Change te border color readmore link within the slider

I am looking for a way to change the border surrounding the readmore link, within the nivo slider. I have changed the color in the Css, but that didn’t change the color.

In my Css I have changed in it into this

.readmore {
display: table;
float: center;
margin: 2.5em auto 0;
width: 150px;
border: 2px solid #ED1C24;
}

Can somebody tell me what I did wrong and which class I should change instead.

On my website you can see what I mean. The border should be red, but is white.

Thank you in advance.
Marleen