body{
background:black;
display:flex;
justify-content:center;
align-items:center;
height:100vh;
font-family:Arial;
}

.calculator{
width:260px;
}

#display{
width:100%;
height:80px;
font-size:60px;
text-align:right;
background:black;
color:white;
border:none;
margin-bottom:20px;
padding-right:10px;
overflow:hidden;
}
.buttons{
display:grid;
grid-template-columns:repeat(4,1fr);
gap:10px;
}

button{
height:60px;
font-size:20px;
border-radius:50%;
border:none;
background:#456;
color:white;
}
button:active{
transform:scale(0.9);
transition:0.1s;
}

button:hover{
background:#555;
}

.zero{
grid-column:span 2;
border-radius:40px;
}
.top{
    background: #a5a5a5;
    color:black;
}
.operator{
background:#ff9f0a;
color:white;
}
#history{
color:#aaa;
font-size:18px;
text-align:right;
height:80px;
overflow-y:auto;
display:flex;
flex-direction:column-reverse;
margin-bottom:10px;
padding-right:10px;
}