:root {
      --bg: #ffffff;
      --text: #111111;
      --muted: #555555;
      --line: #e8e8e8;
      --soft: #f7f7f7;
      --accent: #111111;
      --font: "Noto Sans SC", "PingFang SC", "Microsoft YaHei", "Heiti SC", sans-serif;
    }

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

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font);
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      min-height: 100vh;
    }

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

    .container {
      width: min(1100px, calc(100% - 48px));
      margin: 0 auto;
    }

    /* Header */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--line);
    }

    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      min-height: 72px;
      gap: 24px;
    }

    .brand {
      font-size: 1.15rem;
      font-weight: 700;
      letter-spacing: 0.02em;
      white-space: nowrap;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 28px;
      list-style: none;
    }

    .nav-links > li > a {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text);
    }

    .nav-dropdown {
      position: relative;
    }

    .nav-dropdown > .nav-trigger {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text);
      cursor: pointer;
      user-select: none;
      background: none;
      border: none;
      font-family: inherit;
      padding: 0;
    }

    .nav-dropdown > .nav-trigger .arrow {
      display: inline-block;
      width: 0;
      height: 0;
      border-left: 4px solid transparent;
      border-right: 4px solid transparent;
      border-top: 5px solid var(--text);
      transition: transform 0.2s ease;
    }

    .nav-dropdown:hover > .nav-trigger .arrow {
      transform: rotate(180deg);
    }

    .dropdown-panel {
      position: absolute;
      right: 0;
      top: 100%;
      min-width: 220px;
      padding-top: 12px;
      opacity: 0;
      visibility: hidden;
      transform: translateY(6px);
      transition: opacity 0.18s ease, transform 0.18s ease, visibility 0.18s;
      pointer-events: none;
    }

    .dropdown-panel-inner {
      background: #fff;
      border: 1px solid var(--line);
      box-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
      padding: 8px 0;
    }

    .nav-dropdown:hover .dropdown-panel {
      opacity: 1;
      visibility: visible;
      transform: translateY(0);
      pointer-events: auto;
    }

    .dropdown-panel-inner a {
      display: block;
      padding: 10px 16px;
      font-size: 0.9rem;
      color: var(--muted);
      transition: background 0.15s ease, color 0.15s ease;
    }

    .dropdown-panel-inner a:hover {
      background: var(--soft);
      color: var(--text);
    }

    /* Hero */
    .hero {
      padding: 120px 0 96px;
      border-bottom: 1px solid var(--line);
    }

    .hero h1 {
      font-size: clamp(2.4rem, 5.5vw, 4.2rem);
      font-weight: 900;
      letter-spacing: -0.03em;
      line-height: 1.15;
      max-width: 14ch;
      margin-bottom: 28px;
    }

    .hero p {
      max-width: 42rem;
      font-size: 1.05rem;
      color: var(--muted);
      font-weight: 400;
      line-height: 1.85;
    }

    /* Sections */
    section {
      padding: 88px 0;
    }

    .section-title {
      font-size: clamp(1.6rem, 3vw, 2rem);
      font-weight: 700;
      margin-bottom: 40px;
      letter-spacing: -0.02em;
    }

    /* Business cards */
    .business-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 20px;
    }

    .biz-card {
      border: 1px solid var(--line);
      background: #f4f4f4;
      border-radius: 4px;
      padding: 28px 24px 30px;
      transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
    }

    .biz-card:hover {
      border-color: #111;
      transform: translateY(-2px);
      box-shadow: 0 10px 28px rgba(0, 0, 0, 0.06);
    }

    .biz-card h3 {
      font-size: 1.15rem;
      font-weight: 700;
      margin-bottom: 12px;
      line-height: 1.35;
    }

    .biz-card .desc {
      font-size: 0.9rem;
      color: var(--muted);
      margin-bottom: 22px;
      line-height: 1.7;
      min-height: 4.6em;
    }

    .biz-card .advantages {
      list-style: none;
      display: flex;
      flex-direction: column;
      gap: 10px;
    }

    .biz-card .advantages li {
      position: relative;
      padding-left: 18px;
      font-size: 0.88rem;
      color: var(--text);
      line-height: 1.5;
    }

    .biz-card .advantages li::before {
      content: "";
      position: absolute;
      left: 0;
      top: 0.55em;
      width: 6px;
      height: 6px;
      background: #111;
      border-radius: 50%;
    }

    /* Contact */
    .contact {
      background: var(--soft);
      border-top: 1px solid var(--line);
      border-bottom: 1px solid var(--line);
    }

    .contact-form {
      max-width: 560px;
      display: flex;
      flex-direction: column;
      gap: 18px;
    }

    .field label {
      display: block;
      font-size: 0.9rem;
      font-weight: 500;
      margin-bottom: 8px;
    }

    .field input,
    .field textarea {
      width: 100%;
      border: 1px solid #d0d0d0;
      background: #fff;
      color: var(--text);
      font-family: inherit;
      font-size: 0.95rem;
      padding: 12px 14px;
      outline: none;
      transition: border-color 0.15s ease;
    }

    .field input:focus,
    .field textarea:focus {
      border-color: #111;
    }

    .field textarea {
      min-height: 140px;
      resize: vertical;
    }

    .field .error {
      display: none;
      margin-top: 6px;
      font-size: 0.8rem;
      color: #b00020;
    }

    .field.invalid .error {
      display: block;
    }

    .field.invalid input,
    .field.invalid textarea {
      border-color: #b00020;
    }

    .submit-btn {
      align-self: flex-start;
      margin-top: 6px;
      border: 1px solid #111;
      background: #111;
      color: #fff;
      font-family: inherit;
      font-size: 0.95rem;
      font-weight: 500;
      padding: 12px 28px;
      cursor: pointer;
      transition: background 0.15s ease, color 0.15s ease;
    }

    .submit-btn:hover {
      background: #fff;
      color: #111;
    }

    .form-message {
      display: none;
      font-size: 0.9rem;
      color: #1a7f37;
    }

    .form-message.show {
      display: block;
    }

    .form-message.form-error {
      color: #b00020;
    }

    /* Footer */
    .site-footer {
      padding: 36px 0 48px;
      text-align: center;
    }

    .site-footer .copy {
      font-size: 0.85rem;
      color: var(--muted);
      margin-bottom: 10px;
    }

    .site-footer .icp {
      font-size: 0.85rem;
      color: var(--muted);
    }

    .site-footer .icp a:hover {
      color: var(--text);
      text-decoration: underline;
    }

    @media (max-width: 900px) {
      .business-grid {
        grid-template-columns: 1fr;
      }

      .biz-card .desc {
        min-height: 0;
      }

      .hero {
        padding: 88px 0 72px;
      }
    }

    @media (max-width: 600px) {
      .container {
        width: calc(100% - 32px);
      }

      .nav {
        min-height: 64px;
      }

      .brand {
        font-size: 0.95rem;
      }

      .nav-links {
        gap: 16px;
      }

      section {
        padding: 64px 0;
      }
    }