On the listing detail page, on mobile, you will notice that under the CTA buttons (Ask a Question and Schedule a Tour) there is a 'Call Now' button which displays the display phone number set up from the General Settings, as illustrated below:
The default color is green, instead of the blue for the CTAs to make it stand out. We suggest that if you update this button, to make it a color that stands out from the rest.
You can use the following code for this button:
.sidx-small-screen .sidx-call-button .sidx-primary-alt {
background: #hexcode !important;
color: #hexcode !important;
}
The color part will change the font color. If you'd like to leave it white, simply remove that part of the code when applying it to your admin.
Remember, place this code in the custom CSS box under Settings > Design. Clear your caches and check your mobile web page in an incognito browser to see the change!