The new account switcher design is based on cards with rounded corners stacked on top of each other and uses the same colour palette as your wallpaper. Darker cards are used to highlight important options and the active account, while lighter cards show other options.
It uses the lightest colour hue for text, making it easily legible. Google is also working on improving accessibility in Android 14 to make this text more legible when the high-contrast text toggle in Settings is enabled.