:root {
      color-scheme: light;
      --ink: #17213a;
      --muted: #606b82;
      --blue: #2873cf;
      --blue-dark: #2058a3;
      --ice: #f3f7fc;
      --line: #dce5f1;
      --lavender: #f4f1ff;
      --white: #fff;
      --shadow: 0 18px 50px rgba(29, 56, 97, .09);
      --radius: 24px;
    }
    * { box-sizing: border-box; }
    html { scroll-behavior: smooth; }
    body {
      margin: 0;
      background: #fff;
      color: var(--ink);
      font-family: Inter, ui-sans-serif, system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
      line-height: 1.65;
    }
    a { color: var(--blue-dark); }
    .page-shell { width: min(1160px, calc(100% - 40px)); margin: 0 auto; }
    .site-header {
      display: flex; justify-content: space-between; align-items: center;
      padding: 23px 0; border-bottom: 1px solid var(--line);
    }
    .brand { display: flex; align-items: center; gap: 12px; font-weight: 800; letter-spacing: .08em; }
    .brand-mark {
      width: 38px; height: 38px; display: grid; place-items: center; border-radius: 12px;
      color: white; background: linear-gradient(145deg, #38a6ec, #315cc1);
      font-size: 17px; box-shadow: 0 7px 16px rgba(40, 115, 207, .25);
    }
    .header-note { color: var(--muted); font-size: 13px; letter-spacing: .08em; text-transform: uppercase; }
    main { padding-bottom: 68px; }
    .hero {
      display: grid; grid-template-columns: 1.02fr .98fr; gap: clamp(32px, 6vw, 80px);
      align-items: center; padding: 64px 0 58px;
    }
    .eyebrow {
      margin: 0 0 14px; color: var(--blue-dark); font-weight: 750;
      letter-spacing: .14em; text-transform: uppercase; font-size: 12px;
    }
    h1, h2, h3 { line-height: 1.18; letter-spacing: -.025em; }
    h1 { font-size: clamp(37px, 5vw, 60px); margin: 0 0 20px; max-width: 720px; }
    h2 { font-size: clamp(29px, 3.6vw, 42px); margin: 0 0 17px; }
    h3 { font-size: 20px; margin: 0 0 8px; }
    p { margin: 0 0 16px; }
    .lead { color: #4f5c75; font-size: clamp(17px, 1.6vw, 20px); max-width: 620px; }
    .hero-facts { display: flex; flex-wrap: wrap; gap: 10px; margin: 26px 0 28px; }
    .pill {
      border: 1px solid #d4e5f8; border-radius: 999px; padding: 8px 12px;
      color: #285c9f; background: #f5faff; font-size: 13px; font-weight: 700;
    }
    .button {
      display: inline-flex; align-items: center; justify-content: center; gap: 10px;
      padding: 13px 19px; border-radius: 12px; background: var(--blue);
      color: white; font-weight: 750; text-decoration: none; box-shadow: 0 10px 25px rgba(40, 115, 207, .2);
    }
    .button:hover { background: var(--blue-dark); }
    .small-note { color: var(--muted); font-size: 13px; margin-top: 13px; }
    .media-frame {
      position: relative; overflow: hidden; display: block; margin: 0;
      background: #f7f9fd; border: 1px solid var(--line); border-radius: var(--radius);
      box-shadow: var(--shadow);
    }
    .media-frame img {
      display: block; width: 100%; height: 100%;
      object-fit: contain; object-position: center;
    }
    .square-frame { aspect-ratio: 1 / 1; }
    .detail-frame { aspect-ratio: 4 / 3; }
    .case-frame { aspect-ratio: 20 / 13; box-shadow: none; }
    .dimension, .image-label {
      position: absolute; z-index: 1; top: 12px; left: 12px;
      padding: 6px 9px; border: 1px solid rgba(255,255,255,.82); border-radius: 999px;
      background: rgba(255,255,255,.92); color: #2a3a58; font-size: 11px;
      line-height: 1.2; font-weight: 750; box-shadow: 0 4px 14px rgba(28,42,67,.1);
    }
    .image-label { top: auto; left: 12px; bottom: 12px; color: #fff; background: rgba(26,41,69,.88); border-color: transparent; }
