Add large size buttons variant and make disabled state global

src/routes/photos.svelte

@@ -296,9 +296,10 @@
                     </p>
 
                     <Button
-                        text={!ended ? 'See more photos' : "You've seen it all!"}
                         tag="button"
+                        text={!ended ? 'See more photos' : "You've seen it all!"}
                         on:click={loadMorePhotos}
+                        class="button--large button--beige"
                         disabled={ended}
                     />