/* ==========================================================================
     Reset & Base
     ========================================================================== */
  * { margin: 0; padding: 0; box-sizing: border-box; }

  html { scroll-behavior: smooth; }

  body {
    font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
    color: var(--text-main);
    line-height: 1.6;
    background-color: var(--bg-light);
  }

  a { cursor: pointer; text-decoration: none; color: inherit; }

  img { max-width: 100%; height: auto; display: block; }

  :root {
    --primary: #d71920;
    --primary-hover: #b5151a;
    --primary-light: #fdf3f3;
    --text-main: #333333;
    --text-light: #555555;
    --bg-light: #f8f9fa;
    --bg-white: #ffffff;
    --border-color: #eaeaea;

    --side: 8%;
    --shadow-sm: 0 4px 15px rgba(0, 0, 0, 0.02);
    --shadow-md: 0 10px 30px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 15px 40px rgba(0, 0, 0, 0.15);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  }

  a:focus-visible, button:focus-visible {
    outline: 3px solid var(--primary);
    outline-offset: 2px;
  }

  .page {
    max-width: 1400px;
    margin: 0 auto;
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
  }

  .section { padding: 80px var(--side); }
  .bg-light { background: var(--bg-light); }

  /* ==========================================================================
     Breadcrumb
     ========================================================================== */
  .breadcrumb {
    padding: 18px var(--side);
    background: var(--bg-white);
    border-bottom: 1px solid var(--border-color);
    font-size: 13px;
    color: #888;
  }
  .breadcrumb a { color: #888; transition: var(--transition); }
  .breadcrumb a:hover { color: var(--primary); }
  .breadcrumb span { margin: 0 8px; color: #ccc; }
  .breadcrumb strong { color: var(--text-light); font-weight: 600; }

  /* ==========================================================================
     Hero Section
     ========================================================================== */
  .hero {
    position: relative;
    height: 600px;
    background: #222;
    overflow: hidden;
    display: flex;
    align-items: center;
  }
  .hero img.hero-bg {
    position: absolute; top: 0; left: 0;
    width: 100%; height: 100%;
    object-fit: cover; opacity: 0.85; z-index: 1;
  }
  .hero-inner { position: absolute; right: var(--side); width: 45%; min-width: 420px; z-index: 10; }
  .hero-content {
    background: var(--bg-white);
    padding: 45px;
    border-left: 8px solid var(--primary);
    box-shadow: var(--shadow-lg);
    border-radius: 0 8px 8px 0;
  }
  .hero-content h1 { font-size: 38px; line-height: 1.2; margin-bottom: 20px; color: #111; }
  .hero-content h1 span { color: var(--primary); }
  .hero-content p { font-size: 16px; color: var(--text-light); margin-bottom: 30px; }
  .hero-cta {
    display: inline-flex; align-items: center; gap: 12px;
    background: var(--primary); color: #fff;
    padding: 15px 35px; font-size: 16px; font-weight: bold;
    border-radius: 4px; transition: var(--transition);
  }
  .hero-cta:hover { background: var(--primary-hover); transform: translateY(-2px); box-shadow: var(--shadow-md); }

  /* ==========================================================================
     Intro / Key Takeaways  (SEO 新增)
     ========================================================================== */
  .intro { padding: 60px var(--side) 0; }
  .intro h2 { font-size: 26px; font-weight: 800; color: #111; margin-bottom: 18px; }
  .intro p { font-size: 16px; color: var(--text-light); margin-bottom: 16px; max-width: 1100px; }
  .intro p strong { color: #111; }

  .key-takeaways {
    margin: 30px 0 0;
    padding: 26px 30px;
    background: var(--primary-light);
    border-left: 5px solid var(--primary);
    border-radius: 0 8px 8px 0;
  }
  .key-takeaways h3 { font-size: 16px; text-transform: uppercase; letter-spacing: 1px; color: var(--primary); margin-bottom: 12px; }
  .key-takeaways ul { list-style: none; }
  .key-takeaways li { position: relative; padding-left: 24px; margin-bottom: 8px; font-size: 15px; color: #222; }
  .key-takeaways li::before { content: "▸"; position: absolute; left: 0; color: var(--primary); font-weight: bold; }