    .section { padding: 62px 0; border-top: 1px solid var(--line); scroll-margin-top: 24px; }
    .section-heading { max-width: 740px; margin-bottom: 28px; }
    .section-kicker { color: var(--blue-dark); font-size: 12px; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; margin-bottom: 9px; }
    .section-intro { color: var(--muted); max-width: 790px; font-size: 17px; }
    .principle-grid { display: grid; grid-template-columns: .9fr 1.1fr; align-items: center; gap: clamp(28px, 6vw, 74px); }
    .principle-copy { display: grid; gap: 15px; }
    .step { padding: 17px 18px; border: 1px solid var(--line); border-radius: 16px; background: var(--white); }
    .step strong { display: block; color: var(--blue-dark); margin-bottom: 4px; }
    .step p { color: var(--muted); margin: 0; font-size: 15px; }
    .details-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 22px; }
    .before-after-grid { display: grid; grid-template-columns: repeat(2, minmax(0,1fr)); gap: 22px; }
    .illustration-note {
      margin-top: 20px; padding: 14px 17px; color: #5d547c; background: var(--lavender);
      border-left: 3px solid #8570d6; border-radius: 8px 14px 14px 8px; font-size: 14px;
    }
    .table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 18px; box-shadow: 0 10px 30px rgba(29,56,97,.05); }
    table { width: 100%; border-collapse: collapse; min-width: 620px; background: white; }
    th, td { padding: 16px 18px; border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
    th { width: 31%; color: #334865; background: #f5f8fc; font-size: 14px; }
    td { color: #526179; }
    tr:last-child th, tr:last-child td { border-bottom: 0; }
    .table-note { color: var(--muted); font-size: 13px; margin: 13px 0 0; }
    .faq-list { display: grid; gap: 11px; }
    .faq-item { border: 1px solid var(--line); border-radius: 15px; padding: 0 18px; background: #fff; }
    .faq-item summary { position: relative; cursor: pointer; padding: 17px 28px 17px 0; list-style: none; font-weight: 750; }
    .faq-item summary::-webkit-details-marker { display: none; }
    .faq-item summary::after { content: "+"; position: absolute; right: 0; color: var(--blue-dark); font-size: 23px; top: 11px; }
    .faq-item[open] summary::after { content: "−"; }
    .faq-item p { margin: -3px 0 18px; max-width: 900px; color: var(--muted); }
    .closing {
      margin-top: 55px; padding: clamp(25px, 5vw, 48px); border-radius: 26px;
      background: linear-gradient(125deg, #eef7ff, #f5f3ff); border: 1px solid #dbe8f7;
      display: flex; justify-content: space-between; align-items: center; gap: 28px;
    }
    .closing h2 { font-size: clamp(25px, 3vw, 34px); margin-bottom: 8px; }
    .closing p { margin: 0; color: var(--muted); }
    .footnote { color: var(--muted); font-size: 12px; padding-top: 24px; }
    @media (max-width: 800px) {
      .hero, .principle-grid { grid-template-columns: 1fr; }
      .hero { padding-top: 42px; }
      .hero-copy { order: 1; }
      .hero-visual { order: 2; max-width: 590px; width: 100%; margin: 0 auto; }
      .principle-grid { gap: 25px; }
      .closing { align-items: flex-start; flex-direction: column; }
    }
    @media (max-width: 560px) {
      .page-shell { width: min(100% - 28px, 1160px); }
      .site-header { padding: 17px 0; }
      .header-note { font-size: 10px; max-width: 120px; text-align: right; }
      .hero { gap: 26px; padding: 34px 0 38px; }
      .section { padding: 42px 0; }
      .details-grid, .before-after-grid { grid-template-columns: 1fr; gap: 15px; }
      .dimension, .image-label { font-size: 10px; }
      th, td { padding: 13px 14px; }
    }
    @media (prefers-reduced-motion: reduce) {
      html { scroll-behavior: auto; }
    }