.bt-column-resizer {
    position: absolute;
    right: 0;
    width: 3px;
    height: 24px;
    background: rgba(0, 0, 0, 0.5);
    cursor: col-resize;
    user-select: none;
    touch-action: none;
}

.bt-column-resizer.bt-column-resizing {
    background: blue;
    opacity: 1;
}

@media (hover: hover) {
    .bt-column-resizer {
        opacity: 0;
    }

    *:hover > .bt-column-resizer {
        opacity: 1;
    }
}