How do I make the font in firefox browser bold and big?

i run my laptop out an hdmi output to my tv 's hdmi input---it lookd good but is still hard to read words--i can't figure out how to make the words appear dark black and bold in firefox--I have already changed my computer to 120 dpi but it is still not clear enough to read from 5 feet away-- if i zoom in too much then the web page is hard to navigate --though i can see the words better--and i don't want to have to zoom for every new web page-- i also use the magnifier but it is annoying--so if anyone knows the trick to just making the font dark black and bold in firefox that would be great--thanks for your time !!How do I make the font in firefox browser bold and big?
Use Photoshop.How do I make the font in firefox browser bold and big?
In the options on the content tab you change the default font and size. (tools - options in Windows, edit - preferences in Linux)

There's a check box to allow pages to use their font. Unchecking it forces the page to use your selection. I would also examine settings in your video card output. You may find changes in interlacing or progressive scanning, ';flicker'; adjustment and sharpness will help.