Dynamic CSS loading using variable in jinja

I have a variable UI_BRAND that has the value of blue

I have the following code:

    <link rel="stylesheet" href="">

I need UI_BRAND-styles.css to evaluate to blue-styles.css. I've tried using inside if the already existing brackets, but I know that's not allowed.

What would be the best way to dynamically load this CSS file using the value of UI_BRAND ?

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