@import url('Assets/fonts/noto.css');

body, html {
    margin: 0;
    padding: 0;
    font-family: 'Noto Serif TC', serif; 
    /* Deep slate premium background gradient */
    background: radial-gradient(circle at center, #374151 0%, #111827 100%);
    color: #e5e7eb;
}

/* --- LAYOUT WRAPPERS --- */
.reader-container {
    position: relative;
    width: 100%;
    height: calc(100vh - 180px); /* More gap top and bottom */
    margin-top: 90px;
    padding: 0 60px; /* Guaranteed gap left and right */
    box-sizing: border-box;
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1200px;
}

.book-container {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    height: 100%;
    max-width: 860px; /* Scientifically restricted to fit 3x internal mathematical page ratios in standard Macbooks */
    
    /* Dynamic transform engine combining zoom and panning */
    --zoom: 1;
    --translate-x: 0%;
    --pan-x: 0px;
    --pan-y: 0px;
    transform: translate(calc(var(--translate-x) + var(--pan-x)), var(--pan-y)) scale(var(--zoom));
    transition: transform 0.6s cubic-bezier(0.645, 0.045, 0.355, 1);
}

.book-container.zoomed {
    transition: transform 0.1s ease-out; /* Faster responsive panning */
}

.book-container.center-cover {
    --translate-x: -25%;
}
.book-container.center-back-cover {
    --translate-x: 25%;
}

#book {
    /* Subtle outer shadow for the entire book */
    filter: drop-shadow(0 20px 40px rgba(0,0,0,0.5));
}

/* Gesture Overlay for Panning */
.zoom-overlay {
    display: none;
    position: absolute;
    top: 0; left: 0; width: 100%; height: 100%;
    z-index: 50;
    cursor: grab;
}
.book-container.zoomed .zoom-overlay {
    display: block;
}
.zoom-overlay:active {
    cursor: grabbing;
}

/* --- STPAGEFLIP PAGE STYLING --- */
.my-page {
    background-color: #fcfbf8; /* Warm off-white, paper aesthetics */
    color: #2c2925;
    overflow: hidden;
    /* Inner shadow to simulate spine and rounded edges */
    box-shadow: inset 0 0 40px rgba(0,0,0,0.04), inset -1px 0 2px rgba(255,255,255,0.5);
    border-left: 1px solid rgba(0,0,0,0.05);
    background-image: linear-gradient(to right, rgba(0,0,0,0.03) 0%, transparent 5%, transparent 95%, rgba(0,0,0,0.03) 100%);
}

/* Hard covers (thick cardstock) */
.cover-page, .back-cover-page {
    background-color: #f1ede3; 
    box-shadow: inset 6px 0 30px rgba(0,0,0,0.1), inset -2px 0 5px rgba(255,255,255,0.5);
    border-radius: 2px 6px 6px 2px;
}

/* Spine edge accent for covers */
.cover-page::before {
    content: '';
    position: absolute;
    left: 0; top: 0; bottom: 0;
    width: 12px;
    background: linear-gradient(to right, rgba(0,0,0,0.15) 0%, rgba(255,255,255,0.05) 50%, rgba(0,0,0,0.15) 100%);
    box-shadow: 2px 0 5px rgba(0,0,0,0.1);
    z-index: 10;
}

/* Vertical Text Typography */
.vertical-text {
    writing-mode: vertical-rl;
    text-orientation: upright;
}

.page-content {
    padding: 50px 40px;
    height: 100%;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
}

.page-content p {
    text-indent: 2em;
    line-height: 2.2;
    font-size: 1.15rem;
    letter-spacing: 0.05rem;
    color: #3f3c37;
    text-align: justify;
}

.page-content h2 {
    font-size: 1.8rem;
    font-weight: 600;
    color: #2c2925;
    margin-left: 15px; /* Spacing in vertical mode */
}

/* --- NAVIGATION ARROWS (Giant Side Controls) --- */
.nav-arrow {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.05); /* very subtle */
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255,255,255,0.6);
    font-size: 2rem;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    z-index: 50;
    width: 64px;
    height: 64px;
    border-radius: 50%;
    display: flex;
    justify-content: center;
    align-items: center;
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}
.nav-arrow:hover {
    color: #fff;
    background: rgba(255, 255, 255, 0.15);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-50%) scale(1.1);
    box-shadow: 0 10px 25px rgba(0,0,0,0.3);
}
.nav-arrow.nav-prev { left: 4%; }
.nav-arrow.nav-next { right: 4%; }


/* --- TOP NAVBAR --- */
.top-nav {
    position: fixed;
    top: 0; left: 0; width: 100%; height: 60px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 30px;
    box-sizing: border-box;
    z-index: 100;
    background: linear-gradient(to bottom, rgba(17, 24, 39, 0.9), transparent);
    pointer-events: none; /* Let clicks pass through except on children */
}
.top-nav > * {
    pointer-events: auto; /* Re-enable clicks on header items */
}
.logo-area {
    display: flex;
    align-items: center;
    filter: drop-shadow(0 2px 4px rgba(0,0,0,0.5));
}

/* --- BOTTOM TOOLBAR (GLASSMORPHISM) --- */
.bottom-toolbar {
    position: fixed;
    bottom: 30px; left: 50%;
    transform: translateX(-50%);
    height: 56px;
    display: flex;
    justify-content: center;
    align-items: center;
    background: rgba(31, 41, 55, 0.65); /* Sleek translucent dark */
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    box-shadow: 0 10px 30px rgba(0,0,0,0.4), inset 0 1px 0 rgba(255,255,255,0.1);
    border-radius: 28px; /* Pill shaped toolbar */
    z-index: 100;
    padding: 0 15px;
    box-sizing: border-box;
    color: rgba(255,255,255,0.7);
}

.toolbar-btn {
    background: transparent;
    border: none;
    color: rgba(255,255,255,0.6);
    font-size: 1.35rem;
    cursor: pointer;
    margin: 0 6px;
    width: 40px; height: 40px;
    border-radius: 50%;
    transition: all 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
}
.toolbar-btn:hover {
    color: white;
    background: rgba(255,255,255,0.15);
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.divider {
    width: 1px;
    height: 24px;
    background: rgba(255,255,255,0.15);
    margin: 0 10px;
}

.page-indicator {
    background: rgba(0, 0, 0, 0.4);
    color: #fff;
    padding: 4px 16px;
    border-radius: 20px;
    font-size: 0.95rem;
    font-family: 'Courier New', Courier, monospace;
    font-weight: 500;
    letter-spacing: 1px;
    margin: 0 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 1px solid rgba(255,255,255,0.05);
}

/* Mobile Adjustments - Perfect UI/UX */
@media (max-width: 768px) {
    .nav-arrow { display: none; }
    
    .top-nav { height: 50px; padding: 0 15px; }
    .logo-area img { height: 35px; }
    
    .reader-container { 
        height: calc(100vh - 130px); /* More gap top and bottom */
        margin-top: 65px; 
        padding: 0 20px; /* Beautiful gap left and right */
        box-sizing: border-box;
    }
    
    .bottom-toolbar { 
        bottom: 10px;
        padding: 0 5px; 
        height: 50px;
        width: 95%; /* Make it fill more on mobile */
        border-radius: 15px;
        justify-content: space-evenly;
    }
    .toolbar-btn { 
        margin: 0 2px; 
        font-size: 1.25rem; 
        width: 36px; height: 36px;
    }
    .divider { margin: 0 5px; }
    
    .page-indicator { 
        margin: 0 2px; 
        font-size: 0.85rem; 
        padding: 4px 10px;
    }
    .hide-on-mobile { display: none; }
}