You can either specify the font
setting in the settings (unfortunately you have to do it for each chart element separately) or you can use CSS to redefine the Arial
font:
@font-face {
font-family: Arial;
src: local("Wingdings");
}
See http://jsfiddle.net/oj5xurqv/ - note that I used Wingdings so that it is very obvious that all texts are changed. Wingdings font does not work on Firefox but if you change it to something else, you can see that the approach works there as well.