#bingc-phone-button svg.bingc-phone-button-circle
circle.bingc-phone-button-circle-inside {
 fill: #ca1429 !important;
 }
 #bingc-phone-button:hover svg.bingc-phone-button-circle
circle.bingc-phone-button-circle-inside {
 fill: #ca1429 !important;
 }
 #bingc-phone-button div.bingc-phone-button-tooltip {
 background: #ca1429 !important;
 }
 #bingc-phone-button div.bingc-phone-button-tooltip svg.bingc-phone-button-arrow
polyline {
 fill: #ca1429 !important;
 }



 #bingc-passive > div.bingc-passive-overlay {
 background: #ca1429 !important;
 }

Для изменения цвета фона активной формы:

 #bingc-active {
 background: #ca1429 !important;
 }