Improve the CSS to make the end result pixel perfect

Currently, a single CSS rule is necessary to make Aloha Editor work well inside of Edit.

This is the whole of css/drupal.aloha.edit.css:

/**
 * @file
 * Styles for Aloha Editor UI when used by the Edit module.
 */

/**
 * Ensures multi-row toolbars work well.
 *
 * This indeed implies that it is broken on the back-end ('aloha-for-textareas')
 * so it warrants a todo. However, it's not a trivial problem to solve: on the
 * back-end the common case is to have a very wide, single-row AE toolbar.
 * Because there is no box-shadow around it, we need a border. But a bottom-
 * border for buttons and a bottom-border for the .aloha-toolbar-panels
 * container implies *double* borders, which is ugly. For now I've chosen to
 * have a pretty common case on the back-end, at the cost of a broken multi-row
 * experience (lack of bottom border).
 *
 * @todo See above. CSS wizardry needed.
 */

.edit-toolbar .aloha-toolbar-panels button {
  border: 1px solid #aaa;
  border-top: 0;
  border-left: 0; /* LTR */
}