.block, .atom {
    position: relative;
    display: inline-block;
    margin-bottom: 10px;
}
.block::before, .atom::before {
    position: absolute;
    top: 90%;
    height: 8px;
    width: 100%;
    content: "";
    box-sizing: border-box;
    border-radius: 0 0 3px 3px;
}
.block.true::before, .atom.true::before {
    border: 3px green solid;
    border-top: 0;
}
.block.false::before, .atom.false::before {
    border: 1px red dashed;
    border-top: 0;
}
.block.neutral::before, .atom.neutral::before {
    border: 2px black solid;
    border-top: 0;
}
.above .below {
    position: absolute;
    width: 100%;
    left: 0;
    top: 140%;
    font-size: 0.75em;
    text-align: center;
}