/* ===========================================================
   book.css — all styling for the eBook viewer
   =========================================================== */

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    width: 100%;
    overflow: hidden;
    background: #ffffff;
    transition: background 0.6s ease;
    font-family: sans-serif;
    touch-action: none; /* let our custom pinch handler control gestures */
}

#stage {
    position: relative;
    width: 100%;
    height: calc(100% - 90px); /* leave room for bottom bar */
    display: flex;
    align-items: center;
    justify-content: center;
    overflow: hidden;
}

#zoomWrapper {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    transform-origin: center center;
    transition: transform 0.05s linear;
}

#book {
    box-shadow: 0 0 30px rgba(0,0,0,0.35);
}

.my-page {
    background: #fff;
    /* subtle paper-like inner edge so interior pages read as thin paper */
    box-shadow: inset 0 0 0 1px rgba(0,0,0,0.04);
}
.my-page img {
    width: 100%;
    height: 100%;
    object-fit: contain;
    display: block;
    -webkit-user-select: none;
    user-select: none;
    cursor: zoom-in;
}

/* ---------- Front cover (bookpage0.png only) ---------- */
.my-page.cover-page {
    background: linear-gradient(150deg, #2b2b2b 0%, #1a1a1a 55%, #262626 100%);
    border-radius: 6px;
    position: relative;
    /* layered inset shadows fake a thick board edge + slight sheen */
    box-shadow:
        inset 0 0 0 2px rgba(255,255,255,0.06),
        inset 0 0 55px rgba(0,0,0,0.55),
        inset 0 2px 0 rgba(255,255,255,0.08),
        0 0 25px rgba(0,0,0,0.5);
}
.my-page.cover-page img {
    border-radius: 6px;
    filter: contrast(1.08) saturate(1.05);
}
/* faint printed-cardboard grain, purely decorative */
.my-page.cover-page::after {
    content: "";
    position: absolute;
    inset: 0;
    pointer-events: none;
    border-radius: 6px;
    background: repeating-linear-gradient(115deg, rgba(255,255,255,0.025) 0 2px, transparent 2px 4px);
    mix-blend-mode: overlay;
}

/* ---------- Bottom control bar ---------- */
#controls {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    height: 90px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    background: rgba(255,255,255,0.85);
    backdrop-filter: blur(6px);
    box-shadow: 0 -2px 10px rgba(0,0,0,0.1);
    border-top: 2px solid rgba(210,210,210,0.6);
    transition: background 0.6s ease;
}

.btn-row {
    display: flex;
    align-items: center;
    gap: 14px;
}

button {
    border: none;
    border-radius: 10px;
    padding: 10px 20px;
    font-size: 15px;
    font-weight: bold;
    color: white;
    cursor: pointer;
    letter-spacing: 0.3px;
    transition: transform 0.1s ease, box-shadow 0.1s ease;
}

button:active {
    transform: translateY(2px) scale(0.97);
}

#prevBtn {
    background: linear-gradient(180deg, #ff8a80 0%, #e53935 55%, #b71c1c 100%);
    box-shadow: 0 4px 0 #7f0000, 0 6px 10px rgba(0,0,0,0.35);
    text-shadow: 0 1px 2px rgba(0,0,0,0.4);
}
#prevBtn:active {
    box-shadow: 0 2px 0 #7f0000, 0 3px 6px rgba(0,0,0,0.35);
}

#nextBtn {
    background: linear-gradient(180deg, #a5f5b3 0%, #43a047 55%, #1b5e20 100%);
    box-shadow: 0 4px 0 #0b3d0e, 0 6px 10px rgba(0,0,0,0.35);
    text-shadow: 0 1px 2px rgba(0,0,0,0.4);
}
#nextBtn:active {
    box-shadow: 0 2px 0 #0b3d0e, 0 3px 6px rgba(0,0,0,0.35);
}

