body {
  background-image: linear-gradient(to right top, #1b283b, #1d2440, #261f42, #321641, #3f073a);
  margin: 0;
  color: #85929e;
  font-family: arial;
  text-align: center;
}
.arithmetics {
  height: 600px;
  width: 850px;

}
.numbers {
  font-size: 20px;
  height: 30px;
  width: 210px;
  margin: 20px;
  margin-top: 30px;
  background: none;
  border: none;
  border-bottom: 2px solid #85929e;
  color: #85929e;
}
.btns {
  background: none;
  color: #85929e;
  border: 2px solid #85929e;
}
.conversions {
  width: 800px;
  height: 600px;
}
.lists, li {
  display: inline-block;
}

.article {
  text-align: left;
padding:0% 10% 5%;
}

a {
  color:yellow;
}