<Modal
...
style={{
overlay: {
position: 'fixed',
top: 0,
left: 0,
right: 0,
bottom: 0,
backgroundColor: 'rgba(255, 255, 255, 0.75)'
},
content: {
position: 'absolute',
top: '40px',
left: '40px',
right: '40px',
bottom: '40px',
border: '1px solid #ccc',
background: '#fff',
overflow: 'auto',
WebkitOverflowScrolling: 'touch',
borderRadius: '4px',
outline: 'none',
padding: '20px'
}
}}
...
>