body {
    margin: 0;
    font-family: "Lato", sans-serif;
}
.ex1 {
    border: 1px ;
    padding: 35px;
}
.ex2 {
    border: 1px solid red;
    margin: 35px;
}
.sidebar {
    margin: 0;
    padding: 0;
    width: 200px;
    background-color: LemonChiffon;
    position: fixed;
    height: 100%;
    overflow: auto;

}

    .sidebar a {
        display: block;
        color: Black;
        padding: 16px;
        text-decoration: none;
    }

        .sidebar .active {
            background-color: Olive;
            color: white;
        }

        .sidebar a:hover:not(.active) {
            background-color: #555;
            color: white;
        }

div.content {
    margin-left: 200px;
    padding: 1px 16px;
    height: 1000px;
}

@media screen and (max-width: 700px) {
    .sidebar {
        width: 100%;
        height: auto;
        position: relative;
    }

        .sidebar a {
            float: left;
        }

    div.content {
        margin-left: 0;
    }
}

@media screen and (max-width: 400px) {
    .sidebar a {
        text-align: center;
        float: none;
    }


}

.completed {
    background-color: lightgreen;
    color: white;
}

.center {
    display: block;
    margin-left: auto;
    margin-right: auto;
    width: 50%;
}
.button {
    background-color: #04AA6D; /* Green */
    border: none;
    color: white;
    padding: 15px 32px;
    text-align: center;
    text-decoration: none;
    display: inline-block;
    font-size: 16px;
    margin: 4px 2px;
    cursor: pointer;
}

.button2 {
    background-color: #008CBA;
}
/* Blue */
.button3 {
    background-color: #f44336;
}
/* Red */
.button4 {
    background-color: #e7e7e7;
    color: black;
}
/* Gray */
.button5 {
    background-color: #555555;
}
/* Black */