CSS Deep Dive: The Best Way to Customize Select Arrows for Dark Mode

Customizing the arrow of a <select> element is a common challenge when implementing dark mode. While hardcoding colors directly into an SVG Data URI works, it's terrible for maintenance. This article dives deep into this issue, starting with the common hardcoded SVG approach, analyzing its drawbacks, and finally introducing the modern best practice using `mask-image`. This technique completely decouples the icon's shape from its color, allowing for easy theming with simple CSS variables—the elegant solution recommended by the DP@lib00 team.