*{
        box-sizing: border-box;
}

body{
        background-image: url("../img/pattern.gif");
}

.padre{
        width: 95%;
        height: 400px;
        margin: 20px auto;
        background-color: darkgray;
        border: 5px solid black;
        padding: 1%;
        display: flex;
        flex-wrap: wrap;  
        justify-content: space-between;      
}
h1{
        width: 100%;
        background-color: lightgray;
        text-align: center;
        padding: 1%;
        border-bottom: 4px double black;
        height: 80px;
}

.uno{
        width: 32%;
        height: 220px;
        padding: 16px;
        background-color: lightgoldenrodyellow;
}

.dos{
        width: 32%;
        height: 220px;
        padding: 16px;
        background-color: purple ;
        text-align: center;
}

.tres{
        width: 32%;
        height: 220px;
        padding: 16px;
        background-color: pink;
        text-align: right;
}