Add canonical grammar and CodeMirror playground

site/decodal-site/src/style.css

@@ -419,43 +419,26 @@ button:disabled {
   text-align: left;
 }
 
-.editor-wrap {
+.code-editor {
   background: var(--editor-bg);
   flex: 1;
   min-height: 0;
-  position: relative;
 }
 
-.editor-wrap pre,
-.editor-wrap textarea {
-  border: 0;
-  box-sizing: border-box;
-  font: 14px/1.5 ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", monospace;
-  inset: 0;
-  margin: 0;
-  overflow: auto;
-  padding: 12px;
-  position: absolute;
-  tab-size: 2;
-  white-space: pre;
+.code-editor .cm-editor {
+  height: 100%;
 }
 
-.editor-wrap pre {
-  color: var(--editor-text);
-  pointer-events: none;
+.code-editor .cm-line {
+  padding: 0;
 }
 
-.editor-wrap textarea {
-  background: transparent;
-  caret-color: var(--editor-text);
-  color: transparent;
-  outline: none;
-  resize: none;
-  width: 100%;
+.code-editor .cm-activeLine {
+  background: rgb(59 130 246 / 0.08);
 }
 
-.editor-wrap textarea::selection {
-  background: var(--selection);
+.code-editor .cm-activeLineGutter {
+  background: rgb(59 130 246 / 0.12);
 }
 
 .output-pane pre {