:root {
    --bg-main: #f8fafc;
    --bg-card: #ffffff;
    --border-color: #e2e8f0;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --primary-blue: #2563eb;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    margin: 0;
    padding: 0;
    -webkit-font-smoothing: antialiased;
}

.site-header {
    padding: 40px 20px 20px 20px;
    background-color: var(--bg-main);
}

.sticky-controls {
    position: sticky;
    top: 0;
    z-index: 100;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-color);
    padding: 20px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05);
}

.header-top {
    text-align: center;
    max-width: 1200px;
    margin: 0 auto 20px auto;
    position: relative;
}

.dev-badge-container {
    position: absolute;
    top: -20px;
    right: 0;
    display: flex;
    flex-direction: column;
    gap: 8px;
    align-items: flex-end;
}

.dev-badge-icon {
    vertical-align: middle;
    margin-right: 6px;
    border-radius: 2px;
}

.dev-badge {
    display: inline-flex;
    align-items: center;
    background: linear-gradient(135deg, #eff6ff, #e0f2fe);
    color: #2563eb;
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 11px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    border: 1px solid #bfdbfe;
    box-shadow: 0 2px 4px rgba(37, 99, 235, 0.05);
}

.dev-badge:hover {
    background: linear-gradient(135deg, #e0f2fe, #bfdbfe);
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(37, 99, 235, 0.1);
}

.donate-badge {
    background: linear-gradient(135deg, #fffbeb, #fef3c7);
    color: #d97706;
    border: 1px solid #fde68a;
    box-shadow: 0 2px 4px rgba(217, 119, 6, 0.05);
}

.donate-badge:hover {
    background: linear-gradient(135deg, #fef3c7, #fde68a);
    box-shadow: 0 4px 8px rgba(217, 119, 6, 0.1);
}

.title-group {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.title-group h1 {
    margin: 0;
    font-size: 32px;
    font-weight: 800;
    background: linear-gradient(135deg, #2563eb, #4f46e5);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.total-badge {
    background: #eff6ff;
    color: #1d4ed8;
    border: 1px solid #bfdbfe;
    padding: 6px 14px;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 700;
}

.subtitle {
    color: var(--text-muted);
    font-size: 15px;
    margin: 8px 0 0 0;
}

.controls-wrapper {
    max-width: 900px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.search-container {
    position: relative;
    width: 100%;
}

.search-icon {
    position: absolute;
    left: 16px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 18px;
    opacity: 0.5;
}

.search-container input {
    width: 100%;
    box-sizing: border-box;
    padding: 16px 20px 16px 45px;
    background-color: #ffffff;
    border: 1px solid #cbd5e1;
    border-radius: 16px;
    color: var(--text-main);
    font-size: 16px;
    transition: all 0.3s ease;
    box-shadow: inset 0 2px 4px rgba(0, 0, 0, 0.02);
}

.search-container input:focus {
    border-color: var(--primary-blue);
    outline: none;
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.1);
}

.search-container input::placeholder {
    color: #94a3b8;
}

.filter-row {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 8px;
}

.pill-btn {
    background: #ffffff;
    border: 1px solid var(--border-color);
    color: var(--text-muted);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
}

.pill-btn:hover {
    background: #f1f5f9;
    color: var(--text-main);
}

.pill-btn.active {
    background: transparent;
    color: inherit;
    border-color: transparent;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
}

.lvl-btn[data-level="A1"].active {
    background: #d1fae5;
    color: #047857;
    border-color: #a7f3d0;
}

.lvl-btn[data-level="A2"].active {
    background: #fef3c7;
    color: #b45309;
    border-color: #fde68a;
}

.lvl-btn[data-level="A2-B1"].active {
    background: #ffedd5;
    color: #c2410c;
    border-color: #fed7aa;
}

.lvl-btn[data-level="B1"].active {
    background: #fee2e2;
    color: #b91c1c;
    border-color: #fecaca;
}

.lvl-btn[data-level="B2"].active {
    background: #ede9fe;
    color: #6d28d9;
    border-color: #ddd6fe;
}

.lvl-btn[data-level="C1"].active {
    background: #dbeafe;
    color: #1d4ed8;
    border-color: #bfdbfe;
}

