.vk-app-bottom-nav a{
  position:relative;
  transition:all .2s ease;
}

.vk-app-bottom-nav a.is-active{
  background:linear-gradient(
    135deg,
    #00ff9d,
    #7b2eff
  ) !important;

  color:#fff !important;

  box-shadow:
    0 8px 24px rgba(123,46,255,.28),
    0 4px 14px rgba(0,255,157,.22);

  transform:translateY(-1px);
}

.vk-app-bottom-nav a.is-active span,
.vk-app-bottom-nav a.is-active i{
  color:#fff !important;
}

.vk-app-bottom-nav a.is-active::before{
  content:"";
  position:absolute;
  inset:0;
  border-radius:18px;
  padding:1px;
  background:linear-gradient(
    135deg,
    rgba(255,255,255,.45),
    rgba(255,255,255,.05)
  );
  -webkit-mask:
    linear-gradient(#fff 0 0) content-box,
    linear-gradient(#fff 0 0);
  -webkit-mask-composite:xor;
  pointer-events:none;
}