editor-style.css

/*
Theme Name:         Roots
Description:        Used to style the TinyMCE editor
*/

img.left, p img.left, .alignleft { margin: 0 1.5em 1.5em 0; float: left; }
img.right, p img.right, .alignright { margin: 0 0 1.5em 1.5em; float: right; }