When I try to use left: -webkit-calc(100% - 100px); (assuming that left: 0; is initial state) it works in iOS 6.0.1 just fine. But when I do the sa
left: -webkit-calc(100% - 100px);
left: 0;
You can fix this by initialising the property with anything but auto:
.menu { left: 0; transition: left 1s linear; } .menu-open .menu { left: -webkit-calc(100% - 50px); left: calc(100% - 50px); }