Adding CSS to Child Theme

I added scss code to /sass/theme/_child_theme.scss
but it does not seem to be working.
Am I doing it wrong?

//colors
$white: white;
$black: black;
$red: red;

.navbar-toggleable-md {
	background-color: $white!important;
}
.navbar-toggler-icon {
	background-color: $black!important;
}
.navbarNavDropdown {
	color: $black!important;
	float: left!important;
}
.nav-link {
	color: $red!important;
}
.page-id-65 div {
	margin: auto !important;
}