# selector-pseudo-element-case > **Warning** This rule is deprecated and will be removed in the future. See [the migration guide](../../../docs/migration-guide/to-15.md). Specify lowercase or uppercase for pseudo-element selectors. ```css a::before {} /** ↑ * This pseudo-element selector */ ``` The [`fix` option](../../../docs/user-guide/options.md#fix) can automatically fix all of the problems reported by this rule. ## Options `string`: `"lower"|"upper"` ### `"lower"` The following patterns are considered problems: ```css a:Before {} ``` ```css a:bEfOrE {} ``` ```css a:BEFORE {} ``` ```css a::Before {} ``` ```css a::bEfOrE {} ``` ```css a::BEFORE {} ``` ```css input::-MOZ-PLACEHOLDER {} ``` The following patterns are _not_ considered problems: ```css a:before {} ``` ```css a::before {} ``` ```css input::-moz-placeholder {} ``` ### `"upper"` The following patterns are considered problems: ```css a:Before {} ``` ```css a:bEfOrE {} ``` ```css a:BEFORE {} ``` ```css a::Before {} ``` ```css a::bEfOrE {} ``` ```css a::before {} ``` ```css input::-moz-placeholder {} ``` The following patterns are _not_ considered problems: ```css a:BEFORE {} ``` ```css a::BEFORE {} ``` ```css input::-MOZ-PLACEHOLDER {} ```