Is it possible to change only the alpha of a rgba background colour on hover?

Question

I have a set of tags with differing rgba background colours but the same alpha. Is it possible to write a single css style that will change only the o

Answer 1

there is an alternative,you can add a linear-gradient background image onto the original color.

a{
  background: green
}
a:hover{
  background-image:linear-gradient(hsla(0,0%,0%,.2) 100%,transparent 100%) // darker
}
a:hover{
  background-image:linear-gradient(hsla(255,100%,100%,.2) 100%,transparent 100%) // lighter
}

also, with css3 filter property,you can do that too,but it seems that it will change the text color

a:hover{
   filter: brightness(80%) //darker
}
a:hover{
   filter: brightness(120%) //lighter
}

here is a jsfiddle:https://jsfiddle.net/zhangyu911013/epwyL296/2/