.calc-background {
  background-color: #222;
  width: 300px;
  margin: 100px auto 0 auto;
  height: 500px;
  border-radius: 4%;
  box-shadow: 5px 5px 5px #333;
  overflow: auto;
}

.calc-screen {
  background-color: #272727;
  width: 250px;
  height: 120px;
  margin-top: 20px;
  margin-left: 25px; 
  /* overflow: auto; */
  text-align: right;
  font-family: 'Courier New', Courier, monospace;
}

ul.calc-buttons {
  text-align: center;
}

ul.calc-buttons li {
  display: inline-block;
  margin: 0.25rem;
}

ul.calc-buttons li button {
  border-radius: 50%;
  width: 3.75rem;
  height: 3.75rem;
  text-align: center;
  background-color: #222;
  color: white;
  border: 1px solid #292929;
  box-shadow: 1px 1px 5px #000;
  font-size: 1.75rem;
  font-family: 'Quicksand', Helvetica, sans-serif;
  font-weight: 300;
  display: table-cell;
  vertical-align: middle;
}

ul.calc-buttons li button:hover {
  cursor: pointer;
}

ul.calc-buttons li button:focus {
  outline: none;
}

ul.calc-buttons li button:active {
  box-shadow: 0 3px 0 #222;
  top: 3px;
}

section.calc-buttons {
  height: 300px;
  width: 300px;
  margin-top: 20px;
}

section.calc-buttons ul li button.function {
  color: #888;
}

section.calc-buttons ul li button.operator {
  color: #f89156;
}

.calc-screen-top {
  height: 25px;
  margin: 2px 2px 0 2px;
  width: auto;
  font-size: 1.5rem;
  color: #888;
}

.calc-screen-bottom {
  height: 60px;
  line-height: 60px;
  width: auto;
  margin: 30px 2px 0 2px;
  font-size: 3rem;
  color: #eee;
}