Couple things on this.
The ticker is responsive by default. If you use the ticker width setting it makes the ticker non-responsive. Please remove the 900 in your ticker width setting and set it to 0 or leave it blank. The ticker will then be responsive.
A responsive ticker takes on the width of its containing element. So, the issue you will need to resolve is getting your containing elements to be the width you want.
I have come up with this custom css for you to get this working. This also makes the ticker visible on mobile, since your theme or some other css hides the area the ticker is located on mobile. Add the following anywhere you can add custom css:
#menu-item-26148 {
width: calc(100vw - 300px);
}
#menu-item-26148 a {
display: block;
width: 100%;
}
@media only screen and (max-width: 1019px) {
.mob-menu-on-tab #secondary-wrap {
display: block;
}
}
@media only screen and (max-width: 767px) {
.mob-menu-on-tab #secondary-navigation {
display: block;
padding-left:20px;
padding-right:20px;
}
}