themes-wordpress/blockbase/inc/customizer/wp-customize-color-palette-control.css

.customize-control-color-palette .color-palette-group {
	display: grid;
	flex-wrap: wrap;
	grid-template-columns: 1fr 1fr 1fr;
	column-gap: 15px;
	row-gap: 15px;
}

.customize-control-color-palette .color-palette-group input {
    display: none;    
}

.customize-control-color-palette .color-palette-group .color-option {
	padding: 0;
}

.customize-control-color-palette input:checked + .color-option .custom-color-palette {
    border-color: #2271b1;
}

.custom-color-palette {
	position: relative;
	display: flex;
	border-radius: 2px;
	border: 1px solid rgba(0,0,0,0.1);
	height: 50px;
	width: 72px;
	overflow: hidden;
}

.color-palette-label {
	background: #000;
	color: #fff;
	font-size: 10px;
	opacity: 0.7;
	position: absolute;
	bottom: 5px;
	right: 0;
	left: 0;
	line-height: 1.2;
	padding: 2px 0 3px 5px;
}

.color-stripe {
	flex: 1 1 auto;
	border: 1px solid rgba(0,0,0,0.1);
}