:root {
      --ink: #0b174b;
      --muted: #3b4b77;
      --blue: #075bea;
      --purple: #6414c5;
      --page: #fff;
      --line: #e4e9f2;
      --radius: 12px;
      --shadow: 0 2px 3px rgba(18, 43, 89, .075);
    }
    * { box-sizing: border-box; }
    body { margin: 0; background: var(--page); color: var(--ink); font: 15px/1.35 Arial, Helvetica, sans-serif; }
    a { color: inherit; }
    .page { width: min(100%, 1800px); margin: auto; padding: 10px 12px 18px; }
    .hero { min-height: 107px; position: relative; overflow: hidden; border-radius: 13px; background: linear-gradient(103deg,#d8e6ff 0%,#edf9ff 49%,#d4e3ff 100%); display: grid; place-content: center; text-align: center; padding: 16px 120px; }
    .hero h1 { margin: 0 0 7px; font-size: clamp(25px,2.4vw,35px); letter-spacing: -.8px; }
    .hero p { margin: 0; font-size: 15px; }
    .wave { position: absolute; top: 14px; width: 27%; height: 80px; opacity: .56; pointer-events: none; }
    .wave.left { left: 2%; } .wave.right { right: 2%; transform: scaleX(-1); }
    .wave path { fill: none; stroke: #6b9cff; stroke-width: 2; stroke-dasharray: 3 8; stroke-linecap: round; }
    .wave path + path { stroke: #b7a9ff; opacity: .7; }
    .panel { margin-top: 10px; border-radius: 14px; background: linear-gradient(118deg,#f4f7fc,#f2f7ff 70%,#f7f9ff); padding: 18px; }
    .section-heading { display: flex; gap: 15px; align-items: flex-start; margin-bottom: 17px; }
    .section-heading .section-icon { width: 40px; height: 40px; flex: 0 0 40px; background: var(--blue); -webkit-mask: var(--icon-url) center / contain no-repeat; mask: var(--icon-url) center / contain no-repeat; }
    .section-heading h2 { font-size: 21px; letter-spacing: -.35px; margin: 0 0 2px; }
    .section-heading p { margin: 0; color: var(--muted); }
    .panel { padding-top: 16px; }
    .category-grid { display: grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap: 16px; }
    .category { min-width: 0; background: #fff; border: 1px solid #e5e9f1; border-radius: 9px; overflow: hidden; box-shadow: var(--shadow); }
    .category-head { display: flex; gap: 13px; align-items: center; padding: 13px 17px; min-height: 49px; }
    .category-head h3 { margin: 0; font-size: 15px; letter-spacing: -.2px; }
    .category-head .category-icon { width: 27px; height: 27px; flex: 0 0 27px; background: currentColor; -webkit-mask: var(--icon-url) center / contain no-repeat; mask: var(--icon-url) center / contain no-repeat; }
    .category.blue .category-head { background: #e4efff; color: #0752d8; }
    .category.mint .category-head { background: #dff8ef; color: #005849; }
    .category.amber .category-head { background: #fff1d5; color: #935600; }
    .category.pink .category-head { background: #ffe1ee; color: #b00053; }
    .category.lavender .category-head { background: #f0e5ff; color: #5815ae; }
    .category-items { padding: 8px 15px 12px; min-height: 220px; }
    .tool { position: relative; display: block; padding: 11px 24px 12px 11px; text-decoration: none; border-bottom: 1px solid var(--line); border-radius: 5px; }
    .tool-entry { border-bottom: 1px solid var(--line); }
    .tool-entry:last-child { border-bottom: 0; }
    .tool-entry .tool { border-bottom: 0; }
    .tool:hover, .tool:focus-visible { background: #f4f8ff; outline: none; }
    .tool strong { display: block; font-size: 14px; color: var(--ink); line-height: 1.24; }
    .tool span { display: block; color: var(--muted); font-size: 13px; line-height: 1.23; margin-top: 2px; }
    /* Tiny, quiet link icon below a tool. Click to reveal mirrors / related resources. */
    .tool-extra { margin: -3px 10px 7px 11px; font-size: 12px; color: var(--muted); }
    .tool-extra summary { display: inline-flex; align-items: center; justify-content: center; width: 23px; height: 21px; cursor: pointer; border-radius: 5px; color: #8492aa; list-style: none; vertical-align: middle; }
    .tool-extra summary::-webkit-details-marker { display: none; }
    .tool-extra summary::before { content: ""; width: 15px; height: 15px; background: currentColor; -webkit-mask: url('icons2/link.svg') center / contain no-repeat; mask: url('icons2/link.svg') center / contain no-repeat; }
    .tool-extra summary:hover, .tool-extra summary:focus-visible, .tool-extra[open] summary { color: #075bea; background: #edf4ff; }
    .tool-extra summary:focus-visible { outline: 2px solid #075bea; outline-offset: 2px; }
    .tool-extra[open] summary { margin-bottom: 6px; }
