:root {
    --main-text-color: rgba(0,0,0,.87); 
    --main-back-color: rgba(255,255,255,.7);
    --main-body-color: #fff;
    --main-image-color: rgba(255,255,255,.5);
    --main-back-color-focus: rgba(255,255,255,.9);
    --main-add-border-color: rgba(0,0,0,0.25);
    --black-logo: brightness(0);
    --main-round: 12px;
}
@media screen and (prefers-color-scheme: dark) {
    :root {
        --main-text-color: rgba(255,255,255,.87); 
        --main-back-color: rgba(0,0,0,.7);
        --main-body-color: #000;
        --main-image-color: rgba(0,0,0,.5);
        --main-back-color-focus: rgba(0,0,0,.9);
        --main-add-border-color: rgba(255,255,255,0.25);
        --black-logo: brightness(100);
    }
}