*{
  margin: 10px;
  font-family: "Arial", "Calibri";
}

body{
  background: grey;
}

h1{
  background: #14408A;
  text-align: center;
  color: white;
}

.toc{
  background: #6B98E6;
  padding: 10px;
}

.lesson{
  background: #BAC9E3;
  padding: 5px;
}

.lesson-title{
  background: #6B98E6;
  padding: 5px;
}

.lesson-content{
  background: #B7B9BD;
  padding: 5px;
}

.content-concept{
  background: #97B5E9;
  padding: 5px;
}

.content-title{
  background:#97D0E9;
  padding: 1px;
}

.content-description{
  background: #55A4FE;
  padding: 5px;
}

.lists{
  font-weight: Bold;
}

.sublist{
  font-weight: normal;
}

img{
  max-width: 100%;
  display: block;
  margin: auto;
}