How I make dark/light theme

I'm developing a website that requires a dark/light theme switch, and I've come across various approaches to achieve this, including:

• Using Tailwind CSS
• Creating a Context to store the theme
• Utilizing an external React library
• Employing TypeScript styled components
• Simply using CSS

How would you choose an approach for a small application? I opted to use just CSS because it's the method I'm less familiar with. Now, I realize that it's actually the simplest way to accomplish this task. I used the :root:has(#theme-switch:not(:checked)) selector, and it worked smoothly in all my module.css files.