* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: #061324;
  font-family: Arial, Helvetica, sans-serif;
}

main {
  width: 100%;
  min-height: 100vh;
  background: #061324;
}

.site-image {
  width: 100%;
  height: auto;
  display: block;
}

.call-button {
  position: fixed;
  right: 18px;
  bottom: 18px;
  background: #1378ff;
  color: white;
  text-decoration: none;
  padding: 14px 20px;
  border-radius: 10px;
  font-weight: 800;
  box-shadow: 0 8px 25px rgba(0,0,0,.35);
}

@media (max-width: 700px) {
  .call-button {
    left: 18px;
    right: 18px;
    text-align: center;
  }
}