h1{
  border-left: solid 7px #1FB251;
  font-size: 23px;
  /*font-size: 2.3rem;*/
  margin-bottom: 20px;
  background: #F2F2F2;
  padding: 15px 20px;
  font-weight: bold;
}

h2{
  border-bottom: solid 3px #1FB251;
  font-size: 21px;
  /*font-size: 2.1rem;*/
  margin-bottom: 20px;
  padding: 10px 0;
  font-weight: bold;
}

.markdown-section ul {
  background-color: #f7f7f7;
  padding: 10px 15px 10px 35px;
}

.book-summary ul.summary li.active>a {
  color: #1FB251;
  background: 0 0;
  text-decoration: none;
}

/*右画面の表示サイズ*/
.book.font-size-2 .book-body .page-inner section {
  font-size: 1.8rem;
}

/* 画像の中央ぞろえ */
img[title=css3],
img[title=structure_mixed_with_styles],
img[title=address_book],
img[title=Database],
img[title=protocol],
img[title=client_server],
img[title=P2P]
{
  margin-left: 50%;
  transform: translateX(-50%);
}

img[title=structure_mixed_with_styles],
img[title=protocol],
img[title=client_server],
img[title=P2P]
{
  width: 60%;
  margin-top: 50px;
}

.markdown-section .license h2 {
  font-size: 1em;
  border: none;
  line-height: 1em;
  margin: 0;
}
.markdown-section .license pre{
  font-size: 0.8em;
}