Nice forum!  I'd recommend change the forum primary color to your theme dark blue. Please navigate to Dashboard > Forums > Settings > Styles admin page, click on #12 color of the Default Blue Style and change the value to #0088cc . Then put this css code in Custom CSS Code textarea to fix topic/post creator form fields height:

#wpforo #wpforo-wrap input, #wpforo #wpforo-wrap input, #wpforo #wpforo-wrap input, #wpforo #wpforo-wrap textarea, #wpforo #wpforo-wrap select{
height: auto;
}
#wpforo #wpforo-wrap .wpfl-1 .wpforo-last-topic-user {
 width: 136px;
}

Save these changes, delete all caches and do Ctrl+F5 on forum front to load new codes.

https://wpforo.com/wp-content/uploads/2018/04/forovehiculos.png