Creating a line under navigation bar

Site URL: https://www.annseely.com/

I am trying to create a line under my navigation bar that looks like the one on this website : https://designformankind.comconver

I've been able to successfully get the double lines under my navigation using this code:

header#header {
    border-bottom: 1px solid white;
}
header#header:after {
    content: "";
    display: block;
    height: 1.5px;
    width: 100%;
    background: hsla(223, 8%, 15%, .25);
    position: absolute;
    bottom: 16px;
}
header#header:before {
    content: "";
    display: block;
    height: 1.5px;
    width: 100%;
    background: hsla(223, 8%, 15%, .25);
    position: absolute;
    bottom: 19px;
}

However, when I reduce the width, I can't get it to center; it stays left justified. How do I reduce the width and have it centered?

Hi,

It looks like you solved with answer on Facebook?

I see on this page, tablet, some text columns are narrow. Do you want to increase width?

https://www.annseely.com/about

Similar on blog posts https://www.annseely.com/blog/why-need-business-niche

Some pages have very long content, especially blog page. You should consider adding a back to top button.

The footer on mobile seems long. Do you want to change to 2 columns footer?