--- a/layout/generic/nsGridContainerFrame.cpp
+++ b/layout/generic/nsGridContainerFrame.cpp
@@ -1315,17 +1315,18 @@ class MOZ_STACK_CLASS nsGridContainerFra
       mRepeatAutoEnd = mRepeatAutoStart;
       const auto& styleSubgrid = aTracks.mTemplate.AsSubgrid();
       mHasRepeatAuto =
           styleSubgrid->fill_idx != std::numeric_limits<size_t>::max();
       if (mHasRepeatAuto) {
         const auto& lineNameLists = styleSubgrid->names;
         int32_t extraAutoFillLineCount = mClampMaxLine - lineNameLists.Length();
         mRepeatAutoStart = styleSubgrid->fill_idx;
-        mRepeatAutoEnd = mRepeatAutoStart + extraAutoFillLineCount + 1;
+        mRepeatAutoEnd =
+            mRepeatAutoStart + std::max(0, extraAutoFillLineCount + 1);
       }
     } else {
       mClampMinLine = kMinLine;
       mClampMaxLine = kMaxLine;
       if (mHasRepeatAuto) {
         mTrackAutoRepeatLineNames =
             aTracks.mTemplate.GetRepeatAutoValue()->line_names.AsSpan();
       }

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-001-ref.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-001-ref.html
@@ -158,16 +158,55 @@ html,body {
   <div style="grid-column:4"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
 </div></div>
 
+<div class="grid"><div class="subgrid fill-0k">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0l">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0m">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
 <div class="grid"><div class="subgrid fill-1a">
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-001.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-001.html
@@ -32,16 +32,19 @@ html,body {
 .fill-0c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [x] [z] [z] [z] */
 .fill-0d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [z] [z] */
 .fill-0e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [z] */
 .fill-0f  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 .fill-0g  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0h  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0i  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0j  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
+.fill-0k  { grid-template-columns: subgrid repeat(auto-fill, [y]) repeat(100, [z]) }  /* [z] [z] [z] [z] [z] */
+.fill-0l  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) repeat(100, [z]) }  /* [x] [z] [z] [z] [z] */
+.fill-0m  { grid-template-columns: subgrid  repeat(100, [x]) repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 
 .fill-1a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] [z] }  /* [y] [z] [z] [z] [z] */
 .fill-1b  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [y] [z] [z] [z] */
 .fill-1c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [y] [z] [z] */
 .fill-1d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [y] [z] */
 .fill-1e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [y] */
 
 .fill-2a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] }  /* [y] [y] [z] [z] [z] */
@@ -190,16 +193,55 @@ html,body {
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>
   <div style="grid-column:y -3"></div>
   <div style="grid-column:y -4"></div>
   <div style="grid-column:y -5"></div>
 </div></div>
 
+<div class="grid"><div class="subgrid fill-0k">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0l">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0m">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div>
+
 <div class="grid"><div class="subgrid fill-1a">
   <div style="grid-column:y 5"></div>
   <div style="grid-column:y 4"></div>
   <div style="grid-column:y 3"></div>
   <div style="grid-column:y 2"></div>
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>
@@ -397,16 +439,19 @@ html,body {
     "subgrid [x] [x] [z] [z] [z]",
     "subgrid [x] [x] [x] [z] [z]",
     "subgrid [x] [x] [x] [x] [z]",
     "subgrid [x] [x] [x] [x] [x]",
     "subgrid [x] [x] [x] [x] [x]",
     "subgrid [x] [x] [x] [x] [x]",
     "subgrid [x] [x] [x] [x] [x]",
     "subgrid [x] [x] [x] [x] [x]",
+    "subgrid [z] [z] [z] [z] [z]",
+    "subgrid [x] [z] [z] [z] [z]",
+    "subgrid [x] [x] [x] [x] [x]",
     "subgrid [y] [z] [z] [z] [z]",
     "subgrid [x] [y] [z] [z] [z]",
     "subgrid [x] [x] [y] [z] [z]",
     "subgrid [x] [x] [x] [y] [z]",
     "subgrid [x] [x] [x] [x] [y]",
     "subgrid [y] [y] [z] [z] [z]",
     "subgrid [x] [y] [y] [z] [z]",
     "subgrid [x] [x] [y] [y] [z]",

