how to change color month picker and solve the toggle previous button problem?

[cheekean2012]

Ionic version: (check one with "x")
[ ] 2.x
[ ] 3.x
[ ] 4.x
[x] 6.x

Ion2-calendar mode: (check one with "x")
[ x] components mode
[ ] modal mode

I'm submitting a ... (check one with "x")
[ ] bug report
[ ] feature request
[ x] help me

Current behavior:
I want to custom my month picker color, but it doesn't works. And I also want to allow toggle previous month button, but now I only can press from month picker not in toggle previous button.

Expected behavior:
The custom color in my optionsRange, and the color value is 'primary'.
For the toggle previous button is need to available, not just only can show current or future month.

Steps to reproduce:
Create a color in optionsRange: CalendarComponentOptions, and change the color month picker
I don't have any idea to know how to fixed the button problem.

Related code:

in my html page to change the month picker color is
<ion-calendar name="date" style="background-color: black;" [options]="optionsRange" formControlName="date"
(onChange)="onChange($event)" type="string" [format]="'YYYY-MM-DD'">

in my component.page.ts to change the month picker color code is
optionsRange: CalendarComponentOptions = {
color:'primary',
};

Sorry, I'm a new beginner to start to learn using plugin. thanks