Header / Border Issue

Greetings WordPress Fam,

I’m currently trying to put a border around my header image and navbar, but when I add the code into the appearance editor, a border will not show on the right side of the header. From what I could tell, it looks like the border that I have applied exists, but it has pushed the header image over the right side, essentially overlapping that section of the border. Help please!

Here is the website – https://www.thesiegesound.com

Here is the current existing code for my header:

/*********************************************************************************************

3. Header ————————- header.php

*********************************************************************************************/

#header {
border: 3px solid #999;

}

#logo {
float: left;
margin: 3px 5px 25px;
}

#logo h1 {
line-height:1.3;
}

#logo h1 a {
color:#fff;
font-size:16px;
font-weight:bold;
}

#logo h1 a:hover {
color:#DBDFE1;
}

#navbar {
float: left;
margin: 5px 16px 5px 30px;
color:#fff;
}