Add background color to ion-tabs - ionic-framework

Question

I am using Ionic 4 and I created an Ionic tabs page app for navigation. What I want to do now is add a background-color to my ion-tabs but nothing I tried is working. I tried adding the $colors variable to my variable.scss and using color="primary" but that didn't work. Here is my code:
HTML
<ion-tabs>
<ion-tab label="Home" icon="home" href="/tabs/(home:home)">
<ion-router-outlet name="home"></ion-router-outlet>
</ion-tab>
<ion-tab label="Passport" icon="information-circle" href="/tabs/(passport:passport)">
<ion-router-outlet name="passport"></ion-router-outlet>
</ion-tab>
<ion-tab label="Tours" icon="contacts" href="/tabs/(tours:tours)">
<ion-router-outlet name="tours"></ion-router-outlet>
</ion-tab>
</ion-tabs>
Variable.scss
// Ionic Variables and Theming. For more info, please see:
// http://ionicframework.com/docs/theming/
/** Ionic CSS Variables **/
:root {
/** primary **/
--ion-color-primary: #3880ff;
--ion-color-primary-rgb: 56,128,255;
--ion-color-primary-contrast: #ffffff;
--ion-color-primary-contrast-rgb: 255,255,255;
--ion-color-primary-shade: #3171e0;
--ion-color-primary-tint: #4c8dff;
/** secondary **/
--ion-color-secondary: #0cd1e8;
--ion-color-secondary-rgb: 12,209,232;
--ion-color-secondary-contrast: #ffffff;
--ion-color-secondary-contrast-rgb: 255,255,255;
--ion-color-secondary-shade: #0bb8cc;
--ion-color-secondary-tint: #24d6ea;
/** tertiary **/
--ion-color-tertiary: #7044ff;
--ion-color-tertiary-rgb: 112,68,255;
--ion-color-tertiary-contrast: #ffffff;
--ion-color-tertiary-contrast-rgb: 255,255,255;
--ion-color-tertiary-shade: #633ce0;
--ion-color-tertiary-tint: #7e57ff;
/** success **/
--ion-color-success: #10dc60;
--ion-color-success-rgb: 16,220,96;
--ion-color-success-contrast: #ffffff;
--ion-color-success-contrast-rgb: 255,255,255;
--ion-color-success-shade: #0ec254;
--ion-color-success-tint: #28e070;
/** warning **/
--ion-color-warning: #ffce00;
--ion-color-warning-rgb: 255,206,0;
--ion-color-warning-contrast: #ffffff;
--ion-color-warning-contrast-rgb: 255,255,255;
--ion-color-warning-shade: #e0b500;
--ion-color-warning-tint: #ffd31a;
/** danger **/
--ion-color-danger: #f04141;
--ion-color-danger-rgb: 245,61,61;
--ion-color-danger-contrast: #ffffff;
--ion-color-danger-contrast-rgb: 255,255,255;
--ion-color-danger-shade: #d33939;
--ion-color-danger-tint: #f25454;
/** dark **/
--ion-color-dark: #222428;
--ion-color-dark-rgb: 34,34,34;
--ion-color-dark-contrast: #ffffff;
--ion-color-dark-contrast-rgb: 255,255,255;
--ion-color-dark-shade: #1e2023;
--ion-color-dark-tint: #383a3e;
/** medium **/
--ion-color-medium: #205532;
--ion-color-medium-rgb: 152,154,162;
--ion-color-medium-contrast: #ffffff;
--ion-color-medium-contrast-rgb: 255,255,255;
--ion-color-medium-shade: #86888f;
--ion-color-medium-tint: #a2a4ab;
/** light **/
--ion-color-light: #f4f5f8;
--ion-color-light-rgb: 244,244,244;
--ion-color-light-contrast: #000000;
--ion-color-light-contrast-rgb: 0,0,0;
--ion-color-light-shade: #d7d8da;
--ion-color-light-tint: #f5f6f9;
}

Answer 1

You can directly change background by applying css to .tabbar class
.tabs-md .tabbar , .tabs-ios .tabbar{
background: red;
}