clean up some css for github issues: input prepend z-index, modals revamped for responsive

lib/forms.less

@@ -96,6 +96,7 @@ input[type=file] {
 // Chrome on Linux and Mobile Safari need background-color
 select {
   background-color: @white;
+  vertical-align: middle;
 }
 
 // Make multiple select elements height not fixed
@@ -304,13 +305,10 @@ textarea[readonly] {
 // Allow us to put symbols and text within the input field for a cleaner look
 .input-prepend,
 .input-append {
-  overflow: hidden;
   input {
     .border-radius(0 3px 3px 0);
   }
   .add-on {
-    position: relative;
-    z-index: 2;
     float: left;
     display: block;
     width: auto;

lib/modals.less

@@ -13,7 +13,8 @@
   &.fade { opacity: 0; }
 }
 
-.modal-backdrop, .modal-backdrop.fade.in {
+.modal-backdrop,
+.modal-backdrop.fade.in {
   .opacity(80);
 }
 

lib/responsive.less

@@ -43,6 +43,18 @@
   .horizontal-form .form-actions {
     padding-left: 0;
   }
+
+  // Modals
+  .modal {
+    position: fixed;
+    top: 20px;
+    left: 20px;
+    right: 20px;
+    width: auto;
+    .close {
+      padding: 10px;
+    }
+  }
 }