CitrusClient / app / src / main / res / drawable / rounded_gray_rectangle.xml

<!-- rounded_gray_rectangle.xml -->
<shape xmlns:android="http://schemas.android.com/apk/res/android"
    android:shape="rectangle">
    <solid android:color="#D3D3D3" /> <!-- 灰色の色 -->
    <corners android:radius="8dp" /> <!-- 丸みの半径 -->
</shape>