style: fix stylelint issues

.stylelintrc.json

@@ -24,7 +24,10 @@
                 "ignoreAtRules": ["function", "if", "each", "include", "mixin"]
             }
         ],
-        "value-keyword-case": null
+        "value-keyword-case": null,
+        "string-quotes": "single",
+        "value-no-vendor-prefix": null,
+        "property-no-vendor-prefix": null
     },
     "plugins": ["stylelint-scss"],
     "syntax": "scss"