diff --git a/flying-saucer-core/src/main/java/org/xhtmlrenderer/css/style/derived/BorderPropertySet.java b/flying-saucer-core/src/main/java/org/xhtmlrenderer/css/style/derived/BorderPropertySet.java
index c4defe2f8..7c6b2f415 100644
--- a/flying-saucer-core/src/main/java/org/xhtmlrenderer/css/style/derived/BorderPropertySet.java
+++ b/flying-saucer-core/src/main/java/org/xhtmlrenderer/css/style/derived/BorderPropertySet.java
@@ -1,5 +1,6 @@
 package org.xhtmlrenderer.css.style.derived;
 
+import com.google.errorprone.annotations.CheckReturnValue;
 import com.google.errorprone.annotations.InlineMe;
 import org.jspecify.annotations.Nullable;
 import org.xhtmlrenderer.css.constants.CSSName;
@@ -38,11 +39,11 @@
  */
 public class BorderPropertySet extends RectPropertySet {
     private static final Corners NO_CORNERS = new Corners(BorderRadiusCorner.UNDEFINED, BorderRadiusCorner.UNDEFINED, BorderRadiusCorner.UNDEFINED, BorderRadiusCorner.UNDEFINED);
-    private static final Styles NO_STYLES = new Styles(HIDDEN, HIDDEN, HIDDEN, HIDDEN);
+    private static final Styles NO_STYLES = new Styles(null, null, null, null);
     private static final Colors NO_COLORS = new Colors(TRANSPARENT, TRANSPARENT, TRANSPARENT, TRANSPARENT);
     public static final BorderPropertySet EMPTY_BORDER = new BorderPropertySet(0.0f, 0.0f, 0.0f, 0.0f, NO_STYLES, NO_CORNERS, NO_COLORS);
 
-    private record Styles(IdentValue top, IdentValue right, IdentValue bottom, IdentValue left) {
+    private record Styles(@Nullable IdentValue top, @Nullable IdentValue right, @Nullable IdentValue bottom, @Nullable IdentValue left) {
         private boolean hasHidden() {
             return top == HIDDEN || right == HIDDEN || bottom == HIDDEN || left == HIDDEN;
         }
@@ -211,18 +212,26 @@ public boolean noLeft() {
         return styles.left() == NONE || (int) left() == 0;
     }
 
+    @Nullable
+    @CheckReturnValue
     public IdentValue topStyle() {
         return styles.top();
     }
 
+    @Nullable
+    @CheckReturnValue
     public IdentValue rightStyle() {
         return styles.right();
     }
 
+    @Nullable
+    @CheckReturnValue
     public IdentValue bottomStyle() {
         return styles.bottom();
     }
 
+    @Nullable
+    @CheckReturnValue
     public IdentValue leftStyle() {
         return styles.left();
     }
diff --git a/flying-saucer-core/src/main/java/org/xhtmlrenderer/newtable/CollapsedBorderValue.java b/flying-saucer-core/src/main/java/org/xhtmlrenderer/newtable/CollapsedBorderValue.java
index 6e8b02ac6..55b22864a 100644
--- a/flying-saucer-core/src/main/java/org/xhtmlrenderer/newtable/CollapsedBorderValue.java
+++ b/flying-saucer-core/src/main/java/org/xhtmlrenderer/newtable/CollapsedBorderValue.java
@@ -19,23 +19,26 @@
  */
 package org.xhtmlrenderer.newtable;
 
+import com.google.errorprone.annotations.CheckReturnValue;
+import org.jspecify.annotations.Nullable;
 import org.xhtmlrenderer.css.constants.IdentValue;
 import org.xhtmlrenderer.css.parser.FSColor;
 import org.xhtmlrenderer.css.style.derived.BorderPropertySet;
 
 /**
  * This class encapsulates all information related to a particular border side
- * along with an overall precedence (e.g. cell borders take precendence over
+ * along with an overall precedence (e.g. cell borders take precedence over
  * row borders).  It is used when comparing overlapping borders when calculating
  * collapsed borders.
  */
 public class CollapsedBorderValue {
+    @Nullable
     private final IdentValue _style;
     private final int _width;
     private final FSColor _color;
     private final int _precedence;
 
-    public CollapsedBorderValue(IdentValue style, int width, FSColor color, int precedence) {
+    public CollapsedBorderValue(@Nullable IdentValue style, int width, FSColor color, int precedence) {
         _style = style;
         _width = width;
         _color = color;
@@ -46,49 +49,61 @@ public FSColor color() {
         return _color;
     }
 
+    @Nullable
+    @CheckReturnValue
     public IdentValue style() {
         return _style;
     }
 
+    @CheckReturnValue
     public int width() {
         return _width;
     }
 
+    @CheckReturnValue
     public CollapsedBorderValue withWidth(int width) {
         return new CollapsedBorderValue(_style, width, _color, _precedence);
     }
 
+    @CheckReturnValue
     public int precedence() {
         return _precedence;
     }
 
+    @CheckReturnValue
     public boolean defined() {
         return _style != null;
     }
 
+    @CheckReturnValue
     public boolean exists() {
         return _style != null && _style != IdentValue.NONE && _style != IdentValue.HIDDEN;
     }
 
+    @CheckReturnValue
     public boolean hidden() {
         return _style == IdentValue.HIDDEN;
     }
 
+    @CheckReturnValue
     public static CollapsedBorderValue borderLeft(BorderPropertySet border, int precedence) {
         return new CollapsedBorderValue(
                 border.leftStyle(), (int)border.left(), border.leftColor(), precedence);
     }
 
+    @CheckReturnValue
     public static CollapsedBorderValue borderRight(BorderPropertySet border, int precedence) {
         return new CollapsedBorderValue(
                 border.rightStyle(), (int)border.right(), border.rightColor(), precedence);
     }
 
+    @CheckReturnValue
     public static CollapsedBorderValue borderTop(BorderPropertySet border, int precedence) {
         return new CollapsedBorderValue(
                 border.topStyle(), (int)border.top(), border.topColor(), precedence);
     }
 
+    @CheckReturnValue
     public static CollapsedBorderValue borderBottom(BorderPropertySet border, int precedence) {
         return new CollapsedBorderValue(
                 border.bottomStyle(), (int)border.bottom(), border.bottomColor(), precedence);