:root {
    --bg-body: #f2efe2;
    --bg-shelf: #ffffff;
    --text-main: #2c2c2c;
    --text-muted: #888888;
    --ui-border: rgba(0,0,0,0.08);
    --btn-hover: rgba(0,0,0,0.05);
    --spinner-color: #333;
    --spinner-bg: rgba(253, 250, 245, 0.9);
    --cover-shadow: 0 4px 8px rgba(0,0,0,0.15);
    --accent-color: #2c2c2c;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg-body: #1a1a1a;
        --bg-shelf: #222222;
        --text-main: #e0e0e0;
        --text-muted: #aaaaaa;
        --ui-border: rgba(255,255,255,0.1);
        --btn-hover: rgba(255,255,255,0.1);
        --spinner-color: #ddd;
        --spinner-bg: rgba(20, 20, 20, 0.9);
        --cover-shadow: 0 4px 8px rgba(0,0,0,0.5);
        --accent-color: #e0e0e0;
    }
}

html, body { 
    margin: 0;
    background-color: var(--bg-shelf); 
    color: var(--text-main);
    font-family: 'Georgia', 'Merriweather', serif;
    height: 100dvh;
    overflow: hidden;
    -webkit-tap-highlight-color: transparent;
    touch-action: none; 
}

#reader-logo {
    position: absolute;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: auto;
    z-index: 15; 
    cursor: pointer;
    opacity: 1;
    transition: opacity 0.3s ease, transform 0.4s cubic-bezier(0.25, 1, 0.5, 1);
    -webkit-user-select: none;
    transform: translate(-50%, calc(-60px - env(safe-area-inset-bottom)));
}

#reader-logo:hover {
    opacity: .7;
}
.view-section.ui-hidden .reader-header {
    transform: translateY(-100%);
}

.view-section.ui-hidden .reader-footer {
    transform: translateY(100%);
}
.view-section.ui-hidden #reader-logo {
    transform: translate(-50%, 0);
}

.view-section { 
    display: none; 
    width: 100%; 
    height: 100%; 
    position: relative;
}
.view-section.active { display: flex; flex-direction: column; }

#login-view {
    justify-content: center;
    align-items: center;
    background: var(--bg-body);
}
.login-card {
    padding: 40px;
    background: var(--bg-shelf);
    border: 1px solid var(--ui-border);
    border-radius: 8px;
    box-shadow: var(--cover-shadow);
    text-align: center;
    width: 300px;
}
.login-title {
    font-family: sans-serif;
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-bottom: 20px;
    font-size: 1.2rem;
    color: var(--text-muted);
}
.login-input {
    width: 100%;
    padding: 12px;
    margin-bottom: 15px;
    box-sizing: border-box;
    border: 1px solid var(--ui-border);
    border-radius: 4px;
    background: var(--bg-body);
    color: var(--text-main);
    font-size: 16px;
}
.login-btn {
    width: 100%;
    padding: 12px;
    background: var(--accent-color);
    color: var(--bg-body);
    border: none;
    border-radius: 4px;
    font-size: 14px;
    font-weight: bold;
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 1px;
}
.login-error {
    color: #ef4444;
    font-size: 14px;
    margin-top: 15px;
    display: none;
    font-family: sans-serif;
}

#shelf-view {
    padding: 40px 20px;
    overflow-y: auto; 
    box-sizing: border-box;
    background: var(--bg-shelf);
}

h1.shelf-title {
    text-align: center;
    font-family: sans-serif;
    font-weight: 300;
    margin-bottom: 30px;
    color: var(--text-muted);
    letter-spacing: 2px;
    text-transform: uppercase;
    font-size: 1.5rem;
}

.grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 30px;
    max-width: 1000px;
    margin: 0 auto;
    padding-bottom: 40px;
}

@media (max-width: 600px) {
    #shelf-view { padding: 20px 15px; }
    .grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px; 
    }
}

.book-card {
    cursor: pointer;
    transition: transform 0.2s ease;
    display: flex;
    flex-direction: column;
    align-items: center;
}
.book-card:hover { transform: translateY(-5px); }

