How to make white shadows in Tailwind CSS

I’m currently in the process of making a portfolio website with a light and dark mode. In light mode, the cards on the site have a shadow to create a sense of distance from the background. I want to make that same effect in dark mode, but I can’t figure out how to make a white shadow in tailwind. I have looked up on the documentation, other questions on similar topics, and still no luck. You can find the full code here.

Here’s what I’ve tried so far:

1. I’ve tried defining my own custom shadow in tailwind.config.js using

theme: {
    extend: {
      boxShadow: {
        'dark-sm': '0 1px 2px 0 rgba(255, 255, 255, 0.05)',
      },
    },
  },

2. I’ve also tried using the shadows keyword instead of boxShadow:

theme: {
    extend: {
      shadows: {
        'red': 'rgba(255, 0, 0, 0.1)',
      }
    },
  },

when I call

<div className = "dark:shadow-dark-sm"></div>

or

<div className = "dark:shadow-red"></div>

nothing happens, even if I try it with a different color and not in dark mode.

There was one time when I was able to change the color using the boxShadow method, but it doesn’t work any more and I have no idea why. Any help would be appreciated!