body {
    background-color: #efefef;
}
.golden {
    color: rgb(239, 173, 8);
    font-size: 16px;
}

.hover-glow {
    font-weight: 700;
    display: inline-block;
    transition: filter 6s ease, color 6s ease, text-shadow 6s ease;
    filter: brightness(1);
    color: inherit;
}
.hover-glow:hover {
    filter: brightness(3);
    color: #f9f0c1;
    text-shadow: 0 0 8px rgba(255,255,255,0.95), 0 0 20px rgba(255,255,255,0.6);
}

.turnto-black {
    position: relative;
    display: inline-block;
}

.turnto-black img {
    display: block;
    filter: grayscale(0%);
    transition: filter 5s ease;
}

.turnto-black:hover img {
    filter: grayscale(100%);
}

.turnto-black::after {
    content: "卒";
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #fff;
    font-size: 2em;
    font-weight: bold;
    text-shadow: 0 1px 2px rgba(0,0,0,.6);
    opacity: 0;
    transition: opacity 3s ease;
    pointer-events: none;
}

.turnto-black:hover::after {
    opacity: 1;
}