geopf-extensions-openlayers/src/packages/CSS/Controls/OverviewMap/GPFoverviewMap.css

French Geoportal Extensions for OpenLayers libraries

div[id^="GPoverviewMap-"] {
    left: 0.5em;
    bottom: 10.5em;
}

button[id^="GPshowOverviewMap-"] {}

.ol-overviewmap.ol-collapsed .ol-overviewmap-map {
    border: none;
    height: 100px;
    width: 100px;
}

.ol-overviewmap .ol-overviewmap-box {
    border: 2px solid red;
}

.ol-overviewmap:not(.ol-collapsed) button {
    position: relative;
}
/* 
.ol-overviewmap .ol-overviewmap-map {
    position: relative;
    left: 50px;
} 
*/