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                <div class="box green">
 <h1>Vermeide unerwartete Ergebnisse durch Verwendung von einheitslosem line-height!</h1>
   <p> Diese h1 line-height ist von seiner eigenen font-size berechnet (30px × 1.1) = 33px</p>
   <p>nach einem Beispiel von MDN</p>

<div class="box red">
 <h1>Vermeide unerwartete Ergebnisse durch Verwendung von einheitslosem line-height!</h1>
  <p>Diese h1 line-height stammt von der der font-size  (15px × 1.1) = 16.5px,  nicht gerade das erwünschte Ergebnis</p>
  <p>nach einem Beispiel von MDN</p>

<!-- The first <h1> line-height is calculated from its own font-size   (30px × 1.1) = 33px  --> 
<!-- The second <h1> line-height results from the red div's font-size  (15px × 1.1) = 16.5px,  probably not what you want -->


                .green {
  line-height: 1.1;
  border: 2px solid green;
.red {
  line-height: 1.1em;
  border: 2px solid red;
h1 {
  font-size: 30px;
.box {
  box-sizing: border-box;
  min-width: 200px;
  max-width: 250px;
  display: inline-block;
  vertical-align: top;
  font-size: 15px;
  padding: .55em;
  margin: 1em;