.fb1c {
width: 100%;
height: 80%;
background: repeating-linear-gradient(
90deg,
var(--building-color4) ,
var(--building-color4) 10%,
transparent 10%,
transparent 15%
) ,
repeating-linear-gradient(90deg,
var(--building-color4) 0%,
var(--building-color4) 10%,
var(--window-color4) 10%,
var(--window-color4) 90%
);
}
error: You should add a repeating-linear-gradient
with a first color of --building-color4
from 0%
to 10%
.