package_description: @keyframes or @counter-style will be overridden by those who share the same identifiers and appear later in stylesheets. So we can discard all of them except the last one. When defined inside a @media or @supports rule, @keyframes and @counter-style rules only override global rules in some of the client browsers so they need handled separately. This plugin has taken care of this and transforms the PostCss AST safely.
package_installation: npm i postcss-discard-overridden