body,input {
    font-family: 'Trebuchet MS', 'Lucida Sans Unicode', 'Lucida Grande', 'Lucida Sans', Arial, sans-serif;
    font-size: 26pt;
    line-height: 1.2;
}

input,
input:focus {
    border: 0 none;
    border-bottom: 3px solid black;
    outline: 0 none;
    padding: 5px .5em;
    box-sizing: border-box;
    width: 4em;
    text-align: right;
}

.counter {
    text-align: center;
}

.scoreboard {
    display: flex;
    flex-direction: row;
    min-height: 20px;
    width: 500px;
    margin: auto;

    background-color: gray;
    /*border-left: 2px solid gray;*/
    box-sizing: border-box;
}

.score {
    /*width: 40px;*/
    flex: 1;
    border-right: 1px solid white;
    box-sizing: border-box;
}

.score.richtig { background-color: #4BB543; }
.score.falsch { background-color: orangered; }

.problem-card {
    max-width: 500px;
    min-height: 200px;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: center;
    margin: 40px auto;
    text-align: left;
    box-shadow: 0 0 1px 0 gray;
    padding: 20px 30px;
    text-align: center;

    transition: box-shadow 0.5s ease-in;
}

.problem-card.richtig {
    box-shadow: 0 0 10px 0 #4BB543;
}

.problem-card.falsch {
    box-shadow: 0 0 10px 0 orangered;
}