swarm ui: the start page ends with the slug, its gradients animated

hyperhive / we are the wired between two shaded gradients that pulse in a
wave, still under reduced motion. It sits under 2em from the bottom edge,
clear of the setup assistant.

frontend/packages/swarm-ui/src/pages/StartPage.css

@@ -21,3 +21,11 @@
     0 0 0.4em color-mix(in srgb, var(--purple) 55%, transparent),
     0 0 1.2em var(--bg);
 }
+/* The slug sits at the foot of the page, over the rain. It stays under 2em
+ * from the bottom edge, where the setup assistant starts (bottom-right,
+ * `SetupAssistant.css`), so the two never overlap, however narrow the window. */
+.start-page .ui-slug {
+  position: absolute;
+  inset: auto 0 0;
+  margin: 0 0 0.4em;
+}