.lvl-btn[data-level="all"].active {
    background: #f1f5f9;
    color: var(--text-main);
    border-color: #cbd5e1;
}

.pub-btn[data-pub="Penguin Readers"].active {
    background: #ffedd5;
    color: #ea580c;
    border-color: #fed7aa;
}

.pub-btn[data-pub="Cambridge Reader"].active {
    background: #fce7f3;
    color: #be185d;
    border-color: #fbcfe8;
}

.pub-btn[data-pub="Macmillan Reader"].active {
    background: #cffafe;
    color: #0f766e;
    border-color: #a5f3fc;
}

.pub-btn[data-pub="Black Cat"].active {
    background: #f1f5f9;
    color: #0f172a;
    border-color: #cbd5e1;
}

.pub-btn[data-pub="National Geographic"].active {
    background: #fef08a;
    color: #854d0e;
    border-color: #fde047;
}

.pub-btn[data-pub="Step Into Reading"].active {
    background: #ccfbf1;
    color: #0f766e;
    border-color: #99f6e4;
}

.pub-btn[data-pub="Oxford Bookworms"].active {
    background: #e0e7ff;
    color: #3730a3;
    border-color: #c7d2fe;
}

.pub-btn[data-pub="All Aboard Reading"].active {
    background: #fee2e2;
    color: #991b1b;
    border-color: #fecaca;
}

.pub-btn[data-pub="Easy Classic"].active {
    background: #fef3c7;
    color: #92400e;
    border-color: #fde68a;
}

.pub-btn[data-pub="Who HQ Reader"].active {
    background: #f3e8ff;
    color: #6b21a8;
    border-color: #e9d5ff;
}

.lvl-btn[data-level="Footprint Reader"].active {
    background: #ffedd5;
    color: #c2410c;
    border-color: #fed7aa;
}

.lvl-btn[data-level="Page Turners"].active {
    background: #e0e7ff;
    color: #4338ca;
    border-color: #c7d2fe;
}

.lvl-btn[data-level="Foundation Reader"].active {
    background: #fae8ff;
    color: #a21caf;
    border-color: #f5d0fe;
}

.lvl-btn[data-level="Windows on Literacy"].active {
    background: #ffe4e6;
    color: #be123c;
    border-color: #fecdd3;
}

.lvl-btn[data-level="Reading Expedition"].active {
    background: #d1fae5;
    color: #047857;
    border-color: #a7f3d0;
}

.lvl-btn[data-level="Theme Sets"].active {
    background: #f3e8ff;
    color: #7e22ce;
    border-color: #e9d5ff;
}

.lvl-btn[data-level="Early Read"].active {
    background: #e0f2fe;
    color: #0369a1;
    border-color: #bae6fd;
}

.lvl-btn[data-level="Green Apple"].active {
    background: #dcfce7;
    color: #15803d;
    border-color: #bbf7d0;
}

.lvl-btn[data-level="Reading N Training"].active {
    background: #ede9fe;
    color: #5b21b6;
    border-color: #ddd6fe;
}

.lvl-btn[data-level="Penguin Young Reader"].active {
    background: #fef08a;
    color: #ca8a04;
    border-color: #fde047;
}

.lvl-btn[data-level="Penguin Kids"].active {
    background: #fecdd3;
    color: #e11d48;
    border-color: #fda4af;
}

.lvl-btn[data-level="Macmillan Literature Collections"].active {
    background: #e2e8f0;
    color: #475569;
    border-color: #cbd5e1;
}

.pub-btn[data-pub="all"].active {
    background: #f1f5f9;
    color: var(--text-main);
    border-color: #cbd5e1;
}

/* Layout with sidebar */
.layout-container {
    display: flex;
    max-width: 1600px;
    margin: 40px auto;
    padding: 0 20px;
}

.sidebar {
    width: 250px;
    flex-shrink: 0;
}

.sidebar-sticky {
    position: sticky;
    top: 180px;
    /* Збільшений відступ, щоб не перекривалося верхньою панеллю */
}

.sidebar-title {
    font-size: 16px;
    color: var(--text-main);
    margin: 0 0 16px 0;
    padding-left: 12px;
}

/* Shuffle Toggle (iOS style) */
.shuffle-toggle {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    user-select: none;
    -webkit-tap-highlight-color: transparent;
}