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-002.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-002.html
@@ -35,16 +35,19 @@ html,body {
 .fill-0c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [x] [z] [z] [z] */
 .fill-0d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [z] [z] */
 .fill-0e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [z] */
 .fill-0f  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 .fill-0g  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0h  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0i  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0j  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
+.fill-0k  { grid-template-columns: subgrid repeat(auto-fill, [y]) repeat(100, [z]) }  /* [z] [z] [z] [z] [z] */
+.fill-0l  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) repeat(100, [z]) }  /* [x] [z] [z] [z] [z] */
+.fill-0m  { grid-template-columns: subgrid  repeat(100, [x]) repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 
 .fill-1a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] [z] }  /* [y] [z] [z] [z] [z] */
 .fill-1b  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [y] [z] [z] [z] */
 .fill-1c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [y] [z] [z] */
 .fill-1d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [y] [z] */
 .fill-1e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [y] */
 
 .fill-2a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] }  /* [y] [y] [z] [z] [z] */
@@ -193,16 +196,55 @@ html,body {
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>
   <div style="grid-column:y -3"></div>
   <div style="grid-column:y -4"></div>
   <div style="grid-column:y -5"></div>
 </div></div></div>
 
+<div class="grid"><div class="subgrid fill-0k"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0l"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0m"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
 <div class="grid"><div class="subgrid fill-1a"><div class="subgrid">
   <div style="grid-column:y 5"></div>
   <div style="grid-column:y 4"></div>
   <div style="grid-column:y 3"></div>
   <div style="grid-column:y 2"></div>
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-003.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-003.html
@@ -40,16 +40,19 @@ html,body {
 .fill-0c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [x] [z] [z] [z] */
 .fill-0d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [z] [z] */
 .fill-0e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [z] */
 .fill-0f  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 .fill-0g  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0h  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0i  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0j  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
+.fill-0k  { grid-template-columns: subgrid repeat(auto-fill, [y]) repeat(100, [z]) }  /* [z] [z] [z] [z] [z] */
+.fill-0l  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) repeat(100, [z]) }  /* [x] [z] [z] [z] [z] */
+.fill-0m  { grid-template-columns: subgrid  repeat(100, [x]) repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 
 .fill-1a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] [z] }  /* [y] [z] [z] [z] [z] */
 .fill-1b  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [y] [z] [z] [z] */
 .fill-1c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [y] [z] [z] */
 .fill-1d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [y] [z] */
 .fill-1e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [y] */
 
 .fill-2a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] }  /* [y] [y] [z] [z] [z] */
@@ -199,16 +202,55 @@ html,body {
   <div style="grid-row:y 1"></div>
   <div style="grid-row:y -1"></div>
   <div style="grid-row:y -2"></div>
   <div style="grid-row:y -3"></div>
   <div style="grid-row:y -4"></div>
   <div style="grid-row:y -5"></div>
 </div></div></div>
 
+<div class="grid"><div class="subgrid fill-0k"><div class="subgrid">
+  <div style="grid-row:y 5"></div>
+  <div style="grid-row:y 4"></div>
+  <div style="grid-row:y 3"></div>
+  <div style="grid-row:y 2"></div>
+  <div style="grid-row:y 1"></div>
+  <div style="grid-row:y -1"></div>
+  <div style="grid-row:y -2"></div>
+  <div style="grid-row:y -3"></div>
+  <div style="grid-row:y -4"></div>
+  <div style="grid-row:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0l"><div class="subgrid">
+  <div style="grid-row:y 5"></div>
+  <div style="grid-row:y 4"></div>
+  <div style="grid-row:y 3"></div>
+  <div style="grid-row:y 2"></div>
+  <div style="grid-row:y 1"></div>
+  <div style="grid-row:y -1"></div>
+  <div style="grid-row:y -2"></div>
+  <div style="grid-row:y -3"></div>
+  <div style="grid-row:y -4"></div>
+  <div style="grid-row:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0m"><div class="subgrid">
+  <div style="grid-row:y 5"></div>
+  <div style="grid-row:y 4"></div>
+  <div style="grid-row:y 3"></div>
+  <div style="grid-row:y 2"></div>
+  <div style="grid-row:y 1"></div>
+  <div style="grid-row:y -1"></div>
+  <div style="grid-row:y -2"></div>
+  <div style="grid-row:y -3"></div>
+  <div style="grid-row:y -4"></div>
+  <div style="grid-row:y -5"></div>
+</div></div></div>
+
 <div class="grid"><div class="subgrid fill-1a"><div class="subgrid">
   <div style="grid-row:y 5"></div>
   <div style="grid-row:y 4"></div>
   <div style="grid-row:y 3"></div>
   <div style="grid-row:y 2"></div>
   <div style="grid-row:y 1"></div>
   <div style="grid-row:y -1"></div>
   <div style="grid-row:y -2"></div>

