What should be the values of bizeir curve for to be linear

**By putting the below values as a parameter for cubic bizeir function i am unable to clear this challenge.

Your code so far


<style>

  .balls{
    border-radius: 50%;
    background: linear-gradient(
      35deg,
      #ccffff,
      #ffcccc
    );
    position: fixed;  
    width: 50px;
    height: 50px;
    margin-top: 50px;
    animation-name: bounce;
    animation-duration: 2s;
    animation-iteration-count: infinite;
  }
  #ball1 { 
    left: 27%;
    animation-timing-function: cubic-bezeir(0,0, 1,1);
   //animation-timing-function:linear;
  }
  #ball2 { 
    left: 56%;
    animation-timing-function: ease-out;
  }

@keyframes bounce {
  0% {
    top: 0px;
  } 
  100% {
    top: 249px;
  }
} 

</style>

<div class="balls" id="ball1"></div>
<div class="balls" id="ball2"></div>

Your browser information:

User Agent is: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:61.0) Gecko/20100101 Firefox/61.0.

Link to the challenge:
https://learn.freecodecamp.org/responsive-web-design/applied-visual-design/learn-how-bezier-curves-work

You are almost there. The instructions say to use the values for cubic-bezeir from the example:

animation-timing-function: cubic-bezier(0.25, 0.25, 0.75, 0.75);