My back to top button has dissapeared

I want clarify this theme:
I want a button float right down in a page.
The problem it´s that now my button isn´t float right, I´ve seen that he is here:

In Appearance my configuration is:

The CSS code is this:

.go-to-section {
    display: block;
    height: 50px;
	  right: 20px;
    bottom: 20px;
    line-height: 50px;
    width: 60px;
	
		color: white;
	text-decoration: none;
    text-align: center;
	opacity: 1;
		visibility: visible;
    position: fixed;
	background-color: white;
		border-radius: 7px;
		z-index: 10;
		transition: opacity 300ms ease-in-out;
		font-size: 17px;
    background: rgba(0,110,188,.63);
}

The button isn´t dissapeared, but he isn´t float :(
How can I get that this can become a float button right down?

I hope that this you help :)

Hi there,

it is because your HTML contains additional white space ie - remove extra space between <a and class.

ie.
<a class="go-to-section smooth-scroll" href="#windows-android-mac-ios-linux">Menu</a>

Wow!!

You are great humain! =)

Thanks David!

Glad to be of help :)