Make twitter.com tolerable with user styles.

twitter-styles.css

@-moz-document domain("twitter.com") {    
    /* Collapse media in tweets and show an arrow to indicate their existence, but only at the top level. */
    li.stream-item .has-content .AdaptiveMedia,
    li.stream-item .has-cards .card2 {
        display: none;
    }

    li.stream-item .has-content:after,
    li.stream-item .has-cards:after,
    li.stream-item .js-pinned .user-pinned:after {
        color: #ccd6dd;
        content: '\279a';
        display: block;
        font-size: 1.25rem;
        margin-top: -1.3em;
        position: absolute;
        right: 10px;
        top: 100%;
    }

    li.stream-item:hover .has-content:after,
    li.stream-item:hover .has-cards:after,
    li.stream-item:hover .js-pinned .user-pinned:after {
        color: #069;
    }

    /* Hide the Moments tab, because I will never click it anyway. */
    #global-actions .js-moments-tab {
        display: none !important;
    }

    /* Hide Trending and Who to Follow, because I don't care. */
    .module.trends,
    .module.wtf-module {
        display: none !important;
    }

    /* Hide "activity" tweets, such as other people's likes, because that is literally not what I signed up for. */
    .stream-item[data-suggestion-json*='ActivityTweet'] {
        display: none !important;
    }

    /* Hide mid-stream who-to-follow spam. I'll find my own people, thanks. */
    .stream-item[id^='stream-item-who_to_follow'] {
        display: none !important;
    }

    /* Hide "in case you missed it" garbage. Stop trying to make me feel bad for having a life outside Twitter. */
    .stream-item.has-recap {
        display: none !important;
    }
}