diff --git a/src/components/DatePicker.spec.ts b/src/components/DatePicker.spec.ts
index 54fefe4..8d0ae95 100644
--- a/src/components/DatePicker.spec.ts
+++ b/src/components/DatePicker.spec.ts
@@ -68,6 +68,19 @@ describe('DatePicker', () => {
     expect(wrapper.emitted('update:modelValue')).toEqual([[null]])
   })
 
+  /**
+   * jsdom 不做布局，量不到真实高度，所以这里锁的是「机制」：
+   * 按钮必须靠 self-stretch 跟着整行走，而不是写死 py。
+   * 曾经写死 py-1，比输入框矮 8px；输入框内边距一改还会再次错位。
+   */
+  it('清除按钮靠 self-stretch 对齐输入框高度，不写死内边距', () => {
+    const button = mountPicker('2026-10-20').find('button')
+    expect(button.classes()).toContain('self-stretch')
+    expect(button.classes()).toContain('items-center')
+    expect(button.classes()).not.toContain('py-1')
+    expect(button.classes()).not.toContain('py-1.5')
+  })
+
   it('默认带「截止日期」可访问性标签，可覆盖', () => {
     expect(mountPicker(null).find('input').attributes('aria-label')).toBe('截止日期')
     expect(mountPicker(null, '开始日期').find('input').attributes('aria-label')).toBe('开始日期')
diff --git a/src/components/DatePicker.vue b/src/components/DatePicker.vue
index 7ca1bc5..55ead3c 100644
--- a/src/components/DatePicker.vue
+++ b/src/components/DatePicker.vue
@@ -86,10 +86,14 @@ function openPicker(): void {
       </span>
     </div>
 
+    <!--
+      高度靠 self-stretch 跟着这一行走，而不是写死 py：
+      输入框改内边距时按钮会自动跟上，不会再次一高一矮。
+    -->
     <button
       v-if="modelValue"
       type="button"
-      class="shrink-0 rounded-md border border-slate-300 px-2.5 py-1 text-xs text-slate-600 transition hover:bg-slate-100 dark:border-zinc-600 dark:text-zinc-300 dark:hover:bg-zinc-800"
+      class="inline-flex shrink-0 items-center justify-center self-stretch rounded-md border border-slate-300 px-2.5 text-xs text-slate-600 transition hover:bg-slate-100 dark:border-zinc-600 dark:text-zinc-300 dark:hover:bg-zinc-800"
       @click="emit('update:modelValue', null)"
     >
       清除