Need to adjust Atlantic dropdown menu to be full screen width. Right now it is a long drop down

[urbanelifestyle]

currently my navigation menu is dropping down into a vertical drop like a long list. 

In the Atlantic "LIght version" theme preview it shows the dropdown across the whole screen.  How do I get mine to do this?

@urbanelifestylehome is my shop please help need to get my site live.  Appreciate it so much

[paramSoft]

Please provide website url and if your store is password protected then also provide password

[urbanelifestyle]

Here is the url: https://urbane-lifestyle-home.myshopify.com
PW: 24Morello

[paramSoft]

it is showing wrong password

[urbanelifestyle]

Please try:

weelye

[paramSoft]

Please place this code at the end of theme.scss

.list--inline>li, .site-nav, .site-header__mobile-nav, .site-header {
position: unset !important;
}

div[data-section-id="header"] {
  position: relative !important;
}
.site-nav__dropdown {
    width: 100%;
    top: 66px;
}

[urbanelifestyle]

What section am I supposed to paste this code in? Im not following how to do this.

[paramSoft]

Go to Theme Editor -> Main theme -> Edit code -> Assets -> theme.scss

Pasts this code at the end of theme.scss file