A system and method are described for automatically generating style sheet formatting for stylistic edits to a Web page in a Web development environment. The Web development environment detects the user's selection of particular content of the Web page and captures any stylistic changes that the user makes to the content. Using the stylistic changes, the Web development environment searches a style data structure to determine whether any style rules already exist that correspond to the user's stylistic changes. If the Web development environment does not find a pre-existing style rule, it automatically generates one or more style rules for the stylistic edits and associates those rules with the selected content. If a pre-existing style rule exists within the style data structure, the Web development environment assigns the pre-existing style rule to the selected content.