PSA: those fairy lights you're stapling to your bookshelf are a fire hazard, learned this the hard way last month
My neighbor had hers strung tight against the wood for 2 years with no airflow and the cheap transformer finally melted a scorch mark into the shelf top, so please leave a gap and check that little box is not hot to the touch like I did after she showed me.
Yikes, glad your neighbor caught it before anything actually caught fire. I had the same setup on my headboard and ended up swapping to a timer plug plus those stick-on clips that hold the wire a bit off the wood, which keeps things way cooler. Takes like five minutes and you stop thinking about it, so worth doing if yours are still pressed flat.