blog-static/themes/vanilla/assets/scss/sidenotes.scss

@import "variables.scss";
@import "mixins.scss";

$sidenote-accommodate-shrink: 10rem;
$sidenote-width: 30rem;
$sidenote-offset: 1.5rem;
$sidenote-padding: 1rem;
$sidenote-highlight-border-width: .2rem;

@mixin below-two-sidenotes {
    @media screen and
        (max-width: $container-width +
            2 * ($sidenote-width + 2 * $sidenote-offset)) {
        @content;
    }
}

@mixin below-one-sidenote {
    @media screen and
        (max-width: $container-width +
            ($sidenote-width + 3 * $sidenote-offset)) {
        @content;
    }
}

.sidenote {
    &:hover {
        .sidenote-label {
            background-color: $primary-color;
            color: white;
        }

        .sidenote-content {
            border: $sidenote-highlight-border-width dashed;
            padding: $sidenote-padding -
                ($sidenote-highlight-border-width - $standard-border-width);
            border-color: $primary-color;
        }
    }
}

.sidenote-label {
    border-bottom: .2rem solid $primary-color;
}

.sidenote-checkbox {
    display: none;
}

.sidenote-content {
    display: block;
    position: absolute;
    width: $sidenote-width;
    margin-top: -1.5rem;

    &.sidenote-right {
        right: 0;
        margin-right: -($sidenote-width + $sidenote-offset);
    }

    &.sidenote-left {
        left: 0;
        margin-left: -($sidenote-width + $sidenote-offset);
    }

    @include bordered-block;
    padding: $sidenote-padding;
    box-sizing: border-box;
    text-align: left;
}

.sidenote-delimiter {
    display: none;
}

@mixin hidden-sidenote {
    position: static;
    margin-top: 1rem;
    margin-bottom: 1rem;
    width: 100%;
    display: none;

    .sidenote-checkbox:checked ~ & {
        display: block;
    }
}

@include below-two-sidenotes {
    .sidenote-content.sidenote-left {
        @include hidden-sidenote;
        margin-left: 0rem;
    }

    .container {
        left: -$sidenote-width/2
    }
}

@include below-one-sidenote {
    .post-content {
        max-width: 100%;
    }

    .sidenote-content.sidenote-right {
        @include hidden-sidenote;
        margin-right: 0rem;
    }

    .container {
        position: initial;
    }
}