diff --git a/lib/promrelabel/debug.qtpl b/lib/promrelabel/debug.qtpl
index 0b612a165..ba50ed85d 100644
--- a/lib/promrelabel/debug.qtpl
+++ b/lib/promrelabel/debug.qtpl
@@ -73,12 +73,12 @@ function submitRelabelDebugForm(e) {
 {% func relabelDebugFormInputs(metric, relabelConfigs string) %}
     <div>
         Relabel configs:<br/>
-        <textarea name="relabel_configs" style="width: 100%; height: 15em" class="m-1">{%s relabelConfigs %}</textarea>
+        <textarea name="relabel_configs" style="width: 100%; height: 15em; font-family: monospace" class="m-1">{%s relabelConfigs %}</textarea>
     </div>
 
     <div>
         Labels:<br/>
-        <textarea name="metric" style="width: 100%; height: 5em" class="m-1">{%s metric %}</textarea>
+        <textarea name="metric" style="width: 100%; height: 5em; font-family: monospace" class="m-1">{%s metric %}</textarea>
     </div>
 {% endfunc %}
 
diff --git a/lib/promrelabel/debug.qtpl.go b/lib/promrelabel/debug.qtpl.go
index 40f29ec89..7219027c7 100644
--- a/lib/promrelabel/debug.qtpl.go
+++ b/lib/promrelabel/debug.qtpl.go
@@ -181,11 +181,11 @@ func RelabelDebugStepsHTML(targetURL, targetID string, dss []DebugStep, metric,
 //line lib/promrelabel/debug.qtpl:73
 func streamrelabelDebugFormInputs(qw422016 *qt422016.Writer, metric, relabelConfigs string) {
 //line lib/promrelabel/debug.qtpl:73
-	qw422016.N().S(`<div>Relabel configs:<br/><textarea name="relabel_configs" style="width: 100%; height: 15em" class="m-1">`)
+	qw422016.N().S(`<div>Relabel configs:<br/><textarea name="relabel_configs" style="width: 100%; height: 15em; font-family: monospace" class="m-1">`)
 //line lib/promrelabel/debug.qtpl:76
 	qw422016.E().S(relabelConfigs)
 //line lib/promrelabel/debug.qtpl:76
-	qw422016.N().S(`</textarea></div><div>Labels:<br/><textarea name="metric" style="width: 100%; height: 5em" class="m-1">`)
+	qw422016.N().S(`</textarea></div><div>Labels:<br/><textarea name="metric" style="width: 100%; height: 5em; font-family: monospace" class="m-1">`)
 //line lib/promrelabel/debug.qtpl:81
 	qw422016.E().S(metric)
 //line lib/promrelabel/debug.qtpl:81