diff --git a/HellionChat/Ui/StyleEngine/Widgets/SectionHeader.cs b/HellionChat/Ui/StyleEngine/Widgets/SectionHeader.cs
new file mode 100644
index 0000000..3aac2b6
--- /dev/null
+++ b/HellionChat/Ui/StyleEngine/Widgets/SectionHeader.cs
@@ -0,0 +1,156 @@
+using System.Numerics;
+using Dalamud.Bindings.ImGui;
+using HellionChat.Util;
+
+namespace HellionChat.Ui.StyleEngine.Widgets;
+
+internal readonly record struct SectionHeaderColors
+{
+    public SectionHeaderColors() { }
+
+    public uint TitleAbgr { get; init; }
+    public uint DescriptionAbgr { get; init; }
+    public uint AccentAbgr { get; init; }
+    public uint BorderAbgr { get; init; }
+    public uint HoverAbgr { get; init; }
+}
+
+internal readonly record struct SectionHeaderStyle
+{
+    public SectionHeaderStyle() { }
+
+    public float PadY { get; init; } = 6f;
+    public float AccentBarWidth { get; init; } = 2f;
+    public float ChevronInset { get; init; } = 6f;
+}
+
+// Collapsible section heading. Replaces ImGui.CollapsingHeader, whose framed
+// bar is the single most ImGui-looking element in the settings window.
+//
+// State lives here rather than in ImGui's per-window storage: that keys off the
+// label, so once the titles are localised the open/closed state would reset on
+// every language switch and translated titles could collide. Callers pass a
+// stable key instead, built from an ASCII literal that never gets translated.
+internal static class SectionHeader
+{
+    private static readonly Dictionary<uint, bool> Open = [];
+
+    internal static void Reset() => Open.Clear();
+
+    internal static bool Draw(
+        uint key,
+        string title,
+        string? description,
+        SectionHeaderColors colors,
+        bool defaultOpen = false,
+        bool disabled = false,
+        SectionHeaderStyle? styleOverride = null
+    )
+    {
+        var style = styleOverride ?? new SectionHeaderStyle();
+        var scale = Metrics.Scale;
+        var padY = style.PadY * scale;
+
+        if (!Open.TryGetValue(key, out var open))
+        {
+            open = defaultOpen;
+            Open[key] = open;
+        }
+
+        var origin = ImGui.GetCursorScreenPos();
+        var width = ImGui.GetContentRegionAvail().X;
+        var titleHeight = ImGui.GetTextLineHeight();
+        var descHeight = description is null ? 0f : titleHeight;
+        var size = WidgetGeometry.SectionHeader(width, titleHeight, descHeight, padY, 1f * scale);
+
+        ImGui.SetCursorScreenPos(origin);
+        var clicked = ImGui.InvisibleButton($"##hellion-section-{key}", size) && !disabled;
+        var hovered = ImGui.IsItemHovered() && !disabled;
+        var hoverAmount = HoverState.Query(key, hovered);
+
+        if (clicked)
+        {
+            open = !open;
+            Open[key] = open;
+        }
+
+        // BeginDisabled only dims ImGui's own widgets, so a draw-list header
+        // would stay at full opacity while everything around it fades. The
+        // ThemePicker wraps two of its headers exactly like that.
