Another forum member also mentioned to me there is another issue with the code. You used two single quotes and curly quotes instead of straight quotes (I made the changes red). It should be like this:
Code:
@font-face {
font-family: 'merida';
font-weight: normal;
font-style: normal;
src: url("./Fonts/MERIFONT.TTF");
}
.diagram{
font-family: 'merida';
font-size: 1em;
font-weight: normal;
font-style: normal;
}