    .sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
    .extra-links { display: flex; flex-wrap: wrap; gap: 6px; }
    .extra-links a { background: #edf4ff; border: 1px solid #d6e4ff; color: #1247a7; text-decoration: none; border-radius: 5px; padding: 4px 8px; }
    .extra-links a:hover, .extra-links a:focus-visible { background: #dce9ff; text-decoration: underline; }
    .tool::after { content: ''; position: absolute; right: 8px; top: 18px; width: 7px; height: 7px; border-right: 2px solid #0860df; border-top: 2px solid #0860df; transform: rotate(45deg); }
    .support { display: flex; align-items: center; gap: 23px; background: linear-gradient(96deg,#fff1f8,#fff4fc 65%,#fff0f9); border: 1px solid #ffd4e8; border-radius: 13px; padding: 13px 22px; margin-top: 10px; min-height: 80px; }
    .support-icon { display: grid; place-items: center; flex: 0 0 58px; height: 58px; border-radius: 50%; background: #ffd4e9; color: #e10070; font-size: 32px; }
    .support-copy { flex: 1; }
    .support h2 { font-size: 19px; margin: 0 0 2px; } .support p { margin: 0; color: var(--muted); }
    .support-button { white-space: nowrap; border-radius: 40px; background: #e60070; padding: 12px 20px; color: white; text-decoration: none; font-weight: 700; }
    .support-button:hover { background: #c70060; }
    .external-grid { display: grid; grid-template-columns: 1fr 1.25fr; gap: 10px; margin-top: 10px; }
    .external-panel { border-radius: 13px; padding: 15px 22px 22px; min-width: 0; }
    .friends { background: linear-gradient(110deg,#edf5ff,#e9f3ff); }
    .resources { background: linear-gradient(110deg,#e9faf5,#effcf8); }
    .external-panel .section-heading { margin-bottom: 14px; gap: 13px; }
    .external-panel .section-heading h2 { font-size: 20px; }
    .external-panel .section-heading .section-icon { width: 34px; height: 34px; flex-basis: 34px; }
    .resources .section-heading .section-icon { background: #00775b; }
    .external-cards { display: grid; grid-template-columns: repeat(2,minmax(0,1fr)); gap: 12px 16px; }
    .resources .external-cards { grid-template-columns: repeat(3,minmax(0,1fr)); }
    .external-tool { background: #fff; border: 1px solid #e6edf3; box-shadow: var(--shadow); border-radius: 8px; min-height: 55px; padding: 12px 34px 11px 18px; position: relative; display: block; text-decoration: none; }
    .external-tool:hover, .external-tool:focus-visible { background: #f7faff; outline: 2px solid #b8d7ff; }
    .external-tool strong { display: block; color: #081650; font-size: 14px; line-height: 1.2; }
    .external-tool span { display: block; color: var(--muted); font-size: 13px; line-height: 1.25; margin-top: 3px; }
    .external-tool .external-icon { position: absolute; width: 17px; height: 17px; right: 17px; top: 17px; background: #0864ef; -webkit-mask: var(--icon-url) center / contain no-repeat; mask: var(--icon-url) center / contain no-repeat; }
    .back { display: inline-block; color: var(--purple); text-decoration: none; font-weight: 700; margin: 10px 0 0 12px; }
    .back:hover { text-decoration: underline; }
    .legal { margin: 15px 12px 0; color: var(--muted); font-size: 12px; }
    .legal a { color: var(--blue); }
    @media (max-width: 1200px) { .category-grid { grid-template-columns: repeat(3,minmax(0,1fr)); } .external-grid { grid-template-columns: 1fr; } }
    @media (max-width: 760px) { .page { padding: 8px; } .hero { padding: 22px 16px; } .wave { display: none; } .category-grid { grid-template-columns: repeat(2,minmax(0,1fr)); } .resources .external-cards { grid-template-columns: repeat(2,minmax(0,1fr)); } .support { flex-wrap: wrap; } .support-button { margin-left: 80px; } }
    @media (max-width: 520px) { .category-grid, .external-cards, .resources .external-cards { grid-template-columns: 1fr; } .category-items { min-height: 0; } .panel { padding: 13px; } .support { gap: 10px; padding: 12px; } .support h2 { font-size: 17px; } .support-button { margin: 7px 0 0; text-align: center; width: 100%; } }

/* Icon assets: add a class to HTML; all URLs and presentation remain here. */
.icon-data-encoding { --icon-url: url("icons2/data-encoding.svg"); }
.icon-file-analysis { --icon-url: url("icons2/file-analysis.svg"); }
.icon-radio-signal { --icon-url: url("icons2/radio-signal.svg"); }
.icon-guides { --icon-url: url("icons2/guides.svg"); }
.icon-friends { --icon-url: url("icons2/friends.svg"); }
.icon-resources { --icon-url: url("icons2/resources.svg"); }
.icon-external-link { --icon-url: url("icons2/external-link.svg"); }