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-004-ref.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-004-ref.html
@@ -158,16 +158,55 @@ html,body {
   <div style="grid-column:4"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
   <div style="grid-column:1"></div>
 </div></div>
 
+<div class="grid"><div class="subgrid fill-0k">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0l">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
+<div class="grid"><div class="subgrid fill-0m">
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:4"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+  <div style="grid-column:1"></div>
+</div></div>
+
 <div class="grid"><div class="subgrid fill-1a">
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:4"></div>
   <div style="grid-column:1"></div>

--- a/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-004.html
+++ b/testing/web-platform/tests/css/css-grid/subgrid/repeat-auto-fill-004.html
@@ -35,16 +35,19 @@ html,body {
 .fill-0c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [x] [z] [z] [z] */
 .fill-0d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [z] [z] */
 .fill-0e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [z] */
 .fill-0f  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 .fill-0g  { grid-template-columns: subgrid [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0h  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0i  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [x] [x] */
 .fill-0j  { grid-template-columns: subgrid [x] [x] [x] [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
+.fill-0k  { grid-template-columns: subgrid repeat(auto-fill, [y]) repeat(100, [z]) }  /* [z] [z] [z] [z] [z] */
+.fill-0l  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) repeat(100, [z]) }  /* [x] [z] [z] [z] [z] */
+.fill-0m  { grid-template-columns: subgrid  repeat(100, [x]) repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [x] */
 
 .fill-1a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] [z] }  /* [y] [z] [z] [z] [z] */
 .fill-1b  { grid-template-columns: subgrid [x] repeat(auto-fill, [y]) [z] [z] [z] }  /* [x] [y] [z] [z] [z] */
 .fill-1c  { grid-template-columns: subgrid [x] [x] repeat(auto-fill, [y]) [z] [z] }  /* [x] [x] [y] [z] [z] */
 .fill-1d  { grid-template-columns: subgrid [x] [x] [x] repeat(auto-fill, [y]) [z] }  /* [x] [x] [x] [y] [z] */
 .fill-1e  { grid-template-columns: subgrid [x] [x] [x] [x] repeat(auto-fill, [y]) }  /* [x] [x] [x] [x] [y] */
 
 .fill-2a  { grid-template-columns: subgrid repeat(auto-fill, [y]) [z] [z] [z] }  /* [y] [y] [z] [z] [z] */
@@ -193,16 +196,55 @@ html,body {
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>
   <div style="grid-column:y -3"></div>
   <div style="grid-column:y -4"></div>
   <div style="grid-column:y -5"></div>
 </div></div></div>
 
+<div class="grid"><div class="subgrid fill-0k"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0l"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
+<div class="grid"><div class="subgrid fill-0m"><div class="subgrid">
+  <div style="grid-column:y 5"></div>
+  <div style="grid-column:y 4"></div>
+  <div style="grid-column:y 3"></div>
+  <div style="grid-column:y 2"></div>
+  <div style="grid-column:y 1"></div>
+  <div style="grid-column:y -1"></div>
+  <div style="grid-column:y -2"></div>
+  <div style="grid-column:y -3"></div>
+  <div style="grid-column:y -4"></div>
+  <div style="grid-column:y -5"></div>
+</div></div></div>
+
 <div class="grid"><div class="subgrid fill-1a"><div class="subgrid">
   <div style="grid-column:y 5"></div>
   <div style="grid-column:y 4"></div>
   <div style="grid-column:y 3"></div>
   <div style="grid-column:y 2"></div>
   <div style="grid-column:y 1"></div>
   <div style="grid-column:y -1"></div>
   <div style="grid-column:y -2"></div>