.jpanel-1:before { content: "-"; }
.jpanel-1 { visibility:hidden; }

.jpanel0:after { content: "A"; }
.jpanel0 { background: yellow; }
.jpanel1:after { content: "B";}
.jpanel1 { background: cyan; }
.jpanel2:after { content: "C";}
.jpanel2 { background: lime; }
.jpanel3:after { content: "D";}
.jpanel3 { background: magenta; }
.jpanel4:after { content: "E";}
.jpanel4 { background: orange; }
.jpanel5:after { content: "F";}
.jpanel5 { background: OrangeRed; }
.jpanel { width: 16px; text-align: center; padding: 2px;}