:root {
      --theme: #0B3D91;
      --theme-dark: #082c68;
      --wood: #b77b43;
      --wood-light: #f4e3cf;
      --green: #3c7a54;
      --ink: #17202a;
      --muted: #657180;
      --line: #dfe5eb;
      --paper: #f6f8fa;
      --white: #ffffff;
      --shadow: 0 18px 45px rgba(23, 32, 42, .08);
      --radius: 8px;
    }

    * { 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: 1.6;
    }
    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 {
      background: #10243d;
      color: #dce6f1;
      font-size: 13px;
    }
    .topbar .container {
      min-height: 34px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: 20px;
    }
    .topbar a { color: #fff; }

    .header {
      position: relative;
      z-index: 20;
      background: var(--white);
      border-bottom: 1px solid var(--line);
    }
    .header-inner {
      min-height: 76px;
      display: flex;
      align-items: center;
      gap: 34px;
    }
    .logo {
      display: inline-flex;
      align-items: center;
      gap: 10px;
      flex: 0 0 auto;
      font-size: 18px;
      font-weight: 800;
      color: var(--theme-dark);
      white-space: nowrap;
    }
    .logo img {
      width: 34px;
      height: 34px;
      object-fit: contain;
    }
    .main-nav { flex: 1; }
    .nav-list {
      display: flex;
      justify-content: center;
      align-items: center;
      gap: 4px;
      list-style: none;
      margin: 0;
      padding: 0;
    }
    .nav-list > li { position: relative; }
    .nav-link {
      display: inline-flex;
      align-items: center;
      min-height: 76px;
      padding: 0 13px;
      color: #354252;
      font-size: 14px;
      white-space: nowrap;
    }
    .nav-link:hover,
    .nav-link:focus-visible { color: var(--theme); }
    .has-arrow::after {
      content: "";
      width: 6px;
      height: 6px;
      margin: -3px 0 0 8px;
      border-right: 1px solid currentColor;
      border-bottom: 1px solid currentColor;
      transform: rotate(45deg);
    }

    .dropdown-panel,
    .mega-menu {
      position: absolute;
      top: calc(100% - 1px);
      left: 50%;
      z-index: 30;
      width: 310px;
      padding: 20px;
      visibility: hidden;
      opacity: 0;
      transform: translate(-50%, 8px);
      background: #fff;
      border: 1px solid var(--line);
      border-radius: 0 0 var(--radius) var(--radius);
      box-shadow: 0 18px 34px rgba(13, 32, 54, .14);
      transition: opacity .18s ease, transform .18s ease, visibility .18s ease;
    }
    .mega-menu {
      width: 620px;
    }
    .dropdown-panel::before,
    .mega-menu::before {
      content: "";
      position: absolute;
      left: 0;
      right: 0;
      top: -12px;
      height: 12px;
    }
    .nav-list > li:hover > .dropdown-panel,
    .nav-list > li:focus-within > .dropdown-panel,
    .nav-list > li:hover > .mega-menu,
    .nav-list > li:focus-within > .mega-menu {
      visibility: visible;
      opacity: 1;
      transform: translate(-50%, 0);
    }
    .drop-title,
    .mega-title {
      margin: 0 0 12px;
      color: var(--theme-dark);
      font-size: 13px;
      font-weight: 800;
      letter-spacing: .08em;
    }
    .drop-item {
      display: block;
      padding: 9px 0;
      border-bottom: 1px solid #edf0f3;
      color: #3e4a58;
      font-size: 13px;
    }
    .drop-item:hover { color: var(--theme); }
    .mega-grid {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 8px;
    }
    .mega-card {
      display: flex;
      min-width: 0;
      gap: 9px;
      padding: 10px;
      background: #f7f9fb;
      border: 1px solid #edf0f3;
      border-radius: 5px;
    }
    .mega-card:hover { border-color: #b9cce5; }
    .mega-card img {
      width: 32px;
      height: 32px;
      flex: 0 0 32px;
      object-fit: contain;
      border-radius: 4px;
      background: #fff;
    }
    .mega-card > span {
      min-width: 0;
      display: grid;
      gap: 3px;
      color: var(--muted);
      font-size: 11px;
      line-height: 1.45;
    }
    .mega-card strong {
      overflow: hidden;
      color: var(--ink);
      font-size: 12px;
      text-overflow: ellipsis;
      white-space: nowrap;
    }
    .mega-footer {
      display: block;
      margin-top: 16px;
      padding-top: 12px;
      border-top: 1px solid var(--line);
      color: var(--theme);
      font-size: 13px;
      font-weight: 700;
    }

