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

/* Apparence des onglets lus */
.tabbrowser-tab[selected] .tab-label{
font-weight: normal !important;
font-size: 16px !important;
background-color: transparent !important; }

/* Apparence des onglets non lus */
.tabbrowser-tab[unread] .tab-label{
color: green !important;
font-weight: bold !important;
font-style: italic !important;
font-size: 16px !important;
background-color: lightyellow !important; }