  /* ==========================================================================
     Section Banner
     ========================================================================== */
  .section-banner {
    background-color: var(--primary);
    color: #ffffff;
    padding: 70px var(--side);
    display: grid;
    grid-template-columns: 640px 1fr;
    align-items: center;
    column-gap: 60px; row-gap: 16px;
    overflow: hidden;
  }
  /* 原为 h2，现改用 p —— 避免与内容区 H2 争夺标题层级 */
  .section-banner .banner-title {
    font-size: 56px; font-weight: 800; margin: 0;
    text-transform: uppercase; letter-spacing: 1px;
    line-height: 1.1; white-space: nowrap;
  }
  .section-banner p.banner-desc { font-size: 16px; margin: 0; line-height: 1.6; color: #ffffff; max-width: 600px; white-space: nowrap; }

  /* ==========================================================================
     Section Headers
     ========================================================================== */
  .section-header { text-align: center; margin-bottom: 60px; }
  .section-header .tag { display: inline-block; color: var(--primary); font-weight: 700; font-size: 20px; letter-spacing: 1.5px; text-transform: uppercase; margin-bottom: 12px; }
  .section-header h2 { font-size: 36px; font-weight: 800; color: #111; margin-bottom: 15px; }
  .section-header p { font-size: 16px; color: var(--text-light); max-width: 650px; margin: 0 auto; }

  /* ==========================================================================
     01 Comparison Cards
     ========================================================================== */
  .gen-compare { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
  .gen-card {
    background: var(--bg-white); border: 1px solid var(--border-color);
    border-radius: 8px; padding: 35px 30px; box-shadow: var(--shadow-sm);
    transition: var(--transition); display: flex; flex-direction: column;
  }
  .gen-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
  .gen-card.featured { border: 2px solid var(--primary); background: var(--primary-light); position: relative; transform: scale(1.03); z-index: 2; }
  .gen-card.featured:hover { transform: scale(1.03) translateY(-5px); }
  .badge {
    position: absolute; top: -14px; left: 50%; transform: translateX(-50%);
    background: var(--primary); color: #fff; padding: 4px 16px;
    border-radius: 20px; font-size: 13px; font-weight: bold; letter-spacing: 0.5px; white-space: nowrap;
  }
  .gen-card h3 { font-size: 22px; margin-bottom: 5px; text-align: center; color: #111; }
  .gen-card h3 a { color: inherit; transition: var(--transition); }
  .gen-card h3 a:hover { color: var(--primary); }
  .gen-card .subtitle { color: #666; font-size: 14px; text-align: center; margin-bottom: 25px; font-weight: 500; }
  .feature-list { list-style: none; flex-grow: 1; }
  .feature-list li { margin-bottom: 15px; display: flex; align-items: flex-start; gap: 12px; font-size: 15px; line-height: 1.4; }
  .feature-list li.bad { color: #666; }
  .feature-list li.good { color: #111; font-weight: 600; }
  .icon-svg { width: 18px; height: 18px; flex-shrink: 0; margin-top: 2px; }
  .icon-success { color: #28a745; }
  .icon-warning { color: #dc3545; }

  /* ==========================================================================
     02 Specification Table  (SEO 新增)
     ========================================================================== */
  .spec-wrap { overflow-x: auto; margin-bottom: 70px; box-shadow: var(--shadow-sm); border-radius: 8px; }
  .spec-table { width: 100%; border-collapse: collapse; background: var(--bg-white); font-size: 15px; }
  .spec-table caption { text-align: left; padding: 18px 24px; font-weight: 700; font-size: 17px; color: #111; background: var(--primary-light); border-bottom: 2px solid var(--primary); }
  .spec-table th, .spec-table td { padding: 14px 24px; text-align: left; border-bottom: 1px solid var(--border-color); }
  .spec-table thead th { background: #fafafa; color: #111; font-weight: 700; width: 32%; }
  .spec-table tbody tr:hover { background: var(--primary-light); }
  .spec-table td strong { color: var(--primary); }

