--- a/layout/generic/nsContainerFrame.cpp
+++ b/layout/generic/nsContainerFrame.cpp
@@ -1778,25 +1778,25 @@ nsContainerFrame::PullNextInFlowChild(Co
     nsContainerFrame::ReparentFrameView(frame, nextInFlow, this);
   }
   return frame;
 }
 
 bool
 nsContainerFrame::ResolvedOrientationIsVertical()
 {
-  uint8_t orient = StyleDisplay()->mOrient;
+  StyleOrient orient = StyleDisplay()->mOrient;
   switch (orient) {
-    case NS_STYLE_ORIENT_HORIZONTAL:
+    case StyleOrient::Horizontal:
       return false;
-    case NS_STYLE_ORIENT_VERTICAL:
+    case StyleOrient::Vertical:
       return true;
-    case NS_STYLE_ORIENT_INLINE:
+    case StyleOrient::Inline:
       return GetWritingMode().IsVertical();
-    case NS_STYLE_ORIENT_BLOCK:
+    case StyleOrient::Block:
       return !GetWritingMode().IsVertical();
   }
   NS_NOTREACHED("unexpected -moz-orient value");
   return false;
 }
 
 // static
 bool

--- a/layout/style/nsCSSProps.cpp
+++ b/layout/style/nsCSSProps.cpp
@@ -1781,20 +1781,20 @@ const KTableEntry nsCSSProps::kObjectFit
   { eCSSKeyword_contain,    NS_STYLE_OBJECT_FIT_CONTAIN },
   { eCSSKeyword_cover,      NS_STYLE_OBJECT_FIT_COVER },
   { eCSSKeyword_none,       NS_STYLE_OBJECT_FIT_NONE },
   { eCSSKeyword_scale_down, NS_STYLE_OBJECT_FIT_SCALE_DOWN },
   { eCSSKeyword_UNKNOWN,    -1 }
 };
 
 const KTableEntry nsCSSProps::kOrientKTable[] = {
-  { eCSSKeyword_inline,     NS_STYLE_ORIENT_INLINE },
-  { eCSSKeyword_block,      NS_STYLE_ORIENT_BLOCK },
-  { eCSSKeyword_horizontal, NS_STYLE_ORIENT_HORIZONTAL },
-  { eCSSKeyword_vertical,   NS_STYLE_ORIENT_VERTICAL },
+  { eCSSKeyword_inline,     StyleOrient::Inline },
+  { eCSSKeyword_block,      StyleOrient::Block },
+  { eCSSKeyword_horizontal, StyleOrient::Horizontal },
+  { eCSSKeyword_vertical,   StyleOrient::Vertical },
   { eCSSKeyword_UNKNOWN,    -1 }
 };
 
 // Same as kBorderStyleKTable except 'hidden'.
 const KTableEntry nsCSSProps::kOutlineStyleKTable[] = {
   { eCSSKeyword_none,   NS_STYLE_BORDER_STYLE_NONE },
   { eCSSKeyword_auto,   NS_STYLE_BORDER_STYLE_AUTO },
   { eCSSKeyword_dotted, NS_STYLE_BORDER_STYLE_DOTTED },

--- a/layout/style/nsRuleNode.cpp
+++ b/layout/style/nsRuleNode.cpp
@@ -1415,16 +1415,17 @@ struct SetEnumValueHelper
   DEFINE_ENUM_CLASS_SETTER(StyleFillRule, Nonzero, Evenodd)
   DEFINE_ENUM_CLASS_SETTER(StyleFloat, None, InlineEnd)
   DEFINE_ENUM_CLASS_SETTER(StyleFloatEdge, ContentBox, MarginBox)
   DEFINE_ENUM_CLASS_SETTER(StyleUserFocus, None, SelectMenu)
   DEFINE_ENUM_CLASS_SETTER(StyleUserSelect, None, MozText)
   DEFINE_ENUM_CLASS_SETTER(StyleUserInput, None, Auto)
   DEFINE_ENUM_CLASS_SETTER(StyleUserModify, ReadOnly, WriteOnly)
   DEFINE_ENUM_CLASS_SETTER(StyleWindowDragging, Default, NoDrag)
+  DEFINE_ENUM_CLASS_SETTER(StyleOrient, Inline, Vertical)
 #ifdef MOZ_XUL
   DEFINE_ENUM_CLASS_SETTER(StyleDisplay, None, Popup)
 #else
   DEFINE_ENUM_CLASS_SETTER(StyleDisplay, None, InlineBox)
 #endif
 
 #undef DEF_SET_ENUMERATED_VALUE
 };
@@ -6449,17 +6450,17 @@ nsRuleNode::ComputeDisplayData(void* aSt
            parentDisplay->mTransformBox,
            NS_STYLE_TRANSFORM_BOX_BORDER_BOX);
 
   // orient: enum, inherit, initial
   SetValue(*aRuleData->ValueForOrient(),
            display->mOrient, conditions,
            SETVAL_ENUMERATED | SETVAL_UNSET_INITIAL,
            parentDisplay->mOrient,
-           NS_STYLE_ORIENT_INLINE);
+           StyleOrient::Inline);
 
   // shape-outside: none | [ <basic-shape> || <shape-box> ] | <image>
   const nsCSSValue* shapeOutsideValue = aRuleData->ValueForShapeOutside();
   switch (shapeOutsideValue->GetUnit()) {
     case eCSSUnit_Null:
       break;
     case eCSSUnit_None:
     case eCSSUnit_Initial:

