Color theme fix for gradients

src/js/colorModeJS.tw

 :: colorModeJS [script]
 
 window.setColors = function(colorMap){
+    let props = ["color","backgroundColor","backgroundImage"];
     let styleSheetArray = Array.from(document.styleSheets);
     styleSheetArray.forEach( styleSheet => {
         let cssRules = Array.from(styleSheet.cssRules);
         cssRules.forEach( cssRule => {
             if ( cssRule.type === 1 ){
-                let color = cssRule.style.color;
-                let bgcolor = cssRule.style.backgroundColor;
-                if (
-                    color != "" &&
-                    color != "inherit" ){
-                    cssRule.style.color = colorMap[color] || color;
-                    console.log('color: ',color);
-                }
-                if (
-                    bgcolor != "" &&
-                    bgcolor != "inherit" &&
-                    bgcolor != "transparent" ){
-                    cssRule.style.backgroundColor = colorMap[bgcolor] || bgcolor;
-                    console.log('color: ',color);
-                }
+                props.forEach( propName => {
+                    let currentValue = cssRule.style[propName];
+                    if (
+                        currentValue != "" &&
+                        currentValue != "inherit" &&
+                        currentValue != "transparent"){
+                        cssRule.style[propName] = colorMap[currentValue] || currentValue;
+                    }
+                })
             }
         });
     });