  /* ==========================================================================
     03 Zig-Zag Core Advantages
     ========================================================================== */
  .zig-zag-row { display: flex; align-items: center; gap: 60px; margin-bottom: 90px; }
  .zig-zag-row:last-child { margin-bottom: 0; }
  .zig-zag-row:nth-child(even) { flex-direction: row-reverse; }
  .zz-img { flex: 1; border-radius: 8px; overflow: hidden; box-shadow: var(--shadow-md); background: var(--bg-white); }
  .zz-img img { width: 100%; min-height: 350px; object-fit: cover; transition: var(--transition); }
  .zz-img:hover img { transform: scale(1.02); }
  .zz-text { flex: 1; }
  .zz-text h3 { font-size: 26px; color: #111; margin-bottom: 20px; display: flex; align-items: center; gap: 15px; font-weight: 700; }
  .zz-text h3 span { background: var(--primary); color: #fff; width: 36px; height: 36px; display: flex; align-items: center; justify-content: center; border-radius: 50%; font-size: 16px; flex-shrink: 0; }
  .zz-text h3 a { transition: var(--transition); }
  .zz-text h3 a:hover { color: var(--primary); }
  .zz-text p { color: var(--text-light); margin-bottom: 25px; font-size: 16px; }
  .zz-bullets { list-style: none; }
  .zz-bullets li { position: relative; padding-left: 28px; margin-bottom: 12px; color: #222; font-weight: 500; font-size: 15px; }
  .zz-bullets li::before { content: "\2713"; position: absolute; left: 0; top: -2px; color: var(--primary); font-weight: bold; font-size: 18px; }

  /* ==========================================================================
     04 Applications
     ========================================================================== */
  .applications { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
  .app-card {
    background: var(--bg-white); border-radius: 8px; overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.04); border: 1px solid var(--border-color);
    transition: var(--transition); display: flex; flex-direction: column;
  }
  .app-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-md); }
  .app-img-wrap { height: 220px; overflow: hidden; border-bottom: 3px solid var(--primary); }
  .app-img-wrap img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.6s ease, filter 0.6s ease; filter: brightness(1.12) contrast(1.08) saturate(1.1); }
  .app-card:hover .app-img-wrap img { transform: scale(1.05); filter: brightness(1.18) contrast(1.12) saturate(1.15); }
  .app-content { padding: 24px 20px; flex-grow: 1; display: flex; flex-direction: column; }
  .app-content h3 { font-size: 18px; margin: 0 0 10px; font-weight: 700; color: #111; text-align: center; }
  .app-content p { font-size: 14px; color: var(--text-light); text-align: center; line-height: 1.6; }

  /* ==========================================================================
     05 Assembly Guide  (SEO 新增)
     ========================================================================== */
  .assembly-steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; counter-reset: step; }
  .assembly-card {
    background: var(--bg-white); border: 1px solid var(--border-color);
    border-radius: 8px; padding: 28px 22px; box-shadow: var(--shadow-sm);
    transition: var(--transition); position: relative;
  }
  .assembly-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-top-color: var(--primary); border-top-width: 3px; }
  .assembly-card .num { font-size: 13px; font-weight: 800; color: var(--primary); letter-spacing: 1px; display: block; margin-bottom: 10px; }
  .assembly-card h3 { font-size: 16px; color: #111; font-weight: 700; margin-bottom: 10px; }
  .assembly-card p { font-size: 14px; color: var(--text-light); line-height: 1.6; }

  /* ==========================================================================
     06 Timeline
     ========================================================================== */
  .process-timeline { display: grid; grid-template-columns: repeat(4, 1fr); gap: 0; position: relative; margin-top: 40px; z-index: 1; align-items: stretch; }
  .process-step {
    background: var(--bg-white); padding: 28px 18px 22px; border: 1px solid #e5e5e5;
    border-radius: 8px; text-align: center; position: relative;
    transition: var(--transition); border-top: 3px solid #e5e5e5; z-index: 2; margin: 0 12px;
  }
  .process-step:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); border-top-color: var(--primary); }
  .process-step:last-child { border-top-color: var(--primary); }
  .process-icon { width: 52px; height: 52px; margin: 0 auto 16px; display: block; }
  .step-number { position: absolute; top: 14px; right: 16px; font-size: 12px; font-weight: 700; color: #aaa; letter-spacing: 0.5px; }
  .process-step:last-child .step-number { color: var(--primary); }
  .process-step h3 { font-size: 15px; margin-bottom: 10px; color: #111; font-weight: 700; }
  .process-step p { font-size: 13px; color: var(--text-light); line-height: 1.6; }
  .process-step:not(:last-child)::after { content: "\2192"; position: absolute; right: -20px; top: 50%; transform: translateY(-50%); font-size: 20px; color: var(--primary); font-weight: bold; z-index: 3; }

