:root {
      --theme: #0B3D91;
      --theme-dark: #06295f;
      --ink: #10233f;
      --muted: #64748b;
      --line: #d9e3ef;
      --surface: #ffffff;
      --soft: #f3f7fb;
      --ice: #eaf4ff;
      --shadow: 0 18px 50px rgba(11, 61, 145, .10);
      --radius: 10px;
    }

    * {
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      margin: 0;
      color: var(--ink);
      background: #f7faff;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Microsoft YaHei", "微软雅黑", Arial, sans-serif;
      line-height: 1.7;
    }

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

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

    button {
      font: inherit;
    }

    .container {
      width: min(1180px, calc(100% - 40px));
      margin: 0 auto;
    }

    .topbar {
      color: #dcecff;
      background: #071b38;
      font-size: 13px;
    }

    .topbar-inner {
      min-height: 36px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 20px;
    }

    .topbar-contact {
      display: flex;
      flex-wrap: wrap;
      gap: 18px;
    }

    .topbar a:hover {
      color: #ffffff;
    }

    .header {
      position: relative;
      z-index: 20;
      background: #ffffff;
      border-bottom: 1px solid var(--line);
    }

    .header-inner {
      min-height: 76px;
      display: flex;
      align-items: center;
      gap: 30px;
    }

    .logo {
      min-width: 190px;
      display: inline-flex;
      align-items: center;
      gap: 10px;
      color: var(--theme-dark);
      font-size: 19px;
      font-weight: 800;
      white-space: nowrap;
    }

    .logo img {
      width: 38px;
      height: 38px;
      object-fit: contain;
    }

    .main-nav {
      flex: 1;
      align-self: stretch;
    }

    .nav-list {
      height: 100%;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 4px;
      padding: 0;
      margin: 0;
      list-style: none;
    }

    .nav-item {
      position: relative;
      height: 100%;
      display: flex;
      align-items: center;
    }

    .nav-link {
      position: relative;
      display: inline-flex;
      align-items: center;
      min-height: 44px;
      padding: 9px 13px;
      color: #30435e;
      font-size: 14px;
      font-weight: 700;
      white-space: nowrap;
    }

    .nav-link:hover,
    .nav-link:focus-visible {
      color: var(--theme);
    }

    .has-arrow::after {
      content: "";
      width: 6px;
      height: 6px;
      margin-left: 8px;
      border-right: 1px solid currentColor;
      border-bottom: 1px solid currentColor;
      transform: rotate(45deg) translateY(-2px);
    }

    .dropdown-panel,
    .mega-menu {
      position: absolute;
      top: calc(100% + 1px);
      left: 50%;
      z-index: 30;
      width: 360px;
      padding: 22px;
      background: #ffffff;
      border: 1px solid var(--line);
      box-shadow: var(--shadow);
      opacity: 0;
      visibility: hidden;
      transform: translate(-50%, 8px);
      transition: opacity .2s ease, transform .2s ease, visibility .2s ease;
    }

    .mega-menu {
      width: min(760px, 78vw);
    }

    .dropdown-panel::before,
    .mega-menu::before {
      content: "";
      position: absolute;
      top: -14px;
      left: 0;
      right: 0;
      height: 14px;
    }

    .nav-item:hover > .dropdown-panel,
    .nav-item:focus-within > .dropdown-panel,
    .nav-item:hover > .mega-menu,
    .nav-item:focus-within > .mega-menu {
      opacity: 1;
      visibility: visible;
      transform: translate(-50%, 0);
    }

    .panel-title {
      margin: 0 0 13px;
      color: var(--theme-dark);
      font-size: 15px;
    }

    .panel-list {
      display: grid;
      gap: 9px;
      margin: 0;
      color: #53657d;
      font-size: 13px;
    }

    .panel-list a:hover,
    .mega-card:hover strong {
      color: var(--theme);
    }

