body, html {
  background-color: #C2DEFC;
  font-size: 0;
}
.calculator {
  background-color: #000;
  width: 400px;
  margin: 0px auto;
  padding: 5px;
  text-align: center;
  border-radius: 55px;
  box-shadow: 10px 10px 8px #888888;
}
input[type="text"] {
  background: black;
  color: white;
  width: 290px;
  height: 90px;
  border-top-left-radius: 50px;
  margin: 5px;
  direction: rtl;
  font-size: 60px;
  border: none;
  float: left;
}
button {
  font-family: 'Arial', sans-serif;
  width: 90px;
  height: 90px;
  margin: 5px;
  padding: 0;
  border: 0;
  font-size: 48px;
  background-color: #D4D4D4;
}
button:hover {
  cursor: pointer;
  background-color: #ABABAB;
}
button:active {
  border-style: inset;
  border-width: 5px;
  border-color: #ABABAB;
}

button.operation {
  background-color: #FF9100;
}
button.operation:hover {
  background-color: #BD6B00;
}
button.operation:active {
  border-style: inset;
  border-width: 5px;
  border-color: #BD6B00;
}
button.result {
  background-color: #FFF700;
}
button.result:hover{
  background-color: #C4BE00;
}
button.result:active {
  border-style: inset;
  border-width: 5px;
  border-color: #C4BE00;
}
button.delete {
  background-color: #FF0000;
}
button.delete:hover {
  background-color: #BD0000;
}
button.delete:active {
  border-style: inset;
  border-width: 5px;
  border-color: #BD0000;
}
button:focus {
  outline: 0;
}
.corner-tl {
  border-top-left-radius: 50px;
}
.corner-tr {
  border-top-right-radius: 50px;
}
.corner-bl {
  border-bottom-left-radius: 50px;
}
.corner-br {
  border-bottom-right-radius: 50px;
}