sandbox.css

:is(.admonition):is(.admonish-sandbox) {
    transition-property: width, margin-left;
    transition-duration: 300ms;
    transition-timing-function: ease-out;
    margin-left: 0;
    position: relative;
    box-sizing: border-box;
    max-width: 1380px;
}

@media only screen and (min-width: 1081px) {
    :is(.admonition):is(.admonish-sandbox):is([open]) {
        --sandbox-width: calc(
            100vw - var(--sidebar-width) - calc(var(--page-padding) + 1.2rem) *
                2 - 6px - 4px
        );

        width: var(--sandbox-width);
        margin-left: calc(calc(min(var(--sandbox-width), 1380px) - 100%) / 2 * -1 + 4px);
        z-index: 10;
    }

    body.sidebar-hidden :is(.admonition):is(.admonish-sandbox):is([open]) {
        --sandbox-width: calc(
            100vw - calc(var(--page-padding) + 1.2rem) * 2 - 4px
        );
    }
}

@media only screen and (min-width: 1380px) {
    :is(.admonition):is(.admonish-sandbox):is([open]) {
        --sandbox-width: calc(
            100vw - var(--sidebar-width) -
                calc(var(--page-padding) + 1.2rem + 90px) * 2 - 6px - 4px
        );
    }

    body.sidebar-hidden :is(.admonition):is(.admonish-sandbox):is([open]) {
        --sandbox-width: calc(
            100vw - calc(var(--page-padding) + 1.2rem + 90px) * 2 - 4px
        );
    }
}