html
{
    background-repeat: no-repeat;
    background-size: cover;
    background-position: center;
    transition: 500ms all ease-in-out;
}
table tr:nth-child(even) 
{
    background-color: white;
    background-color: rgba(250,250,250,0.95);
}
table tr:nth-child(odd) 
{
    background-color: white;
    background-color: rgba(250,250,250,0.75);
}
table th 
{
    background-color: black;
    color: white;
}
table 
{
    width:75%;
    margin-left: auto;
    margin-right: auto;
}

table, th, td 
{
    border-bottom: 1px solid black;
    border-collapse: collapse;
}

th, td 
{
    padding: 15px;
    text-align: left;
}

body
{
    text-align: center;
    
}

ul 
{
    list-style-type: none;
    margin: 0;
    padding: 0;
    overflow: hidden;
    background-color: rgba(0, 0, 0,0.75);
}

li 
{
    float: left;
}

li a 
{
    width: 100px;
    height: 20px;
    line-height: 20px;
    display: block;
    color: whitesmoke;
    border-bottom: 3px solid transparent;
    border-top: 3px solid transparent;
    text-align: center;
    padding: 8px 16px;
    text-decoration: none;
    transition: 250ms all ease-in-out;
}   

li a:hover 
{
    /*background-color: rgba(250,250,250,1);
    color: black;
    border-top: 2px solid black;*/
    border-bottom: 3px solid white;
    color: white;
    font-size: 18px;
}

.active 
{
    background-color: rgb(216, 10, 10) !important;
    color: white !important;
    border-top: 3px solid transparent !important;
    border-bottom: 3px solid transparent !important;
    font-size: 16px !important;
}

#math 
{
    padding-top: 0;
    margin-top: 0;
    background-color: rgba(246, 250, 250,0.5);
    width: 100%;
    margin-right: auto;
    margin-left: auto;
    
}


#footer
{
    color: white;
    margin-right: auto;
    margin-left: auto;
    text-align: right;
}
#footer span
{
    background-color: black;
    background-color: rgba(0,0,0,0.25);
    border-radius: 8px 0px 0px 8px;
}

button
{
    background-color: whitesmoke;
    color: black;
    font-size: 18px;
    padding: 10px;
    outline: none;
    border-radius: 25px;
    width: 150px;
    transition: all 250ms ease-in-out;
}

button:hover
{
    width: 200px;
    background-color: black;
    color: whitesmoke;
    
}

h1
{
    padding:10px;
    margin: 0;
}

#container
{
    width: 95%;
    margin-left:auto;
    margin-right:auto;
}
hr
{
    width: 300px;
    border: 2px solid lightgray;
    border-radius: 5px
}
textarea
{
    outline: none;
    border-bottom: 2px black solid ;
    font-size: 15px;
}


@media only screen and (max-width: 600px) 
{
    #container
    {
        width: 95%;
    }
    hr
    {
        width: 150px;
    }
    
}
@media only screen and (max-width: 720px) 
{
    textarea, table
    {
        width: 90%;
    }
}

input
{
    width: 300px;
    display: block;
    margin: 5px auto;
    padding: 5px;
    height: 30px;
    background-color: white;
    
    font-size: 1.1875rem;
    border: 2px transparent solid;
    border-bottom: 2px solid black;

    overflow-x: visible;
    border-radius: 0;
 
            
}
input:focus
{
    border: 2px solid black;
    background-color: rgba(0,0,0,0.25);
    color: white;
    outline: none;
}

a
{
    display: none;
}