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;