:root {
    --primary-color: #2563eb;
    --primary-dark: #1d4ed8;
    --secondary-color: #10b981;
    --secondary-dark: #0d9668;
    --danger-color: #ef4444;
    --danger-dark: #dc2626;
    --warning-color: #f59e0b;
    --warning-dark: #d97706;
    --info-color: #3b82f6;
    --info-dark: #2563eb;
    --light-bg: #f8fafc;
    --dark-bg: #0f172a;
    --card-bg: #ffffff;
    --border-color: #e2e8f0;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.12);
    --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1);
    --radius-sm: 6px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --transition: all 0.2s ease;
    --sidebar-collapsed: 70px;
    --sidebar-expanded: 320px;
    --topbar-height: 60px;
    --right-panel-width: 360px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

body {
    background: linear-gradient(135deg, #f8fafc 0%, #e2e8f0 100%);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow: hidden;
}

.container {
    display: grid;
    grid-template-columns: auto 1fr;
    grid-template-rows: auto 1fr;
    height: 100vh;
}

.top-header {
    grid-column: 1 / -1;
    background: linear-gradient(135deg, var(--dark-bg) 0%, #1e293b 100%);
    color: white;
    padding: 0 24px;
    height: var(--topbar-height);
    display: flex;
    align-items: center;
    justify-content: space-between;
    box-shadow: var(--shadow-lg);
    border-bottom: 1px solid rgba(255,255,255,0.1);
    z-index: 100;
}

.top-header-left {
    display: flex;
    align-items: center;
    gap: 20px;
}

.top-header-right {
    display: flex;
    align-items: center;
    gap: 15px;
}

.header-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-weight: 600;
    font-size: 18px;
}

.header-logo-icon {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    width: 36px;
    height: 36px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
}

.quick-actions {
    display: flex;
    gap: 10px;
    align-items: center;
}

.quick-btn {
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    color: white;
    padding: 8px 16px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 13px;
}

.quick-btn:hover {
    background: rgba(255,255,255,0.2);
    transform: translateY(-1px);
}

.quick-btn.active {
    background: var(--primary-color);
}

.sheets-navigation {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 0 20px;
}

.sheets-counter {
    background: rgba(255,255,255,0.1);
    padding: 6px 12px;
    border-radius: var(--radius-md);
    font-size: 13px;
    color: white;
}

.sheet-pagination {
    display: flex;
    gap: 5px;
}

.sheet-page-btn {
    background: rgba(255,255,255,0.1);
    border: none;
    color: white;
    width: 32px;
    height: 32px;
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
}

.sheet-page-btn:hover {
    background: rgba(255,255,255,0.2);
}

.sheet-page-btn.active {
    background: var(--primary-color);
}

.compact-sidebar {
    width: var(--sidebar-collapsed);
    background: var(--card-bg);
    border-right: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    padding: 16px 0;
    transition: width 0.3s ease;
    overflow: hidden;
    z-index: 90;
}

.compact-sidebar:hover {
    width: var(--sidebar-expanded);
}

.compact-sidebar:hover .nav-item-label {
    opacity: 1;
    transform: translateX(0);
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 14px 20px;
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    border-left: 3px solid transparent;
    white-space: nowrap;
}

.nav-item:hover {
    background: var(--light-bg);
    color: var(--primary-color);
    border-left-color: var(--primary-color);
}

.nav-item.active {
    background: linear-gradient(90deg, rgba(37, 99, 235, 0.1), transparent);
    color: var(--primary-color);
    border-left-color: var(--primary-color);
}

.nav-item i {
    font-size: 18px;
    min-width: 24px;
}

.nav-item-label {
    margin-left: 16px;
    font-size: 14px;
    font-weight: 500;
    opacity: 0;
    transform: translateX(-10px);
    transition: all 0.3s ease;
}

.compact-sidebar:hover .nav-item-label {
    opacity: 1;
    transform: translateX(0);
}

.main-area {
    display: grid;
    grid-template-columns: 1fr var(--right-panel-width);
    height: 100%;
    overflow: hidden;
}

.canvas-zone {
    display: flex;
    flex-direction: column;
    background: var(--light-bg);
    padding: 20px;
    gap: 16px;
    overflow: hidden;
}

.canvas-toolbar {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    padding: 16px 20px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-sm);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.toolbar-group {
    display: flex;
    gap: 12px;
    align-items: center;
}

.canvas-viewport {
    flex: 1;
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    position: relative;
}

.sheets-container {
    position: relative;
    width: 100%;
    height: 100%;
    overflow: auto;
}

.sheet-canvas-container {
    position: relative;
    margin-bottom: 20px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    background: var(--light-bg);
    min-height: 500px;
}

.sheet-header {
    background: var(--dark-bg);
    color: white;
    padding: 8px 15px;
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.sheet-utilization {
    font-size: 12px;
    opacity: 0.9;
}

