numix-gtk-theme/gtk-3.0/scss/widgets/_toggle.scss

/***********************
 ! Check and Radio items
************************/

$suffix: if($variant == "dark", "-dark", "");

@mixin toggle($type) {
    background-image: none;

    -gtk-icon-source: url("../assets/#{$type}-unchecked#{$suffix}.png");

    &:insensitive { -gtk-icon-source: url("../assets/#{$type}-unchecked-insensitive#{$suffix}.png"); }

    &:checked, &:active {
        -gtk-icon-source: url("../assets/#{$type}-checked#{$suffix}.png");

        &:insensitive { -gtk-icon-source: url("../assets/#{$type}-checked-insensitive#{$suffix}.png"); }
    }

    &:inconsistent {
        -gtk-icon-source: url("../assets/#{$type}-mixed#{$suffix}.png");

        &:insensitive { -gtk-icon-source: url("../assets/#{$type}-mixed-insensitive#{$suffix}.png"); }
    }

    &.menuitem {
        -gtk-icon-source: none;

        &:insensitive { -gtk-icon-source: none; }

        &:checked, &:active {
            -gtk-icon-source: url("../assets/menuitem-#{$type}-checked.png");

            &:hover { -gtk-icon-source: url("../assets/menuitem-#{$type}-checked-hover.png"); }

            &:insensitive { -gtk-icon-source: url("../assets/menuitem-#{$type}-checked-insensitive.png"); }
        }

        &:inconsistent {
            -gtk-icon-source: url("../assets/menuitem-#{$type}-mixed.png");

            &:hover { -gtk-icon-source: url("../assets/menuitem-#{$type}-mixed-hover.png"); }

            &:insensitive { -gtk-icon-source: url("../assets/menuitem-#{$type}-mixed-insensitive.png"); }
        }
    }
}

@include exports("checkradio") {
    * {
        -GtkCheckButton-indicator-size: 16;
        -GtkCheckMenuItem-indicator-size: 16;
    }

    .radio { @include toggle("radio"); }

    .check { @include toggle("checkbox"); }

    GtkIconView.content-view.cell.check {
        -gtk-icon-source: url("assets/grid-selection-unchecked#{$suffix}.png");

        &:active { -gtk-icon-source: url("assets/grid-selection-checked#{$suffix}.png"); }
    }
}


/********
 ! Switch
*********/

@include exports("switch") {
    GtkSwitch {
        padding: 0;
        border-radius: $roundness;
        font: bold condensed;
        outline-offset: -4px;

        &.slider {
            @include linear-gradient(shade($bg_color, 1.2));

            border: 1px solid rgba(0, 0, 0, .2);
            box-shadow: 0 1px 2px -1px fade-out($dark_shadow, .08);

            &:insensitive {
                border-color: rgba(0, 0, 0, .1);
                background-color: shade($bg_color, .9);
                box-shadow: none;
            }
        }

        &.trough {
            @include linear-gradient(shade($bg_color, .95), to top);

            border: 1px solid border_normal($bg_color);
            color: $fg_color;
            box-shadow: inset 1px 0 fade-out($dark_shadow, .13),
                        inset 0 1px fade-out($dark_shadow, .12),
                        inset -1px 0 fade-out($dark_shadow, .13),
                        inset 0 -1px fade-out($dark_shadow, .15);

            &:active {
                @include linear-gradient($selected_bg_color, to top);

                border-color: shade($selected_bg_color, .9);
                color: $selected_fg_color;
            }

            &:insensitive {
                @include linear-gradient(shade($bg_color, .9), to top);

                border-color: border_insensitive($bg_color);
                color: mix($fg_color, $bg_color, .5);
            }
        }
    }
}