* {
    box-sizing: border-box;
}



body {
    background-color: var( --background-color );
}




/*
** Title structure
*/

.title-block .chapter-link {
    font-family: roboto-medium;
    font-size: 20px;
    color: var( --medium );
    margin-bottom: 30px;
}

.title-block .chapter-link h3 {
    float: right;
}

.title-block .theorem-number {
    font-family: roboto-black;
    font-size: 36px;
    color: var( --dark );
    margin: 20px 0 20px 0;
}

.title-block .theorem-description {
    font-family: roboto-light;
    font-size: 24px;
    color: var( --medium );
    padding-left: 30px;
    padding-bottom: 10px;
    border-bottom-style: solid;
    border-bottom-width: 3px;
    border-bottom-color: var( --dark );
}


/*
**  Block structure
*/

.block {
    width: 50%;
    background-color: var( --white );
    margin-left: 25%;
    margin-top: 30px;
    display: flex;
    flex-direction: column;
    padding: 20px 40px 20px 20px;
    border-radius: 5px;
    box-shadow: 2px 2px #ccc;
}



.breakout-box {
    font-family: roboto-medium;
    font-size: 28px;
    margin: 30px 15% 30px 15%;
    background-color: var( --highlight );
    padding: 20px;
    text-align: center;
    border-radius: 20px;
}



.block .block-title {
    font-family: roboto-bold;
    font-size: 30px;
    color: var( --medium );
}




.block p {
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-size: 20px;
    margin-top: 10px;
    margin-left: 20px;
    line-height: 1.5;
    text-indent: 30px;
}


.qed-square {
    font-size: 40px;
    line-height: 0.5;
    float: right;
    color: var( --dark );
}




/*
** Accordion
*/

.accordion {
    width: 100%;
    margin-top: 30px;
}

.accordion .contentBx {
    position: relative;
    margin: 10px 20px;
}


.accordion .contentBx .label {
    font-family: Roboto-Medium;
    font-size: 20px;
    line-height: 1.5;
    position: relative;
    padding: 20px;
    background-color: var( --medium );
    color: #fff;
    cursor: pointer;
}


.accordion .contentBx .label::before {
    content: '+';
    position: absolute;
    top: 50%;
    right: 20px;
    transform: translateY(-50%);
    font-size: 1.5em;
}



.accordion .contentBx.active .label::before {
    content: '-';
}



.accordion .contentBx .content {
    font-family: Georgia, 'Times New Roman', Times, serif;
    font-size: 20px;
    line-height: 1.5;
    position: relative;
    background-color: #fff;
    height: 0;
    overflow: hidden;
    transition: 0.5s;
    overflow-y: auto;
}


.accordion .contentBx.active .content {
    height: auto;
    padding: 10px;
}





/*
**  Footer
*/

footer {
    height: auto;
    width: 100%;
    display: flex;
    margin-top: 50px;
    background-color: var( --dark );
    color: #ccc;
    padding-top: 30px;
    padding-bottom: 30px;
}

footer .company-info {
    width: 25%;
    padding-left: 50px;
    display: flex;
    flex-direction: column;
}


footer .company-info .logo {
    height: 30%;
    width: auto;
}


footer .company-title {
    font-size: 20px;
    font-family: Roboto-Medium;
    margin-top: 2px;
}



footer .navigation-links {
    width: 25%;
}

footer li {
    font-family: Roboto-Medium;
    font-size: 20px;
    color: #ccc;
    margin-top: 5px;
}


footer .legal-links {
    width: 25%;
}


.book-info {
    font-style: italic;
    font-weight: bold;
    color: black;
}

.book-title{
    color: red;
}