body, ul, li {
    /* position: relative; */
    margin: 0;
    padding: 0;
    font-family: 'Gill Sans', 'Gill Sans MT', Calibri, 'Trebuchet MS', sans-serif;
    list-style: none;
}

header, footer {
    position: fixed;
    z-index: 9;
    width: 100%;
    height: 45px;
    font-size: 24px;
    color: #333;
    font-weight: bold;
    text-align: center;
    line-height: 50px;
    background: #d9ffd9;
}

footer {
    bottom: 0;
}

section {
    padding: 51px 0;
}

nav {
    background: #fff;
    color: #333;
}

    nav li {
        padding: 5px 10px;
    }

        nav li.active {
            background: #77d677;
        }

article {
    /*position: absolute;*/
    padding: 0px;
    font-size: 24px;
    text-align: center;
    background: #fff;
    /*height: 600px;
    top: 52px;
    bottom: 51px;*/
}
/* default */
section.default nav {
    position: absolute;
    top: 52px;
    bottom: 51px;
    /* float: left;
  height: 100%; */
    width: 100px;
}

    section.default nav li {
        padding: 5px 5px;
    }

        section.default nav li.active {
            background: #77d677;
        }

section.default article {
    padding-left: 100px;
}
/* flexModal */
section.flexModal {
    display: flex;
}

    section.flexModal nav {
        width: 100px;
    }

    section.flexModal article {
        flex: 1;
    }

/* fixedLeft */
section.fixedLeft nav {
    position: fixed;
    top: 52px;
    bottom: 51px;
}

section.fixedLeft article {
    margin-left: 100px;
}