First attempt

Not great - text overruns the boxes unless a limited height is set, but
varying heights of headers leads to uneven lengths of content.

blog/layouts/_default/terms.html

@@ -13,9 +13,11 @@
             {{ $.Data.Singular | humanize }}: {{ $key }}
           </a>
         </h2>
+        <div class="clearfix w-100">
         {{ range $value.Pages }}
-          {{ partial "summary.html" . }}
+          {{ partial "tag-summary.html" . }}
         {{ end }}
+        </div>
       {{ end }}
     </section>
   </div>

blog/layouts/partials/tag-summary.html

@@ -0,0 +1,17 @@
+{{/*
+    I don't want to _fully_ override the "summary.html" partial that exists in the theme, in case it's used anywhere else -
+    but this different summary allows me to make the summaries of articles in the tags page a bit more compact.
+*/}}
+<div class="relative w-30 mb4 bg-white nested-copy-line-height" style="float:left; margin-right: 5px; height: 250px;">
+    <div class="bg-white mb3 pa4 gray overflow-hidden;" style="height:250px;">
+    <span class="f6 db">{{ humanize .Section }}</span>
+    <h1 class="f3 near-black">
+        <a href="{{ .RelPermalink }}" class="link black dim">
+        {{ .Title }}
+        </a>
+    </h1>
+    <div class="nested-links f5 lh-copy nested-copy-line-height restrict-inner-p-to-250" style="height:250px">
+        {{ .Summary  }}
+    </div>
+    </div>
+</div>

blog/static/css/custom.css

@@ -72,3 +72,19 @@ figcaption {
     border-bottom: 2px solid #009879;
 }
 
+.clearfix::after {
+  content: "";
+  clear: both;
+  display: table;
+}
+
+/**
+ Hacky hack hack...but I can't find where the `<p>` inside the Summary is created
+
+ Unforunately, setting a static height doesn't work, because if the header of the summary runs to two lines then this pushes
+ the `<p>` down further.
+ */
+.restrict-inner-p-to-250 > p {
+  height: 96px;
+  overflow: hidden;
+}