feat(legal): add legal notice error handling

The legal notice view now shows an error box if the legal notice could
not be loaded.

src/styles/variables/colors.css

@@ -84,6 +84,9 @@ body {
     --light-hover:          var(--light-d-2);
 
     --invert: invert(0);
+
+    --color-negative-bg:     oklch(59% 0.22706 29.244);
+    --color-negative-border: oklch(51% 0.22706 29.244);
 }
 
 @media (prefers-color-scheme: dark) {