.c-ontainer { position: relative; height: 2400px; width: 100%; background-color: black; color: white; font-size: 24px; line-height: 200px; text-align: center; } .line { position: absolute; height: 4px; width: 100%; background-color: red; animation: move 2s linear infinite; animation-timing-function: cubic-bezier(0.1, 0.4, 0.5, 0.1); } @keyframes move { from { top: 0px; } to { top: 2400px; } } #lr-overlay-wrapper { background: black; width: 100vw; height: 100vh; left: 0; top: 0; } #lr-overlay-content { position: fixed; text-align: center; font-size: 24px; white-space: nowrap; z-index: 2147483647; } /*--???布局--*/