Edited CSS and it doesn't work!

On my website (using the Onetone theme) there is a title that is defined as H1.

In my stylesheet, I see where H1 is described:

}
h1 {
	font-size:24px;
	line-height:1;

which I then change to

h1 {
        color: red;
	font-size:24px;
	line-height:1;
}

No effect whatsoever! I have tried using hex, taking the space away after color, changing it in Custom CSS and the theme’s space for custom CSS instead of the stylesheet – nothing. What am I doing wrong?

Thank you!