* {
font-family: 'Myriad Pro', 'myriad-pro', sans-serif;
font-size: 32px;
box-sizing: border-box;
margin: 0;
padding: 0;
}
.calculator {
overflow: hidden;
width: 417px;
height: auto;
margin: 100px 2em;
padding: 20px 20px 9px;
border-radius: 20px;
background: linear-gradient(#ddd, #b3b3b3, #9f9f9f);
box-shadow:0 0 3px 4px white, 0 0 3px 3px, 0 -1px 3px rgba(190, 255, 255, .5), 2px 3px 3px rgba(0, 0, 0, .2), inset 0 -1px 1px rgba(0, 0, 0, .5), inset 0 1px 1px rgba(255, 255, 255, 1);
}
.row0 .screen {
height: 65px;
margin: 5px 5px 11px ;
border-radius: 10px;
background: linear-gradient(#eefcd7, #d6e4c1);
box-shadow:inset 0 0 2px 1px,inset 0 0 5px white,
0 0 1px gray,
-2px -2px 2px 1px gray,
2px -2px 2px 1px gray,
0 2px 2px gray,
0 4px 2px 1px white
}
.row1,
.row2,
.row3,
.row4,
.row5,
.row6 {
width: 100%;
}
#zero {
width: 183px;
padding-left: 35px;
text-align: left;
}
#equal {
line-height: 229px;
height: 141px;
margin: 0 0 -141px;
}
button,
.row0 {
overflow: hidden;
}
#MR,
#multiply,
#minus,
#plus,
#equal {
margin-right: 0;
}
button {
font-size: 36px;
line-height: 65px;
float: left;
width: 86px;
height: 65px;
margin: 0 11px 11px 0;
text-align: center;
color: black;
border-radius: 20px;
background: linear-gradient(#e9e9e9, #dadada, #c8c8c8);
box-shadow: 1px 1px 2px 1px rgba(0, 0, 0, .3), -1px -1px 2px 1px rgba(0, 0, 0, .3), -1px 1px 2px 1px rgba(0, 0, 0, .3), 1px -1px 2px 1px rgba(0, 0, 0, .3);
text-shadow: 0 2px white;
}
button:focus,
button.focus {
outline: none !important;
}
body {
display:flex;
}
<!DOCTYPE html>
<body>
<div class="calculator">
<div class="row0">
<div class="screen"><span id="output"></span></div>
</div>
<div class="row1">
<button type="button" id="MC">MC</button>
<button type="button" id="M+">M+</button>
<button type="button" id="M-">M-</button>
<button type="button" id="MR">MR</button>
</div>
<div class="row2">
<button type="button" id="C">C</button>
<button type="button" id="plusminus">±</button>
<button type="button" id="divide">÷</button>
<button type="button" id="multiply">×</button>
</div>
<div class="row3">
<button type="button" id="7">7</button>
<button type="button" id="8">8</button>
<button type="button" id="9">9</button>
<button type="button" id="minus">−</button>
</div>
<div class="row4">
<button type="button" id="4">4</button>
<button type="button" id="5">5</button>
<button type="button" id="6">6</button>
<button type="button" id="plus">+</button>
</div>
<div class="row5">
<button type="button" id="1">1</button>
<button type="button" id="2">2</button>
<button type="button" id="3">3</button>
<button type="button" id="equal">=</button>
</div>
<div class="row6">
<button type="button" id="zero">0</button>
<button type="button" id="dot">.</button>
</div>
</div>
</body>