an class="content">Terms defined by this specification</span><a class="self-link" href="#index-defined-here"></a></h3>
  <ul class="index">
   <li><a href="#dom-customstateset-add">add</a><span>, in § 2</span>
   <li><a href="#dom-customstateset-add">add(value)</a><span>, in § 2</span>
   <li><a href="#custom-state-pseudo-class">custom state pseudo class</a><span>, in § 3</span>
   <li><a href="#customstateset">CustomStateSet</a><span>, in § 2</span>
   <li><a href="#dom-elementinternals-states"