1) Log into your App Manager and select your app.

2) Click Colors from the left-hand-side of the screen (or the middle of the screen).

3) Scroll down to the Advanced SCSS box. If there is already code in the advanced SCSS box, do not remove it.  Start a new line “after” the last character in the box, then paste the above code.

/*** BEGIN: CUSTOMIZE BACK BUTTON ***/
button.button.back-button.buttons.button-clear.header-item::before {
background: #ff9000;
height: 20px;
width: 50px;
content: '<back';
font-size: small;
color: white;
border: 1px dashed white;
}
/*** END: CUSTOMIZE BACK BUTTON ***/

4) Click Save.

NOTE: Be sure to change the appropriate settings to fit your needs (ie the hex color code, font color, etc).