Identify css operators

components/prism-css-extras.js

@@ -14,11 +14,15 @@ Prism.languages.insertBefore('css', 'function', {
 		pattern: /(var\()[^)]+(?=\))/,
 		lookbehind: true
 	},
+	'operator': {
+		pattern: /(\s)[+\-*\/](?=\s)/,
+		lookbehind: true
+	},
 	'hexcode': /#[\da-f]{3,8}/i,
 	'entity': /\\[\da-f]{1,8}/i,
 	'unit': {
 		pattern: /(\d)(?:%|[a-z]+)/,
 		lookbehind: true
 	},
 	'number': /-?[\d.]+/
-});
+});

tests/languages/css!+css-extras/operator_feature.test

@@ -0,0 +1,34 @@
+width: calc(100% - 20px);
+height: -20px;
+content: 'this - is not an operator';
+
+----------------------------------------------------
+
+[
+	["property", "width"],
+	["punctuation", ":"],
+	["function", "calc"],
+	["punctuation", "("],
+	["number", "100"],
+	["unit", "%"],
+	["operator", "-"],
+	["number", "20"],
+	["unit", "px"],
+	["punctuation", ")"],
+	["punctuation", ";"],
+
+	["property", "height"],
+	["punctuation", ":"],
+	["number", "-20"],
+	["unit", "px"],
+	["punctuation", ";"],
+
+	["property", "content"],
+	["punctuation", ":"],
+	["string", "'this - is not an operator'"],
+	["punctuation", ";"]
+]
+
+----------------------------------------------------
+
+Checks for operators.

tests/languages/css!+css-extras/variable_feature.test

@@ -19,16 +19,16 @@ calc(100% - var(--margin-size) * 2)
 	["punctuation", "("],
 	["number", "100"],
 	["unit", "%"],
-	" - ",
+	["operator", "-"],
 	["function", "var"],
 	["punctuation", "("],
 	["variable", "--margin-size"],
 	["punctuation", ")"],
-	" * ",
+	["operator", "*"],
 	["number", "2"],
 	["punctuation", ")"]
 ]
 
 ----------------------------------------------------
 
-Checks for variables.
+Checks for variables.