.container { width: 100%; height: 100%; display: flex; overflow: hidden; } .main { height: 100%; flex: 1 1 auto; } .asideToggle { display: none; } @media only screen and (max-width: 500px) { .asideToggle { width: 36px; height: 36px; padding: 0; border: 2px solid rgba(0, 0, 0, 0.2); border-radius: 4px; display: block; position: absolute; top: 10px; left: 10px; z-index: 999; background-color: #fff; background-clip: padding-box; cursor: pointer; user-select: none; outline: currentcolor none medium; } .asideToggle:hover { background-color: #f4f4f4; } .asideOpen { left: 0; } }