* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    line-height: 1.6;
    color: var(--text);
    background: var(--background);
    font-family: var(--font-family, system-ui, -apple-system, sans-serif);
    min-height: 100vh;
    transition: var(--transition);
    padding: 0 20px;
}

.top-controls {
    position: fixed;
    top: 30px;
    right: 30px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 22;
}

.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px 0;
}

.library-overview {
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 24px;
    margin: 14px 0 24px;
    padding: 8px 2px 20px;
    border-bottom: 1px solid var(--border);
}

.library-overview-kicker {
    margin: 0 0 2px;
    color: var(--button-bg);
    font-size: .72rem;
    font-weight: 760;
    letter-spacing: .12em;
    text-transform: uppercase;
}

.library-overview h1 {
    margin: 0;
    color: var(--text);
    font-size: clamp(1.65rem, 3vw, 2.25rem);
    font-weight: 780;
    letter-spacing: -.035em;
    line-height: 1.15;
}

.library-summary {
    display: flex;
    align-items: center;
    gap: 8px;
}

.library-summary-item {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    min-height: 36px;
    padding: 0 11px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--card-bg);
    color: var(--text-secondary);
    font-size: .8rem;
    font-variant-numeric: tabular-nums;
    white-space: nowrap;
}

.library-summary-item i {
    color: var(--button-bg);
}

.breadcrumb-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 20px 0 0;
}

.library-breadcrumb {
    justify-content: space-between;
    gap: 24px;
    min-height: 76px;
    padding: 18px 24px;
}

.library-breadcrumb .breadcrumb-current {
    flex: 0 0 auto;
    gap: 10px;
    font-size: 1.2rem;
    letter-spacing: -0.01em;
}

.library-meta,
.library-meta-item,
.library-meta-action {
    display: inline-flex;
    align-items: center;
}

.library-meta {
    gap: 12px;
    color: var(--text-secondary);
    font-size: 0.875rem;
    line-height: 1;
}

.library-meta-item {
    gap: 6px;
    white-space: nowrap;
    font-variant-numeric: tabular-nums;
}
.library-meta-item i,
.library-meta-action i { color: var(--button-bg); }

.library-meta-item + .library-meta-item::before,
.library-meta-action::before,
.library-language::before {
    content: '';
    width: 1px;
    height: 18px;
    margin-right: 12px;
    background: var(--border);
}

.library-meta-action {
    gap: 5px;
    min-height: 36px;
    padding: 0 2px;
    border: 0;
    background: transparent;
    color: inherit;
    font: inherit;
    cursor: pointer;
}

.library-meta-action:hover,
.library-meta-action:focus-visible { color: var(--breadcrumb-link-hover); }

.library-language {
    display: inline-flex;
    align-items: center;
    min-height: 36px;
    gap: 6px;
    color: var(--text-secondary);
}

.library-language i { color: var(--button-bg); }

.library-language select {
    min-height: 36px;
    padding: 0 26px 0 7px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: transparent;
    color: var(--text);
    font: inherit;
}

.library-language select:focus-visible {
    outline: 2px solid var(--button-bg);
    outline-offset: 2px;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.breadcrumb {
    display: flex;
    align-items: center;
    margin: 20px 0;
    padding: 28px 24px;
    background: var(--card-bg);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.breadcrumb::before {
    content: '';
    position: absolute;
    inset: 0 0 auto;
    height: 4px;
    background: linear-gradient(to right, var(--primary), var(--secondary));
}

.breadcrumb-current {
    color: var(--text);
    font-weight: 600;
}

@media (max-width: 700px) {
    .library-overview {
        align-items: flex-start;
        flex-direction: column;
        gap: 14px;
        margin-top: 4px;
    }

    .library-summary {
        flex-wrap: wrap;
    }

    .library-breadcrumb {
        align-items: flex-start;
        flex-wrap: wrap;
        gap: 12px;
        min-height: 0;
        padding: 16px;
    }

    .library-meta { width: 100%; flex-wrap: wrap; gap: 8px 12px; }

    .library-meta-item + .library-meta-item::before,
    .library-meta-action::before,
    .library-language::before { display: none; }
}

.theme-toggle {
    width: 50px;
    height: 50px;
    border-radius: 50%;

    background: var(--card-bg);
    border: none;

