body {
     background-color: #000;
     display: flex;
     justify-content: center;
     align-items: center;
     height: 100vh;
     margin: 0;
     font-family: 'SF Pro Display', sans-serif;
 }

 .calculator {
     background-color: #000;
     border-radius: 40px;
     width: 320px;
     padding: 20px;
     box-shadow: 0 0 20px rgba(255, 255, 255, 0.1);
 }

 .display input {
     width: 100%;
     height: 60px;
     background-color: #000;
     border: none;
     color: #fff;
     font-size: 48px;
     text-align: right;
     margin-right: 30px;
     padding: 10px;
     border-radius: 10px;
     outline: none;
 }
.display{
    padding-right: 20px;
    padding-bottom:15px ;
}

 .buttons {
     display: grid;
     grid-template-columns: repeat(4, 1fr);
     gap: 10px;
 }

 button {
     height: 70px;
     border: none;
     border-radius: 50%;
     font-size: 24px;
     cursor: pointer;
     transition: all 0.2s;
 }

 /* Button colors */
 .btn-gray {
     background-color: #a5a5a5;
     color: black;
 }

 .btn-orange {
     background-color: #ff9f0a;
     color: white;
 }

 .btn-dark {
     background-color: #333;
     color: white;
 }

 /* Button active effect */
 button:active {
     filter: brightness(1.2);
 }

 /* Zero button wider */
 .zero {
     grid-column: span 2;
     border-radius: 40px;
     text-align: left;
     padding-left: 30px;
 }