Improve sprite styling

web/styles.css

@@ -292,8 +292,15 @@ button.color-select:hover {
   box-shadow: 0px 0px 8px var(--shadow);
 }
 
-.pkmn-tile img {
+.pkmn-tile a {
   height: 64px;
+  display: inline-flex;
+  justify-content: center;
+  align-items: center;
+}
+
+.pkmn-tile img {
+  max-height: 100%;
 }
 
 .pkmn-tile button {