html { height: 100%; }
body { height: 100vh; height: 100dvh; display: flex; flex-direction: column; overflow: hidden; }
.site-header { flex: 0 0 auto; }
.portal-main { flex: 1 1 0; min-height: 0; padding: 0; margin: 0; display: flex; }
.portal-frame { display: block; flex: 1 1 0; width: 100%; height: 100%; min-height: 0; border: 0; }