Make top menu wider

Hi, I changed the color of top menu now I need to make wider to fit the whole page and center the buttons , is any way to do it running default V 3.90
Thanks.

mariocesar wrote:

You can direct change in css. Also you can direct modify view pages for add new class

Thank you, I changed to CSS

.header-menu {
  position: relative;
  z-index: 5;
  width: 100%;
  margin: 0 auto 30px;
  border-top: 1px solid #ddd;
  border-bottom: 1px solid #ddd;
  padding: 25px 0;
  text-align: center;

but don't work.