On mobile devices, there is a feature that allows a user to use their current location when doing a search by location. Once they click into the location field, a small dropdown will populate and the user will then click on the option to use their location. (If you don't see this on your website when using your mobile device, check here to troubleshoot)
If you're looking to update the background color of the "Use My Current Location" optio, you can use this code:
.sidx-container .sidx-suggestions-use-geo .sidx-geo-search-button.sidx-geo-search-button {
background: #hexcode !important;
}
If you'd like to also change the font color, include this code just below the background color:
color: #hexcode !important;
Remember, place this code in the custom CSS box under Settings > Design. Clear your caches and check your web page in an incognito browser to see the change!