+        var alpha = disabled ? 0.5f : 1f;
+        var dl = ImGui.GetWindowDrawList();
+        var max = origin + size;
+
+        if (hoverAmount > 0f)
+            dl.AddRectFilled(
+                origin,
+                max,
+                ColourUtil.ApplyAlpha(colors.HoverAbgr, hoverAmount * alpha)
+            );
+
+        var barWidth = style.AccentBarWidth * scale;
+        dl.AddRectFilled(
+            origin,
+            new Vector2(origin.X + barWidth, origin.Y + titleHeight + padY * 2f),
+            ColourUtil.ApplyAlpha(colors.AccentAbgr, alpha)
+        );
+
+        var textX = origin.X + barWidth + style.ChevronInset * scale * 2f;
+        dl.AddText(
+            new Vector2(textX, origin.Y + padY),
+            ColourUtil.ApplyAlpha(colors.TitleAbgr, alpha),
+            title
+        );
+
+        DrawChevron(
+            dl,
+            new Vector2(
+                origin.X + barWidth + style.ChevronInset * scale,
+                origin.Y + padY + titleHeight * 0.5f
+            ),
+            titleHeight * 0.28f,
+            open,
+            ColourUtil.ApplyAlpha(colors.TitleAbgr, alpha)
+        );
+
+        if (description is not null)
+            dl.AddText(
+                ImGui.GetFont(),
+                ImGui.GetFontSize(),
+                new Vector2(textX, origin.Y + padY + titleHeight),
+                ColourUtil.ApplyAlpha(colors.DescriptionAbgr, alpha),
+                description,
+                width - (textX - origin.X)
+            );
+
+        dl.AddLine(
+            new Vector2(origin.X, max.Y - 1f * scale),
+            new Vector2(max.X, max.Y - 1f * scale),
+            ColourUtil.ApplyAlpha(colors.BorderAbgr, alpha),
+            1f * scale
+        );
+
+        ImGui.SetCursorScreenPos(origin);
+        ImGuiP.ItemSize(new Vector2(width, size.Y - ImGui.GetStyle().ItemSpacing.Y));
+
+        return open;
+    }
+
+    private static void DrawChevron(ImDrawListPtr dl, Vector2 centre, float r, bool open, uint abgr)
+    {
+        if (open)
+            dl.AddTriangleFilled(
+                centre + new Vector2(-r, -r * 0.5f),
+                centre + new Vector2(r, -r * 0.5f),
+                centre + new Vector2(0f, r * 0.7f),
+                abgr
+            );
+        else
+            dl.AddTriangleFilled(
+                centre + new Vector2(-r * 0.5f, -r),
+                centre + new Vector2(r * 0.7f, 0f),
+                centre + new Vector2(-r * 0.5f, r),
+                abgr
+            );
+    }
+}
diff --git a/HellionChat/Ui/Windows/WidgetGalleryWindow.cs b/HellionChat/Ui/Windows/WidgetGalleryWindow.cs
index 3e3a143..227ed6a 100644
--- a/HellionChat/Ui/Windows/WidgetGalleryWindow.cs
+++ b/HellionChat/Ui/Windows/WidgetGalleryWindow.cs
@@ -45,6 +45,7 @@ internal sealed class WidgetGalleryWindow : Window
         );
         ImGui.Separator();
 
+        DrawSectionHeaderSection(c);
         DrawRowSection(c);
         DrawToggleSection(c);
         DrawSettingRowSection(c);
@@ -101,6 +102,54 @@ internal sealed class WidgetGalleryWindow : Window
         ImGui.Spacing();
     }
 
+    private void DrawSectionHeaderSection(ThemeColors c)
+    {
+        var colors = new SectionHeaderColors
+        {
+            TitleAbgr = _palette.Abgr(Token.Text, c),
+            DescriptionAbgr = _palette.Abgr(Token.TextMuted, c),
+            AccentAbgr = _palette.Abgr(Token.AccentPrimary, c),
+            BorderAbgr = _palette.Abgr(Token.Border, c),
+            HoverAbgr = _palette.Abgr(Token.SurfaceHover, c),
+        };
+
+        if (
+            SectionHeader.Draw(
+                ImGui.GetID("gallery.section.open"u8),
+                "Open by default",
+                null,
+                colors,
+                defaultOpen: true
+            )
+        )
+            ImGui.TextDisabled("  content of the open section");
+
+        if (
+            SectionHeader.Draw(
+                ImGui.GetID("gallery.section.described"u8),
+                "With a description",
+                "Explains what the section groups, wrapped to the available width.",
+                colors
+            )
+        )
+            ImGui.TextDisabled("  content of the described section");
+
+        // Disabled: BeginDisabled only dims ImGui's own widgets, so a draw-list
+        // header has to fade itself.
+        using (ImRaii.Disabled())
+        {
+            SectionHeader.Draw(
+                ImGui.GetID("gallery.section.disabled"u8),
+                "Disabled",
+                null,
+                colors,
+                disabled: true
+            );
+        }
+
+        ImGui.Spacing();
+    }
+
     private void DrawToggleSection(ThemeColors c)
     {
         ImGui.TextUnformatted("Toggle");