Problem with wordpress JOURNEY theme! Previous edited style.css still giving problems

General information for the website: Science Innovation wordpress site
Kind of development: Customization of existing website
Description of every page/module: My site is scinnova.com you can see the problem if you go on there.

Few days back i edited my journey 1.0.1 wordpress theme to sort out the header image scaling problem when going from computer to mobile. So it wasnt scaling down properly.

I found a code recommended on this page and edited the parent style.css:
https://wordpress.org/support/topic/scaling-header-image-for-mobile?replies=8

And the code i added is:

@media screen and (max-width: 768px) {
#masthead {
margin-bottom: 230px;
}
#parallax-bg {
background-repeat: no-repeat;
background-size: 768px 230px;
}
}
@media screen and (max-width: 767px) {
#masthead {
margin-bottom: 145px !important;
}
#parallax-bg {
background-repeat: no-repeat;
background-size: 600px 180px;
}
@media only screen and (max-width: 400px) {
#masthead {
margin-bottom: 110px !important;
}
#parallax-bg {
background-repeat: no-repeat;
background-size: 400px 120px;
}
}


After editing the theme got messed up and i decided to delete the theme and restore to a previous backup of wordpress hoping this would undo everything. I then downloaded a premium version of JOURNEY 1.1.7 and successfully installed it, but its stilled messed up with the same problems as before. I can seem to undo the code i entered previously regardless of what i do.

Really need help for this thanks.
Description of requirements/features: Any further info required please message me. Please see what the problem is and I will give the job to whomever is confident they know what the problem is and can solve it thanks. A quick solution would be ideal.
Extra services needed: Customization
Extra notes: