src/index.css
.leaflet-container {
height: 100%;
width: 100%;
/* Due to interactions between leaflet setting the font size to 0.75rem and boostrap setting
our document default to 10px, this results in a very small font. This brings back the older
12px default from leaflet. If we upgrade boostrap (newer versions do not change the default
font size) this can be removed.*/
font-size: 12px !important;
}