Flex Box Demo

by bergb

HTML

<div class="container">
    <div class="gallery"> 
        <div class="gallery-item">1</div>
        
    </div>
</div>

CSS

html, body {
    height: 100%;
}
body {
    margin: 0;
}
.container {
    height: 100%;
    padding: 0;
    margin: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}
.gallery {
    width: auto;
    border: 1px solid blue;
}
.gallery-item {
    background-color: tomato;
    padding: 5px;
    width: 20px;
    height: 20px;
    margin: 10px;
    line-height: 20px;
    color: white;
    font-weight: bold;
    font-size: 2em;
    text-align: center;
}