Fixed gradients on buttons not showing up correctly.

Adjusted some CSSnano options.

build.js

@@ -35,11 +35,18 @@ const buildTasks = {
 // PREP
 const config = JSON.parse(fs.readFileSync(configFile));
 
-const postcssPlugins = [];
-if(!isDebugBuild) postcssPlugins.push(require('cssnano'));
-postcssPlugins.push(require('autoprefixer')({
-    remove: false,
-}));
+const postcssPlugins = [ require('autoprefixer')({ remove: false }) ];
+if(!isDebugBuild)
+    postcssPlugins.push(require('cssnano')({
+        preset: [
+            'cssnano-preset-default',
+            {
+                minifyGradients: false,
+                reduceIdents: false,
+                zindex: true,
+            }
+        ],
+    }));
 
 const swcJscOptions = {
     target: 'es5',