<link href="https://cdn.jsdelivr.net/npm/leaflet@1.9.3/dist/leaflet.min.css" rel="stylesheet"></link>
<script src="https://cdn.jsdelivr.net/npm/leaflet@1.9.3/dist/leaflet.min.js"></script>
<div id="map"></div>

* {
  margin: 0;
}

#map { 
  height: 100vh;
}

const map = L.map('map').setView([0, 0], 2);

L.tileLayer('https://tile.openstreetmap.org/{z}/{x}/{y}.png', {
    attribution: '&copy; <a href="https://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors'
}).addTo(map);