Range-slider background color v1

Hi all,
My range-slider from Framework v1 doesn’t work propertly.
I haven’t any background color from my range-slider (lower values).
I know in V2 this can work, but I can’t migrate to V2 (this is complicated for me).

This is the code demo : https://codepen.io/anon/pen/QQBqVK

I want my lower values are background blue, only on IOS (android work great).
How can I do this ?
Can you help me please

The range slider layout used in v1 doesn’t support well styling in latest iOS’es. You can try to use some third party range slider plugin instead if v2 is not an option for you