    .mega-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 26px;
    }

    .mega-column {
      min-width: 0;
    }

    .mega-card {
      display: grid;
      grid-template-columns: 42px 1fr;
      gap: 10px;
      align-items: center;
      padding: 8px 0;
      border-bottom: 1px solid #edf2f7;
    }

    .mega-card:last-child {
      border-bottom: 0;
    }

    .mega-card img {
      width: 42px;
      height: 42px;
      border-radius: 7px;
      object-fit: cover;
      background: var(--soft);
    }

    .mega-card strong,
    .mega-card small {
      display: block;
    }

    .mega-card strong {
      overflow: hidden;
      color: var(--ink);
      font-size: 13px;
      font-weight: 700;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .mega-card small {
      overflow: hidden;
      color: var(--muted);
      font-size: 11px;
      line-height: 1.55;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .mega-footer {
      display: block;
      margin-top: 16px;
      padding-top: 13px;
      border-top: 1px solid var(--line);
      color: var(--theme);
      font-size: 13px;
      font-weight: 700;
    }

    .header-btns {
      display: flex;
      align-items: center;
      gap: 9px;
      white-space: nowrap;
    }

    .member-btn,
    .open-account {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      min-height: 38px;
      padding: 7px 13px;
      border-radius: 6px;
      font-size: 13px;
      font-weight: 700;
    }

    .member-btn {
      color: var(--theme);
      border: 1px solid #b9cde7;
      background: #f5f9ff;
    }

    .open-account {
      color: #ffffff;
      background: var(--theme);
    }

    .member-btn:hover {
      background: var(--ice);
    }

    .open-account:hover {
      background: var(--theme-dark);
    }

    .hamburger {
      display: none;
      width: 42px;
      height: 40px;
      padding: 8px;
      border: 1px solid var(--line);
      border-radius: 6px;
      background: #ffffff;
      cursor: pointer;
    }

    .hamburger span {
      display: block;
      width: 21px;
      height: 2px;
      margin: 4px auto;
      background: var(--theme);
      transition: transform .2s ease, opacity .2s ease;
    }

    .hamburger.active span:first-child {
      transform: translateY(6px) rotate(45deg);
    }

    .hamburger.active span:nth-child(2) {
      opacity: 0;
    }

    .hamburger.active span:last-child {
      transform: translateY(-6px) rotate(-45deg);
    }

    .drawer-overlay {
      position: fixed;
      inset: 0;
      z-index: 50;
      background: rgba(4, 19, 42, .52);
      opacity: 0;
      visibility: hidden;
      transition: opacity .2s ease, visibility .2s ease;
    }

    .drawer-overlay.open {
      opacity: 1;
      visibility: visible;
    }

    .mobile-drawer {
      position: fixed;
      top: 0;
      right: 0;
      z-index: 60;
      width: min(390px, 88vw);
      height: 100vh;
      overflow-y: auto;
      background: #ffffff;
      box-shadow: -18px 0 45px rgba(5, 25, 55, .20);
      transform: translateX(100%);
      transition: transform .25s ease;
    }

    .mobile-drawer.open {
      transform: translateX(0);
    }

    .drawer-head {
      min-height: 72px;
      display: flex;
      align-items: center;
      gap: 13px;
      padding: 16px 20px;
      color: var(--theme-dark);
      font-weight: 800;
      border-bottom: 1px solid var(--line);
    }

    .drawer-head span {
      flex: 1;
    }

    .drawer-head a {
      padding: 6px 10px;
      color: #ffffff;
      border-radius: 5px;
      background: var(--theme);
      font-size: 13px;
    }

    .drawer-close {
      width: 35px;
      height: 35px;
      padding: 0;
      color: var(--theme-dark);
      border: 1px solid var(--line);
      border-radius: 5px;
      background: #ffffff;
      font-size: 24px;
      line-height: 1;
      cursor: pointer;
    }

