/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.625rem 1.25rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.875rem;
    transition: background var(--transition), color var(--transition), border-color var(--transition), opacity var(--transition);
    white-space: nowrap;
}

.btn-primary {
    background: var(--primary);
    color: #fff;
}

.btn-primary:hover:not(:disabled) {
    background: var(--primary-dark);
}

.btn-outline {
    background: var(--surface);
    border: 1px solid var(--border);
    color: var(--text-secondary);
}

.btn-outline:hover:not(:disabled) {
    border-color: var(--primary);
    color: var(--primary);
}

.btn-danger-soft {
    background: var(--danger-soft);
    color: var(--danger);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-sm {
    padding: 0.4rem 0.85rem;
    font-size: 0.8rem;
}

.btn-lg {
    padding: 0.85rem 1.5rem;
    font-size: 1rem;
}

/* ===== Cards ===== */
.card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
}

.card-padded {
    padding: 1.25rem;
}

.card-header {
    font-weight: 600;
    font-size: 1rem;
    margin-bottom: 1rem;
}

/* ===== Stat cards ===== */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    padding: 1.25rem;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.stat-icon {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
}

.stat-icon.blue { background: var(--primary-soft); color: var(--primary); }
.stat-icon.green { background: var(--success-soft); color: var(--success); }
.stat-icon.red { background: var(--danger-soft); color: var(--danger); }
.stat-icon.purple { background: var(--purple-soft); color: var(--purple); }

.stat-label {
    font-size: 0.8rem;
    color: var(--text-muted);
}

.stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    line-height: 1.2;
}

.stat-info {
    min-width: 0;
}

.stat-info .stat-label {
    margin-bottom: 0.1rem;
}

/* ===== Badges ===== */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
}

.badge-success { background: var(--success-soft); color: var(--success); }
.badge-warning { background: var(--warning-soft); color: var(--warning-text); }
.badge-danger { background: var(--danger-soft); color: var(--danger-text); }
.badge-muted { background: var(--surface-muted); color: var(--text-muted); }
.badge-primary { background: var(--primary-soft); color: var(--primary); }

/* ===== Alert banner ===== */
.alert-banner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    padding: 0.875rem 1.25rem;
    border-radius: var(--radius-md);
    background: var(--danger-soft);
    border: 1px solid var(--danger-border);
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.alert-banner .alert-content {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    color: var(--danger-text);
}

.alert-banner .alert-action {
    color: var(--primary);
    font-weight: 600;
    white-space: nowrap;
}

/* ===== Book initials avatar ===== */
.book-avatar {
    width: 44px;
    height: 44px;
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
    color: #fff;
    flex-shrink: 0;
}

.book-thumb {
    display: inline-flex;
    flex-shrink: 0;
    line-height: 0;
}

.book-cover {
    object-fit: cover;
    border-radius: var(--radius-sm);
    background: var(--surface-muted);
    flex-shrink: 0;
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.85rem;
    color: #fff;
    flex-shrink: 0;
}

/* ===== Lists ===== */
.list-item {
    display: flex;
    align-items: center;
    gap: 0.875rem;
    padding: 0.875rem 0;
    border-bottom: 1px solid var(--border);
}

.list-item:last-child {
    border-bottom: none;
}

.list-item-body {
    flex: 1;
    min-width: 0;
}

.list-item-title {
    font-weight: 600;
    font-size: 0.9rem;
}

.list-item-meta {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-top: 0.15rem;
}

/* ===== Empty / loading states ===== */
.empty-state, .loading-state {
    text-align: center;
    padding: 3rem 1.5rem;
    color: var(--text-muted);
}

.empty-state i, .loading-state i {
    font-size: 2.5rem;
    margin-bottom: 0.75rem;
    opacity: 0.5;
}

.empty-state-sub {
    margin-top: 0.35rem;
    font-size: 0.85rem;
}

.empty-state-action {
    margin-top: 1rem;
}

.loading-spinner {
    width: 32px;
    height: 32px;
    border: 3px solid var(--border);
    border-top-color: var(--primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
    margin: 0 auto 1rem;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

/* ===== Toast / popup ===== */
.toast {
    position: fixed;
    bottom: calc(var(--bottom-nav-height) + 1rem);
    left: 50%;
    transform: translateX(-50%) translateY(0.5rem);
    background: var(--text);
    color: #fff;
    padding: 0.75rem 1.25rem;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    z-index: 500;
    max-width: 90vw;
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0.25s ease, transform 0.25s ease, visibility 0.25s ease;
}

.toast.show {
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
    transform: translateX(-50%) translateY(0);
}

.toast.success {
    background: var(--success);
}

.toast.error {
    background: var(--danger);
}

/* ===== Grid layouts ===== */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.25rem;
}

/* ===== Filter chips ===== */
.filter-chips {
    display: flex;
    gap: 0.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.25rem;
}

.chip {
    padding: 0.4rem 0.85rem;
    border-radius: var(--radius-full);
    border: 1px solid var(--border);
    background: var(--surface);
    font-size: 0.8rem;
    font-weight: 500;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.chip:hover {
    border-color: var(--primary);
    color: var(--primary);
}

.chip.active {
    background: var(--primary);
    border-color: var(--primary);
    color: #fff;
}

/* ===== Table ===== */
.data-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

.data-table th {
    text-align: left;
    padding: 0.75rem 1rem;
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.04em;
    color: var(--text-muted);
    border-bottom: 1px solid var(--border);
    background: var(--surface-muted);
}

.data-table td {
    padding: 0.875rem 1rem;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}

.data-table tr:last-child td {
    border-bottom: none;
}

.table-wrap {
    overflow-x: auto;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    background: var(--surface);
}

.link-action {
    color: var(--primary);
    font-weight: 600;
    font-size: 0.85rem;
}

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