ox-extended {
    background: url("thumb/sandbox.png");
    background-size: contain;
  }
  #tufte {
    background: url("thumb/tufte.png");
    background-size: contain;
  }
  #vela {
    background: url("thumb/vela.png");
    background-size: contain;
  }
  #academic {
    background: url("thumb/academic.png");
    background-size: contain;
  }
  #celeste {
    background: url("thumb/celeste.png");
    background-size: contain;
  }
  #bootstrap5 {
    background: url("thumb/bootstrap5.png");
    backgroun