div 들을 넣을 책꽂이 만들기 : grid-auto-flow 속성

<div id="container">

    <div id="one"></div>
    <div id="two"></div>
    <div id="three"></div>
    <div id="four"></div>

</div>

#container {

    position            : absolute;
    width               : 200px;
    height              : 200px;
    background-color    : rgb(10, 10, 10);

    display             : grid;
    grid-auto-flow      : column; /* 책꽂이 */

}

#one    { background-color:  red; }
#two    { background-color:  green; }
#three  { background-color:  blue; }
#four   { background-color:  yellow; }