/* Prevent blue borders or outlines on linked images */
a img {
    border: none !important;
    outline: none !important;
}

/* Prevent focus outlines on links (the cause of the blue border) */
a:focus,
a:active {
    outline: none !important;
}

/* Optional: remove borders from all images, just in case */
img {
    border: none !important;
}