gecko-dev/mail/base/skin/subscribe.css

/* ===== subscribe.css ==================================================
  == Styles for the Subscribe dialog.
  ======================================================================= */

@import url("chrome://messenger/skin/");

@namespace url("http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul");

/* ::::: Subscription Icons  :::::: */

treechildren::-moz-tree-image(subscribedColumn),
treechildren::-moz-tree-image(subscribedColumn2) {
  margin-right: 2px;
  list-style-image: url("chrome://messenger/skin/icons/dot.gif");
}

treechildren::-moz-tree-image(subscribedColumn, Subscribed-true),
treechildren::-moz-tree-image(subscribedColumn2, subscribed) {
  list-style-image: url("chrome://messenger/skin/icons/check.gif");
}

treechildren::-moz-tree-image(subscribedColumn, Subscribable-false) {
  list-style-image: none;
}

treechildren::-moz-tree-cell-text(nameColumn, Subscribable-false) {
  color: gray;
  font-style: italic;
}

/* ::::: Folders :::::: */

treechildren::-moz-tree-image(nameColumn) {
  margin-right: 2px;
  list-style-image: url("chrome://messenger/skin/icons/folder-closed.png");
}

treechildren::-moz-tree-image(nameColumn, ServerType-nntp),
treechildren::-moz-tree-image(nameColumn2, nntp) {
  margin-right: 2px;
  list-style-image: url("chrome://messenger/skin/icons/folder-newsgroup.png");
}

/* ::::: Servers :::::: */

.subscribeMenuItem {
  list-style-image: url("chrome://messenger/skin/icons/server-mail.png");
}

.subscribeMenuItem[ServerType="imap"][IsSecure="true"] {
  list-style-image: url("chrome://messenger/skin/icons/server-remote-lock.png");
}

.subscribeMenuItem[ServerType="nntp"] {
  list-style-image: url("chrome://messenger/skin/icons/server-news.png");
}

.subscribeMenuItem[ServerType="nntp"][IsSecure="true"] {
  list-style-image: url("chrome://messenger/skin/icons/server-news-lock.png");
}