:root {
  color-scheme: light;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  color: #202124;
  background: #f5f7f8;
}

* {
  box-sizing: border-box;
}

body {
  max-width: 860px;
  margin: 0 auto;
  padding: 32px 40px 64px;
  background: #fff;
  line-height: 1.85;
  font-size: 16px;
  overflow-wrap: anywhere;
}

h1 {
  margin: 0 0 28px;
  padding-bottom: 18px;
  border-bottom: 1px solid #e5e7eb;
  font-size: 30px;
  line-height: 1.35;
  text-align: center;
}

h2,
h3 {
  margin-top: 2em;
  line-height: 1.5;
}

p,
li {
  text-align: justify;
}

a {
  color: #1769aa;
}

nav#TOC {
  margin: 20px 0 32px;
  padding: 18px 22px;
  border: 1px solid #e5e7eb;
  border-radius: 12px;
  background: #f8fafc;
}

table {
  width: 100%;
  border-collapse: collapse;
  overflow-x: auto;
}

th,
td {
  padding: 10px;
  border: 1px solid #dfe3e8;
  vertical-align: top;
}

@media (max-width: 640px) {
  body {
    padding: 22px 18px 48px;
    font-size: 15px;
  }

  h1 {
    font-size: 25px;
  }

  ol,
  ul {
    padding-left: 1.5em;
  }
}