On: Ask HN: Why can't I see downvote or upvote arrows ...

[false]

This makes upvote a CSS triangle. Could be extended for downvotes as well.

    /* 13.328px = 1em */
    .votearrow[title=upvote] {
        background: none !important;
    }
        .votearrow[title=upvote]:after {
            content: '';
            display: block;
            position: relative;
            top: -1px;
            width: 0;
            height: 0;
            border: .3em solid transparent;
            border-bottom: .6em solid #999;
        }