markdown.css

h1 {
    padding: 0.4em 0.5em;/*文字の上下 左右の余白*/
    color: #494949;/*文字色*/
    background: #f4f4f4;/*背景色*/
    border-left: solid 5px #7db4e6;/*左線*/
    border-bottom: solid 3px #d7d7d7;/*下線*/
}

h2 {
    position: relative;
    padding: 0.5em;
    background: #7db4e6;
    color: white;
}

h2::before {
    position: absolute;
    content: '';
    top: 100%;
    left: 0;
    border: none;
    border-bottom: solid 15px transparent;
    border-right: solid 20px rgb(149, 158, 155);
}

ul {
    list-style-type: none;
}

ul {
    margin: 0;
    padding: 0;
    list-style-type: none;
}

ul {
    position: relative;
    margin-left: 15px;
}

ul:before {
    content: "";
    display: block;
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    width: 0;
}

ul li {
    position: relative;
    margin: 0;
    padding: 7px 15px;
}

ul li:before {
    content: "";
    display: block;
    position: absolute;
    top: 15px;
    left: 0;
    width: 15px;
    height: 0;
}

ul li:last-child:before {
    top: 15px;
    bottom: 0;
    height: auto;
    background-color: #fff;
}