.shuffle-label {
    font-size: 13px;
    color: #64748b;
    font-weight: 500;
    transition: color 0.3s;
}

.shuffle-toggle:hover .shuffle-label {
    color: #3b82f6;
}

.shuffle-container {
    margin-top: 12px;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    gap: 8px;
    padding-left: 12px;
}

.shuffle-switch-wrapper {
    margin: 0;
    display: inline-block;
}

.shuffle-label-text {
    font-size: 13px;
    font-weight: 500;
    color: #64748b;
    cursor: pointer;
    user-select: none;
}

.ad-empty {
    padding: 0 !important;
    background: transparent !important;
    border: none !important;
    box-shadow: none !important;
}

.switch-wrapper {
    position: relative;
    display: inline-block;
    width: 28px;
    height: 16px;
}

.switch-wrapper input {
    opacity: 0;
    width: 0;
    height: 0;
}

.switch-slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #cbd5e1;
    transition: .3s;
    border-radius: 20px;
}

.switch-slider:before {
    position: absolute;
    content: "";
    height: 12px;
    width: 12px;
    left: 2px;
    bottom: 2px;
    background-color: white;
    transition: .3s;
    border-radius: 50%;
    box-shadow: 0 1px 3px rgba(0,0,0,0.2);
}

input:checked + .switch-slider {
    background-color: #3b82f6;
}

input:checked + .switch-slider:before {
    transform: translateX(12px);
}

.filter-column {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 30px;
}

.sidebar-btn {
    background: transparent;
    border: none;
    color: var(--text-muted);
    padding: 10px 12px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: all 0.2s;
}

.sidebar-btn:hover {
    background: #f1f5f9;
    color: var(--text-main);
}

.sidebar-btn.active {
    background: #eff6ff;
    color: #2563eb;
    font-weight: 600;
}

.ad-block {
    background: #f8fafc;
    border: 2px dashed #cbd5e1;
    border-radius: 12px;
    height: 300px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #94a3b8;
    font-size: 13px;
    font-weight: 500;
    text-align: center;
    padding: 20px;
}

.main-content {
    flex-grow: 1;
    min-width: 0;
}

.books-grid {
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    /* 5 колонок, бо зліва сайдбар */
    gap: 24px;
}

.book-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    height: 100%;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.book-card:hover {
    transform: translateY(-6px);
    border-color: #bfdbfe;
    box-shadow: 0 12px 20px -5px rgba(0, 0, 0, 0.1);
}

.cover-slider {
    display: flex;
    overflow-x: auto;
    scroll-snap-type: x mandatory;
    scrollbar-width: none;
    /* Firefox */
    -ms-overflow-style: none;
    /* IE/Edge */
    width: 100%;
}

.cover-slider::-webkit-scrollbar {
    display: none;
    /* Safari/Chrome */
}

.slider-btn {
    position: absolute;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.8);
    border: 1px solid #cbd5e1;
    color: #333;
    border-radius: 50%;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 14px;
    z-index: 10;
    transition: all 0.2s;
    opacity: 0;
    /* Приховано за замовчуванням */
}

.book-card:hover .slider-btn {
    opacity: 1;
    /* З'являється при наведенні */
}

.slider-btn:hover {
    background: #ffffff;
    box-shadow: 0 2px 6px rgba(0, 0, 0, 0.2);
}

.prev-btn {
    left: 8px;
}

.next-btn {
    right: 8px;
}

.book-cover {
    flex: 0 0 100%;
    width: 100%;
    height: 280px;
    object-fit: cover;
    background-color: #f1f5f9;
    border-bottom: 1px solid var(--border-color);
    scroll-snap-align: start;
}

.book-info {
    padding: 16px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.book-info h3 {
    margin: 0 0 12px 0;
    font-size: 16px;
    font-weight: 700;
    line-height: 1.3;
    color: var(--text-main);
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 20px;
    margin-top: auto;
}

.tag {
    padding: 4px 8px;
    border-radius: 6px;
    font-size: 11px;
    font-weight: 800;
    border: 1px solid transparent;
    text-transform: uppercase;
    letter-spacing: 0.3px;
}

.tag.level-A0-A1 {
    background: #e0f2fe;
    color: #0369a1;
    border-color: #bae6fd;
}

