.youtube-thumbnail {
    display: inline-block;
    position: relative;
    max-width: 560px;
}

.youtube-thumbnail img {
    width: 100%;
    height: auto;
    display: block;
}

.youtube-thumbnail::after {
    content: '';
    position: absolute;
    inset: 0;
    background: url("data:image/svg+xml;utf8,\
<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 68 48'>\
<path d='M66.52 7.85a8 8 0 0 0-5.6-5.6C55.6 1 34 1 34 1S12.4 1 7.08 2.25a8 8 0 0 0-5.6 5.6A83.6 83.6 0 0 0 0 24a83.6 83.6 0 0 0 1.48 16.15 8 8 0 0 0 5.6 5.6C12.4 47 34 47 34 47s21.6 0 26.92-1.25a8 8 0 0 0 5.6-5.6A83.6 83.6 0 0 0 68 24a83.6 83.6 0 0 0-1.48-16.15z' fill='%23000' fill-opacity='0.6'/>\
<path d='M45 24 27 14v20' fill='%23fff'/>\
</svg>") center/68px no-repeat;
}