Front-page looks like it did in my head :)

app/assets/stylesheets/application.scss

@@ -37,3 +37,11 @@ a {
 .buttons {
   padding-top: $padding-large-vertical;
 }
+
+caption {
+  font-size: 1.5em;
+}
+
+.filler {
+  background-image: image-url('confectionary.png');
+}

app/controllers/welcome_controller.rb

@@ -1,12 +1,21 @@
 class WelcomeController < ApplicationController
   def index
+    @hours = 36
     @metrics = []
     [
       GlucoseMeasurement,
       CarbohydrateIntake,
       MedicationEvent
     ].each do |model|
-      @metrics.concat model.where(datetime: (Time.now - 48.hours)..Time.now)
+      @metrics.concat model.where(datetime: (Time.now - @hours.hours)..Time.now)
     end
+
+    @widest = widest @metrics
+  end
+
+  private
+
+  def widest metrics
+    metrics.map { |m| m.class }.uniq.map { |u| u.fields.count }.max
   end
 end

app/views/welcome/index.html.erb

@@ -6,9 +6,13 @@
 </div>
 
 <table class='table table-bordered table-striped'>
+  <caption>
+    Last <%= @hours %> hours
+  </caption>
+
   <% date_sift(@metrics).each_pair do |day, values| %>
     <tr>
-      <th colspan=64>
+      <th colspan='<%= @widest + 2 %>'>
         <% date = Time.parse(day) %>
         <%= date.strftime "%A %B #{date.day.ordinalize}" %>
       </th>
@@ -22,10 +26,15 @@
         <td>
           <%= class_name(value).short_name %>
         </td>
+        <% count = 0 %>
         <% class_name(value).fields.each do |field| %>
           <td class='<%= "#{value.class.name.underscore.gsub('_', '-')}-#{field}" %>'>
             <%= value.send(field) %>
           </td>
+          <% count += 1 %>
+        <% end %>
+        <% (@widest - count).times do %>
+          <td class='filler'></td>
         <% end %>
       </tr>
     <% end %>

spec/controllers/welcome_controller_spec.rb

@@ -1,5 +1,13 @@
-require 'rails_helper'
-
-RSpec.describe WelcomeController, type: :controller do
-
+describe WelcomeController, type: :controller do
+  let(:metrics) {
+    [
+      create(:glucose_measurement),
+      create(:medication_event),
+      create(:carbohydrate_intake),
+      create(:physical_exercise)
+    ]
+  }
+  it 'knows which metric has the most fields' do
+    expect(described_class.new.send(:widest, metrics)).to eq 2
+  end
 end