.tag.level-A1 {
    background: #d1fae5;
    color: #047857;
    border-color: #a7f3d0;
}

.tag.level-A2 {
    background: #fef3c7;
    color: #b45309;
    border-color: #fde68a;
}

.tag.level-A2-B1 {
    background: #ffedd5;
    color: #c2410c;
    border-color: #fed7aa;
}

.tag.level-B1 {
    background: #fee2e2;
    color: #b91c1c;
    border-color: #fecaca;
}

.tag.level-B2 {
    background: #ede9fe;
    color: #6d28d9;
    border-color: #ddd6fe;
}

.tag.level-C1 {
    background: #dbeafe;
    color: #1d4ed8;
    border-color: #bfdbfe;
}

.tag.level-Unknown {
    background: #f1f5f9;
    color: #64748b;
    border-color: #e2e8f0;
}

.tag.pub-penguin {
    background: #ffedd5;
    color: #ea580c;
    border-color: #fed7aa;
}

.tag.pub-cambridge {
    background: #fce7f3;
    color: #be185d;
    border-color: #fbcfe8;
}

.tag.pub-macmillan {
    background: #cffafe;
    color: #0f766e;
    border-color: #a5f3fc;
}

.tag.pub-default {
    background: #f1f5f9;
    color: #64748b;
    border-color: #e2e8f0;
}

.tag.pub-black {
    background: #f1f5f9;
    color: #0f172a;
    border-color: #cbd5e1;
}

.tag.pub-national {
    background: #fef08a;
    color: #854d0e;
    border-color: #fde047;
}

.tag.pub-step {
    background: #ccfbf1;
    color: #0f766e;
    border-color: #99f6e4;
}

.tag.pub-oxford {
    background: #e0e7ff;
    color: #3730a3;
    border-color: #c7d2fe;
}

.tag.pub-all {
    background: #fee2e2;
    color: #991b1b;
    border-color: #fecaca;
}

.tag.pub-easy {
    background: #fef3c7;
    color: #92400e;
    border-color: #fde68a;
}

.tag.pub-who {
    background: #f3e8ff;
    color: #6b21a8;
    border-color: #e9d5ff;
}

.tag.level-Footprint-Reader {
    background: #ffedd5;
    color: #c2410c;
    border-color: #fed7aa;
}

.tag.level-Page-Turners {
    background: #e0e7ff;
    color: #4338ca;
    border-color: #c7d2fe;
}

.tag.level-Foundation-Reader {
    background: #fae8ff;
    color: #a21caf;
    border-color: #f5d0fe;
}

.tag.level-Windows-on-Literacy {
    background: #ffe4e6;
    color: #be123c;
    border-color: #fecdd3;
}

.tag.level-Reading-Expedition {
    background: #d1fae5;
    color: #047857;
    border-color: #a7f3d0;
}

.tag.level-Theme-Sets {
    background: #f3e8ff;
    color: #7e22ce;
    border-color: #e9d5ff;
}

.tag.level-Early-Read {
    background: #e0f2fe;
    color: #0369a1;
    border-color: #bae6fd;
}

.tag.level-Green-Apple {
    background: #dcfce7;
    color: #15803d;
    border-color: #bbf7d0;
}

.tag.level-Reading-N-Training {
    background: #ede9fe;
    color: #5b21b6;
    border-color: #ddd6fe;
}

.tag.level-Penguin-Young-Reader {
    background: #fef08a;
    color: #ca8a04;
    border-color: #fde047;
}

.tag.level-Penguin-Kids {
    background: #fecdd3;
    color: #e11d48;
    border-color: #fda4af;
}

.tag.level-Macmillan-Literature-Collections {
    background: #e2e8f0;
    color: #475569;
    border-color: #cbd5e1;
}

.download-btn {
    width: 100%;
    background: #f8fafc;
    color: var(--text-muted);
    text-align: center;
    border: 1px solid var(--border-color);
    padding: 12px;
    text-decoration: none;
    border-radius: 12px;
    font-weight: 600;
    font-size: 14px;
    transition: all 0.3s;
    box-sizing: border-box;
}

.book-card:hover .download-btn {
    background: var(--primary-blue);
    color: white;
    border-color: var(--primary-blue);
}

