.Layout { height: 100vh; .left { position: fixed; left: 0; top: 0; bottom: 0; background-color: #2c2c2c; width: 55px; display: flex; flex-direction: column; overflow: hidden; .leftList,.leftListBottom { width: 100%; .leftItem { text-align: center; padding: 10px 0; color: #808080; cursor: pointer; &:hover { color: #f8ffff; } position: relative; .activeLine{ position: absolute; left: 0; top: 6px; bottom: 6px; width: 3px; background-color: white; } } } .leftList{ flex-grow: 1; flex-shrink: 0; } } .right{ margin-left: 55px; } }