#container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.content {
  width: 400px;
  height: 40px;
  box-shadow: 2px 4px 10px rgba(0, 0, 0, .2);
  border-radius: 60px;
  overflow: hidden;
}

.subscription {
  position: relative;
  width: 100%;
  height: 100%;
}

.subscription .add-email{
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
  outline: none;
  padding: 0 20px;
}

.subscription .submit-email {
  position: absolute;
  top: 0;
  right: 0;
  height: calc(100% - 2px);
  width: 100px;
  border: none;
  border-radius: 60px;
  outline: none;
  margin: 1px;
  padding: 0 20px;
  cursor: pointer;  
  background: #0c1228;
  color: #54c72b;
  transition: width .35s ease-in-out,
    background .35s ease-in-out;
}

.subscription.done .submit-email {
  width: calc(100% - 2px);
  background: #54c72b;
}

.subscription .submit-email .before-submit,
.subscription .submit-email .after-submit {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  text-align: center;
  line-height: 38px;
  transition: visibility .35s ease-in-out,
    opacity .35s ease-in-out;
}

.subscription.done .submit-email .before-submit,
.subscription:not(.done) .submit-email .after-submit {
  visibility: hidden;
  opacity: 0;
}

.subscription .submit-email .after-submit {
  transition-delay: .35s;
}

.subscription:not(.done) .submit-email .before-submit,
.subscription.done .submit-email .after-submit {
  visibility: visible;
  opacity: 1;
}