Modernize frontend assets and security baseline

css/site.css

@@ -203,6 +203,49 @@ body.custom-background { background-color: #ffffff; }
   width:18%;
 }
 
+/* Modern shared interactions and responsive media. */
+.fluid-width-video-wrapper {
+  position: relative;
+  width: 100%;
+  aspect-ratio: var(--video-aspect, 16 / 9);
+}
+
+.fluid-width-video-wrapper iframe,
+.fluid-width-video-wrapper object,
+.fluid-width-video-wrapper embed {
+  position: absolute;
+  inset: 0;
+  width: 100%;
+  height: 100%;
+}
+
+#toTop.is-visible {
+  display: block;
+}
+
+#toTop {
+  padding: 0;
+  border: 0;
+}
+
+#branding > picture {
+  display: block;
+}
+
+#branding > picture + #header-container {
+  height: 100%;
+}
+
+@media (max-width: 650px) {
+  #access.is-open {
+    display: block;
+  }
+
+  #access .menu-item-has-children.submenu-open > .sub-menu {
+    display: block;
+  }
+}
+
 /* The migrated content only uses columns and video embeds from WordPress blocks. */
 .wp-block-columns {
   display: flex;