jitsi-meet/css/overlay/_overlay.scss

.overlay {
    &__container,
    &__container-light {
        top: 0;
        left: 0;
        width: 100%;
        height: 100%;
        position: fixed;
        z-index: $overlayZ;
        background: $defaultBackground;
        &.filmstrip-only {
            @include transparentBg($filmstripOnlyOverlayBg, 0.8);
        }
    }

    &__container-light {
        @include transparentBg($defaultBackground, 0.7);
        &.filmstrip-only {
            @include transparentBg($filmstripOnlyOverlayBg, 0.2);
        }
    }

    &__content {
        position: absolute;
        margin: 0 auto;
        height: 100%;
        width: 56%;
        left: 50%;
        @include transform(translateX(-50%));
        &.filmstrip-only {
            left: 0px;
            width: 100%;
            @include transform(none);
        }

        &_bottom {
            position: absolute;
            bottom: 0;
        }
    }

    &__policy {
        position: absolute;
        bottom: 24px;
        width: 100%;
    }
}