Hello @espinelli,
Please provide me the website link so I can better understand what you want to achieve.
This is the selector for the testimonial box:
#testimonials .section-content .testimonials-carousel .carousel-testimonial .testimonial-content,
#testimonials .section-content .testimonials-carousel .carousel-testimonial .testimonial-content:after {
background-color: #682e66;
}
As for the contact form background color, please have a look here:
https://colorlibsupport.com/t/change-contact-form-font-to-black/
This is the code to change the box color and border, just change the red to your color code:
#contact-us .section-content .wpcf7-form p .wpcf7-text,
#contact-us .section-content .wpcf7-form p .wpcf7-textarea{
background-color: red !important;
border: 1px solid red !important;
}
There might appear some malfunctions and I cannot fully assist you to change the all the colors as it would require to much custom work.
I hope this gets you further with the setup.
Regards