use quotes on attr selectors more consistently

less/forms.less

@@ -75,9 +75,9 @@ label select {
 }
 
 // Mini reset for unique input types
-input[type=image],
-input[type=checkbox],
-input[type=radio] {
+input[type="image"],
+input[type="checkbox"],
+input[type="radio"] {
   width: auto;
   height: auto;
   padding: 0;
@@ -90,7 +90,7 @@ input[type=radio] {
 }
 
 // Reset the file input to browser defaults
-input[type=file] {
+input[type="file"] {
   padding: initial;
   line-height: initial;
   border: initial;
@@ -100,16 +100,16 @@ input[type=file] {
 }
 
 // Help out input buttons
-input[type=button],
-input[type=reset],
-input[type=submit] {
+input[type="button"],
+input[type="reset"],
+input[type="submit"] {
   width: auto;
   height: auto;
 }
 
 // Set the height of select and file controls to match text inputs
 select,
-input[type=file] {
+input[type="file"] {
   height: 28px; /* In IE7, the height of the select element cannot be changed by height, only font-size */
   *margin-top: 4px; /* For IE7, add top margin to align select with labels */
   line-height: 28px;
@@ -128,7 +128,7 @@ select[size] {
 }
 
 // Remove shadow from image inputs
-input[type=image] {
+input[type="image"] {
   .box-shadow(none);
 }
 
@@ -138,7 +138,7 @@ textarea {
 }
 
 // Hidden inputs
-input[type=hidden] {
+input[type="hidden"] {
   display: none;
 }
 
@@ -152,8 +152,8 @@ input[type=hidden] {
 .checkbox {
   padding-left: 18px;
 }
-.radio input[type=radio],
-.checkbox input[type=checkbox] {
+.radio input[type="radio"],
+.checkbox input[type="checkbox"] {
   float: left;
   margin-left: -18px;
 }
@@ -193,8 +193,8 @@ textarea:focus {
   .box-shadow(@shadow);
   outline: thin dotted \9; /* IE6-8 */
 }
-input[type=file]:focus,
-input[type=checkbox]:focus,
+input[type="file"]:focus,
+input[type="checkbox"]:focus,
 select:focus {
   .box-shadow(none); // override for file inputs
   .tab-focus();