#ex1 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .box {
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}

#ex2 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .box {
        float: left;
        margin-right: 15px;
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}

#ex3 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .box {
        float: right;
        margin-left: 15px;
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}

#ex4 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .special {
        background-color: rgb(148 255 172);
        padding: 10px;
        color: purple;
    }

    .box {
        float: right;
        margin: 15px;
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}

#ex5 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .special {
        background-color: rgb(148 255 172);
        padding: 10px;
        color: purple;
    }

    .cleared {
        clear: left;
    }

    .box {
        float: left;
        margin: 15px;
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}

#ex6 {
    width: 90%;
    max-width: 900px;
    margin: 0 auto;
    font:
        0.9em/1.2 Arial,
        Helvetica,
        sans-serif;

    .wrapper {
        background-color: rgb(148 255 172);
        padding: 10px;
        color: purple;
        display: flow-root;
    }


    .box {
        float: left;
        margin: 15px;
        width: 150px;
        height: 100px;
        border-radius: 5px;
        background-color: rgb(207 232 220);
        padding: 1em;
    }
}