body {
  background-color: #222;
  color: #fff;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  background-color: #333;
  padding: 20px;
}

nav {
  display: flex;
  align-items: center;
  justify-content: center;
}

nav ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  align-items: center;
  justify-content: center;
}

nav ul li {
  margin-left: 10px;
}

nav ul li a {
  color: #fff;
  text-decoration: none;
}

footer {
  background-color: #424242;
  color: #fff;
  padding: 20px;
  text-align: center;
  margin-top: auto;
}

main {
  flex: 1 0 auto;
  display: flex;
  align-items: center;
  justify-content: center;
}

section{
   padding-left: 10%;
   padding-right: 10%
}

.imagenf {
  width: 50px;
  height: 40px;
  border-radius: 100%;
}

.envia{
  background-color: #2d8ea6;
}