colouring-montreal/app/src/frontend/map.css

.map-notice {
    padding: 0.5rem 0.75rem;
    background: #fff;
    border: 1px solid #fff;
    border-radius: 4px;
    z-index: 1000;
    position: absolute;
    box-shadow: 0px 0px 1px 1px #222;
    visibility: hidden;
}
.leaflet-container {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
}
.leaflet-container .leaflet-control-zoom {
    border: 1px solid #fff;
    box-shadow: 0 0 1px 1px #222;
}
.leaflet-grab {
    cursor: crosshair;
}
@media (min-width: 768px){
    /* Only show the "Click a building ..." notice for larger screens */
    .map-notice {
        left: 25.5rem;
        top: 0.5rem;
        visibility: visible;
    }
}