[AlanHK]

Originally Posted by odedta

Try to validate via idpf just to be on the safe side. It seems far fetched that an epub reader would ignore a simple css rule as that

Validates, no errors.
Same with "Flight Crew" in Sigil.
And http://jigsaw.w3.org/css-validator/validator

Originally Posted by Section8

Have you tried an equivalent "margin" such as: "margin: 2em 0 0;" ?

Tried all of these. All look about the same in Calibre or Sigil, all have no head space in FBReader.

.noindent {
  display: block;
  text-indent: 0;
  margin-top: 2em;
 }
.noindent {
  display: block;
  text-indent: 0;
  margin-top: 36px;
 }

.noindent {
  display: block;
  text-indent: 0;
  margin-top: 36pt;
 }

.noindent {
  display: block;
  text-indent: 0;
  margin: 36px 0px 0px 0px;
 }

Doesn't anyone here use FBReader?

I sent an email to their support, but no response. They don't seem to have a dedicated forum.
Though I think it's a one-man project and it's free, so I cant complain too much.

Here's the complete CSS just in case anyone sees some weird interaction.
But only "p" should matter, and that has "margin:0".

Spoiler:

p {
  display: block;
  text-align: justify;
  margin: 0;
  text-indent: 18pt;
}

.noindent {
  display: block;
  text-indent: 0;
  margin-top: 2em;
 }

h1 {
  text-align: center;
  display: block;
}
h2 {
  text-align: center;
  display: block;
  font-weight: bold;

} 
h3 {
  text-align: center;
  display: block;
  font-size: 1.29167em;
  font-style: italic;
  font-weight: bold;
  line-height: 1.2;
 }

.center {
   display: block;
   text-align: center;
   text-indent: 0;
}
.poem {
        text-align: left;
        text-indent: 0em;
        margin-left: 20%;
        margin-right: 0.5em;
        margin-bottom: 1em;
        margin-top: 1em;
        }

a { text-decoration: none;}

small { font-size : 0.8em;}