#downloadBtn {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    background: linear-gradient(180deg, #64b5f6 0%, #2196f3 55%, #1565c0 100%);
    box-shadow: 0 3px 0 #0d47a1, 0 5px 10px rgba(21,101,192,0.35);
    text-shadow: 0 1px 2px rgba(0,0,0,0.35);
    padding: 6px 14px;
    font-size: 12px;
    border-radius: 8px;
    position: relative;
    overflow: hidden;
    isolation: isolate;
    transition: transform 0.18s ease, box-shadow 0.18s ease;
}
/* diagonal light sweep across the button on hover */
#downloadBtn::before {
    content: "";
    position: absolute;
    top: 0;
    left: -60%;
    width: 40%;
    height: 100%;
    background: linear-gradient(115deg, transparent, rgba(255,255,255,0.65), transparent);
    transform: skewX(-20deg);
    transition: left 0.55s ease;
    z-index: 1;
}
#downloadBtn:hover::before {
    left: 130%;
}
#downloadBtn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 0 #0d47a1, 0 10px 18px rgba(21,101,192,0.45), 0 0 14px rgba(100,181,246,0.55);
}
#downloadBtn:active {
    background: linear-gradient(180deg, #64b5f6 0%, #1976d2 55%, #0d47a1 100%);
    transform: translateY(1px) scale(0.98);
    box-shadow: 0 2px 0 #0d47a1, 0 3px 6px rgba(21,101,192,0.35);
}
#downloadBtn .dl-icon {
    display: inline-block;
    transition: transform 0.3s ease;
}
#downloadBtn:hover .dl-icon {
    animation: dl-bounce 0.7s ease infinite;
}
@keyframes dl-bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(3px); }
}

#pageNum {
    color: #333;
    font-size: 13px;
    font-weight: 600;
    opacity: 0.75;
}

/* ---------- Fullscreen image viewer ---------- */
#imgViewer {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.92);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    touch-action: none;
}
#imgViewer.open {
    display: flex;
}
#imgViewer img {
    max-width: 100%;
    max-height: 100%;
    touch-action: none;
    -webkit-user-select: none;
    user-select: none;
    will-change: transform;
}
#viewerClose {
    position: fixed;
    top: 14px;
    right: 16px;
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background: rgba(255,255,255,0.15);
    color: #fff;
    font-size: 20px;
    line-height: 42px;
    text-align: center;
    padding: 0;
    z-index: 1001;
}
#viewerPrev,
#viewerNext {
    position: fixed;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255,255,255,0.15);
    color: #fff;
    border-radius: 50%;
    width: 46px;
    height: 46px;
    font-size: 20px;
    padding: 0;
    z-index: 1001;
}
#viewerPrev { left: 16px; }
#viewerNext { right: 16px; }

/* ===========================================================
   Desktop / tablet only — everything below is scoped to
   min-width: 769px so the phone UI stays exactly as-is.
   =========================================================== */
@media (min-width: 769px) {

    #stage {
        height: calc(100% - 100px); /* matches the slightly taller controls bar below */
        padding: 30px 60px;
        box-sizing: border-box;
        /* soft radial "table" surface instead of a flat blank void */
        background: radial-gradient(ellipse at center, rgba(0,0,0,0.07) 0%, rgba(0,0,0,0) 65%);
    }

    #zoomWrapper {
        max-width: 1200px; /* 2-page spread (max ~1500px worth of page width) always ends up smaller than this and the viewport */
        margin: 0 auto;
    }

    #book {
        box-shadow: 0 10px 40px rgba(0,0,0,0.4);
    }

    #controls {
        height: 100px;
        gap: 8px;
        max-width: 1200px;
        left: 50%;
        transform: translateX(-50%);
        border-radius: 18px 18px 0 0;
        box-shadow: 0 -4px 18px rgba(0,0,0,0.12);
    }

    .btn-row {
        gap: 22px;
    }

    button {
        font-size: 16px;
        padding: 12px 26px;
        border-radius: 12px;
    }

    #downloadBtn {
        font-size: 14px;
        padding: 8px 18px;
    }

    #pageNum {
        font-size: 14px;
    }

    #viewerPrev,
    #viewerNext {
        width: 54px;
        height: 54px;
        font-size: 24px;
    }
}