.margin-bottom {
    margin-bottom:15px;
    width: 75%;
    margin-left: auto;
    margin-right: auto;
}

.question{
    margin-top: 15px;
    margin-bottom: 15px;
    border: 1px solid #1b1e21;
    border-radius: 25px;
}

input[type=checkbox].css-checkbox {
    position:absolute; z-index:-1000; left:-1000px; overflow: hidden; clip: rect(0 0 0 0); height:1px; width:1px; margin:-1px; padding:0; border:0;
}

input[type=checkbox].css-checkbox + label.css-label {
    padding-left:25px;
    height:20px;
    display:inline-block;
    line-height:20px;
    background-repeat:no-repeat;
    background-position: 0 0;
    font-size:20px;
    vertical-align:middle;
    cursor:pointer;

}

input[type=checkbox].css-checkbox:checked + label.css-label {
    background-position: 0 -20px;
}
label.css-label {
    background-image:url(http://csscheckbox.com/checkboxes/u/csscheckbox_490b7ac6598bb6e25d0681c50e958cda.png);
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    -khtml-user-select: none;
    -moz-user-select: none;
    -ms-user-select: none;
    user-select: none;
}
.font-size{
    font-size: 2.5rem;
}

.border-bottom-custom{
    border-bottom: #9fcdff;
    border-bottom-width: 1px;
    border-bottom-style: solid;
}

.correct{
    background-color: #28a745;
    border-radius: 25px;
    color:whitesmoke;
}

.false{
    background-color: firebrick;
    border-radius: 25px;
    color:whitesmoke;
}

.white{
    color:whitesmoke;
}
img{
    width:auto;
    max-width: 80%;
}

#overlay {
    position: fixed; /* Sit on top of the page content */
    display: none; /* Hidden by default */
    width: 100%; /* Full width (cover the whole page) */
    height: 100%; /* Full height (cover the whole page) */
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: rgba(0,0,0,0.9); /* Black background with opacity */
    z-index: 2; /* Specify a stack order in case you're using a different order for other elements */
    cursor: pointer; /* Add a pointer on hover */
}

#overlay > table{
	color: white;
}

.upload_failed{
    visibility:hidden;
    color: darkred;
    height: 0px;
}

.nav-link{
    color: #eff3f3;
}

.nav-link :hover{
    color: #bdc1c1;
}

.checkmark {
    position: absolute;
    top: 0;
    left: 0;
    height: 25px;
    width: 25px;
    background-color: #eee;
}

.check {
    position: absolute;
    opacity: 0;
    cursor: pointer;
    height: 0;
    width: 0;
}
.check:checked ~ .checkmark {
    background-color: #2196F3;
}

.checkmark:after {
    content: "";
    position: absolute;
    display: none;
}

/* Show the checkmark when checked */
.check:checked ~ .checkmark:after {
    display: block;
}

.container .checkmark:after {
    left: 9px;
    top: 5px;
    width: 5px;
    height: 10px;
    border: solid white;
    border-width: 0 3px 3px 0;
    -webkit-transform: rotate(45deg);
    -ms-transform: rotate(45deg);
    transform: rotate(45deg);
}