Change the length of the inhale and exhale in a css breathing pacer

I found a tutorial about creating a breath pacer using CSS:

The inhale and the exhale in the code are the same (4s). I want to control with the code the inhale, post-inhale hold, exhale, post exhale hold timing.

How can I do it?

Tutorial link - https://css-tricks.com/recreating-apple-watch-breathe-app-animation/ codepen - https://codepen.io/geoffgraham/pen/zKMEPE

body {
  background: #000;
  display: flex;
  align-items: center;
  height: 100vh;
  justify-content: center;
}

.watch-face {
  height: 125px;
  width: 125px;
  animation: pulse 4s cubic-bezier(0.5, 0, 0.5, 1) alternate infinite;
}

.circle {
  height: 125px;
  width: 125px;
  border-radius: 50%;
  position: absolute;
  mix-blend-mode: screen;
  transform: translate(0, 0);
  animation: center 6s infinite;
}

.circle:nth-child(odd) {
  background: #61bea2;
}

.circle:nth-child(even) {
  background: #529ca0;
}

.circle:nth-child(1) {
  animation: circle-1 4s ease alternate infinite;
}

.circle:nth-child(2) {
  animation: circle-2 4s ease alternate infinite;
}

.circle:nth-child(3) {
  animation: circle-3 4s ease alternate infinite;
}

.circle:nth-child(4) {
  animation: circle-4 4s ease alternate infinite;
}

.circle:nth-child(5) {
  animation: circle-5 4s ease alternate infinite;
}

.circle:nth-child(6) {
  animation: circle-6 4s ease alternate infinite;
}

@keyframes pulse {
  0% {
    transform: scale(.15) rotate(180deg);
  }
  100% {
    transform: scale(1);
  }
}

@keyframes circle-1 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(-35px, -50px);
  }
}

@keyframes circle-2 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(35px, 50px);
  }
}

@keyframes circle-3 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(-60px, 0);
  }
}

@keyframes circle-4 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(60px, 0);
  }
}

@keyframes circle-5 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(-35px, 50px);
  }
}

@keyframes circle-6 {
  0% {
    transform: translate(0, 0);
  }
  100% {
    transform: translate(35px, -50px);
  }
}

<div class="watch-face">
  <div class="circle"></div>
  <div class="circle"></div>
  <div class="circle"></div>
  <div class="circle"></div>
  <div class="circle"></div>
  <div class="circle"></div>
</div>

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