--- a/layout/style/nsStyleConsts.h
+++ b/layout/style/nsStyleConsts.h
@@ -229,20 +229,22 @@ enum class StyleUserModify : uint8_t {
 // -moz-window-dragging
 enum class StyleWindowDragging : uint8_t {
   Default,
   Drag,
   NoDrag,
 };
 
 // orient
-#define NS_STYLE_ORIENT_INLINE     0
-#define NS_STYLE_ORIENT_BLOCK      1
-#define NS_STYLE_ORIENT_HORIZONTAL 2
-#define NS_STYLE_ORIENT_VERTICAL   3
+enum class StyleOrient : uint8_t {
+  Inline,
+  Block,
+  Horizontal,
+  Vertical,
+};
 
 #define NS_RADIUS_FARTHEST_SIDE 0
 #define NS_RADIUS_CLOSEST_SIDE  1
 
 // stack-sizing
 #define NS_STYLE_STACK_SIZING_IGNORE         0
 #define NS_STYLE_STACK_SIZING_STRETCH_TO_FIT 1
 

--- a/layout/style/nsStyleStruct.cpp
+++ b/layout/style/nsStyleStruct.cpp
@@ -3128,17 +3128,17 @@ nsStyleDisplay::nsStyleDisplay(StyleStru
   , mBreakType(StyleClear::None)
   , mBreakInside(NS_STYLE_PAGE_BREAK_AUTO)
   , mBreakBefore(false)
   , mBreakAfter(false)
   , mOverflowX(NS_STYLE_OVERFLOW_VISIBLE)
   , mOverflowY(NS_STYLE_OVERFLOW_VISIBLE)
   , mOverflowClipBox(NS_STYLE_OVERFLOW_CLIP_BOX_PADDING_BOX)
   , mResize(NS_STYLE_RESIZE_NONE)
-  , mOrient(NS_STYLE_ORIENT_INLINE)
+  , mOrient(StyleOrient::Inline)
   , mIsolation(NS_STYLE_ISOLATION_AUTO)
   , mTopLayer(NS_STYLE_TOP_LAYER_NONE)
   , mWillChangeBitField(0)
   , mTouchAction(NS_STYLE_TOUCH_ACTION_AUTO)
   , mScrollBehavior(NS_STYLE_SCROLL_BEHAVIOR_AUTO)
   , mScrollSnapTypeX(NS_STYLE_SCROLL_SNAP_TYPE_NONE)
   , mScrollSnapTypeY(NS_STYLE_SCROLL_SNAP_TYPE_NONE)
   , mScrollSnapPointsX(eStyleUnit_None)

--- a/layout/style/nsStyleStruct.h
+++ b/layout/style/nsStyleStruct.h
@@ -2815,17 +2815,17 @@ struct MOZ_NEEDS_MEMMOVABLE_MEMBERS nsSt
   mozilla::StyleClear mBreakType;  // [reset]
   uint8_t mBreakInside;         // [reset] NS_STYLE_PAGE_BREAK_AUTO/AVOID
   bool mBreakBefore;    // [reset]
   bool mBreakAfter;     // [reset]
   uint8_t mOverflowX;           // [reset] see nsStyleConsts.h
   uint8_t mOverflowY;           // [reset] see nsStyleConsts.h
   uint8_t mOverflowClipBox;     // [reset] see nsStyleConsts.h
   uint8_t mResize;              // [reset] see nsStyleConsts.h
-  uint8_t mOrient;              // [reset] see nsStyleConsts.h
+  mozilla::StyleOrient mOrient; // [reset] see nsStyleConsts.h
   uint8_t mIsolation;           // [reset] see nsStyleConsts.h
   uint8_t mTopLayer;            // [reset] see nsStyleConsts.h
   uint8_t mWillChangeBitField;  // [reset] see nsStyleConsts.h. Stores a
                                 // bitfield representation of the properties
                                 // that are frequently queried. This should
                                 // match mWillChange. Also tracks if any of the
                                 // properties in the will-change list require
                                 // a stacking context.

--- a/widget/nsNativeTheme.cpp
+++ b/widget/nsNativeTheme.cpp
@@ -559,23 +559,23 @@ nsNativeTheme::IsVerticalProgress(nsIFra
   return IsVerticalMeter(aFrame);
 }
 
 bool
 nsNativeTheme::IsVerticalMeter(nsIFrame* aFrame)
 {
   NS_PRECONDITION(aFrame, "You have to pass a non-null aFrame");
   switch (aFrame->StyleDisplay()->mOrient) {
-    case NS_STYLE_ORIENT_HORIZONTAL:
+    case StyleOrient::Horizontal:
       return false;
-    case NS_STYLE_ORIENT_VERTICAL:
+    case StyleOrient::Vertical:
       return true;
-    case NS_STYLE_ORIENT_INLINE:
+    case StyleOrient::Inline:
       return aFrame->GetWritingMode().IsVertical();
-    case NS_STYLE_ORIENT_BLOCK:
+    case StyleOrient::Block:
       return !aFrame->GetWritingMode().IsVertical();
   }
   NS_NOTREACHED("unexpected -moz-orient value");
   return false;
 }
 
 // menupopup:
 bool