<h1 style="background-color: hsla(302, 59, 65, .6);">
foobar
</h1>
https://jsfiddle.net/qoayrhem/1/
In the firefox debugger it says this is an invalid rule.
>Solution :
The second and third values should have %.
https://developer.mozilla.org/en-US/docs/Web/CSS/color_value/hsla()#values
<h1 style="background-color: hsla(302, 59%, 65%, 0.6);">
foobar
</h1>