This function, funcGenerateHTMLForColourGradientBackground, generates the HTML Text required to create a linear colour-gradient background for any number of colours.

It first creates a flex-box that will ensure the internal content is centred both vertically and horizontally, and then creates a div styled to render your colour-gradient background. Use this to easily uplift your Apps' UI!

1. Copy the provided code into your App's Formulas property.
2. Add an 'HTML Text' control to your desired screen.
3. This function works best when the padding on the HTML Text control is set to 0px, so please adjust the default padding to 0px on all sides.
4. In the 'HTML Text' control's 'HtmlText' property, enter the function funcGenerateHTMLForColourGradientBackground( ) and fill out all parameters. Note that the Colours you wish to gradient between must be provided as an array of Power Apps Colour type colours (i.e. RGBA( ) outputs, ColorValue( ) outputs, Color.<Colour Name> outputs etc.). These will be subsequently converted to Hex format by the also included function: funcConvertRGBAColourToHexString.
5. Enjoy your colour-gradient background!

If you wish to embed your colour-gradient background inside a Container (for an out-the-box drop-shadow for example), set the height of your HTML Text control to Parent.Height + 1 to cancel out the -1px embedded in the function that prevents the HTML Text control from rendering its scrollbar.