Anthony Colangelo makes the case for letting the browser and operating system decide how form elements should be styled:
Dropdowns and date pickers are just a sampling of the things that are better handled by systems themselves—a device will always be able to make better decisions about its use than the device-agnostic web.
The simplistic interactions of early input types gave us room to experiment, but the more complex interactions of modern fields leave little room for that. There’s only so much we can control before the browser and operating system take over, and then we’re at their whim. The web isn’t stopping any time soon—we’re headed for more complex input types with even less control exposed.
I agree. Trying to control form styling is a bit like trying to build sites for a specific set of screen widths. Yes, you can keep creating and managing more breakpoints, but you’ll always be fighting a losing battle because there will always be more screen sizes to design for. A better strategy is to choose a minimal amount of breakpoints to suit the content, and use a liquid layout to fill the rest. In the same way, browsers will always be evolving the implementation of their form elements, so trying to keep your own implementation consistent across all platforms will introduce an ongoing maintenance burden. Of course there will be cases where you have to implement your own styles — the form element you want may not exist, or may not be suited to your needs — but if there is no great need then it’s best to leave the specifics of form implementation to the browser.