[increase]

I am using <span class="first-letter">F</span>

as a drop case in epub3 with css as

.first-letter {
display:block;
float:left;
font-size: 5em;
line-height:0.8em;
color:#bf253c;
font-weight:normal;
padding-right: 8px
}

When I use font-family:SerpentisBlack; or any other font that I have loaded into the Fonts folder, it gets ignored in the text.

If I use a standard font i.e. font-family: "Comic Sans MS"; it works

.first-letter {
font-family: "Comic Sans MS";
display:block;
float:left;
font-size: 5em;
line-height:0.8em;
color:#bf253c;
font-weight:normal;
padding-right: 8px
}