#buttons {
  display: flex;
}
.block {
  width: 50%;
}
.inactive {
  opacity:  .5;
  filter:grayscale(1)
}
#screen {
  background: #000;
  padding: 10px;
  padding-top: 5px;
  padding-bottom: 13px;
  width: 98%;
}
#screen #top, #screen #bottom {
  color:whitesmoke;
  text-align:right;
}
#screen #top {
  font-size: 8px;
  height: 16px;
  line-height:16px;
  text-align:right;
  padding-right: 5px;
  white-space:nowrap;
  overflow:hidden;
  text-overflow:ellipsis;
  vertical-align:bottom;
}
#screen #top sup {
  vertical-align:super;
  font-size:12px;
}

#screen #bottom {
  font-size: 32px;
  line-height: 1;
  position:relative;
  padding-top: 4px;
}
#buttons button {
  flex: 1;
  padding: 5px 2px
}
#basic {
  margin-left: 5px;
}

#buttons .basics #equals {
  flex: 0 40%
}
.commands {
  margin-bottom: 5px;
}