docs: function visit(sheet, node) {
    var name = (node.properties || {}).className
    var scoped = {}
    var key
    var parts
    var color
    var style
    var content
  
    /* Always just one class. */
    name = name ? name[0].replace(/hljs-/, '') : ''
  
    for (key in sheet) {
      parts = key.split(' ')
      color = sheet[key]
  
      if (parts[0] === name) {
        if (parts.length === 1) {
          style = color
        } else {
          scoped[parts.slice(1).join(' ')] = color
        }
      } else {
        scoped[key] = color
      }
    }
  
    content = ''
  
    if ('value' in node) {
      content = node.value
    }
  
    if ('children' in node) {
      content = all(scoped, node.children)
    }
  
    if (style) {
      content = style(content)
    }
  
    return content
  }