.youtube-slide a {
    position: relative;
    display: block;
    width: 100%;
}

.youtube-slide-thumb {
    position: relative;
    display: block;
}

.youtube-slide-thumb span, .youtube-slide a span {
    position: absolute;
    cursor: pointer;
    z-index: 3;
    background-color: #fff;
    border-radius: 50%;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%) scale(1);
    transition: .3s ease-in-out;
    display: block;
}

@media (min-width: 768px) {
    .youtube-slide-thumb span, .youtube-slide a span {
        width: 100px;
        height: 100px;
    }
}

.youtube-slide-thumb span::before, .youtube-slide a span::before {
    position: absolute;
    z-index: 4;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    content: '';
    border-style: solid;
    border-color: transparent transparent transparent #e30613;
    border-width: 4.5px 0 4.5px 10px;
}

@media (min-width: 768px) {
    .youtube-slide-thumb span::before, .youtube-slide a span::before {
        border-width: 13.5px 0 13.5px 23px;
    }
}

.youtube-slide-thumb span {
    width: 30px;
    height: 30px;
}

.youtube-slide-thumb span::before {
    border-width: 4.5px 0 4.5px 10px;
}