Why wont my dad let me wear what i want?

my dad is quite religious and he really cares about what people think of him so when i showed him this outfit that i bought recently that consisted of some shorts and a top and cardigan he wasn't too pleased he said i cant wear that sort of thing and i shouldn't of bought it. What i don't get itt i didn't have any skin on show because i had leggings on underneath the shorts that came down to my ankles and i sometimes where dresses that are short with leggings but he never says anything. Im sick of not knowing what i can and cant wear it makes life so difficult and as im quite into my fashion it makes it hard to find clothes that look stylish. plz help i don't really know how to get round him and make him see im not doing this coz i want to show off my body because i don't i just want to look good in the summer months :(