:root {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f8fafc;
    --text-muted: #94a3b8;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --border-color: #334155;
    --header-bg: #1e293b;
    --input-bg: #0f172a;
    --star-active: #f59e0b;
    --danger-color: #dc2626;
    --danger-hover: #b91c1c;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 10px 20px -2px rgba(0, 0, 0, 0.5);
}

body.light-theme {
    --bg-color: #f1f5f9;
    --card-bg: #ffffff;
    --text-color: #0f172a;
    --text-muted: #64748b;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --border-color: #cbd5e1;
    --header-bg: #ffffff;
    --input-bg: #f8fafc;
    --star-active: #d97706;
    --danger-color: #dc2626;
    --danger-hover: #b91c1c;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 10px 20px -2px rgba(0, 0, 0, 0.18);
}

* { box-sizing: border-box; margin: 0; padding: 0; font-family: system-ui, -apple-system, sans-serif; }
body { background-color: var(--bg-color); color: var(--text-color); min-height: 100vh; }

.app-header {
    position: sticky; top: 0; z-index: 100;
    background-color: var(--header-bg); border-bottom: 1px solid var(--border-color);
    box-shadow: var(--shadow); padding: 10px;
}

.header-content-wrapper {
    max-width: 1200px; margin: 0 auto;
    display: flex; flex-direction: column; gap: 8px; align-items: center;
}

.header-row-top { 
    display: flex; align-items: center; justify-content: center; 
    gap: 12px; width: 100%; flex-wrap: wrap; 
}

.app-title { font-size: 1.15rem; font-weight: 700; white-space: nowrap; }

.search-box { position: relative; width: 220px; }
.search-box input {
    width: 100%; padding: 6px 28px 6px 10px; border-radius: 6px;
    border: 1px solid var(--border-color); background-color: var(--input-bg); color: var(--text-color);
    font-size: 0.9rem; transition: border-color 0.2s;
}
.search-box input:focus { border-color: var(--accent-color); outline: none; }

.btn-icon { position: absolute; right: 6px; top: 50%; transform: translateY(-50%); background: none; border: none; color: var(--text-muted); cursor: pointer; padding: 4px; }

.mode-toggle { display: flex; background: var(--input-bg); padding: 2px; border-radius: 6px; border: 1px solid var(--border-color); }
.toggle-btn { background: none; border: none; color: var(--text-muted); padding: 4px 8px; border-radius: 4px; cursor: pointer; font-size: 0.8rem; transition: transform 0.15s; }
.toggle-btn:hover { transform: scale(1.05); }
.toggle-btn.active { background: var(--accent-color); color: #fff; font-weight: 600; }

.header-actions { display: flex; align-items: center; gap: 8px; }
.btn-action { background: var(--input-bg); border: 1px solid var(--border-color); color: var(--text-color); padding: 5px 10px; border-radius: 6px; cursor: pointer; transition: transform 0.2s; }
.btn-action:hover { transform: scale(1.1); }
.badge { background: var(--accent-color); color: #fff; font-size: 0.75rem; padding: 4px 8px; border-radius: 12px; white-space: nowrap; }

.alphabet-nav { 
    display: flex; flex-wrap: nowrap; gap: 2px; 
    justify-content: flex-start; align-items: center;
    width: 100%; overflow-x: auto; padding: 4px 0;
    -webkit-overflow-scrolling: touch; scrollbar-width: none; 
}
.alphabet-nav::-webkit-scrollbar { display: none; }

.nav-btn { 
    background: transparent; border: 1px solid transparent; color: var(--text-muted); 
    padding: 4px 7px; border-radius: 5px; font-size: 0.85rem; font-weight: 600; 
    cursor: pointer; flex-shrink: 0; min-height: 30px; display: flex; align-items: center; justify-content: center;
    transition: transform 0.15s ease, color 0.15s, background-color 0.15s;
}
.nav-btn:hover { color: var(--text-color); border-color: var(--border-color); transform: scale(1.18); z-index: 2; }
.nav-btn.active { background: var(--accent-color); color: #fff; transform: scale(1.05); }
.nav-btn.fav-btn.active { background: var(--star-active); }
.nav-divider { width: 1px; height: 16px; background: var(--border-color); margin: 0 3px; flex-shrink: 0; }

.content-container { padding: 12px; max-width: 1600px; margin: 0 auto; }

.books-grid { 
    display: grid; 
    grid-template-columns: repeat(auto-fill, minmax(155px, 1fr)); 
    gap: 14px; 
}

.book-card {
    background: var(--card-bg); border: 1px solid var(--border-color); border-radius: 8px;
    overflow: hidden; display: flex; flex-direction: column; height: 300px; box-shadow: var(--shadow);
    transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
}

.book-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-hover);
    border-color: var(--accent-color);
}

