Add a level selector

src/style.css

@@ -82,9 +82,34 @@ button:focus-visible {
   fill: red !important;
 }
 .accepting-node {
-  outline: 1px solid #81B1DB;
-  outline-offset: 2px;
-  border-radius: 0.1em;
+  stroke: yellow;
+}
+
+#automaton-selector {
+  width: 100%;
+  max-width: 600px;
+  margin: 0 auto;
+}
+#automaton-collection {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: center;
+  margin: 2em 0;
+}
+
+.card {
+  display: flex;
+  flex-direction: column;
+  align-items: center;
+  padding: 1.5em;
+  margin: 1em;
+  border-radius: 8px;
+  background-color: #1a1a1a;
+  box-shadow: 0 0 0 1px rgba(255, 255, 255, 0.1), 0 2px 4px rgba(0, 0, 0, 0.2);
+  cursor: pointer;
+}
+.card:hover {
+  background-color: #2a2a2a;
 }
 
 @media (prefers-color-scheme: light) {