Use flexbox in write-view

src/sass/views/_write.scss

@@ -1,4 +1,6 @@
 .view-write {
+    display: flex;
+    flex-direction: column;
     margin: 0px;
     padding: 0px;
     color: $color-grey-dark;
@@ -19,6 +21,7 @@
     }
 
     .headers {
+        flex-shrink: 0;
         margin-top: 10px;
 
         p {
@@ -38,6 +41,7 @@
     }
 
     .subject-box {
+        flex-shrink: 0;
         position: relative;
         margin: 20px 0 7px 0;
         width: inherit;
@@ -47,7 +51,6 @@
         height: em(44);
 
         .subject-line {
-            float: left;
             padding: 10px;
             width: 80%;
             color: $color-grey;
@@ -82,6 +85,7 @@
     }
 
     .attachments-box {
+        flex-shrink: 0;
         position: relative;
         margin: 0 0 5px 0;
         width: inherit;
@@ -126,13 +130,10 @@
     }
 
     .body {
+        flex-grow: 1;
         line-height: 1.5em;
         cursor: text;
-
-        @include respond-to(desktop) {
-            height: 445px;
         overflow-y: scroll;
-        }
 
         *[contentEditable] {
             outline: 0px;

src/tpl/write.html

@@ -19,7 +19,7 @@
             <input id="cc{{$index}}" value="{{recipient.address}}" ng-model="recipient.address" ng-trim="false" ng-class="{'label': recipient.secure === true, 'label label-primary': recipient.secure === false && recipient.valid !== true}" auto-size="recipient.address" spellcheck="false" ng-change="onAddressUpdate(cc, $index)" address-input="cc" tabindex="1" ng-mouseover="getKeyId(recipient)">
           </span>
         </p>
-      </div><!--/.address-headers-->
+      </div><!--/.headers-->
 
       <div class="subject-box">
         <div class="subject-line">