.load-more-container {
    text-align: center;
    margin: 40px 0;
}

#load-more-btn {
    background: #ffffff;
    color: var(--text-main);
    border: 1px solid #cbd5e1;
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.2s;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

#load-more-btn:hover {
    background: #f1f5f9;
    transform: scale(1.02);
}

@media (max-width: 1400px) {
    .books-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

@media (max-width: 1024px) {
    .books-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media (max-width: 900px) {
    .layout-container {
        flex-direction: column;
    }

    .sidebar {
        width: 100%;
    }

    .sidebar-sticky {
        position: static;
    }

    .filter-column {
        flex-direction: row;
        overflow-x: auto;
        padding-bottom: 8px;
        scrollbar-width: none;
    }

    .filter-column::-webkit-scrollbar {
        display: none;
    }

    .sidebar-btn {
        flex-shrink: 0;
        background: #ffffff;
        border: 1px solid var(--border-color);
        border-radius: 20px;
        padding: 8px 16px;
    }

    .ad-block {
        display: none;
        /* Ховаємо рекламу на мобільних за замовчуванням */
    }
}

@media (max-width: 768px) {

    .dev-badge-container {
        position: static;
        margin-bottom: 12px;
        text-align: center;
    }

    .books-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 16px;
    }

    .site-header {
        padding: 25px 15px 15px 15px;
    }

    .title-group h1 {
        font-size: 24px;
    }

    .subtitle {
        font-size: 14px;
    }

    .sticky-controls {
        padding: 12px 15px;
    }

    .controls-wrapper {
        gap: 10px;
    }

    .search-container input {
        padding: 10px 16px 10px 38px;
        font-size: 14px;
        border-radius: 12px;
    }

    .search-icon {
        left: 14px;
        font-size: 15px;
    }

    .filter-row {
        flex-wrap: nowrap;
        overflow-x: auto;
        justify-content: flex-start;
        padding-bottom: 4px;
        -webkit-overflow-scrolling: touch;
        scrollbar-width: none;
    }

    .filter-row::-webkit-scrollbar {
        display: none;
    }

    .pill-btn {
        flex-shrink: 0;
        padding: 6px 14px;
        font-size: 12px;
    }

    main {
        padding: 20px 15px;
    }

    .book-cover {
        height: 220px;
    }
}

@media (max-width: 480px) {

    .books-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .site-header {
        padding: 15px 10px 10px 10px;
    }

    .title-group {
        flex-direction: column;
        gap: 8px;
    }

    .title-group h1 {
        font-size: 20px;
        text-align: center;
        line-height: 1.2;
    }

    .total-badge {
        padding: 4px 10px;
        font-size: 12px;
    }

    .subtitle {
        display: none;
    }

    .sticky-controls {
        padding: 10px;
    }

    main {
        padding: 15px 10px;
    }

    .book-card {
        border-radius: 12px;
    }

    .book-cover {
        height: 170px;
    }

    .book-info {
        padding: 10px;
    }

    .book-info h3 {
        font-size: 13px;
        margin-bottom: 8px;
        line-height: 1.2;
    }

    .tags {
        gap: 4px;
        margin-bottom: 12px;
    }

    .tag {
        padding: 3px 6px;
        font-size: 9px;
        border-radius: 4px;
        letter-spacing: 0;
    }

    .download-btn {
        padding: 8px;
        font-size: 12px;
        border-radius: 8px;
    }
}

/* Modal styles */
#image-modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
}

#image-modal.show {
    display: flex;
    justify-content: center;
    align-items: center;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }

    to {
        opacity: 1;
    }
}

.modal-content {
    max-width: 90%;
    max-height: 90vh;
    border-radius: 12px;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
    object-fit: contain;
    animation: zoomIn 0.3s ease;
}

@keyframes zoomIn {
    from {
        transform: scale(0.95);
        opacity: 0;
    }

    to {
        transform: scale(1);
        opacity: 1;
    }
}

.close-modal {
    position: absolute;
    top: 20px;
    right: 30px;
    color: #f8fafc;
    font-size: 44px;
    font-weight: 300;
    cursor: pointer;
    transition: color 0.2s;
    z-index: 1001;
    line-height: 1;
}

.close-modal:hover {
    color: #ef4444;
}

.book-cover {
    cursor: zoom-in;
}