  /* ==========================================================================
     07 FAQ  (SEO 新增)
     ========================================================================== */
  .faq-list { max-width: 1000px; margin: 0 auto; }
  .faq-item { background: var(--bg-white); border: 1px solid var(--border-color); border-radius: 8px; margin-bottom: 16px; overflow: hidden; box-shadow: var(--shadow-sm); }
  .faq-item h3 { font-size: 17px; font-weight: 700; color: #111; padding: 20px 26px 14px; }
  .faq-item p { font-size: 15px; color: var(--text-light); padding: 0 26px 22px; line-height: 1.7; }
  .faq-item p a { color: var(--primary); font-weight: 600; text-decoration: underline; }

  /* ==========================================================================
     08 Bottom CTA  (SEO 新增)
     ========================================================================== */
  .cta-band { background: var(--primary); color: #fff; padding: 70px var(--side); text-align: center; }
  .cta-band h2 { font-size: 34px; font-weight: 800; margin-bottom: 14px; }
  .cta-band p { font-size: 16px; margin-bottom: 28px; opacity: 0.95; }
  .cta-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }
  .btn-white { background: #fff; color: var(--primary); padding: 15px 38px; border-radius: 4px; font-weight: bold; font-size: 16px; transition: var(--transition); }
  .btn-white:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
  .btn-outline { border: 2px solid #fff; color: #fff; padding: 13px 36px; border-radius: 4px; font-weight: bold; font-size: 16px; transition: var(--transition); }
  .btn-outline:hover { background: #fff; color: var(--primary); }
  .cta-contact { margin-top: 26px; font-size: 15px; }
  .cta-contact a { color: #fff; text-decoration: underline; font-weight: 600; }

  /* ==========================================================================
     Responsive Design
     ========================================================================== */
  @media (max-width: 1024px) {
    .gen-compare { grid-template-columns: 1fr; }
    .gen-card.featured { transform: none; }
    .gen-card.featured:hover { transform: translateY(-5px); }
    .zig-zag-row, .zig-zag-row:nth-child(even) { flex-direction: column; gap: 40px; }
    .zz-img { width: 100%; }
    .zz-img img { min-height: 250px; }
    .applications { grid-template-columns: repeat(2, 1fr); }
    .assembly-steps { grid-template-columns: repeat(2, 1fr); }
    .process-timeline { grid-template-columns: repeat(2, 1fr); gap: 30px; margin-top: 20px; }
    .process-step { margin: 0; }
    .process-step:not(:last-child)::after { display: none; }
    .hero-inner { width: 60%; min-width: 320px; }
  }

  @media (max-width: 768px) {
    .section-banner { grid-template-columns: 1fr; padding: 40px 5%; row-gap: 12px; }
    .section-banner .banner-title { font-size: 36px; white-space: normal; }
    .section-banner p.banner-desc { white-space: normal; }
    .section { padding: 60px 5%; }
    .intro { padding: 40px 5% 0; }
    .section-header h2 { font-size: 28px; }
    .applications, .process-timeline, .assembly-steps { grid-template-columns: 1fr; }
    .hero { height: auto; padding: 60px 0; }
    .hero img.hero-bg { position: absolute; inset: 0; }
    .hero-inner { width: 90%; right: 0; left: 5%; position: relative; top: auto; transform: none; margin: 0 auto; }
    .hero-content { padding: 30px; border-radius: 8px; }
    .hero-content h1 { font-size: 30px; }
    .cta-band { padding: 50px 5%; }
    .cta-band h2 { font-size: 26px; }
  }