SOURCE

   <div class="grid-box1">
        <div class="grid1">左适应</div>
        <div class="grid2">右固定</div>
    </div>
    <br>
    <div class="grid-box2">
        <div class="thrbox1">左固定</div>
        <div class="thrbox2">中适应</div>
        <div class="thrbox3">右固定</div>
    </div>

        .grid-box1{
            display: grid;
            grid-template-columns: 1fr 200px;
            grid-template-rows: 200px;
        }
        .grid1{
            background-color: gray;
        }
        .grid2{
            background-color: yellow;
        }
        .grid-box2{
            display: grid;
            grid-template-columns: 200px 1fr 200px;
            grid-template-rows: 200px;
        }
        .thrbox1{
            background-color: gray;
        }
        .thrbox2{
            background-color: yellow;
        }
        .thrbox3{
            background-color: gray;
        }