Custom gmail css when using preview pane

gmail.css

/* Hide to menu bar until hover */

.nH.w-asV.aiw {
  -webkit-transform: translateY(-80%);
  transition: all .2s cubic-bezier(0.18, 0.89, 0.32, 1.28);
  transition-delay: .2s;
  z-index: 1000;
  background-color: #eee;
}

.nH.w-asV.aiw:hover {
  -webkit-transform: translateY(0);
  transition-delay: .05s;
}

.nH.w-asV.aiw,
.nH.w-asV.aiw + .nH {
  position: absolute;
}

.nH.w-asV.aiw + .nH {
  margin-top: 17px;
}

/* Advanced filter box */

div.ZF-Av {
  top: 48px;
  z-index: 2000;
}

/* Hide “Take me to inbox” */
.w-asK.w-atd {
  display: none;
}

/* List tweaks */

.xT {
  font-size: .92rem;
}

.apd {
  padding: 1px 2px 0 0;
}

.yP {
  opacity: .8;
  font-size: 0.9em;
}

.apv:hover .yP:after {
  content: attr(email);
  margin-left: 5px;
  opacity: .6;
}

.apz {
  font-size: .9em;
  opacity: 0.9;
  font-weight: 500;
}