.ul_css {
  list-style-type: none;
    margin: 0;
    padding: 0;
    /* width: 200px; */
    background-color: #f1f1f1;
}

li a {
  display: block;
  color: blue;
  padding: 8px 16px;
  text-decoration: none;
}

/* .a_css {
  display: block;
  width: 60px;
} */

/* 鼠标悬停时改变链接颜色 */
li a:hover {
  background-color: #555;
  color: white;
}

.menu_position{
	position: fixed;
	z-index: 1;
}

.menu_hide{display: none!important}
.menu_show{display: block!important}
.menu_button{
	position: fixed;
	z-index: 1;
}