refactor(ui): app-wide compact, translucent tooltips

Add material::Tooltip / BeginTooltip / EndTooltip wrappers (tooltip_style.h)
that scope a small window padding (8x4, dpi-scaled) and ~85% opacity to
tooltips only, then route the tooltip call sites through them. Menus and combo
dropdowns are untouched (they keep the global opaque PopupBg).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/ui/material/components/buttons.h

@@ -7,6 +7,7 @@
 #include "../colors.h"
 #include "../typography.h"
 #include "../layout.h"
+#include "../tooltip_style.h"
 #include "imgui.h"
 #include "imgui_internal.h"
 
@@ -271,7 +272,7 @@ inline bool IconButton(const char* icon, const char* tooltip, bool enabled) {
     
     // Tooltip
     if (tooltip && hovered) {
-        ImGui::SetTooltip("%s", tooltip);
+        material::Tooltip("%s", tooltip);
     }
     
     return pressed && enabled;

src/ui/material/draw_helpers.h

@@ -6,6 +6,7 @@
 
 #include "colors.h"
 #include "type.h"
+#include "tooltip_style.h"
 #include "../layout.h"
 #include "../schema/element_styles.h"
 #include "../schema/color_var_resolver.h"

src/ui/material/tooltip_style.h

@@ -0,0 +1,66 @@
+// DragonX Wallet - ImGui Edition
+// Copyright 2024-2026 The Hush Developers
+// Released under the GPLv3
+//
+// App-wide tooltip styling: a compact (small padding) and slightly-translucent tooltip. ImGui has
+// no tooltip-specific padding (tooltips inherit WindowPadding, shared with every window) and PopupBg
+// is shared with menus/combos, so we can't restyle tooltips via the global style without side
+// effects. Instead, every tooltip goes through these wrappers, which scope the style to the tooltip:
+//   dragonx::ui::material::Tooltip("fmt", ...);            // replaces ImGui::SetTooltip
+//   if (material::BeginTooltip()) { ...; material::EndTooltip(); }  // replaces ImGui::Begin/EndTooltip
+
+#pragma once
+
+#include <cstdarg>
+
+#include "imgui.h"
+#include "../layout.h"
+
+namespace dragonx {
+namespace ui {
+namespace material {
+
+// Scope tooltip-only styling: small padding + a slightly-transparent background.
+inline void PushTooltipStyle()
+{
+    const float s = Layout::dpiScale();
+    ImGui::PushStyleVar(ImGuiStyleVar_WindowPadding, ImVec2(8.0f * s, 4.0f * s));
+    ImVec4 bg = ImGui::GetStyle().Colors[ImGuiCol_PopupBg];
+    bg.w = 0.85f;  // slightly transparent (the global PopupBg is ~0.98 opaque)
+    ImGui::PushStyleColor(ImGuiCol_PopupBg, bg);
+}
+
+inline void PopTooltipStyle()
+{
+    ImGui::PopStyleColor();
+    ImGui::PopStyleVar();
+}
+
+// Drop-in replacement for ImGui::SetTooltip (same printf-style signature). (No IM_FMTARGS: GCC
+// rejects the format attribute on an inline definition; call sites already passed SetTooltip's check.)
+inline void Tooltip(const char* fmt, ...)
+{
+    PushTooltipStyle();
+    va_list args;
+    va_start(args, fmt);
+    ImGui::SetTooltipV(fmt, args);
+    va_end(args);
+    PopTooltipStyle();
+}
+
+// Drop-in replacements for ImGui::BeginTooltip / ImGui::EndTooltip (must be paired, as before).
+inline bool BeginTooltip()
+{
+    PushTooltipStyle();
+    return ImGui::BeginTooltip();
+}
+
+inline void EndTooltip()
+{
+    ImGui::EndTooltip();
+    PopTooltipStyle();
+}
+
+} // namespace material
+} // namespace ui
+} // namespace dragonx