.btn-up{
    position: fixed;
    z-index: 119;
    background-color:var(--newHeader);
    border: 2px solid var(--NewBorder);
    top: 70px;
    left: 70px;
    border-radius: 40px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
  }
  
  .btn-up::before{
    content: "";
    width: 30px;
    height: 30px;
    background: transparent no-repeat center center;
    background-size: 100% 100%;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' fill='%23fff' viewBox='0 0 16 16'%3E%3Cpath fill-rule='evenodd' d='M7.646 4.646a.5.5 0 0 1 .708 0l6 6a.5.5 0 0 1-.708.708L8 5.707l-5.646 5.647a.5.5 0 0 1-.708-.708l6-6z'/%3E%3C/svg%3E");
  }
  
  .btn-up_hide{
    display: none;
  }
  
  @media (hover: hover) and (pointer: fine) {
    .btn-up:hover {
      background-color:var(--NewContener); /* цвет заднего фона при наведении */
    }
  }