Tidy up the input form a little

Change the title of the page to be more directive about the step in the journey.

Move the  error message into the form.

Remove the heading and increase the label size instead.

Change the button text.

app/templates/input.html

@@ -3,20 +3,32 @@
 {% block head %}
 {{ super() }}
 {% endblock %}
+
+{% block pagecaption %}Mentor matcher{% endblock %}
+{% block pageheading %}Upload your data{% endblock %}
+{% block pageexcerpt %}Upload the mentors and mentees you want to match.{% endblock %}
+
 {% block content %}
-<h1 class="heading-lg">Upload</h1>
-{% if error_message %}
-  <blockquote class="error warning-text">
-    <strong>Error:</strong> {{ error_message }}
-  </blockquote>
-{% endif %}
-  <form method=post enctype=multipart/form-data action="{{ url_for('main.upload') }}">
-    <div class="form-group" style="padding-bottom: 20px;">
-      <label class="label label-md" for="files">
-        Select your files
-      </label>
-      <input type="file" name="files" multiple="" id="files">
+<div class="grid-row">
+  <div class="grid-column-two-thirds">
+    <div class="page--content">
+        <form method=post enctype=multipart/form-data action="{{ url_for('main.upload') }}">
+          {% if error_message %}
+            <blockquote class="error warning-text">
+              <p><strong>An error has occurred</strong></p>
+              <p>{{ error_message }}</p>
+            </blockquote>
+          {% endif %}
+          <div class="form-group">
+            <label class="label label-lg" for="files">
+              Select your files
+            </label>
+            <input type="file" name="files" multiple="" id="files">
+          </div>
+          <hr>
+          <input type="submit" class="button button--action" value="Upload the data ❯">
+        </form>
     </div>
-    <input type="submit" class="button button--action" value="Upload">
-  </form>
+  </div>
+</div>
 {% endblock %}