.cover-wrapper { 
    width: 100%; height: 225px; background: var(--input-bg); 
    position: relative; flex-shrink: 0; overflow: hidden; cursor: pointer;
}
.cover-img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.3s ease; }
.book-card:hover .cover-img { transform: scale(1.05); }

.no-cover { display: flex; flex-direction: column; align-items: center; justify-content: center; height: 100%; color: var(--text-muted); font-size: 0.75rem; }
.no-cover-icon { font-size: 2rem; opacity: 0.4; }

.cover-hover-layer {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.65);
    display: flex; flex-direction: column; justify-content: space-between;
    opacity: 0; transition: opacity 0.2s ease; z-index: 5;
    padding: 8px;
    pointer-events: none;
}

.cover-wrapper:hover .cover-hover-layer,
.cover-wrapper.active .cover-hover-layer {
    opacity: 1;
    pointer-events: auto;
}

.card-actions { 
    display: flex; justify-content: flex-end; gap: 6px; width: 100%; 
}
.action-btn {
    background: rgba(0, 0, 0, 0.75); border: 1px solid rgba(255,255,255,0.2); 
    font-size: 0.85rem; border-radius: 50%;
    width: 32px; height: 32px; cursor: pointer; color: #fff; 
    display: flex; align-items: center; justify-content: center;
    backdrop-filter: blur(4px); text-decoration: none; 
    transition: transform 0.15s, background-color 0.15s;
}
.action-btn:hover { transform: scale(1.2); background: rgba(0, 0, 0, 0.95); }
.action-btn.active { color: var(--star-active); border-color: var(--star-active); }

.btn-read-center {
    align-self: center;
    background: var(--accent-color); color: #fff; text-decoration: none;
    padding: 7px 16px; border-radius: 20px; font-size: 0.82rem; font-weight: bold;
    box-shadow: 0 4px 10px rgba(0,0,0,0.5);
    transform: translateY(10px); transition: transform 0.2s ease, background-color 0.2s;
}

.cover-wrapper:hover .btn-read-center,
.cover-wrapper.active .btn-read-center {
    transform: translateY(0);
}

.btn-read-center:hover {
    background: var(--accent-hover);
    transform: scale(1.08) !important;
}

.cover-meta-bar {
    display: flex; gap: 4px; align-items: center; flex-wrap: wrap; width: 100%;
}
.meta-tag {
    background: rgba(15, 23, 42, 0.85); border: 1px solid rgba(255, 255, 255, 0.2); 
    color: #f1f5f9; font-size: 0.65rem; padding: 2px 5px; border-radius: 4px; backdrop-filter: blur(2px);
    font-weight: 500;
}
.meta-tag.format { color: #60a5fa; font-weight: 700; border-color: rgba(96, 165, 250, 0.6); }

.book-info { padding: 8px 10px; display: flex; flex-direction: column; justify-content: center; gap: 2px; flex: 1; }
.book-title { font-size: 0.82rem; font-weight: 600; color: var(--text-color); line-height: 1.25; display: -webkit-box; -webkit-line-clamp: 2; -webkit-box-orient: vertical; overflow: hidden; }
.book-author { font-size: 0.72rem; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.spinner-container { display: flex; justify-content: center; padding: 20px; }
.spinner { width: 30px; height: 30px; border: 3px solid var(--border-color); border-top-color: var(--accent-color); border-radius: 50%; animation: spin 0.8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.empty-state { text-align: center; color: var(--text-muted); margin-top: 50px; font-size: 1rem; }
.hidden { display: none !important; }

/* Modal pro statistiky */
.modal-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0, 0, 0, 0.7); display: flex;
    justify-content: center; align-items: center; z-index: 1000;
}
.modal-content {
    background: var(--card-bg); color: var(--text-color); border-radius: 8px;
    padding: 20px; width: 90%; max-width: 500px;
    border: 1px solid var(--border-color); box-shadow: var(--shadow-hover);
}
.modal-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 15px; }

/* STYLY PRO ČTEČKU (read.html) */
body.reader-body {
    height: 100vh; display: flex; flex-direction: column; overflow: hidden;
}

.reader-topbar {
    height: 52px; background: var(--header-bg); border-bottom: 1px solid var(--border-color);
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 16px; box-shadow: var(--shadow); z-index: 10; flex-shrink: 0;
}

.book-details { display: flex; flex-direction: column; max-width: 30%; }
.book-title-header { font-size: 0.88rem; font-weight: bold; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; color: var(--text-color); }
.book-author-header { font-size: 0.72rem; color: var(--text-muted); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

.reader-controls-center { display: flex; align-items: center; gap: 8px; }

.font-controls { display: flex; gap: 2px; background: var(--input-bg); border: 1px solid var(--border-color); border-radius: 6px; padding: 2px; }
.btn-font { background: transparent; color: var(--text-muted); border: none; padding: 4px 8px; cursor: pointer; font-weight: bold; font-size: 0.85rem; transition: transform 0.15s, color 0.15s; }
.btn-font:hover { color: var(--text-color); transform: scale(1.1); }

