Selecting first children

by TigerAsks

HTML

<div class="container">
    <div class="card">
        <div class = "front">
            <span>Card1</span>
        </div>
        <div class = "back">
            <span>Hello</span>
            <div>
                <span>World</span>
            </div>
        </div>
    </div>
    <div class="card">
        <div class = "back">
            <span>Hakuna</span>
            <div>
                <span>Matata</span>
            </div>
        </div>
        <div class = "front">
            <span>Card2</span>
        </div>
    </div>
    <div class="card">
        <div class = "back">
            <span>One</span>
            <div>
                <span>Two</span>
            </div>
        </div>
        <div class = "back">
            <span>Three</span>
            <div>
                <span>Four</span>
            </div>
        </div>
        <div class = "front">
            <span>Card3</span>
        </div>
    </div>
</div>

CSS

.container {
    display: flex;
}

.card {
    margin-left: .5rem;
}

.card .back :first-child{
    color: blue;
}

.card .back:first-child{
    background: red;
}

.card .back > :first-child {
    border: solid green 3px;
}

.card > .back:first-of-type > :first-child {
    border-style: dotted;
}