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

.tabbrowser-tab { /* remove if you don't like it, on my setup they're too cramped */
  margin-left: 1px !important;
  margin-right: 1px !important; 
}

.scrollbutton-up { /* remove if you don't like it, on my setup they're too cramped */
  margin-right: 2px !important;
}
.scrollbutton-down-box { /* remove if you don't like it, on my setup they're too cramped */
  margin-left: 2px !important;
}

/* normal state */
.tab-image-left,
.tab-image-right,
.tab-image-middle,
.tab-close-button,
.scrollbutton-up,
.scrollbutton-down-box,
.tabs-alltabs-box {
  background-color: #000000 !important; /* change color here, it was just the first color I grabbed */
}

/* selected & hovered for non selected */
.tabbrowser-tab[selected="true"] > .tab-image-left,
.tabbrowser-tab[selected="true"] > .tab-image-right,
.tabbrowser-tab[selected="true"] > .tab-image-middle,
.tabbrowser-tab[selected="true"] > .tab-close-button,
.tabbrowser-tab:not([selected="true"]):hover > .tab-image-left,
.tabbrowser-tab:not([selected="true"]):hover > .tab-image-right,
.tabbrowser-tab:not([selected="true"]):hover > .tab-image-middle,
.tabbrowser-tab:not([selected="true"]):hover > .tab-close-button {
  background-color: #ffffff !important;
}

/* normal state text */
.tabbrowser-tab > .tab-image-middle > .tab-text {
  color: #ffffff !important;
}

/* selected & hovered for non selected text */
.tabbrowser-tab[selected="true"] > .tab-image-middle > .tab-text,
.tabbrowser-tab:not([selected="true"]):hover > .tab-image-middle > .tab-text {
  color: #000000 !important;
}