.sheet-indicator {
    position: absolute;
    top: 10px;
    left: 10px;
    background: rgba(0,0,0,0.7);
    color: white;
    padding: 5px 10px;
    border-radius: 5px;
    font-size: 12px;
    font-weight: bold;
    z-index: 10;
}

.right-panel {
    background: var(--card-bg);
    border-left: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    overflow: hidden;
    width: var(--right-panel-width);
}

.panel-tabs {
    display: flex;
    background: var(--light-bg);
    border-bottom: 1px solid var(--border-color);
    padding: 8px;
    gap: 4px;
}

.panel-tab {
    flex: 1;
    padding: 12px 8px;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    cursor: pointer;
    transition: var(--transition);
    font-size: 13px;
    font-weight: 500;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
}

.panel-tab:hover {
    background: white;
    color: var(--text-primary);
}

.panel-tab.active {
    background: white;
    color: var(--primary-color);
    box-shadow: var(--shadow-sm);
}

.panel-content {
    flex: 1;
    overflow-y: auto;
    padding: 20px;
}

.panel-section {
    margin-bottom: 24px;
}

.panel-section:last-child {
    margin-bottom: 0;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    padding-bottom: 12px;
    border-bottom: 2px solid var(--border-color);
}

.section-header h3 {
    font-size: 16px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.shapes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: 12px;
    margin-top: 16px;
}

.shape-card {
    background: white;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 16px;
    transition: var(--transition);
    cursor: pointer;
}

.shape-card:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.shape-card.selected {
    border-color: var(--primary-color);
    background: linear-gradient(135deg, rgba(37, 99, 235, 0.05), transparent);
}

.shape-icon {
    width: 40px;
    height: 40px;
    background: var(--light-bg);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 12px;
    color: var(--primary-color);
    font-size: 18px;
}

.shape-name {
    font-weight: 600;
    font-size: 14px;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.shape-details {
    font-size: 12px;
    color: var(--text-secondary);
}

.shape-actions {
    display: flex;
    gap: 8px;
    margin-top: 12px;
}

.shape-quantity-badge {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    padding: 4px 10px;
    border-radius: 10px;
    font-size: 12px;
    font-weight: 600;
    min-width: 32px;
    text-align: center;
    margin-left: auto;
}

.compact-input {
    display: flex;
    gap: 10px;
    align-items: center;
}

.compact-input input {
    flex: 1;
    padding: 10px 14px;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
}

.primary-action {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    padding: 14px 24px;
    border-radius: var(--radius-md);
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
    cursor: pointer;
    transition: var(--transition);
    width: 100%;
    margin-top: 20px;
}

.primary-action:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(37, 99, 235, 0.3);
}

.stats-mini {
    display: flex;
    align-items: center;
    gap: 20px;
}

.stat-mini {
    text-align: center;
}

.stat-value-mini {
    font-size: 18px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.stat-label-mini {
    font-size: 11px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

#nestingCanvas {
    width: 100%;
    height: 100%;
    display: block;
    background: #f8fafc;
}

.canvas-controls {
    position: absolute;
    bottom: 15px;
    right: 15px;
    display: flex;
    gap: 8px;
}

.control-group {
    background: white;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    padding: 6px;
    display: flex;
    gap: 2px;
}

.control-btn {
    width: 32px;
    height: 32px;
    border: none;
    background: white;
    border-radius: 5px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--text-primary);
    transition: var(--transition);
    font-size: 14px;
}

.control-btn:hover {
    background: var(--light-bg);
    color: var(--primary-color);
}

.control-btn.active {
    background: var(--primary-color);
    color: white;
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 14px;
}

.form-control {
    width: 100%;
    padding: 12px 14px;
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 14px;
    transition: var(--transition);
    background: var(--light-bg);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
    background: white;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 12px 18px;
    border: none;
    border-radius: var(--radius-md);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
}

.btn-primary:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--primary-color));
}

.btn-success {
    background: linear-gradient(135deg, var(--secondary-color), var(--secondary-dark));
    color: white;
}

.btn-warning {
    background: linear-gradient(135deg, var(--warning-color), var(--warning-dark));
    color: white;
}

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color), var(--danger-dark));
    color: white;
}

.btn-outline {
    background: transparent;
    border: 2px solid var(--border-color);
    color: var(--text-primary);
}

.btn-outline:hover {
    background: var(--light-bg);
    border-color: var(--primary-color);
}

.btn-small {
    padding: 8px 12px;
    font-size: 13px;
}

.multi-sheet-controls {
    background: var(--card-bg);
    border-radius: var(--radius-md);
    padding: 15px;
    margin-top: 20px;
    border: 1px solid var(--border-color);
}

.multi-sheet-options {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
    margin-top: 15px;
}

.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(15, 23, 42, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
    backdrop-filter: blur(4px);
}

