diff --git a/src/pages/clazz/components/ClazzMatrixView.vue b/src/pages/clazz/components/ClazzMatrixView.vue
index e90768a..6611bec 100644
--- a/src/pages/clazz/components/ClazzMatrixView.vue
+++ b/src/pages/clazz/components/ClazzMatrixView.vue
@@ -304,6 +304,7 @@ export default defineComponent({
 <style scoped lang="less">
 @sidebar-width: 1.2rem;
 @cell-width: 1.8rem;
+@portrait-header-height: 0.72rem;
 
 .matrix-wrapper {
   width: 100%;
@@ -334,9 +335,12 @@ export default defineComponent({
   height: 100%;
   display: flex;
   flex-direction: column;
+  box-sizing: border-box;
   pointer-events: none; /* allow click-through to cells underneath */
 
   .sidebar-corner {
+    height: @portrait-header-height;
+    box-sizing: border-box;
     flex-shrink: 0;
     background: #f7f8fa;
     border-bottom: 1px solid #e8e8e8;
@@ -392,6 +396,7 @@ export default defineComponent({
 /* ─── 行：共用 ─── */
 .sr-header {
   display: flex;
+  height: @portrait-header-height;
   flex-shrink: 0;
 }
 
diff --git a/src/pages/clazz/index.vue b/src/pages/clazz/index.vue
index d234a46..2a67e49 100644
--- a/src/pages/clazz/index.vue
+++ b/src/pages/clazz/index.vue
@@ -1265,6 +1265,10 @@ export default defineComponent({
     min-height: 0;
   }
 
+  :deep(.matrix-sidebar) {
+    padding-bottom: calc(0.72rem + env(safe-area-inset-bottom));
+  }
+
   :deep(.matrix-scroll) {
     padding-bottom: calc(0.72rem + env(safe-area-inset-bottom));
     box-sizing: border-box;