/diy/ - Do It Yourself

Hey diy, I have 2 dogs which love to sit on my bay windowsill and look outside all day. 1 dog developed a leg issue and she can't make the jump onto the sill anymore. I built her some stairs out of 5/4 pine which she now uses but are they strong enough?

I'll upload some pics. What I worry about is how I connected the back stands to the stair horses: I used a biscuit joiner and just put a single 3" drywall screw at 45 degrees into the back.

What do you think?