Put this in Stylus

body {
    background-color: #000000;
    color: #fff;
}
#navigationbar {
    background: -webkit-linear-gradient(left, #181919, #282828);
    background: -o-linear-gradient(left, #181919, #282828);
    background: -webkit-gradient(linear, left top, right top, from(#181919), to(#282828));
    background: linear-gradient(90deg, #000000, #3a3a3a);
}
.theme1 {
    background-color: #0e0e0e;
}
.border1 {
    border: 1px solid #181919
}
.theme2 {
    background-color: #0e0e0e
}