article.valid {
  width: 90%;
  margin: 0 auto 40px;
  text-align: center;
}
@media only screen and (min-width: 500px) {
  article.valid {
    margin: 0 auto 60px;
  }
}
@media only screen and (min-width: 1200px) {
  article.valid {
    width: 75%;
    margin: 20px auto 120px;
  }
}
@media only screen and (min-width: 1700px) {
  article.valid {
    width: 60%;
  }
}
article.valid .valid-introduction {
  width: 90%;
  margin: 0 auto 15px;
}
@media only screen and (min-width: 1200px) {
  article.valid .valid-introduction {
    margin: 0 auto 25px;
  }
}
@media only screen and (min-width: 1700px) {
  article.valid .valid-introduction {
    margin: 0 auto 35px;
  }
}
article.valid p {
  text-align: justify;
}