.footer {
  background: #212529;
  color: #bbb;
  padding: 20px 0;
}

/* banner */
.banner {
  background: linear-gradient(135deg, #007bff, black);
  color: white;
  padding: 20px 0;
  text-align: center;
}
.banner h1 {
  text-shadow: 2px 2px 6px rgba(0,0,0,0.3);
}


.advantage-box {
  text-align: center;
  padding: 20px;
}


/* product */
.product-card {
  transition: transform .2s;
}
.product-card:hover {
  transform: translateY(-5px);
}


/* phone */
.phone-link {
  text-decoration: none;
  color: inherit;
  font-weight: bold;
}
.phone-link:hover {
  color: #007bff;
}