Because browsers offer very little styling and customization options even for the handful of built-in elements. That's why every library under the sun tries to

Because browsers offer very little styling and customization options even for the handful of built-in elements. That's why every library under the sun tries to re-invent them again, and again, and again. https://open-ui.org/ https://open-ui.org/ will finally help with this, but it's a very slow process.