      z-index: -1; /* 保证内容层在背景之上 */
      }

      [/]
      [# th:if="${theme.config.basic.enable_background_light != true} or ${theme.config.basic.background_light_mode == ''} or ${theme.config.basic.background_light_mode == null}"]
      html[data-mode="dark"] body {
        background-repeat: no-repeat;
        background-size: cover;
        position: relative;
      }

      html[data-mode="dark"] body::before {
        content: "";
        position: fixed;
        top: 0;
        