* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    font-family: sans-serif;
}

.calculator {
    
    background: linear-gradient(to bottom, #30cfd0, #330867);
    width: 350px;
    padding: 25px;
    border-radius: 40px;
    box-shadow: 0px 20px 40px rgba(0, 0, 0, 0.4);
}

.display {
    background: white;
    height: 100px;
    width: 100%;
    border-radius: 15px;
    margin-bottom: 25px;
    padding: 20px;
    display: flex;
    justify-content: flex-end;
    align-items: flex-end;
}

#current {
    font-size: 40px;
    font-weight: bold;
    color: #333;
}

.buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
}

.btn {
    border: none;
    height: 60px;
    width: 60px;
    border-radius: 50%;
    font-size: 20px;
    font-weight: bold;
    cursor: pointer;
    box-shadow: 0px 4px 8px rgba(0, 0, 0, 0.2);
}


.btn:hover {
    opacity: 0.9;
}


.num, .back {
    background: linear-gradient(to bottom, #ff9a9e, #fecfef);
    color: #444;
}