html, body {
   margin: 0;
   height: 100%;
}

body {
   display: flex;
   justify-content: center;
   align-items: center;
   background: #f4f4f4;
}

canvas {
   border-radius: 8px;
   box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
}