Set characters according to metadata label

app/templates/macros.jinja

 {% macro render_field(field) %}
-  <div class="input-field">
-    <i class="prefix">{{ field.name[0:1]|upper }}</i>
-      {{ field.label }}
-      {{ field(data_length='255')|safe }}
-  </div>
-  {% if field.errors %}
-    {% for error in field.errors %}
-      <span class="helper-text red-text">{{ error }}</span>
-    {% endfor %}
-  {% endif %}
+<div class="input-field">
+  <i class="prefix">{{ field.label.text[0:1]|upper }}</i>
+  {{ field.label }}
+  {{ field(data_length='255')|safe }}
+  {% for error in field.errors %}
+  <span class="helper-text red-text">{{ error }}</span>
+  {% endfor %}
+</div>
 {% endmacro %}
 
 
 {% macro render_field_with_value(field, corpus_file) %}
-  <div class="input-field">
-    <i class="prefix">{{ field.name[0:1]|upper }}</i>
-      {{ field.label }}
-      {{ field(value=corpus_file[field.name], data_length='255')| safe }}
-  </div>
-  {% if field.errors %}
-    {% for error in field.errors %}
-      <span class="helper-text red-text">{{ error }}</span>
-    {% endfor %}
-  {% endif %}
+<div class="input-field">
+  <i class="prefix">{{ field.label.text[0:1]|upper }}</i>
+  {{ field.label }}
+  {{ field(value=corpus_file[field.name], data_length='255')| safe }}
+  {% for error in field.errors %}
+  <span class="helper-text red-text">{{ error }}</span>
+  {% endfor %}
+</div>
 {% endmacro %}
 
 
 {% macro submit_button(input) %}
-  <button class="btn waves-effect waves-light" id="{{ input.id }}" name="{{ input.name }}" type="submit" value="{{ input.label.text }}">{{ input.label.text }}<i class="material-icons right">send</i></button>
+<button class="btn waves-effect waves-light" id="{{ input.id }}" name="{{ input.name }}" type="submit" value="{{ input.label.text }}">
+  {{ input.label.text }}
+  <i class="material-icons right">send</i>
+</button>
 {% endmacro %}