.fullwidth {
    inline-size: 100%;
    box-sizing: border-box;
}

.fullheight {
    block-size: 100%;
    box-sizing: border-box;
}

.fullsize {
    composes: fullwidth fullheight;
}

@media (orientation: landscape) {
    .fullwide {
        composes: fullwidth;
    }
    .fullnarrow {
        composes: fullheight;
    }
}

@media (orientation: portrait) {
    .fullwide {
        composes: fullheight;
    }
    .fullnarrow {
        composes: fullwidth;
    }
}