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  <p>A specific combination of transitions and the calc() value will crash mobile Safari and Chrome on iOS (the two browsers I was able to test on iOS).</p>
  <p>The calc() value must have a percentage <i>and</i> calculation such as addition or subtraction. The transition must somehow reference that property, even if it doesn't run. So transitioning height in this example will cause the crash, but not transitioning background.</p>
  <p>The code I was working on that surfaced this issue used flex. Transitioning on -webkit-box-flex and -webkit-flex will also cause the crash, assumedly because a flex could modify the property that uses calc()</p>  


                @import "compass/css3";

body {
  margin: 10px;
section {
  padding: 10px;
  width: 500px;
  /* Works
  height: -webkit-calc(100%);
  /* Works
  height: -webkit-calc(10em + 10px);
  /* Crashes mobile Safari */
  height: -webkit-calc(100% + 10px);
  /* Works
  -webkit-transition: background 1s ease-in;
  /* Crashes mobile Safari (a value of 'all' will too) */
  -webkit-transition: height 1s ease-in;
  background: MediumAquamarine;