CSS giving error: "Expected selector for the style rule" - css

Question

I am using ASP.net web application, the default CSS when modified with the following CSS gives error:
Expected selector for the style rule
It seems a CSS version problem. How can I know which version of CSS i am using? How can I upgrade?
Here is the CSS taken from Codepen
$white: #fff;
$google-blue: #4285f4;
$button-active-blue: #1669F2;
.google-btn {
width: 184px;
height: 42px;
background-color: $google-blue;
border-radius: 2px;
box-shadow: 0 3px 4px 0 rgba(0,0,0,.25);
.google-icon-wrapper
{
position: absolute;
margin-top: 1px;
margin-left: 1px;
width: 40px;
height: 40px;
border-radius: 2px;
background-color: $white;
}
.google-icon {
position: absolute;
margin-top: 11px;
margin-left: 11px;
width: 18px;
height: 18px;
}
.btn-text {
float: right;
margin: 11px 11px 0 0;
color: $white;
font-size: 14px;
letter-spacing: 0.2px;
font-family: "Roboto";
}
&:hover {
box-shadow: 0 0 6px $google-blue;
}
&:active {
background: $button-active-blue;
}
}
#import url(https://fonts.googleapis.com/css?family=Roboto:500);

Answer 1

You can convert your syntax with the following css syntax
Check the snippet:
#import url(https://fonts.googleapis.com/css?family=Roboto:500);
.google-btn {
width: 184px;
height: 42px;
background-color: #4285f4;
border-radius: 2px;
box-shadow: 0 3px 4px 0 rgba(0, 0, 0, 0.25);
}
.google-btn .google-icon-wrapper {
position: absolute;
margin-top: 1px;
margin-left: 1px;
width: 40px;
height: 40px;
border-radius: 2px;
background-color: #fff;
}
.google-btn .google-icon {
position: absolute;
margin-top: 11px;
margin-left: 11px;
width: 18px;
height: 18px;
}
.google-btn .btn-text {
float: right;
margin: 11px 11px 0 0;
color: #fff;
font-size: 14px;
letter-spacing: 0.2px;
font-family: "Roboto";
}
.google-btn:hover {
box-shadow: 0 0 6px #4285f4;
}
.google-btn:active {
background: #1669F2;
}
<link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Open+Sans" />
<div class="google-btn">
<div class="google-icon-wrapper">
<img class="google-icon" src="https://upload.wikimedia.org/wikipedia/commons/5/53/Google_%22G%22_Logo.svg" />
</div>
<p class="btn-text"><b>Sign in with google</b></p>
</div>