.tnb-float-contact{
  position: fixed;
  right: 18px;
  bottom: 18px;
  z-index: 99999;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.tnb-float-contact__btn{
  width: 52px;
  height: 52px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  text-decoration: none;
  border: 0;
  background: #222222;
  color: #FFD700;
  border: 2px solid #CF1919;
  box-shadow: 0 10px 22px rgba(0,0,0,.18);
  transition: transform .14s ease, box-shadow .14s ease, filter .14s ease;
  position: relative;
  overflow: visible;
}

.tnb-float-contact__btn::before{
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: 999px;
  pointer-events: none;
  background: transparent;
  border: 2px solid rgba(207,25,25,.85);
  transform: scale(.65);
  opacity: .9;
  z-index: 1;
  animation: tnbFloatWave 1.2s ease-out infinite;
}

.tnb-float-contact__btn:nth-child(2)::before{
  animation-delay: .7s;
}

.tnb-float-contact__btn:nth-child(3)::before{
  animation-delay: 1.4s;
}

.tnb-float-contact__btn:hover{
  filter: brightness(.98);
  transform: translateY(-2px);
  box-shadow: 0 14px 28px rgba(0,0,0,.22);
}

.tnb-float-contact__btn:active{
  transform: scale(.98);
  box-shadow: 0 8px 14px rgba(0,0,0,.14);
}

.tnb-float-contact__btn svg{
  width: 24px;
  height: 24px;
  display: block;
  position: relative;
  z-index: 3;
  color: #FFD700;
  fill: #FFD700;
}

.tnb-float-contact__btn--zalo{
  background: #222222;
  color: #FFD700;
  border: 2px solid #CF1919;
}

.tnb-float-contact__btn::after{
  content: "";
  position: absolute;
  inset: -2px;
  border-radius: 999px;
  pointer-events: none;
  background: radial-gradient(circle at center, rgba(207,25,25,.45) 0%, rgba(207,25,25,0) 60%);
  transform: scale(0.25);
  opacity: 0;
  z-index: 1;
}

.tnb-float-contact__btn:hover::after,
.tnb-float-contact__btn:focus-visible::after{
  animation: tnbFloatRipple .75s ease-out;
}

.tnb-float-contact__btn:active::after{
  animation: tnbFloatRipple .45s ease-out;
}

@keyframes tnbFloatRipple{
  0%{ transform: scale(0.15); opacity: .65; }
  100%{ transform: scale(1.85); opacity: 0; }
}

@keyframes tnbFloatWave{
  0%{ transform: scale(.7); opacity: .75; }
  55%{ opacity: .25; }
  100%{ transform: scale(2.15); opacity: 0; }
}

@media (prefers-reduced-motion: reduce){
  .tnb-float-contact__btn::before{
    animation: none;
  }
}

@media (max-width: 520px){
  .tnb-float-contact{
    right: 12px;
    bottom: 12px;
    gap: 8px;
  }
  .tnb-float-contact__btn{
    width: 48px;
    height: 48px;
  }
}