*{
    margin:0;
    padding:0;
    box-sizing:border-box;
    font-family:'Poppins',sans-serif;
}

body{
    display:flex;
    justify-content:center;
    align-items:center;
    min-height:100vh;
    background:linear-gradient(135deg,#0f172a,#1e293b,#334155);
    overflow:hidden;
}

.calculator{
    width:380px;
    padding:25px;
    border-radius:25px;
    background:rgba(255,255,255,.08);
    backdrop-filter:blur(20px);
    box-shadow:0 15px 40px rgba(0,0,0,.5);
    animation:pop .8s ease;
}

@keyframes pop{
    from{
        transform:scale(.7);
        opacity:0;
    }

    to{
        transform:scale(1);
        opacity:1;
    }
}

.calculator h1{
    color:white;
    text-align:center;
    margin-bottom:20px;
}

#display{
    width:100%;
    height:75px;
    border:none;
    outline:none;
    border-radius:15px;
    padding:15px;
    font-size:32px;
    text-align:right;
    background:#111827;
    color:#38bdf8;
    margin-bottom:20px;
    box-shadow:inset 0 0 10px rgba(0,0,0,.5);
}

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

button{
    height:70px;
    border:none;
    border-radius:18px;
    font-size:22px;
    cursor:pointer;
    color:white;
    background:#334155;
    transition:.25s;
}

button:hover{
    transform:translateY(-5px);
    background:#38bdf8;
    box-shadow:0 0 20px #38bdf8;
}

button:active{
    transform:scale(.92);
}

.operator{
    background:#f97316;
}

.operator:hover{
    background:#fb923c;
        box-shadow:0 0 20px #fb923c;
}

.equal{
    grid-column:span 2;
    background:#22c55e;
}

.equal:hover{
    background:#16a34a;
    box-shadow:0 0 20px #22c55e;
}

.zero{
    grid-column:span 2;
}