🩺 Check elements by KABA

/* ==UserStyle==
@name         🩺 Check elements
@version      20240116.05.40
@namespace    ?
==/UserStyle== */

@-moz-document regexp(".*") {
    :root {
        --warn-color: #f439;
        --info-color: #29f9;
    }

    /* Lazy loading image */
    img {
        outline: 10px solid var(--c, var(--warn-color));
        outline-offset: 8px;

        &[loading=lazy] { --c: var(--info-color) }
    }

    a {
        /* Anchor requires href attribute */
        &:not([href]) {
            &::after {
                position: absolute;
                margin: .25em;
                background: #fffc;
                color: var(--warn-color);
                font-size: small;
                content: "Anchor doesn't have `href`";
            }
        }

        /* (in Anchor) Image requires alt if only image */
        img {
            &[alt=""],
            &:not([alt]) {
                box-shadow: 0 0 0 26px var(--warn-color);
            }
        }
    }
}