Avoid CSS variables for IE11 (#46029)

src/vs/editor/browser/viewParts/indentGuides/indentGuides.css

@@ -9,6 +9,4 @@
 */
 .monaco-editor .lines-content .cigr {
 	position: absolute;
-	--box-shadow-color: rgba(0, 0, 0, 0);
-	box-shadow: 1px 0 0 0 var(--box-shadow-color) inset;
 }

src/vs/editor/browser/viewParts/indentGuides/indentGuides.ts

@@ -130,6 +130,6 @@ export class IndentGuidesOverlay extends DynamicViewOverlay {
 registerThemingParticipant((theme, collector) => {
 	let editorGuideColor = theme.getColor(editorIndentGuides);
 	if (editorGuideColor) {
-		collector.addRule(`.monaco-editor .lines-content .cigr { --box-shadow-color: ${editorGuideColor}; }`);
+		collector.addRule(`.monaco-editor .lines-content .cigr { box-shadow: 1px 0 0 0 ${editorGuideColor} inset; }`);
 	}
 });

src/vs/editor/browser/viewParts/rulers/rulers.css

@@ -6,6 +6,4 @@
 .monaco-editor .view-ruler {
 	position: absolute;
 	top: 0;
-	--box-shadow-color: rgba(0, 0, 0, 0);
-	box-shadow: 1px 0 0 0 var(--box-shadow-color) inset;
 }
\ No newline at end of file

src/vs/editor/browser/viewParts/rulers/rulers.ts

@@ -103,6 +103,6 @@ export class Rulers extends ViewPart {
 registerThemingParticipant((theme, collector) => {
 	let rulerColor = theme.getColor(editorRuler);
 	if (rulerColor) {
-		collector.addRule(`.monaco-editor .view-ruler { --box-shadow-color: ${rulerColor}; }`);
+		collector.addRule(`.monaco-editor .view-ruler { box-shadow: 1px 0 0 0 ${rulerColor} inset; }`);
 	}
 });