change color of primary menu

Hi

My Name is Karolina.
I have problems in your theme.
I want change color of primary manu. I change in style.css
But I don’t see change on page?
And I don’t know way?
Mabye I could help me?

https://www.karolinazajdel.lh.pl/biurompr/

main-navigation a {
display: block;
padding: 0 10px;
overflow: hidden;
font-family: “Roboto Slab”, sans-serif;
font-weight: 300;
color: #0c4da2;
white-space: nowrap;
letter-spacing: -0.01em;
text-overflow: ellipsis;
white-space: nowrap;
word-wrap: normal;
text-decoration: none;
text-shadow: 0 1px rgba(0,0,0,0.25);
-webkit-transition: background-color .15s ease;
-moz-transition: background-color .15s ease;
transition: background-color .15s ease;

I change:

THX
karolina