:root {
      --theme: #0B3D91;
      --theme-deep: #061c45;
      --theme-light: #eaf2ff;
      --ink: #17233d;
      --muted: #64748b;
      --line: #dbe4f0;
      --paper: #f6f9fd;
      --white: #ffffff;
      --shadow: 0 18px 50px rgba(11, 61, 145, .1);
      --radius: 18px;
    }

    * {
      box-sizing: border-box;
    }

    html {
      scroll-behavior: smooth;
    }

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

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

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

    button {
      font: inherit;
    }

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

    .topbar {
      color: #dce9ff;
      background: var(--theme-deep);
      font-size: 13px;
    }

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

    .topbar-links {
      display: flex;
      gap: 20px;
    }

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

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

    .header-inner {
      display: flex;
      align-items: center;
      min-height: 78px;
      gap: 28px;
    }

    .logo {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      min-width: 190px;
      color: var(--theme-deep);
      font-size: 20px;
      font-weight: 800;
      white-space: nowrap;
    }

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

    .main-nav {
      flex: 1;
    }

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

    .nav-item {
      position: relative;
    }

    .nav-link {
      display: block;
      padding: 27px 13px;
      color: #334155;
      font-size: 15px;
      font-weight: 600;
      white-space: nowrap;
    }

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

    .has-arrow::after {
      display: inline-block;
      width: 6px;
      height: 6px;
      margin: 0 0 3px 7px;
      content: "";
      border-right: 1.5px solid currentColor;
      border-bottom: 1.5px solid currentColor;
      transform: rotate(45deg);
    }

    .dropdown-panel,
    .mega-menu {
      position: absolute;
      top: calc(100% - 1px);
      left: 50%;
      visibility: hidden;
      min-width: 250px;
      padding: 18px;
      opacity: 0;
      background: #fff;
      border: 1px solid var(--line);
      border-radius: 0 0 16px 16px;
      box-shadow: var(--shadow);
      transform: translate(-50%, 8px);
      transition: .2s ease;
    }

    .mega-menu {
      width: min(760px, 80vw);
    }

    .dropdown-panel::before,
    .mega-menu::before {
      position: absolute;
      top: -12px;
      right: 0;
      left: 0;
      height: 12px;
      content: "";
    }

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

    .dropdown-panel a {
      display: block;
      padding: 9px 10px;
      border-bottom: 1px solid #edf2f8;
      font-size: 14px;
    }

    .dropdown-panel a:hover {
      color: var(--theme);
      background: var(--theme-light);
    }

    .mega-heading {
      display: flex;
      align-items: baseline;
      justify-content: space-between;
      gap: 14px;
      margin-bottom: 14px;
      color: var(--theme-deep);
    }

    .mega-heading span {
      color: var(--muted);
      font-size: 12px;
      font-weight: 400;
    }

    .mega-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 10px;
    }

    .mega-card {
      min-width: 0;
      padding: 12px;
      border: 1px solid var(--line);
      border-radius: 12px;
      transition: .2s ease;
    }

    .mega-card:hover {
      border-color: #9bb9eb;
      background: #f5f9ff;
      transform: translateY(-2px);
    }

    .mega-card img {
      width: 34px;
      height: 34px;
      margin-bottom: 7px;
      object-fit: contain;
    }

    .mega-card strong,
    .mega-card small {
      display: block;
      overflow: hidden;
      text-overflow: ellipsis;
      white-space: nowrap;
    }

    .mega-card strong {
      color: var(--ink);
      font-size: 13px;
    }

    .mega-card small {
      margin-top: 3px;
      color: var(--muted);
      font-size: 11px;
    }

    .mega-footer {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-top: 14px;
      padding-top: 12px;
      color: var(--theme);
      border-top: 1px solid var(--line);
      font-size: 13px;
    }

    .header-btns {
      display: flex;
      align-items: center;
      gap: 12px;
      white-space: nowrap;
    }

    .member-link {
      color: var(--theme);
      font-size: 14px;
      font-weight: 700;
    }

    .account-link {
      padding: 9px 17px;
      color: #fff;
      background: var(--theme);
      border-radius: 999px;
      font-size: 14px;
      font-weight: 700;
    }

