You can change the size of the icons using one of the following classes:
.la-lg
.la-xs
.la-sm
.la-lx
.la-1x
.la-2x
.la-3x
.la-4x
.la-5x
.la-6x
.la-7x
.la-8x
.la-9x
.la-10x
.la-fw