html, body {
  margin: 0;
  padding: 0;
  height: 100%;
}

#kopf {
  margin: 0;
  padding: 0;
  background-color: aliceblue;
}
#links {
  margin: 0;
  padding: 0;
  background-color: beige;
}
#inhalt {
  margin: 0;
  padding: 0;
  height: 100%;
  display: flex;
  flex-flow: column;
  background-color: lightgrey;
}

#spalten {
  margin: 0;
  padding: 0;
  height: 100%;
  display: flex;
  flex-flow: row;
}

#rechts {
  margin: 0;
  padding: 0;
  overflow: auto;
}