    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    flex-direction: column;

    transition: var(--transition);
    box-shadow: var(--shadow-md);
}

.theme-toggle:hover {
    transform: rotate(15deg);
}

.theme-toggle i {
    font-size: 1.3rem;
    color: var(--text);
    transition: var(--transition);
}

.controls {
    display: block;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
    gap: 15px;
}

.search-container {
    flex: 1;
    min-width: 300px;
    position: relative;
}

.search-box {
    width: 100%;
    padding: 15px 50px 15px 20px;
    border: 2px solid var(--border);
    border-radius: 50px;
    font-size: 1rem;
    transition: var(--transition);
    background: var(--search-bg);
    color: var(--search-text);
}

.search-box:focus {
    outline: none;
    border-color: var(--button-bg);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.search-icon {
    position: absolute;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
    font-size: 1.2rem;
    transition: var(--transition);
}

.filter-container {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.filter-btn {
    background: var(--card-bg);
    border: 2px solid var(--border);
    padding: 10px 20px;
    border-radius: 50px;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text);
}

.filter-btn:hover, .filter-btn.active {
    background: var(--button-bg);
    color: white;
    border-color: var(--button-bg);
}

.stats {
    display: flex;
    flex-wrap: wrap;
    flex-direction: row;
    justify-content: center;
}

.stat-card {
    background: var(--card-bg);
    padding: 5px;
    border-radius: var(--border-radius-lg);
    display: flex;
    align-items: center;
    transition: var(--transition);
}

.stat-card i {
    font-size: 1.5rem;
    color: var(--button-bg);
}

.book-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.book-grid-loading {
    grid-column: 1 / -1;
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 60px 0;
}

.book-card {
    background: var(--book-card-bg);
    border-radius: var(--border-radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: var(--transition);
    position: relative;
    display: flex;
    flex-direction: column;
}

.book-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.15);
}

.book-cover-frame {
    position: relative;
    flex: 0 0 auto;
}

.book-cover {
    width: 100%;
    height: auto;
    aspect-ratio: 4 / 5;
    object-fit: cover;
    display: block;
    border-bottom: 1px solid transparent;
}

.book-card-content {
    padding: 5px 20px;
    flex-grow: 1;
    display: flex;
    flex-direction: column;
}

.book-title {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--book-title);
    line-height: 1.4;
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    transition: var(--transition);
    width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.book-author {
    font-size: 0.9rem;
    color: var(--book-author);
    transition: var(--transition);
    width: 100%;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.book-rating-badge {
    position: absolute;
    z-index: 1;
    right: 10px;
    bottom: 10px;
    display: inline-flex;
    align-items: center;
    gap: 4px;
    min-height: 28px;
    padding: 0 8px;
    border: 1px solid color-mix(in srgb, #fff 44%, transparent);
    border-radius: 999px;
    background: color-mix(in srgb, var(--card-bg) 88%, transparent);
    box-shadow: 0 2px 8px color-mix(in srgb, #000 24%, transparent);
    color: #9a6700;
    font-size: 0.78rem;
    font-weight: 600;
    line-height: 1;
    pointer-events: none;
}

.book-format-badge {
    position: absolute;
    z-index: 1;
    right: 10px;
    bottom: 10px;
    display: inline-flex;
    min-height: 26px;
    align-items: center;
    padding: 0 9px;
    border: 1px solid color-mix(in srgb, #fff 44%, transparent);
    border-radius: 999px;
    background: color-mix(in srgb, var(--button-bg) 92%, transparent);
    box-shadow: 0 2px 8px color-mix(in srgb, #000 24%, transparent);
    color: #fff;
    font-size: .72rem;
    font-weight: 700;
    letter-spacing: .04em;
    line-height: 1;
    pointer-events: none;
}

.pdf-cover-frame .book-rating-badge {
    bottom: 44px;
}

.book-rating-badge i {
    font-size: 0.8em;
}

.book-tags {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: linear-gradient(to top, rgba(0,0,0,0.8), transparent);
    padding: 20px 15px 10px;
    transform: translateY(100%);
    opacity: 0;
    transition: all 0.3s ease;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.book-card:hover .book-tags {
    transform: translateY(0);
    opacity: 1;
}

.book-card a:target{
    background: linear-gradient(to right, var(--primary), var(--secondary));
    color: #e9ecef;
}

.book-card a:target .book-title, .book-card a:target .book-author{
    color: #e9ecef;
}

