simple rng coin and dice

I'm fairly new to coding and I'm working on my first html! Would anyone have some tips when it comes to making code mobile-friendly? I don't know how web designers usually do it

Go check it out :] https://toyhou.se/30700228.bday-raffle

Be sure to join the Trenchkin Research Institute! (If you're interested, of course) Its currently holding an MYO event :0

https://toyhou.se/~forums/5868.species-discussion/591791.trenchkin-research-institute-myo-event?page=24

Make sure to check out the adoptable raffles, such as this one!

https://toyhou.se/30660559.trenchkin-launch-raffle