working basic live collab

frontend/app/globals.css

@@ -106,4 +106,39 @@
   padding: 2px 4px;
   border-radius: 4px;
   margin-left: 56px;
+}
+
+.yRemoteSelection {
+  opacity: 0.5;
+  background-color: var(--user-color);
+  margin-right: -1px;
+}
+
+/* Cursor caret */
+.yRemoteSelectionHead {
+  position: absolute;
+  box-sizing: border-box;
+  height: 100%;
+  border-left: 2px solid var(--user-color);
+}
+
+/* Cursor name */
+.yRemoteSelectionHead::after {
+  position: absolute;
+  top: -1.4em;
+  left: -2px;
+  padding: 2px 6px;
+  background: var(--user-color);
+  color: #fff;
+  border: 0;
+  border-radius: 6px;
+  border-bottom-left-radius: 0;
+  line-height: normal;
+  white-space: nowrap;
+  font-size: 14px;
+  font-style: normal;
+  font-weight: 600;
+  pointer-events: none;
+  user-select: none;
+  z-index: 1000;
 }