style.css

body {
  margin: 0;
  margin-left: 30px;
  margin-right: 30px;
  margin-bottom: 30px;
  color: #c9d1d9;
  background-color: #0d1117;
  font-family: -apple-system,BlinkMacSystemFont,"Segoe UI",Helvetica,Arial,sans-serif,"Apple Color Emoji","Segoe UI Emoji";
  font-size: 16px;
  line-height: 1.5;
  word-wrap: break-word;
}

body a {
  background-color: transparent;
  color: #58a6ff;
  text-decoration: none;
}

body a:active,
body a:hover {
  outline-width: 0;
}

body a:hover {
  text-decoration: underline;
}

body h1,
body h2,
body h3,
body h4,
body h5,
body h6 {
  margin-top: 24px;
  margin-bottom: 16px;
  font-weight: 600;
  line-height: 1.25;
}

body h1 {
  font-weight: 600;
  font-size: 2em;
  text-align: center;
}

body h2 {
  font-weight: 600;
  font-size: 1.75em;
  padding-bottom: .3em;
  border-bottom: 1px solid #21262d;
}

body h3 {
  font-weight: 600;
  font-size: 1.25em;
}

body h4 {
  font-weight: 600;
  font-size: 1em;
}

body p {
  margin-top: 0;
  margin-bottom: 10px;
}

body ul,
body ol {
  margin-top: 0;
  margin-bottom: 0;
  padding-left: 2em;
}

body ol ol,
body ul ol {
  list-style-type: lower-roman;
}

body ul ul ol,
body ul ol ol,
body ol ul ol,
body ol ol ol {
  list-style-type: lower-alpha;
}

body ul ul,
body ul ol,
body ol ol,
body ol ul {
  margin-top: 0;
  margin-bottom: 0;
}

body li>p {
  margin-top: 16px;
}

body li+li {
  margin-top: .25em;
}

body .box {
    position: relative;
    padding: 0.5em 1em;
    margin: 2em 0;
    font-weight: bold;
    border: solid 3px #6091d3;
}

body .box .box-title {
    position: absolute;
    display: inline-block;
    top: -2px;
    left: -2px;
    padding: 0 9px;
    height: 28px;
    line-height: 25px;
    font-size: 1.5em;
    background: #6091d3;
    color: #ffffff;
    font-weight: bold;
}

body .box p {
    margin: 0;
    padding: 0;
}