@zoe Here is the solution, I have used.
<!-- First bring two single value panel under one panel Tag, as you can see below and then add the html tag written below -->
<panel>
<html>
<style>
<!-- Here I have checked the class name used for my pannel, you can check this by clicking right mouse button on browser and then click on inspect or ctrl+shift+I, and the check the class name, here in my case class name is "panel-element-row" should be same for you too. -->
.panel-element-row { <!-- it is class name used in html tag, so you can style it using CSS -->
display:flex; <!-- It is a CSS property, you can google about it, if you want to understand more -->
flex-direction: column;
}
</style>
</html>
<single></single> <!-- Your single value pannel -->
<single></single> <!-- your second single value panel -->
</panel>
