:root {
  --robots: var(--blue);
  --ai: var(--violet);
  --robotics: var(--gold);
  --math: var(--orange);
  --physics: var(--teal);
  --imagination: var(--sky);
}

* { box-sizing: border-box; }
body { min-height: 100vh; min-height: 100svh; }
a { color: inherit; text-decoration: none; }
a { -webkit-tap-highlight-color: transparent; }
a:focus-visible { outline: 2px solid var(--robots); outline-offset: 7px; }
.skip-link { position: fixed; top: 12px; left: 12px; z-index: 20; padding: 12px 18px; border-radius: var(--radius-control); background: var(--surface); color: var(--ink); transform: translateY(-200%); }
.skip-link:focus { transform: none; }

.category-nav { position: fixed; left: max(24px, env(safe-area-inset-left)); top: 50%; transform: translateY(-50%); z-index: 8; display: flex; flex-direction: column; gap: 6px; padding: 8px 0; background: var(--surface); }
.category-nav a { display: flex; align-items: center; gap: 10px; min-height: 44px; padding: 8px 10px; color: var(--muted); font-size: 13px; line-height: 1.5; white-space: nowrap; border-radius: var(--radius-control); transition: color 180ms ease; }
.category-nav a::before { content: ""; width: 5px; height: 5px; flex: 0 0 auto; border-radius: 50%; background: var(--nav-tint); opacity: .3; transition: opacity 180ms ease, transform 180ms ease; }
.category-nav a:hover, .category-nav a.is-hovered, .category-nav a[aria-current="true"] { color: var(--nav-tint); }
.category-nav-label { display: inline-block; transform-origin: left center; transition: transform 180ms ease; }
.category-nav a:hover .category-nav-label, .category-nav a.is-hovered .category-nav-label { transform: scale(1.2); }
.category-nav a:hover::before, .category-nav a.is-hovered::before { opacity: .8; transform: scale(1.2); }
.category-nav a[aria-current="true"] { font-weight: 600; }
.category-nav a[aria-current="true"]::before { opacity: 1; transform: scale(1.4); }
.category-nav a:focus-visible { outline-color: var(--nav-tint); outline-offset: 2px; }
.atlas-main { position: relative; width: min(1560px, 100%); min-height: 100vh; min-height: 100svh; margin: 0 auto; padding: 60px 84px 32px 144px; display: grid; align-content: center; }
.visually-hidden { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip-path: inset(50%); white-space: nowrap; border: 0; }
.random-layout { position: fixed; top: 50%; right: max(24px, env(safe-area-inset-right)); transform: translateY(-50%); z-index: 10; display: grid; place-items: center; width: 44px; height: 44px; padding: 10px; border: 0; background: transparent; color: var(--muted); box-shadow: none; cursor: pointer; transition: color 180ms ease; }
.random-layout[hidden] { display: none; }
.random-layout svg { width: 24px; height: 24px; fill: none; stroke: currentColor; stroke-width: 1.5; stroke-linecap: round; stroke-linejoin: round; transition: transform 180ms ease; }
.random-layout:hover { color: var(--ink); }
.random-layout:hover svg { transform: scale(1.1); }
.random-layout:active svg { transform: scale(.94); }
.random-layout:focus-visible { outline: 2px solid var(--focus-ring); outline-offset: 2px; border-radius: var(--radius-control); }
.galaxy.is-interactive .star-orb { cursor: grab; touch-action: none; user-select: none; -webkit-user-select: none; }
.galaxy.is-dragging { user-select: none; -webkit-user-select: none; }
.galaxy.is-dragging .star-orb { cursor: grabbing; }
.constellation.is-dragging { z-index: 4; }
.constellation:focus-within { z-index: 3; }
.galaxy.is-interactive .constellation { will-change: transform; }
.galaxy.is-interactive .model-node { will-change: transform; }
.galaxy.is-interactive { overflow: clip; }
.galaxy.is-interactive .model-nodes { pointer-events: none; }
.galaxy.is-interactive .model-node { pointer-events: auto; z-index: 2; }
.galaxy.is-interactive .model-node:hover,
.galaxy.is-interactive .model-node:focus-visible { z-index: 3; }
.galaxy.is-interactive .category-star:hover .star-orb,
.galaxy.is-interactive .category-star:focus-visible .star-orb { transform: none; }