    .account-link:hover {
      background: #082d6d;
    }

    .hamburger {
      display: none;
      width: 42px;
      height: 42px;
      padding: 9px;
      cursor: pointer;
      background: transparent;
      border: 1px solid var(--line);
      border-radius: 10px;
    }

    .hamburger span {
      display: block;
      width: 22px;
      height: 2px;
      margin: 4px auto;
      background: var(--theme-deep);
      transition: .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;
      z-index: 40;
      inset: 0;
      visibility: hidden;
      opacity: 0;
      background: rgba(3, 15, 38, .55);
      transition: .25s ease;
    }

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

    .mobile-drawer {
      position: fixed;
      z-index: 50;
      top: 0;
      right: 0;
      bottom: 0;
      width: min(390px, 88vw);
      overflow-y: auto;
      background: #fff;
      box-shadow: -12px 0 35px rgba(3, 15, 38, .2);
      transform: translateX(100%);
      transition: .25s ease;
    }

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

    .drawer-head {
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 22px 20px;
      color: #fff;
      background: var(--theme-deep);
    }

    .drawer-head a {
      margin-left: auto;
      margin-right: 14px;
      color: #cfe0ff;
      font-size: 14px;
    }

    .drawer-close {
      width: 32px;
      height: 32px;
      padding: 0;
      color: #fff;
      cursor: pointer;
      background: transparent;
      border: 1px solid rgba(255, 255, 255, .35);
      border-radius: 50%;
      font-size: 24px;
      line-height: 1;
    }

    .drawer-menu {
      padding: 10px 20px 30px;
    }

    .drawer-link,
    .drawer-toggle {
      display: block;
      width: 100%;
      padding: 14px 0;
      color: var(--ink);
      text-align: left;
      background: transparent;
      border: 0;
      border-bottom: 1px solid var(--line);
      font-weight: 700;
    }

    .drawer-toggle {
      cursor: pointer;
    }

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

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

    .drawer-submenu {
      display: none;
      padding: 5px 0 8px 14px;
      border-bottom: 1px solid var(--line);
    }

    .drawer-submenu.open {
      display: block;
    }

    .drawer-submenu a {
      display: block;
      padding: 8px 0;
      color: var(--muted);
      font-size: 14px;
    }

    .drawer-submenu a:hover {
      color: var(--theme);
    }

    .tool-detail-page {
      padding: 70px 0 90px;
    }

    .tool-breadcrumb {
      margin-bottom: 28px;
      color: var(--muted);
      font-size: 14px;
    }

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

    .tool-layout {
      display: grid;
      grid-template-columns: minmax(0, 1fr) 320px;
      gap: 30px;
      align-items: start;
    }

    .tool-main-card,
    .tool-side-card {
      background: var(--white);
      border: 1px solid var(--line);
      border-radius: var(--radius);
      box-shadow: 0 10px 35px rgba(20, 47, 93, .05);
    }

    .tool-main-card {
      padding: clamp(28px, 5vw, 58px);
    }

    .tool-kicker {
      display: inline-flex;
      align-items: center;
      gap: 8px;
      margin-bottom: 16px;
      color: var(--theme);
      font-size: 13px;
      font-weight: 800;
      letter-spacing: .08em;
    }

    .tool-kicker::before {
      width: 28px;
      height: 2px;
      content: "";
      background: var(--theme);
    }

    .tool-title-row {
      display: flex;
      align-items: flex-start;
      gap: 18px;
    }

    .tool-title-row img {
      width: 64px;
      height: 64px;
      flex: 0 0 64px;
      padding: 12px;
      object-fit: contain;
      background: var(--theme-light);
      border-radius: 16px;
    }

    .tool-main-card h1 {
      margin: 0;
      color: var(--theme-deep);
      font-size: clamp(30px, 4vw, 48px);
      line-height: 1.2;
    }

    .tool-intro {
      margin: 18px 0 0;
      color: var(--muted);
      font-size: 18px;
    }

    .tool-meta {
      display: flex;
      flex-wrap: wrap;
      gap: 10px 18px;
      margin: 28px 0 34px;
      padding: 16px 0;
      color: var(--muted);
      border-top: 1px solid var(--line);
      border-bottom: 1px solid var(--line);
      font-size: 13px;
    }