.book-tag {
    background: var(--book-tag);
    color: var(--book-tag-text);
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
    transition: var(--transition);
}

.book-tag:hover {
    background: var(--book-tag-hover);
    color: white;
    cursor: pointer;
}

.book-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: auto;
    font-size: 0.85rem;
    color: var(--text-secondary);
    transition: var(--transition);
}

.book-format {
    background: var(--button-bg);
    color: white;
    padding: 4px 10px;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 500;
}

.book-link {
    display: block;
    text-decoration: none;
    color: inherit;
}

.reading-controls {
    position: fixed;
    bottom: 30px;
    right: 30px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    z-index: 99;
}

.control-name {
    font-size: 0.5rem;
}

.control-btn {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    background: var(--button-bg);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-md);
    border: none;
    flex-direction: column;
}

.control-btn:hover {
    background: var(--button-hover);
    transform: scale(1.1);
}

.eb-footer {
    text-align: center;
    padding: 10px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-top: 1px solid var(--border);
    transition: var(--transition);
}

.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

.library-state {
    display: grid;
    grid-column: 1 / -1;
    width: min(100%, 760px);
    min-height: 280px;
    box-sizing: border-box;
    place-content: center;
    justify-self: center;
    gap: 12px;
    margin: 18px auto 40px;
    padding: 48px clamp(24px, 6vw, 72px);
    border: 1px dashed color-mix(in srgb, var(--button-bg) 28%, var(--border));
    border-radius: var(--border-radius-xl, 12px);
    background: color-mix(in srgb, var(--card-bg) 92%, var(--background));
    box-shadow: var(--shadow-sm, 0 2px 8px rgba(0, 0, 0, .06));
}

.library-state-icon {
    display: grid;
    width: 72px;
    height: 72px;
    margin: 0 auto 6px;
    place-items: center;
    border-radius: 22px;
    background: color-mix(in srgb, var(--button-bg) 10%, var(--card-bg));
    color: var(--button-bg);
    font-size: 1.9rem;
}

.library-state h2 {
    margin: 0;
    color: var(--text);
    font-size: clamp(1.25rem, 3vw, 1.55rem);
    letter-spacing: -.025em;
}

.library-state p {
    max-width: 520px;
    margin: 0 auto;
    color: var(--text-secondary);
    font-size: .95rem;
    line-height: 1.7;
}

.library-state--filtered {
    min-height: 220px;
}

.book-icon {
    width: 100%;
    height: 120px;
    background: linear-gradient(135deg, var(--button-hover), var(--button-bg));
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2.5rem;
}

.tag-cloud {
    --tag-cloud-gap: 10px;
    --tag-cloud-row-height: calc(1.35rem + 14px);
    display: flex;
    flex-wrap: wrap;
    gap: var(--tag-cloud-gap);
    margin-bottom: 30px;
    justify-content: center;
}

.tag-cloud--overflowing {
    margin-bottom: 12px;
}

.tag-cloud--collapsed:not(.tag-cloud--expanded) {
    max-height: calc(var(--tag-cloud-row-height) * 2 + var(--tag-cloud-gap));
    overflow: hidden;
}

.tag-cloud-item {
    display: inline-flex;
    align-items: center;
    min-height: 34px;
    padding: 5px 14px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--tag-bg);
    color: var(--tag-text);
    font-size: 0.875rem;
    line-height: 1.4;
    white-space: nowrap;
    cursor: grab;
    transition: var(--transition);
}

.tag-cloud-item:hover {
    background: var(--tag-hover);
    border-color: var(--button-bg);
    color: var(--tag-text);
}

.tag-cloud-item.active {
    background: var(--button-bg);
    border-color: var(--button-bg);
    color: var(--button-text);
    box-shadow: var(--shadow-md);
}

.tag-cloud-item:focus-visible {
    outline: 2px solid var(--button-bg);
    outline-offset: 2px;
}

.tag-cloud-item:active {
    cursor: grabbing;
}

/* 固定项（All / NoTag）不可拖拽，弱化视觉以便与可排序的真实标签区分 */
.tag-cloud-item--fixed {
    background: transparent;
    border-style: dashed;
    color: var(--text-secondary);
    cursor: default;
    box-shadow: none;
}

.tag-cloud-item--fixed:hover {
    background: var(--tag-bg);
    border-color: var(--border);
    color: var(--text-secondary);
}

.tag-cloud-item--fixed.active {
    background: var(--button-bg);
    border-color: var(--button-bg);
    color: var(--button-text);
}