.galaxy { position: relative; isolation: isolate; width: 100%; height: clamp(810px, 62vw, 900px); }
.galaxy-lines { position: absolute; z-index: -1; inset: 0; width: 100%; height: 100%; pointer-events: none; overflow: visible; fill: none; stroke: #849393; stroke-width: .85; }
.galaxy-lines .orbit { stroke-dasharray: 3 8; opacity: .36; }
.galaxy-lines .bridge { stroke-dasharray: 4 7; opacity: .25; }
.galaxy-lines .branch path { opacity: .36; transition: stroke 180ms ease, opacity 180ms ease; }
.galaxy-lines .branch [data-category="robots"] { --connection-tint: var(--robots); }
.galaxy-lines .branch [data-category="ai"] { --connection-tint: var(--ai); }
.galaxy-lines .branch [data-category="robotics"] { --connection-tint: var(--robotics); }
.galaxy-lines .branch [data-category="math"] { --connection-tint: var(--math); }
.galaxy-lines .branch [data-category="physics"] { --connection-tint: var(--physics); }
.galaxy-lines .branch [data-category="imagination"] { --connection-tint: var(--imagination); }
.galaxy-lines .branch path.is-active { stroke: var(--connection-tint); opacity: .9; }
.galaxy-lines .orbital-dot { fill: #718782; stroke: none; opacity: .55; }

.constellation { --tint: var(--robots); --rgb: var(--blue-rgb); position: absolute; }
.constellation-robots { left: 27%; top: 20%; }
.constellation-ai { --tint: var(--ai); --rgb: var(--violet-rgb); left: 65%; top: 20%; }
.constellation-robotics { --tint: var(--robotics); --rgb: var(--gold-rgb); left: 27%; top: 52%; }
.constellation-math { --tint: var(--math); --rgb: var(--orange-rgb); left: 69%; top: 52%; }
.constellation-physics { --tint: var(--physics); --rgb: var(--teal-rgb); left: 27%; top: 80%; }
.constellation-imagination { --tint: var(--imagination); --rgb: var(--sky-rgb); left: 69%; top: 80%; }
.category-star { position: absolute; display: flex; flex-direction: column; align-items: center; width: 132px; left: -66px; top: -66px; border-radius: 50%; color: var(--tint); text-align: center; }
.star-orb { position: relative; width: 132px; height: 132px; display: grid; place-items: center; border: 1px solid rgba(var(--rgb), .32); border-radius: 50%; background: var(--paper); transition: transform 300ms ease, border-color 180ms ease, background-color 180ms ease; }
.star-orb::before, .star-orb::after { content: ""; position: absolute; inset: -12px; border: 1px solid rgba(var(--rgb), .12); border-radius: 50%; pointer-events: none; }
.star-orb::after { inset: -26px; border-color: rgba(var(--rgb), .1); border-left-color: rgba(var(--rgb), .28); border-right-color: rgba(var(--rgb), .2); transform: rotate(-32deg) scaleY(.65); }
.star-orb svg { width: 64px; height: 64px; fill: none; stroke: currentColor; stroke-width: 1.1; stroke-linecap: round; stroke-linejoin: round; }
.star-orb .icon-soft { opacity: .3; }
.star-orb .icon-dot { fill: currentColor; stroke: none; }
.category-star:hover .star-orb, .category-star:focus-visible .star-orb { transform: scale(1.04); border-color: rgba(var(--rgb), .75); }
.constellation.is-hovered .star-orb { border-color: rgba(var(--rgb), .75); }
.constellation:has(.model-node:hover, .model-node:focus-visible) .star-orb { border-color: rgba(var(--rgb), .75); }
.constellation.is-selected .star-orb,
.galaxy:not(.is-interactive) .constellation:target .star-orb { border: 2px solid var(--tint); background: color-mix(in srgb, var(--tint) 7%, var(--paper)); }
.constellation.is-selected .star-orb::before,
.galaxy:not(.is-interactive) .constellation:target .star-orb::before { border-color: rgba(var(--rgb), .45); }
.constellation.is-selected .star-orb::after,
.galaxy:not(.is-interactive) .constellation:target .star-orb::after { border-color: rgba(var(--rgb), .3); }

