; }
  .topnav a:not(.lang-toggle):nth-child(n+2) { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .btn { transition: none; }
}