.back-top{
    position: fixed;
    right: 24px;
    bottom: 24px;
    width: 52px;
    height: 52px;
    border-radius: 50%;
    border: none;
    background: #e5e3ff;
    color: #fff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 10px 30px rgba(0,0,0,0.25);
    opacity: 0;
    pointer-events: none;
    transform: translateY(10px) scale(0.9);
    transition: opacity .2s ease, transform .2s ease;
    z-index: 999;
}

.back-top.show{
    opacity: 1;
    pointer-events: auto;
    transform: translateY(0) scale(1);
}

.back-top:hover{
    transform: translateY(0) scale(1.06);
}

.back-top:active{
  transform: translateY(0) scale(0.92);
}