Hello @wyes,
To change the color of Book Now button use below given CSS by going to Admin Panel > Appearance > Customize > Additional CSS.
.wp-travel.trip-headline-wrapper .wp-travel-booknow-btn {
color: #302777;
background: #F44336;
}
Now to change the color of the tab use below given CSS.
.wp-travel-tab-wrapper .tab-list.resp-tabs-list li {
background: #F44336;
color: white;
}
Lastly to change the color of active tab use below given CSS.
.wp-travel-tab-wrapper .tab-list.resp-tabs-list li.resp-tab-active {
background: #96423c70;
}
Here in all above-given CSS, you can change the color code as per your requirement.
Hope this helps.
Let us know if you have any confusion further.
Best Regards!!