:root {
      --header-blue: #2f63b9;
      --header-blue-strong: #214b8d;
      --header-line: #d9e5f7;
      --header-text: #18345f;
      --header-muted: #61789f;
    }

    * { box-sizing: border-box; }

    html {
      margin: 0;
      padding: 0;
      scroll-behavior: smooth;
    }

    body {
      margin: 0;
      padding: 0;
      font-family: Inter, "Segoe UI", "Microsoft YaHei", sans-serif;
      color: var(--header-text);
      background: #ffffff;
    }

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

    .proto-shell {
      min-height: 100vh;
      margin: 0;
      padding: 0;
    }

    .proto-header {
      display: block;
      position: sticky;
      top: 0;
      z-index: 100;
      width: 100%;
      margin: 0;
      padding: 0;
      background: var(--header-blue);
      border-bottom: 1px solid rgba(255,255,255,0.12);
      transition: background-color 0.22s ease, border-color 0.22s ease, box-shadow 0.22s ease;
    }

    .proto-header.is-scrolled {
      background: #ffffff;
      border-bottom-color: var(--header-line);
      box-shadow: 0 6px 18px rgba(19, 53, 102, 0.08);
    }

    .proto-header-inner {
      max-width: 1720px;
      margin: 0 auto;
      padding: 0 10px;
      width: min(100%, 1720px);
      min-height: 82px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 18px;
    }

    .proto-brand {
      display: flex;
      align-items: center;
      gap: 16px;
      min-width: 0;
    }

    .proto-brand-logo {
      width: 92px;
      height: 68px;
      flex: 0 0 92px;
      object-fit: contain;
      background: transparent;
      padding: 0;
      border-radius: 0;
      filter:
        drop-shadow(0 0 1px rgba(255,255,255,0.95))
        drop-shadow(0 2px 5px rgba(13,49,112,0.24));
    }

    .proto-brand-title {
      margin: 0;
      font-size: 18px;
      font-weight: 800;
      color: #fff;
      transition: color 0.22s ease;
    }

    .proto-brand-subtitle {
      margin: 4px 0 0;
      font-size: 12px;
      color: rgba(255,255,255,0.76);
      transition: color 0.22s ease;
    }

    .proto-header.is-scrolled .proto-brand-title {
      color: var(--header-blue-strong);
    }

    .proto-header.is-scrolled .proto-brand-subtitle {
      color: var(--header-muted);
    }

    .proto-header-right {
      display: flex;
      align-items: center;
      gap: 16px;
      flex-wrap: nowrap;
      justify-content: flex-end;
      margin-left: auto;
    }

    .proto-nav {
      display: flex;
      align-items: center;
      gap: 6px;
      flex-wrap: nowrap;
    }

    .proto-nav-link {
      padding: 10px 14px;
      font-size: 14px;
      font-weight: 700;
      color: rgba(255,255,255,0.94);
      transition: color 0.22s ease, opacity 0.22s ease;
    }

    .proto-nav-link.is-active {
      text-decoration: underline;
      text-underline-offset: 5px;
      text-decoration-thickness: 2px;
    }

    .proto-header.is-scrolled .proto-nav-link {
      color: var(--header-blue-strong);
    }

    .proto-control-group {
      display: inline-flex;
      align-items: center;
      gap: 6px;
      flex: 0 0 auto;
    }

    .proto-control-group.is-hidden {
      display: none;
    }

    .proto-control {
      min-width: 84px;
      padding: 10px 16px;
      border-radius: 999px;
      border: 1px solid rgba(255,255,255,0.22);
      color: rgba(255,255,255,0.94);
      font-size: 13px;
      font-weight: 700;
      text-align: center;
      transition: all 0.22s ease;
    }

    .proto-control.is-active {
      background: #ffffff;
      color: var(--header-blue-strong);
      border-color: #ffffff;
    }

    .proto-header.is-scrolled .proto-control {
      border-color: #d4e1f6;
      color: var(--header-blue-strong);
      background: #ffffff;
    }

    .proto-header.is-scrolled .proto-control.is-active {
      background: var(--header-blue);
      border-color: var(--header-blue);
      color: #ffffff;
    }

    .proto-main {
      display: block;
    }

    @media (max-width: 1120px) {
      .proto-header-inner {
        align-items: flex-start;
        padding-top: 14px;
        padding-bottom: 14px;
        min-height: auto;
        flex-direction: column;
      }

      .proto-header-right {
        width: 100%;
        justify-content: flex-start;
        flex-wrap: wrap;
      }

      .proto-nav {
        flex-wrap: wrap;
      }
    }

    @media (max-width: 680px) {
      .proto-header-inner {
        padding-left: 10px;
        padding-right: 10px;
      }

      .proto-brand {
        align-items: flex-start;
      }

      .proto-brand-logo {
        width: 78px;
        height: 60px;
        flex-basis: 78px;
      }
    }