Fix code quality issues and GitHub Actions workflows

playground/test.html

@@ -17,6 +17,7 @@
             height: 100%;
             border: none;
         }
+
         .buttons {
             position: fixed;
             top: 10px;
@@ -32,6 +33,7 @@
             border-radius: 4px;
             cursor: pointer;
         }
+
         button:hover {
             background-color: #005177;
         }