Well you have added custom css to overwrite your white button’s border and background.
I would leave the white button as is if you need to use it and overwrite another one’s colors instead, for example the red button. Hope that makes sense.

As I mentioned earlier, instead of modifying the white button to be red, override the red button to be your color then use that:

input.btn_red, a.btn_red, .btn_red{
	background-color: #b22447;
}
input.btn_red.btn_outline, a.btn_red.btn_outline, .btn_red.btn_outline{
	color: #b22447 !important;
	border: 2px solid #b22447;
}
input.btn_red.btn_outline:hover, a.btn_red.btn_outline:hover, .btn_red.btn_outline:hover {
	background-color: #b22447 !important;
}

As for your logo – that really depends on your image, try working on your image further and make sure you use a retina version of the logo as well.

The Plus sign in the accordions – the relative path to the image is different so it doesn’t get found, instead you can override only the background color:

.acc_control {
    background-color: #b22447;
}