Form width increases on Safari for iPhone - css

Question

I don't understand why form width increases on Safari for iPhone. I tried to modify my CSS, and seems that "font-size" caused the problem. Any Solutions?
This is the code:
HTML:
<input type="text" id="form" class="newsletter_input" name="email">
CSS:
.newsletter_input {
border: 0px solid #fff;
background: #fff;
color: #0ce980;
font-family: 'Lato', Arial;
font-weight: 300;
font-size: 42pt;
width: 855px;
height: 100px;
margin-left: 50px;
margin-top: 10px;
text-align: center;
}
.newsletter_input:focus {
ouline: 0;
}

Answer 1

Mobile Safari (like Chrome for Android, Mobile Firefox and IE Mobile) increases the font size of wide blocks (at all times), such that if you double-tap to zoom in on that block (which fits the block to the screen width), the text will be legible. If you set -webkit-text-size-adjust: 100% (or none), it won't be able to do this, and so when a user double-taps to zoom in on wide blocks the text will be illegibly small; users will be able to read it if they pinch-zoom in, but then the text will be wider than the screen and they'll have to pan horizontally to read each line of text!
Ideally you would fix this by using Responsive Web Design techniques to make your design adapt to mobile screen sizes (in which case you would no longer have any very wide blocks, so mobile browsers would no longer adjust your font sizes).
Finally if you really need to prevent Mobile Safari from adjusting your font sizes you can set -webkit-text-size-adjust: 100%, but do this only as a last resort since it is likely to cause mobile users to have difficulty reading your text, as it'll either be too small or they'll have to pan from side to side after every line they read. Note that you must use 100% not none because none has nasty side-effects in desktop browsers. There are also equivalent -moz-text-size-adjust and -ms-text-size-adjust properties for Mobile Firefox and IE Mobile.
Edit: for example in your case the simplest is probably the 2nd alternative, so you could try adding the following CSS:
/* Mobile browsers only */
#media only screen and (max-device-width: 480px) {
.newsletter_input {
width: 855px;
}
.newsletter_input #form{
font-size:42pt
}
}
Though it's not ideal to hardcode 855px like this; you could improve on that by using a variety of CSS media queries, or getting the device-width from JavaScript.