styles.css

body {
  background: linear-gradient(to bottom right, #4a69bb, #6a98e7);
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  margin: 0;
  font-family: 'Lucida Sans', 'Lucida Sans Regular', 'Lucida Grande', 'Lucida Sans Unicode', Geneva, Verdana, sans-serif;
}

.container {
  background: rgba(30, 29, 29, 0.051);
  backdrop-filter: blur(10px);
  border-radius: 10px;
  padding: 20px;
  width: 55%;
  text-align: center;
  box-shadow: 10px 10px 15px #2d2727,
              -5px -5px 15px #fcf9f9;
}

h1 {
  color: white;
}

.calculator {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 10px;
  padding: 20px;
}


input {
  width: 100%;
  height: 45px;
  font-size: 1.5em;
  color: #0e0a0a;
  margin-bottom: 2rem;
  border: none;
  outline: none;
}

.screen #display{
  text-align: right ;
  padding-right: 0.3em;
  box-shadow: inset 4px 4px 5px #2d2727,
              inset -4px -4px 5px #fcf9f9  ;
}
.buttons, .buttons2 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-column-gap: 10px;
  grid-row-gap: 15px;
}

.buttons2{
  display: none;
}
button {
  width: 100%;
  border: none;
  outline: none;
  padding: 20px 5px;
  font-size: 1.2em;
  background-color: #ddd;
  cursor: pointer;
  border-radius: 5px;
}

button:hover {
  background-color: #ccc;
}

/* Added Some Styling */
.operator{
  background-color: #2f2f2f;
  color: #fff;
}

.operator:hover{
  background-color: #5b5b5b;
}

.fa-delete-left{
  font-size: 1.3em;
}