#lang racket/base (require "core.rkt") (provide (all-defined-out)) (define (make-css-transition property duration #:timing-function [timing-function #f] #:delay [delay #f]) (join-css-strings (filter values (list (make-css-string "transition-property" property) (make-css-string "transition-duration" duration) (and timing-function (make-css-string "transition-timing-function" timing-function)) (and delay (make-css-string "transition-delay" delay))))))