    .drawer-menu {
      padding: 14px 20px 32px;
    }

    .drawer-link,
    .drawer-toggle {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      min-height: 48px;
      padding: 10px 0;
      color: #223958;
      border: 0;
      border-bottom: 1px solid #edf2f7;
      background: transparent;
      text-align: left;
      font-size: 15px;
      cursor: pointer;
    }

    .drawer-toggle::after {
      content: "+";
      color: var(--theme);
      font-size: 20px;
      font-weight: 400;
    }

    .drawer-toggle.active::after {
      content: "−";
    }

    .drawer-submenu {
      display: grid;
      gap: 0;
      max-height: 0;
      padding-left: 14px;
      overflow: hidden;
      opacity: 0;
      transition: max-height .25s ease, opacity .25s ease;
    }

    .drawer-submenu.open {
      max-height: 600px;
      opacity: 1;
    }

    .drawer-submenu a {
      display: block;
      padding: 8px 0;
      color: var(--muted);
      border-bottom: 1px solid #f1f5f9;
      font-size: 13px;
    }

    .footer {
      margin-top: 72px;
      color: #c8d7ec;
      background: #071b38;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 1.4fr 1fr 1fr 1fr;
      gap: 42px;
      padding: 52px 0 40px;
    }

    .footer-brand strong {
      display: block;
      margin-bottom: 14px;
      color: #ffffff;
      font-size: 19px;
    }

    .footer h3 {
      margin: 0 0 14px;
      color: #ffffff;
      font-size: 15px;
    }

    .footer p,
    .footer a {
      display: block;
      margin: 6px 0;
      color: #c8d7ec;
      font-size: 13px;
    }

    .footer a:hover {
      color: #ffffff;
    }

    .footer-bottom {
      padding: 19px 0;
      color: #9fb3d0;
      border-top: 1px solid rgba(214, 232, 255, .16);
      font-size: 12px;
    }

    .tool-detail-page {
      padding: 54px 0 0;
    }

    .tool-breadcrumb {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      align-items: center;
      margin-bottom: 24px;
      color: var(--muted);
      font-size: 13px;
    }

    .tool-breadcrumb a {
      color: var(--theme);
    }

    .tool-layout {
      display: grid;
      grid-template-columns: minmax(0, 1fr) 300px;
      gap: 28px;
      align-items: start;
    }

    .tool-main-card,
    .tool-side-panel {
      background: var(--surface);
      border: 1px solid var(--line);
      border-radius: var(--radius);
      box-shadow: 0 10px 30px rgba(19, 51, 91, .05);
    }

    .tool-main-card {
      min-width: 0;
      padding: clamp(24px, 4vw, 44px);
    }

    .tool-heading {
      display: flex;
      gap: 18px;
      align-items: flex-start;
      padding-bottom: 25px;
      border-bottom: 1px solid var(--line);
    }

    .tool-icon {
      flex: 0 0 72px;
      width: 72px;
      height: 72px;
      padding: 10px;
      object-fit: contain;
      border: 1px solid #c9d9ed;
      border-radius: 12px;
      background: var(--ice);
    }

    .tool-heading h1 {
      margin: 0 0 7px;
      color: var(--theme-dark);
      font-size: clamp(25px, 4vw, 38px);
      line-height: 1.25;
    }

    .tool-intro {
      margin: 0;
      color: var(--muted);
      font-size: 15px;
    }

    .tool-meta {
      display: flex;
      flex-wrap: wrap;
      gap: 10px 22px;
      margin-top: 17px;
      color: var(--muted);
      font-size: 13px;
    }

    .tool-meta strong {
      color: var(--ink);
    }

    .tool-content {
      min-width: 0;
      max-width: 100%;
      margin-top: 30px;
      overflow-x: auto;
      color: #344861;
      font-size: 15px;
    }

    .tool-content h2,
    .tool-content h3 {
      margin: 30px 0 12px;
      color: var(--theme-dark);
      line-height: 1.35;
    }

