1. A method comprising: identifying, by one or more processors associated with one or more computer devices, a plurality of elements included in a document; determining, by one or more processors associated with one or more computer devices, a hierarchical structural representation of the document, the hierarchical structural representation reflecting an interconnection of the plurality of elements in the document; and determining, by one or more processors associated with one or more computer devices, whether one or more of the plurality of elements are hidden based on locations of the one or more of the plurality of elements and the hierarchical structural representation, where the determining whether the one or more of the plurality of elements are hidden includes: identifying respective color values associated with the plurality of elements, identifying a first element, of the plurality of elements, that is associated with a first color value of the respective color values, identifying a second element, of the plurality of elements, that is associated with a second color value of the respective color values, where the first and second color values are included within a particular range of color values, and where the second element appears behind the first element when the document is rendered, and determining that the first element is hidden when no intervening element is located between the first and second elements, the first element being not hidden when at least one intervening element, that is associated with a third color value, is located between the first and second elements, where the third color value is outside of the particular range of color values.