.model-nodes { margin: 0; padding: 0; list-style: none; }
.model-node { position: absolute; display: inline-flex; align-items: center; gap: 9px; width: max-content; min-height: 44px; padding: 8px 10px; border: 1px solid transparent; border-radius: var(--radius-control); font-size: 12px; line-height: 1.5; color: var(--muted); transition: color 180ms ease; }
.model-node::before { content: ""; flex: 0 0 auto; width: 5px; height: 5px; border-radius: 50%; background: var(--tint); transition: box-shadow 180ms ease, transform 180ms ease; }
.model-node:hover, .model-node:focus-visible { color: var(--ink); }
.model-node:hover::before, .model-node:focus-visible::before { box-shadow: 0 0 0 6px rgba(var(--rgb), .14); transform: scale(1.14); }
.model-node:focus-visible { outline-color: var(--tint); }
.node-embodied { left: -191px; top: -140px; }
.node-quadruped { left: 94px; top: -101px; }
.node-drone { left: -211px; top: 106px; }
.node-transformer { left: 86px; top: 75px; }
.node-agent { left: -185px; top: -75px; }
.node-dh { left: -238px; top: 24px; }
.node-quaternion { left: 80px; top: -42px; }
.node-kalman { left: 72px; top: 88px; }
.node-calculus { left: 94px; top: 24px; }
.node-linear-algebra { left: 94px; top: -61px; }
.node-least-squares { left: 94px; top: 102px; }
.node-pendulum { left: 110px; top: -40px; }
.node-newton { left: 90px; top: 75px; }
.node-three-body { left: 110px; top: -40px; }
.constellation-robotics .star-orb { width: 112px; height: 112px; }
.constellation-robotics .category-star { width: 112px; left: -56px; top: -56px; }
.constellation-robotics .star-orb svg { width: 58px; height: 58px; }

@media (min-width: 1500px) and (min-height: 950px) {
  .galaxy { height: 900px; }
}

@media (max-width: 1100px) {
  .galaxy { height: 810px; }
  .node-embodied { left: -158px; top: -145px; }
  .node-quadruped { left: 62px; top: -116px; }
  .node-drone { left: -160px; top: 104px; }
  .node-transformer { left: 45px; top: 110px; }
  .node-dh { left: -150px; }
  .node-calculus, .node-linear-algebra, .node-least-squares { left: 80px; }
}

@media (max-width: 900px) {
  .category-nav { left: max(10px, env(safe-area-inset-left)); gap: 4px; }
  .category-nav a { gap: 7px; padding: 8px 6px; font-size: 12px; }
  .atlas-main { padding: 60px 56px 24px 96px; }
  .random-layout { right: max(6px, env(safe-area-inset-right)); }
  .galaxy { height: auto; min-height: 1120px; max-width: 500px; margin: 0 auto; padding: 12px 16px 26px; display: grid; gap: 0; }
  .galaxy-lines { display: none; }
  .galaxy.is-interactive .galaxy-lines { display: block; }
  .constellation { position: relative; inset: auto; min-height: 270px; display: grid; grid-template-columns: 46% 1fr; align-items: center; gap: 18px; }
  .category-star { position: relative; inset: auto !important; width: 100px; justify-self: center; }
  .constellation-robotics .category-star { width: 96px; }
  .star-orb { width: 100px; height: 100px; }
  .constellation-robotics .star-orb { width: 96px; height: 96px; }
  .star-orb svg { width: 52px; height: 52px; }
  .star-orb::after { inset: -18px; }
  .model-nodes { display: flex; flex-direction: column; gap: 13px; padding-bottom: 40px; }
  .model-node { position: relative; inset: auto; padding: 8px 4px; max-width: 100%; font-size: 12px; gap: 8px; white-space: normal; }
  .model-nodes li:nth-child(2) { margin-left: 8px; }
  .galaxy.is-interactive .constellation { min-height: 360px; grid-template-columns: 1fr; gap: 0; }
  .galaxy.is-interactive .model-nodes { position: absolute; inset: 0; display: block; padding: 0; }
  .galaxy.is-interactive .model-nodes li { margin: 0; }
  .galaxy.is-interactive .model-node { position: absolute; left: 0; top: 0; max-width: 100%; white-space: nowrap; }
}

@media (max-height: 400px) {
  .category-nav { gap: 0; max-height: calc(100svh - 24px); overflow-y: auto; }
  .category-nav a { min-height: 36px; padding-block: 5px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}