event-editor-dialog: Better style sections

This gives them rounded corners and separators.

src/gui/event-editor/gcal-notes-section.ui

@@ -2,6 +2,10 @@
 <interface>
   <template class="GcalNotesSection" parent="GtkBin">
     <property name="can_focus">False</property>
+    <style>
+      <class name="notes-section" />
+    </style>
+
 
     <child>
       <object class="GtkBox">

src/gui/event-editor/gcal-reminders-section.ui

@@ -4,10 +4,6 @@
     <property name="can_focus">False</property>
     <property name="orientation">vertical</property>
 
-    <style>
-      <class name="frame" />
-    </style>
-
     <child>
       <object class="GtkListBox" id="alarms_listbox">
         <property name="visible">True</property>
@@ -15,6 +11,10 @@
         <property name="selection_mode">none</property>
         <signal name="row-activated" handler="on_alarms_listbox_row_activated_cb" object="GcalRemindersSection" swapped="no" />
 
+        <style>
+          <class name="content" />
+        </style>
+
         <child>
           <object class="GtkListBoxRow" id="new_alarm_row">
             <property name="visible">True</property>

src/gui/event-editor/gcal-schedule-section.ui

@@ -10,7 +10,7 @@
         <property name="selection-mode">none</property>
 
         <style>
-          <class name="frame" />
+          <class name="content" />
         </style>
 
         <!-- All Day -->

src/gui/event-editor/gcal-summary-section.ui

@@ -9,7 +9,7 @@
         <property name="selection-mode">none</property>
 
         <style>
-          <class name="frame" />
+          <class name="content" />
         </style>
 
         <!-- Summary -->

src/theme/Adwaita.css

@@ -498,3 +498,18 @@ monthpopover > box {
   padding: 12px;
   background: @theme_bg_color;
 }
+
+.notes-section .frame {
+  border-radius: 8px;
+  -gtk-outline-radius: 7px;
+  border-color: alpha(@borders, 0.7);
+}
+
+.notes-section .frame > textview.view {
+  border-radius: 8px;
+  padding: 8px;
+}
+
+.notes-section .frame > textview.view > text {
+  background: none;
+}