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

    .tool-content {
      min-width: 0;
      max-width: 100%;
      overflow-x: auto;
      color: #334155;
      font-size: 16px;
    }

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

    .tool-content h2,
    .tool-content h3 {
      margin-top: 32px;
      color: var(--theme-deep);
    }

    .tool-content h2 {
      padding-left: 14px;
      border-left: 4px solid var(--theme);
    }

    .tool-content blockquote {
      margin: 24px 0;
      padding: 18px 22px;
      color: #31558c;
      background: var(--theme-light);
      border-radius: 10px;
    }

    .tool-side-card {
      position: sticky;
      top: 24px;
      padding: 24px;
    }

    .tool-side-card h2 {
      margin: 0 0 18px;
      color: var(--theme-deep);
      font-size: 20px;
    }

    .related-tool {
      display: grid;
      grid-template-columns: 42px minmax(0, 1fr);
      gap: 12px;
      padding: 14px 0;
      border-top: 1px solid var(--line);
    }

    .related-tool img {
      width: 42px;
      height: 42px;
      padding: 7px;
      object-fit: contain;
      background: var(--theme-light);
      border-radius: 10px;
    }

    .related-tool strong,
    .related-tool p {
      display: block;
      overflow: hidden;
      text-overflow: ellipsis;
    }

    .related-tool strong {
      color: var(--ink);
      font-size: 14px;
      white-space: nowrap;
    }

    .related-tool p {
      margin: 3px 0 0;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.5;
      display: -webkit-box;
      -webkit-box-orient: vertical;
      -webkit-line-clamp: 2;
    }

    .tool-side-link {
      display: block;
      margin-top: 14px;
      padding: 11px;
      color: var(--theme);
      text-align: center;
      background: var(--theme-light);
      border-radius: 10px;
      font-size: 14px;
      font-weight: 700;
    }

    .footer {
      padding: 58px 0 20px;
      color: #c6d4ec;
      background: #071b3c;
    }

    .footer-grid {
      display: grid;
      grid-template-columns: 1.5fr repeat(3, 1fr);
      gap: 36px;
    }

    .footer-brand strong {
      display: block;
      margin-bottom: 12px;
      color: #fff;
      font-size: 21px;
    }

    .footer p {
      margin: 8px 0;
      font-size: 13px;
      line-height: 1.8;
    }

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

    .footer-grid > div:not(.footer-brand) a,
    .footer-grid > div:not(.footer-brand) span {
      display: block;
      margin: 8px 0;
      color: #c6d4ec;
      font-size: 13px;
    }

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

    .footer-bottom {
      display: flex;
      justify-content: space-between;
      gap: 20px;
      margin-top: 42px;
      padding-top: 18px;
      border-top: 1px solid rgba(198, 212, 236, .2);
      font-size: 12px;
    }

    @media (max-width: 1000px) {
      .main-nav {
        display: none;
      }

      .hamburger {
        display: block;
      }

      .logo {
        flex: 1;
      }

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

      .tool-side-card {
        position: static;
      }
    }

    @media (max-width: 700px) {
      .container {
        width: min(100% - 28px, 1180px);
      }

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

      .topbar-links {
        flex-wrap: wrap;
        gap: 4px 14px;
      }

      .header-inner {
        min-height: 68px;
        gap: 10px;
      }

      .header-btns {
        gap: 7px;
      }

      .member-link {
        display: none;
      }

      .account-link {
        padding: 8px 12px;
        font-size: 13px;
      }

      .tool-detail-page {
        padding: 38px 0 60px;
      }

      .tool-title-row {
        gap: 12px;
      }

      .tool-title-row img {
        width: 50px;
        height: 50px;
        flex-basis: 50px;
        padding: 9px;
      }

      .tool-intro {
        font-size: 16px;
      }

      .tool-main-card {
        padding: 24px 18px;
      }

      .footer {
        padding-top: 40px;
      }

      .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 26px 18px;
      }

      .footer-brand {
        grid-column: 1 / -1;
      }

      .footer-bottom {
        align-items: flex-start;
        flex-direction: column;
        gap: 5px;
      }
    }