fix css issues, remove outdated css

Author: mbektas

css/datagrid.css

@@ -16,50 +16,10 @@
   height: 500px;
 }
 
-.cell-editor-occluder {
-  pointer-events: none;
-  position: absolute;
-  overflow: hidden;
+.lm-DataGrid-cellEditorOccluder {
   margin: var(--datagrid-padding);
 }
 
-.cell-editor-container {
-  pointer-events: auto;
-  position: absolute;
-  background-color: #ffffff;
-  box-sizing: border-box;
-  box-shadow: 0px 0px 6px #006bf7;
-  border: 2px solid #006bf7;
-}
-
-.cell-editor-container.invalid {
-  box-shadow: 0px 0px 6px red;
-  border: 2px solid red;
-}
-
-.cell-editor-container>form {
-  width: 100%;
-  height: 100%;
-  overflow: hidden;
-}
-
-.cell-editor {
-  pointer-events: auto;
-  width: 100%;
-  height: 100%;
-  outline: none;
-  box-sizing: border-box;
-}
-
-.input-cell-editor {
-  background-color: #ffffff;
-  border: 0;
-}
-
-.boolean-cell-editor {
-  margin: 0;
-}
-
 .ipydatagrid-filterMenu {
   border: 1px solid var(--jp-border-color1, #BDBDBD);
   box-shadow: 5px 5px 5px rgba(0, 0, 0, .2);