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;
}