html, body {
  margin: 0;
  padding: 0;
}
body {
  font-family: Arial, Helvetica, sans-serif;
  background: #ecfdf5;
}

.main-button{
  display:inline-block;
  background:#047857;
  color:white;
  padding:14px 26px;
  border-radius:30px;
  font-weight:600;
  text-decoration:none;
  margin-top:18px;
}

.main-button:hover{
  background:#065f46;
}

@keyframes riverMove {
  0% { background-position: 0 0; }
  100% { background-position: 0 400px; }
}

.river-flow{
  animation: riverMove 20s linear infinite;
}