.catalog {
  margin-top: 80px;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: justify;
      -ms-flex-pack: justify;
          justify-content: space-between;
  gap: 20px;
}

.catalog__side-bar {
  width: 100%;
  max-width: 400px;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
  gap: 20px;
}

.catalog__articles {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -webkit-box-direction: normal;
      -ms-flex-direction: column;
          flex-direction: column;
  gap: 20px;
}

.catalog__section-title {
  font-size: 24px;
}

.catalog__title {
  font-size: 32px;
}

.catalog__main {
  width: 100%;
}

@media (max-width: 839px) {
  .catalog {
    -webkit-box-orient: vertical;
    -webkit-box-direction: normal;
        -ms-flex-direction: column;
            flex-direction: column;
  }

  .catalog__side-bar {
    max-width: 100%;
  }
}