.book_content h2 {
    text-align: center;
    margin: 0;
    font-size: 23px;
    margin: 23px;
}
.book_content emphasis {
    font-style: italic;
}
.book_content epigraph {
    display: block;
    font-style: italic;
    background-color: var(--md-sys-color-inverse-on-surface);
    margin: calc(23px/2);
    padding: calc(23px/2);
    border-radius: 10px;
}
.book_content epigraph b {
    margin-left: 15px;
    display: block;
}

.book_content poem {
    display: block;
    margin: 23px 25px;
}
.book_content poem v {
    display: block;
    text-indent: 25px;
}

.book_content p {
    margin: 0;
    text-indent: 25px;
}
.book_content sub {
    line-height: 23px;
}
.reader_container {
    position: relative;
    height: calc(100vh - 30px - 40px);
    border: 1px solid gray;
    /*border-bottom: 0;*/
    border-radius: 15px 15px 0 0;
    overflow: hidden;
    display: flex;
    align-items: center;
}
.book_content {
    overflow:hidden;
    line-height: 23px;
    padding: 0 23px;
    width: 100%;
    color: var(--md-sys-color-on-background);
}
.book_content a {
    color: var(--md-sys-color-on-background);
}
.book_img {
    display: block;
    margin: 0 auto;
    max-width: 100%;
}
.reader_progress {
    position: absolute;
    bottom: 0;
    height: 5px;
    background-color: var(--md-sys-color-primary);
    transition: all 0.5s;
}
.reader_contents {
    position: fixed;
    top: 25px;
    left: 10px;
    overflow: hidden;
    transition: 0.5s;
    transform: translateX(0);
    background: var(--md-sys-color-background);
    z-index: 1;
    border-radius: 15px;
    border: 1px solid var(--md-sys-color-outline);
}

.contents_button {
    display: none;
}

.reader_contents_backdrop {
    visibility: hidden;
    pointer-events: none;
    opacity: 0;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--md-sys-color-outline-variant);
    z-index: 1;
    transition: 0.5s;
}
.reader_contents_backdrop.show {
    visibility: visible;
    opacity: 0.4;
    pointer-events: all;
}
code {
    line-height: 23px;
}
.reader_buttons_container {
    display: flex;
    gap: 25px;
    margin: 20px 0;
}

@media screen and (max-width: 1880px) {
    .reader_contents {
        transform: translateX(calc(-100% - 15px));
        border: none;
    }
    .reader_contents.show {
        transform: translateX(15px);
        box-shadow: 0px 0px 35px -15px var(--md-sys-color-shadow);
    }
    .contents_button {
        display: block;
    }
}

@media screen and (max-width: 750px) { /* кнопки в столбик */
    .reader_buttons_container {
        flex-direction: column;
        gap: 10px;
    }
    .reader_action_button {
        flex-basis: auto;
    }
}