* {
  box-sizing: border-box;
  padding: 0;
  margin: 0;
  font-family: "Open Sans", sans-serif;
}

body {
  background-image: linear-gradient(rgb(168, 39, 39), orange);
  height: 100vh;
}
.keys {
  
  margin: auto;
  height: 425px;
  width: 300px;
  display: grid;
  grid-template-columns: 1fr 1fr 1fr 1fr;
  justify-content: center;
}
.calculator button {
  background-color: white;
  height: 100%;
  outline: none;
  font-size: 17px;
  border: 1px solid rgba(227, 227, 227, 0.7);
}
button:hover {
  background-color: rgb(240, 240, 240);
}

#output {
  background-color: rgb(31, 33, 41);
  margin-top: 0px;
  width: 80%;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  padding: 0 15px 0 0;
  grid-column: span 4;
  color: white;
  font-size: 29px;
}

.calculator .key--operator {
  background-color: rgba(209, 96, 20, 0.281);
  border: 1px solid rgb(245, 99, 1);
  color: white;
}

.calculator .key--operator:hover {
  background-color: rgb(218, 77, 22);
}

.calculator__storage {
  font-size: 20px;
  display: flex;
  align-items: center;
  margin: auto;
  margin-bottom: 0px;
  padding-bottom: 0px;
  height: 25px;
  justify-content: flex-end;
  padding-right: 10px;
  background-color: rgb(23, 25, 34);
  width: 300px;
  font-size: 15px;
  color: rgb(139, 139, 139);
  border-radius: 5px 5px 0 0;
  padding-top: 10px;
  margin-top: 10vh;
}
.calculator__display {
  display: flex;
  align-items: center;
  margin: 0 auto;
  height: 35px;
  justify-content: flex-end;
  padding-right: 10px;
  background-color: rgb(23, 25, 34);
  width: 300px;
  font-size: 20px;
  color: white;
}