table { border: 1px solid; border-collapse: collapse; } td, th { border: 1px solid; } #app-dialog { position: fixed; top: 50%; left: 50%; transform: translate(-50%, -50%); background-color: white; border: 1px solid #ccc; box-shadow: 0px 0px 10px rgba(0, 0, 0, 0.3); padding: 20px; z-index: 555; }