fix: csslint error and browserlist

.csslintrc

@@ -2,6 +2,7 @@
     "adjoining-classes"        : false,
     "box-sizing"               : false,
     "display-property-grouping": false,
+    "fallback-colors"          : false,
     "order-alphabetical"       : false,
     "star-property-hack"       : false,
     "unqualified-attributes"   : false

package.json

@@ -53,9 +53,9 @@
   "browserslist": {
     "production": [
       "last 2 versions",
-      "ie >= 8",
-      "iOS >= 6",
-      "Android >= 4"
+      "ie >= 10",
+      "iOS >= 12",
+      "Android >= 6"
     ]
   }
 }