.page-input-wrapper { display: flex; align-items: center; gap: 4px; font-size: 0.82rem; background: var(--input-bg); padding: 4px 8px; border-radius: 6px; border: 1px solid var(--border-color); }
.page-input-wrapper input { width: 42px; background: var(--bg-color); border: 1px solid var(--border-color); color: var(--text-color); text-align: center; border-radius: 4px; padding: 2px; font-size: 0.85rem; }

.nav-btn-read { background: var(--card-bg); color: var(--text-color); border: 1px solid var(--border-color); padding: 6px 12px; border-radius: 6px; cursor: pointer; font-size: 0.82rem; font-weight: 600; transition: transform 0.15s, background-color 0.15s; }
.nav-btn-read:hover { background: var(--accent-color); color: #fff; transform: scale(1.05); }

.back-btn { background: var(--danger-color); color: #fff; border: none; padding: 6px 14px; border-radius: 6px; cursor: pointer; text-decoration: none; font-weight: 600; font-size: 0.82rem; transition: transform 0.15s, background-color 0.15s; }
.back-btn:hover { background: var(--danger-hover); transform: scale(1.05); }

.reader-view-container { flex: 1; position: relative; width: 100%; height: calc(100vh - 52px); background: #ffffff; }
#viewer { width: 100%; height: 100%; }

.loading-overlay {
    position: absolute; top: 0; left: 0; width: 100%; height: 100%;
    background: var(--bg-color); display: flex; flex-direction: column;
    justify-content: center; align-items: center; z-index: 5; color: var(--text-muted);
}
.pdf-frame { width: 100%; height: 100%; border: none; }

@media (min-width: 600px) {
    .books-grid { grid-template-columns: repeat(auto-fill, minmax(175px, 1fr)); gap: 16px; }
    .book-card { height: 325px; }
    .cover-wrapper { height: 245px; }
    .alphabet-nav { justify-content: center; flex-wrap: wrap; overflow-x: visible; }
}

@media (max-width: 600px) {
    .reader-topbar { height: auto; padding: 6px 10px; flex-wrap: wrap; }
    .book-details { max-width: 65%; }
    .reader-controls-center { width: 100%; order: 3; justify-content: space-between; margin-top: 4px; }
}
/* ==========================================================================
   STYLY PRO STRÁNKU STATISTIK (stat.html)
   ========================================================================== */

/* Kontejner a hlavička statistik */
.stats-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

.stats-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color, #333);
}

.stats-header h1 {
    margin: 0;
    font-size: 1.8rem;
    display: flex;
    align-items: center;
    gap: 10px;
}

.back-link {
    color: var(--accent-color, #4a90e2);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

.back-link:hover {
    text-decoration: underline;
}

/* Kartičky s přehledem (KPI) */
.stats-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.stat-card {
    background: var(--card-bg, #1e1e1e);
    border: 1px solid var(--border-color, #333);
    border-radius: 8px;
    padding: 20px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.stat-card h3 {
    margin: 0 0 10px 0;
    font-size: 1rem;
    color: var(--text-muted, #aaa);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-card .stat-number {
    font-size: 2.2rem;
    font-weight: bold;
    color: var(--text-color, #fff);
}

/* Sekce s tabulkami */
.stats-section {
    background: var(--card-bg, #1e1e1e);
    border: 1px solid var(--border-color, #333);
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

.stats-section h2 {
    margin-top: 0;
    margin-bottom: 15px;
    font-size: 1.3rem;
    color: var(--text-color, #fff);
}

/* Styl Tabulek */
.stats-table {
    width: 100%;
    border-collapse: collapse;
    text-align: left;
}

.stats-table th,
.stats-table td {
    padding: 12px 15px;
    border-bottom: 1px solid var(--border-color, #2a2a2a);
}

.stats-table th {
    background-color: rgba(255, 255, 255, 0.05);
    color: var(--text-muted, #ccc);
    font-weight: 600;
}

.stats-table tbody tr:hover {
    background-color: rgba(255, 255, 255, 0.02);
}

/* Odznaky pro typ akce (Čtení / Stažení) */
.badge-action {
    display: inline-block;
    padding: 4px 10px;
    border-radius: 12px;
    font-size: 0.85rem;
    font-weight: 600;
}

.badge-action.read,
.badge-action.čtení {
    background-color: rgba(74, 144, 226, 0.2);
    color: #4a90e2;
    border: 1px solid rgba(74, 144, 226, 0.4);
}

.badge-action.download,
.badge-action.stažení {
    background-color: rgba(46, 204, 113, 0.2);
    color: #2ecc71;
    border: 1px solid rgba(46, 204, 113, 0.4);
}