Change VSCode style: Properly reduce the Height of tabs

With the help of this extension, you can change the styling of vscode.

I want to reduce the height of filetabs to 20px. I'm using something like this:

.editor-group-container{
    background-color: purple;
    max-height: 0px;
}

.editor-group-container-toolbar{
    background-color: lightblue;
    max-height: 20px;
    line-height: 20px;
    height: 20px;
    padding:0px;margin:0px;
}
.editor-container{
    background-color: lightgreen;
}

.title{
    background-color: lightblue;
    max-height: 20px;
    line-height: 20px;
    height: 20px;
}    

.primary-action-bar{
    background-color: orangered;
    max-height: 20px;
    line-height: 20px;
    height: 20px;
}

.monaco-action-bar .action-label{
    background-color: rgb(154, 165, 7);
    max-height: 20px;
    padding:0px;margin:0px;
    line-height: 20px;
    height: 20px;
}  

.title-label{
    line-height: 20px;
    height: 20px;
}

.tabs-and-actions-container{
    background-color: rgb(167, 108, 0);
    max-height: 20px;
    line-height: 20px;
    height: 20px;
}

.tab{
    background-color: rgb(166, 94, 168);
    max-height: 20px;
}

It works fine for reducing the height of tabs. However, I now have a bar in the bottom, that I cannot remove:

So I'd like to know either:

• How do I remove the bar in the top?
• OR
• How do I set the tab-height properly?