Merci aceflor
The edges aren't straight (mostly the bottom one). The thread I've used is black and those black lines aren't straight either. Yet it's the zipper end pocking out that bothers me.
Actually I have a bad karma (more likely a lack of knowledge) with zippers. I am more of a knitter than a seamstress and I've made several nice cardigans but I can't put a zipper on properly for the life of me. So now I try to avoid them altogether.
I think I'll try a couple more times and maybe I'll be able to make a Christmas present for my mother's smartphone. Fingers crossed