<style> .parent{display: flex;} .child:nth-child(1){flex:1} </style> <div class="parent"> <div class="child">div1</div> <div class="child">div2</div> </div>
부모요소에 display: flex 자식노드에 각각 flex: 1, flex: 2
display: flex
flex: 1
flex: 2