Thank you for your reply.
I created the file in following path
root\jatechnozone\templates\ja_techzone\css\custom.css
This in the content of the files:
}
.acm-slideshow .owl-carousel .item:before {background: none !important;}
}
.navbar-default .navbar-nav > li > span, .navbar-default .navbar-nav > li > a {color: #999999 !important;}
}
I utilize the blue theme as default but I don' take change...