My GMail user style sheet for Windows. Applying this to the url which starts "https://mail.google.com/mail/"

style.css

body {
  font-family: Meiryo;
}
.LW-avf {
  font-family: Meiryo !important;
}
.F {
  font-family: Meiryo !important;
}

div#gbq1 {  
  display: none;
}
div.aeV, div.aeU, div.ae3 {
  display: none;
}

.n1 .n0,
.zF,
.F b {
  color: #5CB7CE !important;
  font-weight: normal !important;
}