Landing: one explorer, with the plane-only view as a toggle inside it

index.html

@@ -40,13 +40,8 @@ a.card p{margin:0;color:var(--muted);font-size:12.5px}
   <video id="v" controls playsinline preload="metadata" src="https://teahub.xyz/maths/videos/raw/commit/ec0bb56210abe087f4731777ffba8d1fa6bab3df/yantra-two-poles.mp4"></video>
   <div class="cards">
     <a class="card" href="sphere/">
-      <h2>On the sphere</h2>
-      <p>Spin the yantra and its inversion on the Riemann sphere. Slide the lift, compare stereographic with great circles, and switch the sphere off to watch only the plane.</p>
-      <span class="go">open explorer →</span>
-    </a>
-    <a class="card" href="inversion/">
-      <h2>On the plane</h2>
-      <p>The yantra inverted in its own outer circle, z ↦ z / |z|². Pan and zoom out to follow the arcs toward infinity.</p>
+      <h2>Explore it</h2>
+      <p>Spin the yantra and its inversion on the Riemann sphere, with the plane underneath. Slide the lift, compare stereographic with great circles, and switch the sphere off to see just the plane.</p>
       <span class="go">open explorer →</span>
     </a>
   </div>