My styles.less configuration (for Atom). Adds contrast between the editor and everything else when using "one-dark-ui" UI theme and "afterglow-like" syntax theme.

styles.less

/*
 * Your Stylesheet
 *
 * This stylesheet is loaded when Atom starts up and is reloaded automatically
 * when it is changed and saved.
 *
 * Add your own CSS or Less to fully customize Atom.
 * If you are unfamiliar with Less, you can read more about it here:
 * http://lesscss.org
 */

@dark-grey: #1b1b1b;

.tree-view,
.tab-bar,
.tab-bar .tab .title,
.status-bar,
atom-panel.top,
atom-panel.bottom,
atom-panel.left,
atom-panel.right {
  background: @dark-grey;
}

.tab-bar {
  box-shadow: inset 0 -1px 0 @dark-grey;
}