#nk-fixed-btn {
    display: none;
    position: fixed;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 9999;
}

#nk-fixed-btn button {
    background: #dd5e6c;
    color: white;
    font-weight: bold;
    font-size: 15px;
    padding: 14px 22px;
    border-radius: 50px;
    border: none;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
    cursor: pointer;
    font-family: "ヒラギノ角ゴ ProN", sans-serif;
    line-height: 1.4;
    text-align: center;
    white-space: nowrap;
}
#nk-fixed-btn button:hover {
    background: #c54857;
}

@media (max-width: 768px) {
    #nk-fixed-btn {
        display: none;
    }
}