    .header-btns {
      display: flex;
      align-items: center;
      gap: 8px;
      flex: 0 0 auto;
    }
    .member-btn,
    .open-btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      min-height: 36px;
      padding: 0 13px;
      border-radius: 5px;
      font-size: 13px;
      font-weight: 700;
    }
    .member-btn { color: var(--theme); }
    .open-btn {
      color: #fff;
      background: var(--theme);
    }
    .open-btn:hover { background: var(--theme-dark); }

    .hamburger {
      display: none;
      width: 40px;
      height: 40px;
      padding: 9px;
      border: 1px solid var(--line);
      border-radius: 5px;
      background: #fff;
      cursor: pointer;
    }
    .hamburger span {
      display: block;
      height: 2px;
      margin: 4px 0;
      background: var(--theme);
      transition: transform .2s ease, opacity .2s ease;
    }
    .hamburger.active span:nth-child(1) { transform: translateY(6px) rotate(45deg); }
    .hamburger.active span:nth-child(2) { opacity: 0; }
    .hamburger.active span:nth-child(3) { transform: translateY(-6px) rotate(-45deg); }

    .drawer-overlay {
      position: fixed;
      inset: 0;
      z-index: 40;
      visibility: hidden;
      opacity: 0;
      background: rgba(8, 21, 36, .48);
      transition: opacity .2s ease, visibility .2s ease;
    }
    .drawer-overlay.open { visibility: visible; opacity: 1; }
    .mobile-drawer {
      position: fixed;
      top: 0;
      right: 0;
      bottom: 0;
      z-index: 50;
      width: min(360px, 88vw);
      overflow-y: auto;
      visibility: hidden;
      transform: translateX(100%);
      background: #fff;
      box-shadow: -12px 0 30px rgba(8, 21, 36, .18);
      transition: transform .24s ease, visibility .24s ease;
    }
    .mobile-drawer.open {
      visibility: visible;
      transform: translateX(0);
    }
    .drawer-head {
      display: flex;
      align-items: center;
      gap: 14px;
      min-height: 70px;
      padding: 0 20px;
      color: var(--theme-dark);
      border-bottom: 1px solid var(--line);
      font-weight: 800;
    }
    .drawer-head span { flex: 1; }
    .drawer-head a {
      color: var(--theme);
      font-size: 13px;
    }
    .drawer-close {
      border: 0;
      background: transparent;
      color: var(--muted);
      font-size: 28px;
      line-height: 1;
      cursor: pointer;
    }
    .drawer-menu { padding: 12px 20px 30px; }
    .drawer-link,
    .drawer-toggle {
      display: block;
      width: 100%;
      padding: 13px 0;
      border: 0;
      border-bottom: 1px solid #edf0f3;
      background: transparent;
      color: var(--ink);
      text-align: left;
      cursor: pointer;
      font-size: 15px;
    }
    .drawer-group .drawer-toggle::after {
      content: "+";
      float: right;
      color: var(--theme);
      font-size: 20px;
      line-height: 1;
    }
    .drawer-group .drawer-toggle.active::after { content: "−"; }
    .drawer-submenu {
      display: none;
      padding: 5px 0 7px 14px;
      border-bottom: 1px solid #edf0f3;
    }
    .drawer-submenu.open { display: block; }
    .drawer-submenu a {
      display: block;
      padding: 8px 0;
      color: var(--muted);
      font-size: 13px;
    }

