Fix #11655: Fix broken disabled states for iOS form controls and buttons

dist/css/bootstrap.css

@@ -1728,6 +1728,7 @@ output {
 fieldset[disabled] .form-control {
   cursor: not-allowed;
   background-color: #eee;
+  opacity: 1;
 }
 textarea.form-control {
   height: auto;
@@ -2029,6 +2030,7 @@ fieldset[disabled] .btn {
   -webkit-box-shadow: none;
           box-shadow: none;
   opacity: .65;
+  opacity: 1;
 }
 .btn-default {
   color: #333;

less/buttons.less

@@ -43,6 +43,7 @@
     pointer-events: none; // Future-proof disabling of clicks
     .opacity(.65);
     .box-shadow(none);
+    opacity: 1; // iOS fix for unreadable disabled content
   }
 }
 

less/forms.less

@@ -33,6 +33,10 @@ label {
 
 
 // Normalize form controls
+//
+// While most of our form styles require extra classes, some basic normalization
+// is required to ensure optimum display with or without those classes to better
+// address browser inconsistencies.
 
 // Override content-box in Normalize (* isn't specific enough)
 input[type="search"] {
@@ -79,8 +83,9 @@ input[type="checkbox"]:focus {
 }
 
 // Fix for Chrome number input
-// Setting certain font-sizes causes the `I` bar to appear on hover of the bottom increment button.
-// See https://github.com/twbs/bootstrap/issues/8350 for more.
+//
+// Setting certain font-sizes causes the `I` bar to appear on hover of the
+// bottom increment button. See https://github.com/twbs/bootstrap/issues/8350.
 input[type="number"] {
   &::-webkit-outer-spin-button,
   &::-webkit-inner-spin-button {
@@ -150,6 +155,7 @@ output {
   fieldset[disabled] & {
     cursor: not-allowed;
     background-color: @input-bg-disabled;
+    opacity: 1; // iOS fix for unreadable disabled content
   }
 
   // Reset height for `textarea`s