.tfw-grader {
    padding: 1em;
    border-radius: 1em;
    border: 4px dashed rgba(0,0,0,.5);
}

.tfw-grader > pre {
    margin: 0;
}


.tfw-grader > pre.error {
    margin: 1em 0 0 0;
    color: #f00;
    font-size: 80%;
    line-height: 100%;
}

.tfw-grader > div.ok {
    display: inline-block;
    color: #0e0;
    text-shadow: 1px 1px 0 #000;
    font-weight: bolder;
    margin: 0 0 0 2em;
    transform: translateX(5em);
    opacity: 0;
}

.tfw-grader > div.ok.show {
    transition: all .3s;
    transform: translateX(0);
    opacity: 1;
}