    .tool-detail-page {
      padding: 48px 0 80px;
    }
    .tool-detail-page .breadcrumb {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
      margin-bottom: 22px;
      color: var(--muted);
      font-size: 13px;
    }
    .tool-detail-page .breadcrumb a { color: var(--theme); }
    .tool-detail-layout {
      display: grid;
      grid-template-columns: minmax(0, 1fr) 300px;
      align-items: start;
      gap: 26px;
    }
    .tool-article,
    .related-tools {
      min-width: 0;
      background: #fff;
      border: 1px solid var(--line);
      border-radius: var(--radius);
      box-shadow: var(--shadow);
    }
    .tool-article { overflow: hidden; }
    .tool-hero {
      display: flex;
      align-items: center;
      gap: 20px;
      padding: 30px;
      background: linear-gradient(135deg, #f3f7fc, #fff);
      border-bottom: 1px solid var(--line);
    }
    .tool-icon {
      width: 76px;
      height: 76px;
      flex: 0 0 76px;
      object-fit: contain;
      padding: 12px;
      background: #fff;
      border: 1px solid #d6e0eb;
      border-radius: 10px;
    }
    .tool-heading { min-width: 0; }
    .tool-heading h1 {
      margin: 0 0 7px;
      color: var(--theme-dark);
      font-size: clamp(26px, 4vw, 40px);
      line-height: 1.2;
    }
    .tool-heading p {
      margin: 0;
      color: var(--muted);
      font-size: 15px;
    }
    .tool-meta {
      display: flex;
      flex-wrap: wrap;
      gap: 10px 18px;
      padding: 16px 30px;
      color: var(--muted);
      border-bottom: 1px solid var(--line);
      font-size: 13px;
    }
    .tool-meta strong {
      color: var(--ink);
      font-weight: 700;
    }
    .tool-content {
      min-width: 0;
      max-width: 100%;
      overflow-x: auto;
      padding: 30px;
      color: #394653;
      font-size: 15px;
    }
    .tool-content img,
    .tool-content video,
    .tool-content iframe {
      max-width: 100%;
      height: auto;
    }
    .tool-content table {
      display: block;
      max-width: 100%;
      overflow-x: auto;
      border-collapse: collapse;
    }
    .tool-content h2,
    .tool-content h3 {
      color: var(--theme-dark);
      line-height: 1.35;
    }
    .tool-content a {
      color: var(--theme);
      text-decoration: underline;
      text-underline-offset: 3px;
    }
    .tool-content blockquote {
      margin: 22px 0;
      padding: 14px 18px;
      border-left: 4px solid var(--green);
      background: #f1f7f2;
      color: #476150;
    }
    .related-tools {
      padding: 22px;
    }
    .related-tools h2 {
      margin: 0 0 16px;
      color: var(--theme-dark);
      font-size: 19px;
    }
    .related-tool {
      display: grid;
      grid-template-columns: 42px minmax(0, 1fr);
      gap: 11px;
      padding: 13px 0;
      border-top: 1px solid var(--line);
    }
    .related-tool img {
      width: 42px;
      height: 42px;
      padding: 6px;
      object-fit: contain;
      border: 1px solid var(--line);
      border-radius: 6px;
    }
    .related-tool strong {
      display: block;
      margin-bottom: 3px;
      color: var(--ink);
      font-size: 14px;
    }
    .related-tool p {
      margin: 0;
      overflow: hidden;
      color: var(--muted);
      font-size: 12px;
      line-height: 1.5;
      display: -webkit-box;
      -webkit-box-orient: vertical;
      -webkit-line-clamp: 2;
    }

    .footer {
      padding: 48px 0 0;
      background: #10243d;
      color: #b9c7d6;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 1.4fr 1fr 1fr 1fr;
      gap: 34px;
      padding-bottom: 36px;
    }
    .footer-brand {
      margin-bottom: 10px;
      color: #fff;
      font-size: 20px;
      font-weight: 800;
    }
    .footer p {
      margin: 0 0 8px;
      font-size: 13px;
      line-height: 1.8;
    }
    .footer h3 {
      margin: 0 0 13px;
      color: #fff;
      font-size: 14px;
    }
    .footer-grid > div > a {
      display: block;
      width: fit-content;
      margin: 6px 0;
      color: #b9c7d6;
      font-size: 13px;
    }
    .footer-grid > div > a:hover { color: #fff; }
    .footer-social { margin-top: 16px; }
    .footer-bottom {
      padding: 17px 0;
      border-top: 1px solid rgba(255,255,255,.12);
      color: #8fa2b7;
      font-size: 12px;
    }

    @media (max-width: 980px) {
      .header-inner { gap: 16px; }
      .nav-link { padding: 0 8px; }
      .member-btn { display: none; }
      .tool-detail-layout { grid-template-columns: minmax(0, 1fr); }
      .related-tools { order: 2; }
    }

    @media (max-width: 760px) {
      .container { width: min(100% - 28px, 620px); }
      .topbar .container { min-height: 42px; align-items: flex-start; justify-content: center; flex-direction: column; gap: 0; padding-top: 6px; padding-bottom: 6px; }
      .topbar .contact { font-size: 12px; }
      .main-nav { display: none; }
      .header-inner { min-height: 66px; justify-content: space-between; }
      .nav-list { display: none; }
      .hamburger { display: block; }
      .open-btn { min-height: 34px; padding: 0 10px; }
      .tool-detail-page { padding: 28px 0 56px; }
      .tool-hero { align-items: flex-start; padding: 22px; gap: 14px; }
      .tool-icon { width: 58px; height: 58px; flex-basis: 58px; padding: 8px; }
      .tool-heading h1 { font-size: 27px; }
      .tool-heading p { font-size: 14px; }
      .tool-meta,
      .tool-content { padding: 20px 22px; }
      .footer { padding-top: 34px; }
      .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 26px 20px; }
      .footer-grid > div:first-child { grid-column: 1 / -1; }
    }

    @media (max-width: 430px) {
      .logo span { max-width: 150px; overflow: hidden; text-overflow: ellipsis; }
      .header-btns { gap: 4px; }
      .tool-hero { display: block; }
      .tool-icon { margin-bottom: 14px; }
      .footer-grid { grid-template-columns: 1fr; }
      .footer-grid > div:first-child { grid-column: auto; }
    }