Add form padding mixin & update intro text

src/newsreader/scss/components/form/_form.scss

@@ -1,3 +1,5 @@
+@import "mixin.scss";
+
 .form {
   display: flex;
   flex-direction: column;
@@ -39,20 +41,24 @@
     display: flex;
     flex-direction: row;
 
-    padding: 15px;
+    @include form-padding;
   }
 
   &__actions {
     display: flex;
     flex-direction: row;
 
-    padding: 15px;
+    @include form-padding;
   }
 
   &__title {
     font-size: 18px;
   }
 
+  &__intro {
+    @include form-padding;
+  }
+
   & .favicon {
     height: 20px;
   }

src/newsreader/scss/components/form/_mixin.scss

@@ -0,0 +1,3 @@
+@mixin form-padding {
+  padding: 15px;
+}

src/newsreader/templates/password-reset/password-reset-form.html

@@ -2,7 +2,7 @@
 {% load i18n %}
 
 {% block intro %}
-  <p>
+  <p class="form__intro">
     {% blocktrans %}
     Forgot your password? Enter your email in the form below and we'll send you
     instructions for creating a new one.