.chart-container {
    margin: 0 auto;
    width: 100%;
    height: 400px;
    overflow-x: hidden; /* no scroll by default */
    position: relative;
}

    .chart-container.scrollable {
        overflow-x: auto; /* enable scroll when class added */
    }

    .chart-container canvas {
        display: block;
        max-width: 100%; /* never exceed container */
    }

    .chart-container.scrollable canvas {
        /* 5px per day of data: pushes wider than container if >1yr */
        min-width: calc(var(--day-count) * 5px);
    }