border-block-start-color: red;
writing-mode: horizontal-tb;
border-block-start-color: #32a1ce;
writing-mode: vertical-rl;
border-block-start-color: rgb(170, 50, 220, .6);
writing-mode: horizontal-tb;
border-block-start-color: hsl(60, 90%, 50%, .8);
writing-mode: vertical-lr;