An auto-completion list for a cascading style sheet (CSS) selector is generated based on user input and contextual information associated with a target document. The user input that triggers the generation of the auto-completion list is entered while creating a CSS selector. A CSS block in the target document is parsed to determine the contextual information associated with the target document corresponding to the user input. The contextual information and the user input are analyzed to determine appropriate elements to add to the CSS selector to complete CSS selector syntax. The appropriate elements are provided in the auto-completion list. The auto-completion list is displayed proximate the location where the user entered the input that triggered generation of the auto-completion list. The user may then select one of the elements displayed in the auto-completion list to add the selected element to the CSS selector syntax.