I have the solution but it only works on chrome for me.
Here you are.
p {
background: linear-gradient(to bottom, #F00 0%,#630000 100%);
background: -moz-linear-gradient(top, #F00 0%,#630000 100%);
background: -webkit-gradient(linear, left top,left bottom, color-stop(0%,#F00 ), color-stop( 100%,#630000));
background: -webkit-linear-gradient(top, #F00 0%,#630000 100%);
background: -o-linear-gradient(top, #F00 0%,#630000 100%);
background: -ms-gradient(to bottom, #F00 0%,#630000 100%);
/*i.e */
filter: progid:DXImageTransform.Microsoft.gradient( startColorstr='#F00', endColorstr='#630000', GradientType=0 );
/* gradient targets only on letter and not on the background*/
-webkit-background-clip: text;
-webkit-text-fill-color: transparent;*/
Obviously
0% means that the gradient starts right from the top
100% means that the gradient ends at the end of the letter.
you can use something like that as well
background: linear-gradient(to bottom, #F00 33%,#630000 100%);
if you want to apply it to specific area.