textual/docs/examples/styles/border.css

Screen {
    background: white;
}
Screen > Label {
    width: 100%;
    height: 5;
    content-align: center middle;
    color: white;
    margin: 1;
    box-sizing: border-box;
}    
#label1 {
    background: red 20%;
    color: red;
    border: solid red;
}
#label2 {
    background: green 20%;
    color: green;
    border: dashed green;
}
#label3 {
    background: blue 20%;
    color: blue;
    border: tall blue;
}