/* ==========================================================================
       Design System & Variables
       Base Canvas Color: #f1f4ff
       Audience: Young Global Stationery Enthusiasts & Aesthetic Desk Curators
       Strict Guardrails: ZERO links (<a>), ZERO buttons (<button>), ZERO brand/company names
       ========================================================================== */
    :root {
      --bg-canvas: #f1f4ff;
      --bg-surface: #ffffff;
      --bg-surface-soft: #f8faff;
      --text-main: #1e293b;
      --text-body: #475569;
      --text-muted: #64748b;
      --accent-slate: #3b5998;
      --accent-cinnabar: #c84b31;
      --border-color: #dce5fc;
      --border-card: #e2e8f0;
      --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
      --shadow-sm: 0 2px 6px rgba(15, 23, 42, 0.04);
      --shadow-md: 0 8px 20px rgba(15, 23, 42, 0.06);
      --radius-lg: 16px;
      --radius-md: 10px;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      background-color: var(--bg-canvas);
      color: var(--text-body);
      font-family: var(--font-family);
      line-height: 1.6;
      font-size: 15px;
      padding: 0;
      margin: 0;
      -webkit-font-smoothing: antialiased;
    }

    .container {
      max-width: 1080px;
      margin: 0 auto;
      padding: 36px 20px 80px;
    }

    /* Header Section */
    .hero-section {
      text-align: center;
      margin-bottom: 36px;
      padding: 32px 24px;
      background: var(--bg-surface);
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
    }

    .hero-badge {
      display: inline-block;
      padding: 6px 14px;
      background-color: #edf2ff;
      color: var(--accent-slate);
      font-size: 13px;
      font-weight: 600;
      border-radius: 20px;
      letter-spacing: 0.5px;
      margin-bottom: 14px;
    }

    .hero-title {
      font-size: 28px;
      font-weight: 700;
      color: var(--text-main);
      letter-spacing: -0.3px;
      margin-bottom: 12px;
      line-height: 1.3;
    }

    .hero-desc {
      font-size: 16px;
      color: var(--text-body);
      max-width: 760px;
      margin: 0 auto 20px;
      line-height: 1.6;
    }

    .feature-tags {
      display: flex;
      flex-wrap: wrap;
      justify-content: center;
      gap: 10px;
      margin-top: 16px;
    }

    .feature-tag-item {
      background: var(--bg-surface-soft);
      border: 1px solid var(--border-color);
      padding: 6px 14px;
      border-radius: var(--radius-md);
      font-size: 13px;
      font-weight: 500;
      color: var(--text-muted);
    }

    /* Product Gallery (2 Columns Grid) */
    .gallery-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
      margin-bottom: 48px;
    }

    .gallery-card {
      background: var(--bg-surface);
      border-radius: var(--radius-lg);
      overflow: hidden;
      border: 1px solid var(--border-color);
      box-shadow: var(--shadow-sm);
      display: flex;
      flex-direction: column;
      transition: transform 0.2s ease, box-shadow 0.2s ease;
    }

    .gallery-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-2px);
    }

    .image-wrapper {
      position: relative;
      width: 100%;
      padding-top: 100%; /* 1:1 Aspect Ratio */
      background-color: var(--bg-canvas);
      overflow: hidden;
    }

    .image-wrapper img {
      position: absolute;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      object-fit: cover;
      display: block;
    }

    .card-info {
      padding: 20px;
      flex-grow: 1;
      display: flex;
      flex-direction: column;
      justify-content: space-between;
    }

    .card-meta {
      display: flex;
      align-items: center;
      justify-content: space-between;
      margin-bottom: 8px;
    }

    .card-step {
      font-size: 12px;
      font-weight: 700;
      color: var(--accent-slate);
      text-transform: uppercase;
      letter-spacing: 0.5px;
    }

    .card-label {
      font-size: 11px;
      padding: 3px 8px;
      background: #edf2ff;
      color: var(--text-muted);
      border-radius: 4px;
      font-weight: 500;
    }

    .card-title {
      font-size: 17px;
      font-weight: 600;
      color: var(--text-main);
      margin-bottom: 8px;
      line-height: 1.4;
    }

    .card-desc {
      font-size: 13px;
      color: var(--text-body);
      line-height: 1.55;
    }

    /* Specifications Section */
    .specs-section {
      background: var(--bg-surface);
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      padding: 32px 28px;
      margin-bottom: 48px;
      box-shadow: var(--shadow-sm);
    }

    .section-title {
      font-size: 22px;
      font-weight: 700;
      color: var(--text-main);
      margin-bottom: 20px;
      text-align: center;
    }

    .specs-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 18px;
    }

    .spec-item {
      background: var(--bg-surface-soft);
      padding: 16px;
      border-radius: var(--radius-md);
      border: 1px solid var(--border-color);
    }

    .spec-name {
      font-size: 12px;
      color: var(--text-muted);
      font-weight: 600;
      text-transform: uppercase;
      letter-spacing: 0.5px;
      margin-bottom: 6px;
    }

    .spec-value {
      font-size: 14px;
      font-weight: 600;
      color: var(--text-main);
    }

    /* FAQ Section (Accordion using <details> and <summary> without buttons/links) */
    .faq-section {
      background: var(--bg-surface);
      border-radius: var(--radius-lg);
      border: 1px solid var(--border-color);
      padding: 36px 30px;
      box-shadow: var(--shadow-sm);
    }

    .faq-list {
      display: flex;
      flex-direction: column;
      gap: 14px;
      margin-top: 24px;
    }

    details.faq-item {
      border: 1px solid var(--border-color);
      border-radius: var(--radius-md);
      background: var(--bg-surface-soft);
      overflow: hidden;
      transition: background 0.2s ease;
    }

    details.faq-item[open] {
      background: #ffffff;
      border-color: var(--accent-slate);
    }

    summary.faq-question {
      padding: 16px 20px;
      font-size: 15px;
      font-weight: 600;
      color: var(--text-main);
      cursor: pointer;
      user-select: none;
      display: flex;
      align-items: center;
      justify-content: space-between;
      list-style: none;
    }

    summary.faq-question::-webkit-details-marker {
      display: none;
    }

    summary.faq-question::after {
      content: "+";
      font-size: 18px;
      font-weight: 400;
      color: var(--accent-slate);
      line-height: 1;
      transition: transform 0.2s ease;
    }

    details.faq-item[open] summary.faq-question::after {
      content: "\2212";
    }

    .faq-answer {
      padding: 0 20px 18px 20px;
      font-size: 14px;
      color: var(--text-body);
      line-height: 1.6;
      border-top: 1px solid rgba(220, 229, 252, 0.4);
      padding-top: 12px;
    }

    /* Footer / Bottom Notice */
    .footer-note {
      text-align: center;
      margin-top: 40px;
      padding: 20px;
      font-size: 13px;
      color: var(--text-muted);
    }

    /* Responsive Breakpoints */
    @media (max-width: 860px) {
      .specs-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 640px) {
      .container {
        padding: 20px 14px 60px;
      }

      .hero-title {
        font-size: 22px;
      }

      .gallery-grid {
        grid-template-columns: 1fr;
        gap: 18px;
      }

      .specs-grid {
        grid-template-columns: 1fr;
      }

      .specs-section, .faq-section, .hero-section {
        padding: 24px 16px;
      }
    }