visually combine subject and content into one input

src/components/emoji_input/emoji_input.vue

@@ -1,7 +1,7 @@
 <template>
   <div
     ref="root"
-    class="input emoji-input"
+    class="emoji-input"
     :class="{ 'with-picker': !hideEmojiButton }"
   >
     <slot

src/components/post_status_form/post_status_form.scss

@@ -216,6 +216,10 @@
     position: relative;
   }
 
+  .subject-input {
+    border-bottom: 1px solid var(--border);
+  }
+
   .character-counter {
     position: absolute;
     bottom: 0;

src/components/post_status_form/post_status_form.vue

@@ -156,12 +156,13 @@
             class="preview-status"
           />
         </div>
+        <div class="input">
           <EmojiInput
             v-if="!disableSubject && (newStatus.spoilerText || alwaysShowSubject)"
             v-model="newStatus.spoilerText"
             enable-emoji-picker
             :suggest="emojiSuggestor"
-          class="input form-control"
+            class="input form-control subject-input unstyled"
           >
             <template #default="inputProps">
               <input
@@ -180,7 +181,7 @@
             v-model="newStatus.status"
             :suggest="emojiUserSuggestor"
             :placement="emojiPickerPlacement"
-          class="input form-control main-input"
+            class="input form-control main-input unstyled"
             enable-sticker-picker
             enable-emoji-picker
             hide-emoji-button
@@ -217,6 +218,7 @@
               </p>
             </template>
           </EmojiInput>
+        </div>
         <div
           v-if="!disableScopeSelector"
           class="visibility-tray"
@@ -238,6 +240,7 @@
               v-model="newStatus.contentType"
               class="input form-control"
               :attrs="{ 'aria-label': $t('post_status.content_type_selection') }"
+              unstyled="true"
             >
               <option
                 v-for="postFormat in postFormats"