<div class="box">
        <div class="first-item">
            <h1>1</h1>
        </div>
        <div class="second-item">
            <h1>2</h1>
        </div>
        <div class="third-item">
            <h1>3</h1>
    
        </div>
        <div class="fourth-item">
            <h1>4</h1>
        </div>
    </div>

.box{
    display:flex;
}
.first-item{
    border-style: solid;
    background-color: aqua;
    text-align: center;
    flex-grow: 1;
    margin: 2px;

}

.second-item{
    border-style: solid;
    background-color: aqua;
    text-align: center;
    flex-grow: 1;
    margin: 2px;

}

.third-item{
    border-style: solid;
    background-color: aqua;
    text-align: center;
    flex-grow: 1;
    margin: 2px;

}

.fourth-item{
    border-style: solid;
    background-color: aqua;
    text-align: center;
    flex-grow: 1;
    margin: 2px;

}