/* =========================================================
   LIVRE — BLUES
   ========================================================= */

.book {
    position: relative;
    width: 100%;
    min-height: 650px;
    padding: 16px;
    box-sizing: border-box;

    background:
        linear-gradient(
            90deg,
            #171f24 0%,
            #26343b 3%,
            #172127 50%,
            #26343b 97%,
            #171f24 100%
        );

    border: 2px solid #745532;
    border-radius: 8px;

    box-shadow:
        inset 0 0 0 2px rgba(0,0,0,.45),
        inset 0 0 18px rgba(0,0,0,.65),
        0 4px 10px rgba(0,0,0,.35);

    overflow: hidden;
}


/* =========================================================
   CONTOURS
   ========================================================= */

.book-contour-top,
.book-contour-left,
.book-contour-right,
.book-contour-bottom {
    position: absolute;
    pointer-events: none;
    z-index: 5;
}

.book-contour-top {
    top: 7px;
    left: 8px;
    right: 8px;
    height: 2px;
    background: #a27a48;
}

.book-contour-bottom {
    bottom: 7px;
    left: 8px;
    right: 8px;
    height: 2px;
    background: #a27a48;
}

.book-contour-left {
    top: 8px;
    bottom: 8px;
    left: 7px;
    width: 2px;
    background: #a27a48;
}

.book-contour-right {
    top: 8px;
    bottom: 8px;
    right: 7px;
    width: 2px;
    background: #a27a48;
}


/* =========================================================
   COINS
   ========================================================= */

.book-corner {
    position: absolute;
    width: 32px;
    height: 32px;
    z-index: 6;
    pointer-events: none;

    border-color: #b08a55;
    border-style: solid;
    opacity: .9;
}

.book-corner-top-left {
    top: 5px;
    left: 5px;
    border-width: 3px 0 0 3px;
}

.book-corner-top-right {
    top: 5px;
    right: 5px;
    border-width: 3px 3px 0 0;
}

.book-corner-bottom-left {
    bottom: 5px;
    left: 5px;
    border-width: 0 0 3px 3px;
}

.book-corner-bottom-right {
    bottom: 5px;
    right: 5px;
    border-width: 0 3px 3px 0;
}


/* =========================================================
   ZONE DES PAGES
   ========================================================= */

.book-page-area {
    position: relative;
    width: 100%;
    min-height: 615px;

    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);

    overflow: hidden;

    background:
        linear-gradient(
            to right,
            #e8dfc8 0%,
            #f5eedc 47%,
            #d7c9aa 50%,
            #f5eedc 53%,
            #e8dfc8 100%
        );

    border: 1px solid #8a6b42;

    box-shadow:
        inset 0 0 25px rgba(80,55,25,.22);
}


/* lignes discrètes du papier */

.book-page-area::before,
.book-page-area::after {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    width: 50%;
    pointer-events: none;
    z-index: 1;

    background:
        repeating-linear-gradient(
            to bottom,
            transparent 0,
            transparent 30px,
            rgba(70,105,115,.09) 31px,
            transparent 32px
        );
}

.book-page-area::before {
    left: 0;
}

.book-page-area::after {
    right: 0;
}


/* =========================================================
   RELIURE CENTRALE
   ========================================================= */

/* .book-spine {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 50%;
    width: 24px;

    transform: translateX(-50%);

    z-index: 10;

    background:
        linear-gradient(
            to right,
            #8b6338 0%,
            #d0a66c 18%,
            #704b2b 35%,
            #c49a61 50%,
            #704b2b 65%,
            #d0a66c 82%,
            #8b6338 100%
        );

    border-left: 1px solid #4a301d;
    border-right: 1px solid #4a301d;

    box-shadow:
        0 0 8px rgba(0,0,0,.45);
} */

.book-spine::before {
    content: "";

    position: absolute;
    top: 10px;
    bottom: 10px;
    left: 50%;

    width: 14px;
    transform: translateX(-50%);

    background:
        repeating-linear-gradient(
            to bottom,
            transparent 0,
            transparent 18px,
            #e1c184 18px,
            #f0ddb8 21px,
            #21084b 21px,
            #19095a 25px,
            transparent 25px,
            transparent 34px
        );

    opacity: .9;
}


/* =========================================================
   CONTENU
   ========================================================= */

.book-lesson-theory {
    position: relative;
    grid-column: 1 / -1;
    z-index: 3;

    min-width: 0;
    padding: 28px 38px;
}

.book-lesson-theory h1,
.book-lesson-theory h2,
.book-lesson-theory h3,
.book-lesson-theory p {
    position: relative;
    z-index: 4;
}


/* =========================================================
   RESPONSIVE
   ========================================================= */

@media (max-width: 900px) {
    .book {
        padding: 10px;
        min-height: 550px;
    }

    .book-page-area {
        min-height: 530px;
    }

    .book-lesson-theory {
        padding: 24px;
    }
}

@media (max-width: 700px) {
    .book {
        min-height: 500px;
    }

    .book-page-area {
        min-height: 480px;
        grid-template-columns: 1fr;
    }

    .book-spine {
        display: none;
    }

    .book-lesson-theory {
        padding: 20px;
    }
}