    .tool-content h2 {
      font-size: 23px;
    }

    .tool-content h3 {
      font-size: 18px;
    }

    .tool-content p {
      margin: 0 0 17px;
    }

    .tool-content ul,
    .tool-content ol {
      padding-left: 22px;
    }

    .tool-content img,
    .tool-content table,
    .tool-content pre,
    .tool-content iframe {
      max-width: 100%;
    }

    .tool-content table {
      border-collapse: collapse;
    }

    .tool-content th,
    .tool-content td {
      padding: 9px 12px;
      border: 1px solid var(--line);
    }

    .tool-content blockquote {
      margin: 22px 0;
      padding: 14px 18px;
      color: var(--theme-dark);
      border-left: 4px solid var(--theme);
      background: var(--ice);
    }

    .tool-tags {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-top: 32px;
      padding-top: 20px;
      border-top: 1px solid var(--line);
    }

    .tool-tags span {
      padding: 4px 10px;
      color: var(--theme);
      border: 1px solid #bed1e9;
      border-radius: 999px;
      background: #f6faff;
      font-size: 12px;
    }

    .tool-side-panel {
      padding: 22px;
    }

    .tool-side-panel h2 {
      margin: 0 0 15px;
      color: var(--theme-dark);
      font-size: 18px;
    }

    .related-tool {
      display: grid;
      grid-template-columns: 42px 1fr;
      gap: 10px;
      padding: 13px 0;
      border-bottom: 1px solid #edf2f7;
    }

    .related-tool:last-child {
      border-bottom: 0;
    }

    .related-tool img {
      width: 42px;
      height: 42px;
      padding: 5px;
      object-fit: contain;
      border: 1px solid var(--line);
      border-radius: 7px;
      background: var(--soft);
    }

    .related-tool strong,
    .related-tool small {
      display: block;
    }

    .related-tool strong {
      overflow: hidden;
      color: var(--ink);
      font-size: 13px;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .related-tool small {
      display: -webkit-box;
      overflow: hidden;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.5;
      -webkit-box-orient: vertical;
      -webkit-line-clamp: 2;
    }

    .related-tool:hover strong {
      color: var(--theme);
    }

    .tool-side-note {
      margin-top: 22px;
      padding: 15px;
      color: #49617d;
      border-left: 3px solid var(--theme);
      background: var(--ice);
      font-size: 13px;
    }

    @media (max-width: 1040px) {
      .header-inner {
        gap: 16px;
      }

      .logo {
        min-width: auto;
      }

      .nav-link {
        padding-inline: 8px;
        font-size: 13px;
      }

      .member-btn {
        display: none;
      }

      .tool-layout {
        grid-template-columns: minmax(0, 1fr) 260px;
      }
    }

    @media (max-width: 860px) {
      .main-nav {
        display: none;
      }

      .hamburger {
        display: block;
      }

      .header-btns {
        margin-left: auto;
      }

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

      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }

      .tool-layout {
        grid-template-columns: 1fr;
      }

      .tool-side-panel {
        order: 2;
      }
    }

    @media (max-width: 560px) {
      .container {
        width: min(100% - 28px, 1180px);
      }

      .topbar-inner {
        align-items: flex-start;
        flex-direction: column;
        gap: 2px;
        padding: 7px 0;
      }

      .topbar-contact {
        gap: 12px;
      }

      .header-inner {
        min-height: 66px;
      }

      .logo {
        font-size: 16px;
      }

      .logo img {
        width: 32px;
        height: 32px;
      }

      .open-account {
        display: none;
      }

      .tool-detail-page {
        padding-top: 30px;
      }

      .tool-heading {
        display: block;
      }

      .tool-icon {
        margin-bottom: 16px;
      }

      .tool-main-card {
        padding: 22px 18px;
      }

      .footer-grid {
        grid-template-columns: 1fr;
        gap: 24px;
        padding: 38px 0 30px;
      }

      .footer {
        margin-top: 48px;
      }
    }