#background-footer,
#background-header,
#background-body {
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    z-index: -2;
    width: 100vw;
    height: 100vh;
}

#background-footer,
#background-header,
#background-body,
#a11y,
#lightSwitch + label::before,
#setContrast,
#colorPalette,
ul.carousel__viewport > li > a > span::before,
ul.carousel__viewport > li > a > span::after,
ul.carousel__viewport > li > a > span,
#list-categories a:hover::after,
.letterine > i {
    -webkit-transition: var(--flashGuard);
       -moz-transition: var(--flashGuard);
         -o-transition: var(--flashGuard);
            transition: var(--flashGuard);
}

#background-body,
.background {
    background-color: var(--bg);
}

#background-header {
    border-bottom: var(--opt-border);
    height: var(--vhead);
}

#background-footer {
    top: unset;
    bottom: 0;
    border-top: var(--opt-border);
    height: var(--vfoot);
}

.has-border {
    --opt-border: var(--border);
}