css
body {
  background-color: #000000;
  color: #FFFFFF;
  font-family: Arial, sans-serif;
  font-size: 20px;
  font-weight: bold;
  line-height: 1.2;
}

h1 {
  font-size: 48px;
  font-weight: bold;
  border-bottom: 4px solid #000000;
  margin-top: 10px;
  text-align: center;
}

h2 {
  font-size: 24px;
  font-weight: bold;
  border-bottom: 4px solid #000000;
  margin-bottom: 20px;
  text-align: center;
}

p {
  font-size: 16px;
  margin-bottom: 20px;
  text-align: justify;
}

a {
  text-decoration: none;
  color: #FF0000;
  background-color: #000000;
  padding: 4px 8px;
  border-radius: 4px;
  border: 4px solid #000000;
  font-weight: bold;
  font-size: 16px;
}

a:hover {
  background-color: #FF0000;
  color: #000000;
  border: 4px solid #FF0000;
}

h1 {
  /* added a new style for h1 as per 3 */
  background-color: #000000;
  border: 4px solid #000000;
  padding: 8px 16px;
  border-radius: 4px;
}

h1 a {
  color: #FFFFFF;
  text-decoration: none;
  text-align: center;
}

/* added new style for h2 */
h2 {
  background-color: #000000;
  border: 4px solid #000000;
  padding: 8px 16px;
  border-radius: 4px;
  margin-bottom: 10px;
}

h2 a {
  color: #FFFFFF;
  text-decoration: none;
  text-align: center;
}

/* added new style for p */
p {
  background-color: #FFFFFF;
  border: 4px solid #000000;
  padding: 8px 16px;
  border-radius: 4px;
}

p a {
  color: #000000;
  text-decoration: none;
  text-align: center;
}

/* added new style for a */
a:visited {
  background-color: #000000;
  color: #FFFFFF;
  text-decoration: none;
  border: 4px solid #000000;
  border-radius: 4px;
  padding: 8px 16px;
  font-size: 16px;
  font-weight: bold;
  text-align: center;
}

/* added new style for a:hover */
a:hover {
  background-color: #000000;
  color: #FFFFFF;
  border: 4px solid #000000;
  border-radius: 4px;
  padding: 8px 16px;
  font-size: 16px;
  font-weight: bold;
  text-align: center;
}

/* added new style for h1, h2, p, a, a:visited, a:hover */
body {
  background-color: #000000;
  color: #FFFFFF;
  font-family: Arial, sans-serif;
  font-size: 20px;
  font-weight: bold;
  line-height: 1.2;
  margin: 0 auto;
}

/* added new style for h1, h2, p, a, a:visited, a:hover */
h1, h2, p, a, a:visited, a:hover {
  text-align: center;
}