SASS notation, what does + mean?

Question

css

header h3 + p {
    font-size: 1.1em;
    margin-top: -0.8em;
    line-height: 1.5em;
  }

  header h4 + p,
  header h5 + p,
  header h6 + p {
    font-size: 0.9em;
    margin-top: -0.6em;
    line-height: 1.5em;
  }

Answer 1

this is standard css functionality.
in this case, header h6 + p means that the style will be applied to the p element that follows the header h6