Module:Message box/style.css

.box
{
    border: solid black 1px;
    border-left: solid black 10px;
    display: flex;
    flex-direction: row;
    justify-content: flex-start;
}

.box .left
{
    height: 40px;
    display: flex;
    flex-direction: column;
    justify-content: center;
}
.box .right
{
    margin: 0;
    margin-left: 20px;
}