body {
  font-family: sans-serif;
  line-height: 1.8;
  margin: 0 auto;
  max-width: 800px;
  padding: 24px;
  min-height: 100hv;

  background-image:
  linear-gradient(
      rgba(42, 69, 159, 0.35),
      rgba(28, 117, 144, 0.35)
    ),
    linear-gradient(
      rgba(0, 0, 0, 0.5),
      rgba(0, 0, 0, 0.5)
    ),
     url("image/periodictable-bk.png");
  background-size: cover;
  background-attachment: fixed;

}


.site-title {
  color: #2c74c6;
}

.intro {
  font-size: 1rem;
}

h1 {
  color: #2c74c6;
  font-size: 2rem;
}

h2 {
  color: #2c74c6;
  font-size: 1.5rem;
}

p {
  color: #849ab3;
  font-size: 1rem;
}

footer {
  width: 100%;
}