:root {
    --bg: #FAFAF9;
    --surface: #FFFFFF;
    --text: #1C1E22;
    --muted: #5B6169;
    --accent: #C77D3B;
    --accent-contrast: #FFFFFF;
    --border: rgba(28, 30, 34, 0.10);
  }

  @media (prefers-color-scheme: dark) {
    :root {
      --bg: #14161A;
      --surface: #1B1E23;
      --text: #F2F1EE;
      --muted: #A7ACB3;
      --accent: #D98F52;
      --accent-contrast: #14161A;
      --border: rgba(242, 241, 238, 0.10);
    }
  }

  * { box-sizing: border-box; }

  html { -webkit-text-size-adjust: 100%; }

  body {
    margin: 0;
    background: var(--bg);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Hiragino Sans", "Hiragino Kaku Gothic ProN",
      "Yu Gothic", "Noto Sans JP", "Segoe UI", sans-serif;
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
  }

  a { color: inherit; }

  .wrap {
    max-width: 760px;
    margin: 0 auto;
    padding: 0 24px;
  }

  header.site-header {
    padding: 28px 0;
    border-bottom: 1px solid var(--border);
  }

  header.site-header .wrap {
    display: flex;
    align-items: center;
    justify-content: space-between;
  }

  .logotype {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 0.02em;
    text-decoration: none;
  }

  .site-header nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: flex-end;
    gap: 8px 18px;
  }

  .site-header nav a {
    font-size: 14px;
    color: var(--muted);
    text-decoration: none;
  }

  .site-header nav a:hover {
    color: var(--text);
  }

  section {
    padding: 72px 0;
  }

  section#hero {
    padding-top: 96px;
    padding-bottom: 88px;
  }

  #hero h1 {
    font-size: clamp(2.4rem, 6vw, 3.4rem);
    line-height: 1.15;
    margin: 0 0 20px;
    letter-spacing: 0.01em;
  }

  #hero .tagline {
    font-size: clamp(1.05rem, 2.4vw, 1.25rem);
    color: var(--muted);
    max-width: 34em;
    margin: 0 0 36px;
  }

  .eyebrow {
    display: inline-block;
    font-size: 13px;
    color: var(--muted);
    border: 1px solid var(--border);
    border-radius: 999px;
    padding: 5px 14px;
    margin-bottom: 24px;
  }

  .btn {
    display: inline-block;
    background: var(--accent);
    color: var(--accent-contrast);
    text-decoration: none;
    font-size: 15px;
    font-weight: 600;
    padding: 13px 26px;
    border-radius: 8px;
  }

  .section-border {
    border-top: 1px solid var(--border);
  }

  h2 {
    font-size: 1.5rem;
    margin: 0 0 20px;
  }

  section p {
    color: var(--muted);
    max-width: 40em;
  }

  section p + p {
    margin-top: 14px;
  }

  .products {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
    margin-top: 28px;
  }

  .product-card {
    padding: 28px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
  }

  .product-card h3 {
    font-size: 1.25rem;
    margin: 0 0 10px;
  }

  .product-card p {
    font-size: 14px;
    margin: 0 0 18px;
  }

  .product-card a {
    color: var(--accent);
    font-weight: 700;
    text-underline-offset: 4px;
  }

  .product-links {
    display: flex;
    flex-wrap: wrap;
    gap: 8px 20px;
  }

  .product-links a { font-size: 14px; }

  .detail-hero { padding: 80px 0 64px; }
  .detail-hero h1 {
    font-size: clamp(2.3rem, 6vw, 3.4rem);
    line-height: 1.25;
    margin: 0 0 22px;
  }
  .detail-hero .intro {
    font-size: 1.08rem;
    color: var(--muted);
    max-width: 40em;
  }
  .breadcrumbs {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 30px;
    color: var(--muted);
    font-size: 13px;
  }
  .breadcrumbs a { text-underline-offset: 3px; }
  .detail-actions { display: flex; flex-wrap: wrap; align-items: center; gap: 12px 24px; margin-top: 28px; }
  .detail-actions .secondary-link { color: var(--accent); font-weight: 700; text-underline-offset: 4px; }
  .facts { display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px; margin-top: 30px; }
  .fact { border: 1px solid var(--border); border-radius: 10px; padding: 18px 20px; background: var(--surface); }
  .fact small { display: block; color: var(--muted); font-size: 12px; }
  .fact strong { display: block; margin-top: 5px; font-size: 1.05rem; }
  .detail-section { padding: 62px 0; }
  .detail-section h2 { max-width: 34em; }
  .detail-section .section-intro { margin-bottom: 28px; }
  .feature-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 14px; }
  .feature { background: var(--surface); border: 1px solid var(--border); border-radius: 10px; padding: 25px; }
  .feature h3 { font-size: 1.08rem; margin: 0 0 10px; }
  .feature p { font-size: 14px; margin: 0; }
  .steps { counter-reset: step; padding: 0; margin: 24px 0 0; list-style: none; }
  .steps li { position: relative; padding: 0 0 25px 52px; border-left: 1px solid var(--border); margin-left: 16px; }
  .steps li:last-child { border-left-color: transparent; padding-bottom: 0; }
  .steps li::before { counter-increment: step; content: counter(step); position: absolute; top: 0; left: -17px; width: 32px; height: 32px; display: grid; place-items: center; background: var(--accent); color: var(--accent-contrast); border-radius: 50%; font-weight: 700; font-size: 13px; }
  .steps h3 { margin: 0 0 4px; font-size: 1.05rem; }
  .steps p { margin: 0; font-size: 14px; }
  .notice { padding: 20px 24px; border-left: 4px solid var(--accent); background: var(--surface); }
  .notice p { margin: 0; }
  .detail-footer-links { display: flex; flex-wrap: wrap; gap: 10px 22px; }
  .detail-footer-links a { text-underline-offset: 3px; }

  .contact-email {
    display: inline-block;
    margin-top: 18px;
    font-size: 1.15rem;
    font-weight: 600;
    color: var(--text);
    text-decoration: none;
    border-bottom: 2px solid var(--accent);
    padding-bottom: 2px;
  }

  footer {
    border-top: 1px solid var(--border);
    padding: 32px 0 48px;
  }

  footer .wrap {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 8px;
    font-size: 13px;
    color: var(--muted);
  }

  @media (max-width: 480px) {
    section { padding: 52px 0; }
    section#hero { padding-top: 64px; padding-bottom: 56px; }
    header.site-header .wrap { align-items: flex-start; gap: 20px; }
    .products { grid-template-columns: 1fr; }
    .facts, .feature-grid { grid-template-columns: 1fr; }
    .detail-hero { padding: 58px 0 48px; }
    .detail-section { padding: 48px 0; }
  }