Hide the "What's happening" sidebar section on EN Twitter

no_twitter_trends.user.css

/* ==UserStyle==
@name           No Trends
@namespace      https://gist.github.com/AprilSylph
@version        1.0.0
@description    Hides the "What's happening" sidebar section on EN Twitter
@author         AprilSylph
==/UserStyle== */
@-moz-document domain("twitter.com") {
    [aria-label="Timeline: Trending now"] {
        display: none;
    }
}