用简单的线性渐变来把图形的右半部分设置为棕色

    1.  .box{
    2.        width: 100px;
    3.        height: 100px;
    4.        border-radius: 50%;
    5.        background: yellowgreen;
    6.        background-image: linear-gradient(to right,transparent 50%, #655 0);
    7.    }
    10.     </style>
    11. </head>
    12. <body>
    13.     <div class="box"></div>

    image.png