gnome-shell-dark-theme/gnome-shell-sass/widgets/_calendar.scss

/* Date/Time Menu */

// overall menu
#calendarArea {
  padding: $base_margin;
}

.datemenu-popover {
  border-radius: $base_border_radius * 1.5 + $base_padding * 3;
}

// calendar menu side column
.datemenu-calendar-column {
  spacing: $base_padding;
  &:ltr { margin-left: $base_padding;}
  &:rtl { margin-right: $base_padding;}
  .datemenu-displays-box {
    spacing: $base_padding;
  }
}

// today button (the date)
.datemenu-today-button {
  @extend %card_flat;
  padding: $base_padding * 1.5;

  // weekday label
  .day-label {
    font-weight: bold;
  }

  // date label
  .date-label {
    @extend %title_2;
  }
}

// the mini calendar
.calendar {
  @extend %card_flat;
  margin-top: 0;
  padding: 0;

  // month header
  .calendar-month-header {

    // prev/next month icons
    .calendar-change-month-back StIcon,
    .calendar-change-month-forward StIcon {
      icon-size: $scalable_icon_size;
    }

    // month label
    .calendar-month-label {
      @extend %heading;
      @extend %flat_button;
      color: $fg_color !important;
      padding: 8px 0;
      width: 10em;
      border-radius: $forced_circular_radius;
      text-align: center;
    }

    .pager-button {
      @extend .icon-button, .flat;
      height: 2.6em;
      width: 2.6em;
      padding: 0;
    }
  }

  // day style
  .calendar-day {
    @extend %numeric;
    @extend %smaller;
    @extend %flat_button;
    border-radius: $forced_circular_radius;
    height: 3em;
    width: 3em;
    margin: 2px;
    padding: 0;
    font-weight: bold;
    text-align: center;

    &.calendar-weekday {}

    &.calendar-weekend {
      color: $insensitive_fg_color;
      @if $contrast == 'high' {
        font-style: italic;
      }
    }

    &.calendar-other-month {
      color: transparentize($fg_color, 0.5);
      font-weight: normal;

      &.calendar-weekend {
        color: transparentize($fg_color, 0.5);
        @if $contrast == 'high' {
          color: $fg_color;
        }
      }

      @if $contrast == 'high' {
        color: $fg_color;
        font-style: italic; // differentiate with a font-style instead of text color
      }
    }

    &.calendar-today {
      @extend %default_button;
      // override colors above for when today is a weekend
      color: -st-accent-fg-color !important;
      &.calendar-day-with-events {
        background-image: url("resource:///org/gnome/shell/theme/calendar-today.svg") !important; // always use light asset with .default style
      }
    }

    &.calendar-day-with-events {
      background-image: if($variant == 'light', url("resource:///org/gnome/shell/theme/calendar-today-light.svg"),url("resource:///org/gnome/shell/theme/calendar-today.svg"));
      background-size: contain;
    }
  }

  // day of week heading
  .calendar-day-heading {
    @extend %numeric;
    @extend %smaller;
    @extend %flat_button;
    font-weight: bold;
    text-align: center;
    margin: $base_margin;
    padding: $base_padding * 0.5 $base_padding;
    border-radius: $base_border_radius;
  }

  // week number style
  .calendar-week-number {
    @extend %smaller;
    font-weight: bold;
    font-feature-settings: "tnum";
    text-align: center;
    margin: $base_padding;
    padding: 0 $base_padding;
    border-radius: $base_border_radius * 0.5;
    background-color: transparentize($insensitive_fg_color, .8);
    color: $insensitive_fg_color;
  }
}

// common style for the date menu widgets
.events-button,
.world-clocks-button,
.weather-button {
  @extend %card;
}

// events
.events-button {

  .events-box {

    // event title
    .events-title {
      @extend %heading;
      color: $insensitive_fg_color;
      padding-bottom: $base_padding;
    }

    // list of events
    .events-list {
      spacing: $base_padding;

      // container for an event
      .event-box {
        spacing: $base_padding;
        border-radius: $base_border_radius;

        .event-summary {
          @extend %heading;
        }

        .event-time {
          @extend %numeric;
          @extend %caption;
          color: $insensitive_fg_color;
        }
      }

      .event-placeholder {
        color: $insensitive_fg_color;
        font-style: italic;
      }
    }
  }
}

// world clocks
.world-clocks-button {

  // title
  .world-clocks-header {
    @extend %heading;
    color: $insensitive_fg_color;

    // change style when no world clocks are configured
    &.no-world-clocks {
      color: $fg_color;
    }
  }

  // clocks
  .world-clocks-grid {
    spacing-rows: $base_padding;
    spacing-columns: $base_padding * 2;

    // city label
    .world-clocks-city {
    }

    // timezone time
    .world-clocks-time {
      @extend %numeric;
      font-weight: bold;

      &:ltr {text-align: right;}
      &:rtl {text-align: left;}
    }

    // timezone offset label
    .world-clocks-timezone {
      @extend %numeric;
      @extend %caption;
      color: $insensitive_fg_color;
    }
  }
}

// weather
.weather-button {

  .weather-box {
    spacing: $base_padding;

    // header
    .weather-header-box {
      spacing: $base_padding;

      .weather-header {
        @extend %heading;
        color: $insensitive_fg_color;

         // change style when no location is configured
        &.no-location {
          color: $fg_color;
        }

        &.location {
          font-weight: normal;
        }
      }
    }

    // weather items
    .weather-grid {
      spacing-rows: $base_padding;
      spacing-columns: $base_padding * 2;

      .weather-forecast-time {
        @extend %smaller;
        padding-top: $base_padding;
        padding-bottom: $base_padding;
      }
      .weather-forecast-icon {
        icon-size: $large_scalable_icon_size;
        margin-bottom: $base_margin;
      }

      .weather-forecast-temp {
        @extend %numeric;
        font-weight: bold;
      }
    }
  }
}