:root {
    color-scheme: dark;
    color: gainsboro;
    --alpha-background: 1;
}

.heading-period-num {
    color: rgb(var(--color-heading-period-num));
    background-color: rgba(var(--color-heading-period-num), var(--alpha-background));
}

.heading-period-time {
    color: rgb(var(--color-heading-period-time));
    background-color: rgba(var(--color-heading-period-time), var(--alpha-background));
}

.day-name {
    color: rgb(var(--color-day-name));
    background-color: rgba(var(--color-day-name), var(--alpha-background));
}

.period-free {
    color: rgb(var(--color-period-free));
    background-color: rgba(var(--color-period-free), var(--alpha-background));
}

td, th {
    border: 1px solid #939393;
}

td > p:nth-child(even) {
    color: white;
}