tauri-app/public/splashscreen.html

<style>
	* {
		margin: 0;
		padding: 0;
		box-sizing: border-box;
	}

	body {
		background-color: #131317;
		color: #fff;

		display: flex;
		align-items: center;
		justify-content: center;
		width: 100dvw;
		height: 100dvh;
	}
</style>

<div>
	<h3>Loading...</h3>
</div>