.tag-cloud-item--fixed.active:hover {
    background: var(--button-bg);
    border-color: var(--button-bg);
    color: var(--button-text);
}

/* 拖拽过程中的占位与选中反馈 */
.tag-cloud-item.sortable-ghost {
    opacity: 0.45;
    background: var(--tag-hover);
}

.tag-cloud-item.sortable-chosen {
    box-shadow: var(--shadow-lg);
    border-color: var(--button-bg);
}

.tag-cloud-item.sortable-drag {
    cursor: grabbing;
}

.tag-cloud-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 36px;
    margin: 0 auto 30px;
    padding: 6px 14px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: var(--card-bg);
    color: var(--text-secondary);
    font: inherit;
    font-size: .875rem;
    cursor: pointer;
    transition: var(--transition);
}

.tag-cloud-toggle:hover,
.tag-cloud-toggle:focus-visible {
    border-color: var(--button-bg);
    color: var(--button-bg);
}

.tag-cloud-toggle:focus-visible {
    outline: 2px solid var(--button-bg);
    outline-offset: 2px;
}

.tag-cloud-toggle[hidden] {
    display: none;
}

@media (max-width: 768px) {
    body {
        padding: 0;
    }

    .container {
        padding: 0 15px;
    }
    
    .book-grid {
        grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
        gap: 15px;
        padding: 0;
    }
    
    .eb-header h1 {
        font-size: 2rem;
    }
    
    .stats {
        flex-direction: row;
        align-items: center;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-container {
        min-width: 100%;
    }
    
    .select-group-header {
        flex-direction: column;
        gap: 10px;
    }
    
    .select-group-header h3 {
        text-align: center;
    }
    
    .group-covers {
        height: 220px;
    }
}

@media (max-width: 480px) {
    .book-grid {
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 12px;
        padding: 0;
    }
    
    .book-rating-badge {
        right: 8px;
        bottom: 8px;
        min-height: 26px;
        padding: 0 7px;
        font-size: 0.74rem;
    }
    
    .library-info {
        padding: 30px 15px;
    }
    
    .group-covers {
        height: 200px;
    }
}

.path-item {
    color: var(--text);
}

.path-item.clickable {
    cursor: pointer;
    color: var(--button-bg);
    transition: var(--transition);
}

.path-item.clickable:hover {
    color: var(--button-hover);
    text-decoration: underline;
}

.path-separator {
    color: var(--text-secondary);
    margin: 0 4px;
}

/* 选择分组弹窗样式 */
.select-group-modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.5);
    display: none;
    justify-content: center;
    align-items: center;
    z-index: 10002;
}

.select-group-modal.active {
    display: flex;
}

.select-group-content {
    width: 90%;
    max-width: 500px;
    max-height: 80vh;
    background: var(--card-bg);
    border-radius: var(--border-radius-lg);
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    display: flex;
    flex-direction: column;
}

.select-group-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
}

.select-group-header h3 {
    margin: 0;
    color: var(--text);
}

.select-group-close-btn {
    width: 32px;
    height: 32px;
    background: var(--border);
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition);
    color: var(--text);
}

.select-group-close-btn:hover {
    background: var(--notification-error);
    color: white;
}

.select-group-body {
    padding: 20px;
    overflow-y: auto;
    flex: 1;
}

.select-group-tree {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.select-group-item {
    display: flex;
    align-items: center;
    padding: 10px 15px;
    background: var(--background);
    border-radius: 6px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.select-group-item:hover {
    background: var(--button-hover);
    color: white;
}

.select-group-item.selected {
    border-color: var(--button-bg);
    background: var(--button-hover);
    color: white;
}

.select-group-item-icon {
    margin-right: 10px;
    font-size: 1rem;
}

.select-group-item-name {
    font-size: 0.95rem;
    font-weight: 500;
}

.select-group-children {
    margin-left: 20px;
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 8px;
}

.select-group-footer {
    padding: 15px 20px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: flex-end;
    flex-shrink: 0;
}

.select-group-confirm-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    background: var(--button-bg);
    color: white;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.95rem;
    transition: var(--transition);
}

.select-group-confirm-btn:hover {
    background: var(--button-hover);
}

/* Desktop styles */
@media (min-width: 769px) {
    .library-info {
        box-shadow: var(--shadow-lg);
    }
}