.whatsapp-btn {
  position: fixed;
  bottom: 1.25rem; /* 20px */
  right: 1.25rem; /* 20px */
  display: inline-flex;
  align-items: center;
  background-color: #25D366;
  color: #fff;
  padding: 0.5rem 0.75rem; /* 8px 12px */
  border-radius: 1.25rem; /* 20px */
  text-decoration: none;
  
  font-size: 1rem; /* 14px */
  font-weight: 500;
  transition: background-color 0.2s ease;
  box-shadow: 0 0.125rem 0.375rem rgba(0, 0, 0, 0.2); /* 2px 6px */
  z-index: 1000;
}

.whatsapp-btn:hover {
  background-color: #1ebe57;
}

.whatsapp-btn img {
  width: 1.50rem; /* 20px */
  height: 1.50rem;
  margin-right: 0.375rem; /* 6px */
}

/* ================================
   TABLET PEQUEÑA
   ================================ */
@media (max-width: 48rem) { /* 768px */
  .whatsapp-btn {
    bottom: 0.9375rem; /* 15px */
    right: 0.9375rem;
    padding: 0.375rem 0.625rem; /* 6px 10px */
    font-size: 0.8125rem; /* 13px */
    border-radius: 1.125rem; /* 18px */
  }

  .whatsapp-btn img {
    width: 1.125rem; /* 18px */
    height: 1.125rem;
    margin-right: 0.3125rem; /* 5px */
  }
}

/* ================================
   MÓVILES GRANDES
   ================================ */
@media (max-width: 37.5rem) { /* 600px */
  .whatsapp-btn {
    bottom: 0.75rem; /* 12px */
    right: 0.75rem;
    padding: 0.3125rem 0.5rem; /* 5px 8px */
    font-size: 0.75rem; /* 12px */
    border-radius: 1rem; /* 16px */
  }

  .whatsapp-btn img {
    width: 1rem; /* 16px */
    height: 1rem;
    margin-right: 0.25rem; /* 4px */
  }
}

/* ================================
   MÓVILES PEQUEÑOS
   ================================ */
@media (max-width: 30rem) { /* 480px */
  .whatsapp-btn {
    bottom: 0.625rem; /* 10px */
    right: 0.625rem;
    padding: 0.25rem 0.375rem; /* 4px 6px */
    font-size: 0.6875rem; /* 11px */
    border-radius: 0.875rem; /* 14px */
  }

  .whatsapp-btn img {
    width: 0.875rem; /* 14px */
    height: 0.875rem;
    margin-right: 0.1875rem; /* 3px */
  }
}

/* ================================
   MÓVILES MUY PEQUEÑOS
   ================================ */
@media (max-width: 22.5rem) { /* 360px */
  .whatsapp-btn {
    bottom: 0.5rem; /* 8px */
    right: 0.5rem;
    padding: 0.1875rem 0.3125rem; /* 3px 5px */
    font-size: 0.625rem; /* 10px */
    border-radius: 0.75rem; /* 12px */
  }

  .whatsapp-btn img {
    width: 0.75rem; /* 12px */
    height: 0.75rem;
    margin-right: 0.125rem; /* 2px */
  }
}