Good evening Hernan and welcome to the Events Calendar Support forum!o
Thank you for reaching out to us.
I would love to help you with this topic.
As you might already know, you can tackle some of the colours using the Appearance > Customize > The Events Calendar menu in your WordPress backend.
You can also use a specific CSS rule such as:
.tribe-grid-allday .tribe-events-week-allday-single, .tribe-grid-body .tribe-events-week-hourly-single, .tribe-grid-allday .tribe-events-week-allday-single:hover, .tribe-grid-body .tribe-events-week-hourly-single:hover {
background-color: #21759b;
border-color: #14455c;
}
Let me know if that helps.
Have a great day!
Geoff B.