Good work! The only thing missing are the black sidelines.
I initially started with the box-shadow property, but ended up setting each side separately using the css-border property.
.container {
border-left: 1px solid hsl(0, 0%, 7%);
border-top: 1px solid hsl(0, 0%, 7%);
border-right: 8px solid hsl(0, 0%, 7%);
border-bottom: 8px solid hsl(0, 0%, 7%);
}
``