.yellow { background: linear-gradient(transparent 70%, #ffff66 70%); }
.purple { background: linear-gradient(transparent 80%, #ff99ff 80%); }
.red-under { background: linear-gradient(transparent 80%, #ffb5c5 80%); }
.pink { background: linear-gradient(transparent 80%, #ffb5c5 80%); }
.green { background: linear-gradient(transparent 80%, #00FF00 80%); }
.red { background: linear-gradient(transparent 50%, #FFA9F2 50%); }
.blue { background: linear-gradient(transparent 70%, #b0e0e6 70%); }

.sikaku {
    padding: 0.5em 1em;
    margin: 2em 0;
    font-weight: bold;
    border: solid 3px #ffb6c1;
}

.sikaku2 {
    padding: 0.5em 1em;
    margin: 2em 0;
    font-weight: bold;
    border: solid 3px #b6c1ff;
}