Derive theme gradients and add solid paint controls

site/index.html

@@ -80,12 +80,16 @@
       <article>
         <h2>Appearance</h2>
         <p>
-          Choose your theme, wallpaper, colors, and motion. Change settings
-          through the app or a KDL config, with live reload.
+          Choose your theme, wallpaper, and colors through Settings or a KDL config, and see changes as you make them.
         </p>
         <a href="docs/configuration.html#appearance">Customize Ferese →</a>
       </article>
     </section>
+    <section class="product-motion page-width" aria-labelledby="continuum-heading">
+      <h2 id="continuum-heading">Continuum motion</h2>
+      <p>Continuum carries your gesture’s momentum into workspace transitions and keeps motion continuous when you change direction. Adjust spring response and speed to your taste, or enable reduced motion.</p>
+      <a href="docs/animation-model.html">Explore the animation model →</a>
+    </section>
     <section class="product-getting-started page-width">
       <h2>Getting started</h2>
       <p>