moodle/blocks/social_activities/styles.css

.block_social_activities li {
    clear: both;
}

.block_social_activities li .column {
    width: 100%;
}

.block_social_activities li .buttons {
    float: right;
    margin: 0;
}

.block_social_activities li .buttons a img {
    vertical-align: text-bottom;
}