header {
    text-align: center;
}
body {
  font-family: "Roboto", sans-serif;
  font-optical-sizing: auto;
  font-weight: 200;
  font-style: normal;
  line-height: 25px;
  background-image: url("https://html5book.ru/wp-content/uploads/2015/05/background13.jpg");
}
.photo {
  margin: auto;
  margin-top: 20px;
  display: block;
  text-align: center;
  border-radius: 100px 100px 100px 100px;
  border: solid 2px;

}
ul {
  padding: 10px 30px 10px 35px;
  font-size: 20px;
  border: solid 1px;
  border-radius: 20px;
}
a {
  text-decoration: none;
}
nav {
  margin-inline: 25%;
}
.linknav {
  margin-left: 15px;
  color: black;
}
main {
  margin-inline: 25%;
  border: solid 2px; 
  border-radius: 50px;
}
footer {
  margin-inline: 25%;
}
ol {
  margin: 5px 30px 15px 10px;
  font-size: 17px;
}
hr {
    color:"lightgray";
}
.code {
   margin: 10px 0 10px 0;
   padding: 10px;
   display: inline-block;
   border: ridge 2px;
   border-radius: 15px;
}