Add title padding

d2layouts/d2sequence/layout.go

@@ -41,6 +41,7 @@ func Layout(ctx context.Context, g *d2graph.Graph, layout func(ctx context.Conte
 		obj.Children = make(map[string]*d2graph.Object)
 		obj.ChildrenArray = nil
 		obj.Box = geo.NewBox(nil, sd.getWidth(), sd.getHeight())
+		obj.LabelPosition = go2.Pointer(string(label.InsideTopCenter))
 		sequenceDiagrams[obj.AbsID()] = sd
 
 		for _, edge := range sd.messages {

d2layouts/d2sequence/sequence_diagram.go

@@ -89,8 +89,11 @@ func newSequenceDiagram(actors []*d2graph.Object, messages []*d2graph.Edge) *seq
 		sd.actorXStep = math.Max(sd.actorXStep, distributedLabelWidth+HORIZONTAL_PAD)
 	}
 
-	sd.maxActorHeight += VERTICAL_PAD
 	sd.messageYStep += VERTICAL_PAD
+	sd.maxActorHeight += VERTICAL_PAD
+	if sd.root.LabelHeight != nil {
+		sd.maxActorHeight += float64(*sd.root.LabelHeight)
+	}
 
 	return sd
 }