How can I reduce the space between main photo and Category on my website?

Store Design
2

Try adding this code to the bottom of theme.css

@media screen and (min-width: 769px) {

#shopify-section-featured-collections {
    margin-top: 45px;
}
.section-header.text-center {
  margin-bottom: 25px;
}
#shopify-section-featured-content {
      margin-top: 45px;
}
}