body{
    font-family: 'Source code pro', Calibri, serif;
    margin: 0px;
    padding: 0px;
    cursor: grab;
}
link{
    display: none;
}
nav{
    width: 100%
    background-color: RGB(100, 100, 100);
    /*position: absolute;*/
}
nav ul{
    margin: 0px;
    padding: 0px;
    overflow: hidden;
    background-color: RGB(100, 100, 100);
}
nav li{
    list-style-type: none;
    float: left;
}
nav a{
    display: inline-block;
    text-decoration: none;
    padding: 20px 30px;
    color: #FFF;
}
.preface-html:hover{
    border-top: 5px solid #ff0000;
    background-color: RGBa(255, 0, 0, 0.20)
}
.txt1-html:hover{
    border-top: 5px solid #4472c4;
    background-color: RGBa(68, 114, 196, 0.20)
}
.txt2-html:hover{
    border-top: 5px solid #70ad47;
    background-color: RGBa(112, 173, 71, 0.20)
}
.txt3-html:hover{
    border-top: 5px solid #e7e6e6;
    background-color: RGBa(231, 230, 230, 0.20)
}
.txt10-html:hover{
    border-top: 5px solid #e7e6e6;
    background-color: RGBa(231, 230, 230, 0.20)
}
.txt4-html:hover{
    border-top: 5px solid #ff0000;
    background-color: RGBa(255, 0, 0, 0.20)
}
.txt5-html:hover{
    border-top: 5px solid #4472c4;
    background-color: RGBa(68, 114, 196, 0.20)
}
.txt6-html:hover{
    border-top: 5px solid #70ad47;
    background-color: RGBa(112, 173, 71, 0.20)
}
.txt7-html:hover{
    border-top: 5px solid #e7e6e6;
    background-color: RGBa(231, 230, 230, 0.20)
}
.txt9-html:hover{
    border-top: 5px solid #70ad47;
    background-color: RGBa(112, 173, 71, 0.20)
}
.txt8-html:hover{
    border-top: 5px solid #ff0000;
    background-color: RGBa(255, 0, 0, 0.20)
}
nav li:hover a{
    padding: 15px 30px 20px 30px
}
.gotoppage{
    float: right;
    /*float: bottom;*/
    /*margin-right: 1.5rem;*/
}
.gotoppage:hover{
    padding: 1px 0px 4px 0px
}
.endpage{
    color: #FFF
}
p{
    margin: 5px;
}
h2{
    text-align: center;
}
h3{
    margin: 10px;
}