.book-cover {
    width: 100%;
    aspect-ratio: 2 / 3;
    background: #444;
    border-radius: 4px;
    box-shadow: var(--cover-shadow);
    margin-bottom: 15px;
    background: linear-gradient(135deg, #444 0%, #222 100%);
}

.cover-blue { background: linear-gradient(135deg, #3b82f6 0%, #1e40af 100%); }
.cover-red { background: linear-gradient(135deg, #ef4444 0%, #991b1b 100%); }
.cover-green { background: linear-gradient(135deg, #10b981 0%, #065f46 100%); }

.book-title {
    font-size: 14px;
    text-align: center;
    line-height: 1.3;
    font-weight: bold;
    color: var(--text-main);
}
.book-author {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
    font-family: sans-serif;
}

#book-container {
    position: relative;
    height: 100%;
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: center;
    cursor: grab;
    overflow: hidden;
    background-color: var(--bg-body);
}
#book-container:active { cursor: grabbing; }

.reader-header {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: calc(50px + env(safe-area-inset-top));
    min-height: 50px;
    display: flex;
    align-items: center;
    padding-top: env(safe-area-inset-top);
    padding-right: 15px;
    padding-bottom: 0;
    padding-left: 15px;
    box-sizing: border-box;
    border-bottom: 1px solid var(--ui-border);
    justify-content: space-between;
    transition: transform 0.4s cubic-bezier(0.25, 1, 0.5, 1);
    background: var(--bg-shelf);
    z-index: 10;
}

.header-btn {
    background: none;
    border: none;
    font-size: 14px;
    color: var(--text-muted);
    cursor: pointer;
    font-family: sans-serif;
    text-transform: uppercase;
    letter-spacing: 1px;
    display: flex;
    align-items: center;
    gap: 5px;
    padding: 10px 0;
}
.header-btn:hover { color: var(--text-main); }

.font-controls {
    display: flex;
    gap: 15px;
    align-items: center;
}

.font-btn {
    font-size: 16px;
    font-weight: bold;
    font-family: serif;
    cursor: pointer;
    background: none;
    border: 1px solid var(--ui-border);
    border-radius: 4px;
    padding: 2px 8px;
    color: var(--text-main);
    min-width: 35px;
}
.font-btn:active { background: var(--btn-hover); }

.reader-title {
    font-size: 14px;
    font-weight: bold;
    color: var(--text-main);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 40%;
}

canvas { background: transparent; display: block; }

.reader-footer {
    position: absolute;
    bottom: 0;
    left: 0;
    width: 100%;
    height: auto;
    min-height: calc(60px + env(safe-area-inset-bottom));
    display: flex;
    align-items: flex-start;
    padding-top: 15px; 
    padding-bottom: env(safe-area-inset-bottom);
    padding-left: 20px;
    padding-right: 20px;
    box-sizing: border-box;
    justify-content: space-between;
    background: var(--bg-shelf);
    border-top: 1px solid var(--ui-border);
    font-family: sans-serif;
    transition: transform 0.4s cubic-bezier(0.25, 1, 0.5, 1);
    z-index: 10;
}

.footer-nav-btn {
    background: transparent;
    border: 1px solid var(--ui-border);
    border-radius: 4px;
    color: var(--text-main);
    padding: 8px 16px;
    font-size: 14px;
    cursor: pointer;
    min-width: 70px;
}
.footer-nav-btn:disabled {
    opacity: 0.3;
    pointer-events: none;
}
.footer-nav-btn:active {
    background: var(--btn-hover);
}

#chapter-label {
    font-size: 12px; 
    color: var(--text-muted);
    padding-top: 8px;
}

#loading-overlay {
    position: absolute;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--spinner-bg);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 20;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
}
#loading-overlay.active { opacity: 1; pointer-events: all; }

.spinner {
    width: 30px; height: 30px;
    border: 3px solid var(--ui-border);
    border-top: 3px solid var(--spinner-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}
@keyframes spin { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }