Problem with responsive design on high-density phone display


I’m trying to create a portfolio site to display some websites that I’ve made.

The site works responsively when displayed on my computer browser at various widths, but when viewed on my phone (Oneplus 6T with 1080 x 2280 px resolution) it won’t hit the specified breakpoints, and looks wrong:

Every search I’ve made makes reference to CSS pixels, but this hasn’t helped.

Here’s my GitHub repo:

How it should look: