Update Gemfile and GitHub Actions workflow for Jekyll

assets/css/custom.css

@@ -12,14 +12,4 @@
   overflow: hidden;
   position: relative;
   margin: 0 auto; /* Center the container */
-}
-
-.iframe-container iframe {
-  position: absolute; /* Position the iframe absolutely within the container */
-  top: 50%; /* Center vertically */
-  left: 50%; /* Center horizontally */
-  width: 400px; /* Set to desired display size's double */
-  height: 226px; /* Set to desired display size's double */
-  transform: translate(-50%, -50%) scale(0.5); /* Adjust scale as needed */
-  transform-origin: 0 0;
-}
+}