#toc ul {
  list-style: none;
  --tab-witdh: 20px;
}

#toc li.toc02 {
  padding-left: calc(0 * var(--tab-witdh));
}

#toc li.toc03 {
  padding-left: calc(1 * var(--tab-witdh));
}

#toc li.toc04 {
  padding-left: calc(2 * var(--tab-witdh));
}

#toc li.toc05 {
  padding-left: calc(3 * var(--tab-witdh));
}

#toc li.toc06 {
  padding-left: calc(4 * var(--tab-witdh));
}

#toc-box {
  border: 2px solid #999999;
  margin-bottom: 15px;
  margin-left: 15px;
  margin-right: 15px;
  border-radius: 5px;
}