.chart-container {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    justify-content: center;
    margin-top: 4em;
}

.chart {
    position: relative;
    width: 100%;
    max-width: 200px;
    height: 200px;
    margin: 0 30px 30px;
}

.chart canvas {
    max-width: 100%;
    max-height: 100%;
}

.chart .title {
    font-size: 1.2em;
    font-weight: bold;
    text-align: center;
    margin-bottom: 10px;
}

@media screen and (max-width: 768px) {
    .chart {
        margin: 40px 10px 10px;
        /* added top margin */
    }
}