React-modal hides behind elements
You need to set the z-index property on the Modal's overlay, which normally has a z-index of 0. The CSS class is .ReactModal__Overlay
Here is the pure-React way of doing it:
const customStyles = { content : { ... }, overlay: {zIndex: 1000}};<Modal style={customStyles}> ...</Modal>
.modal { position: fixed; z-index:9999; top :0; left:0; right:0; bottom:0; background: #464b5e; color: white; outline: none; padding: 3.2rem; text-align: center;}