/* container optional but nice */
.chart-box {
	max-width: 1400px;
	margin: 12px auto;
}

/* the key rule: cap by viewport height */
#priceChart {
	display: block;
	width: 100% !important;
	height: auto !important;              /* Chart.js will respect CSS height when maintainAspectRatio=false */
	max-height: calc(100vh - 240px);      /* tweak 240px to cover your header/controls/footer */