.modal-overlay.active {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--card-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 90%;
    max-width: 480px;
    max-height: 90vh;
    overflow: hidden;
    transform: translateY(20px);
    transition: transform 0.3s ease;
    border: 1px solid var(--border-color);
}

.modal-overlay.active .modal {
    transform: translateY(0);
}

.modal-header {
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: linear-gradient(135deg, var(--dark-bg), #1e293b);
    color: white;
}

.modal-header h3 {
    margin: 0;
    font-size: 17px;
    display: flex;
    align-items: center;
    gap: 8px;
}

.modal-close {
    background: rgba(255,255,255,0.1);
    border: none;
    width: 30px;
    height: 30px;
    border-radius: 7px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: white;
    transition: var(--transition);
    font-size: 14px;
}

.modal-close:hover {
    background: rgba(255,255,255,0.2);
}

.modal-body {
    padding: 20px;
    overflow-y: auto;
    max-height: 60vh;
}

.modal-footer {
    padding: 16px 20px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    background: var(--light-bg);
}

#statsModal .modal-body {
    padding: 20px;
}

#helpModal .modal-body {
    padding: 20px;
    max-height: 70vh;
}

.multi-sheet-summary {
    max-height: 60vh;
    overflow-y: auto;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.summary-card {
    background: var(--light-bg);
    border-radius: var(--radius-md);
    padding: 15px;
    border: 1px solid var(--border-color);
}

.summary-card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.summary-stats {
    font-size: 13px;
}

.summary-stat {
    display: flex;
    justify-content: space-between;
    margin-bottom: 8px;
}

.summary-stat-label {
    color: var(--text-secondary);
}

.summary-stat-value {
    font-weight: 600;
    color: var(--text-primary);
}

.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 14px 20px;
    border-radius: var(--radius-md);
    color: white;
    font-weight: 500;
    z-index: 10000;
    box-shadow: var(--shadow-lg);
    animation: slideIn 0.3s ease forwards;
    max-width: 360px;
    display: flex;
    align-items: center;
    gap: 10px;
    border-left: 4px solid;
    font-size: 13px;
}

.notification i {
    font-size: 18px;
}

.notification-content {
    flex: 1;
}

.notification-close {
    background: none;
    border: none;
    color: white;
    cursor: pointer;
    padding: 3px;
    opacity: 0.8;
    font-size: 14px;
}

.notification-close:hover {
    opacity: 1;
}

.notification-success {
    background: linear-gradient(135deg, var(--secondary-color), var(--secondary-dark));
    border-left-color: #059669;
}

.notification-error {
    background: linear-gradient(135deg, var(--danger-color), var(--danger-dark));
    border-left-color: #dc2626;
}

.notification-warning {
    background: linear-gradient(135deg, var(--warning-color), var(--warning-dark));
    border-left-color: #d97706;
}

.notification-info {
    background: linear-gradient(135deg, var(--info-color), var(--info-dark));
    border-left-color: #2563eb;
}

@keyframes slideIn {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

@keyframes slideOut {
    from { transform: translateX(0); opacity: 1; }
    to { transform: translateX(100%); opacity: 0; }
}

.dimension-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.checkbox-group {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px;
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition);
    margin: 6px 0;
}

.checkbox-group:hover {
    background: var(--light-bg);
}

.checkbox-group input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: var(--primary-color);
}

.checkbox-group label {
    margin: 0;
    cursor: pointer;
    user-select: none;
    font-size: 14px;
}

::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--light-bg);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, var(--primary-dark), var(--secondary-dark));
}

@media (max-width: 1200px) {
    .main-area {
        grid-template-columns: 1fr;
    }

    .right-panel {
        position: relative;
        right: auto;
        top: auto;
        bottom: auto;
        width: 100%;
        height: 400px;
        border-left: none;
        border-top: 1px solid var(--border-color);
        z-index: 10;
        transition: none;
        box-shadow: none;
        margin-top: 20px;
    }

    .right-panel.open {
        right: auto;
    }

    .panel-toggle {
        display: none;
    }

    .panel-toggle {
        display: flex;
        position: absolute;
        left: -40px;
        top: 20px;
        background: var(--primary-color);
        color: white;
        width: 40px;
        height: 40px;
        border-radius: var(--radius-md) 0 0 var(--radius-md);
        align-items: center;
        justify-content: center;
        cursor: pointer;
    }

    .shapes-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .modal {
        width: 95%;
        max-width: 500px;
    }

    .multi-sheet-options {
        grid-template-columns: 1fr;
    }

    .summary-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .container {
        grid-template-columns: 1fr;
    }

    .compact-sidebar {
        width: 0;
        position: fixed;
        left: 0;
        top: var(--topbar-height);
        bottom: 0;
        z-index: 1000;
        box-shadow: var(--shadow-lg);
    }

    .compact-sidebar.open {
        width: var(--sidebar-expanded);
    }

    .compact-sidebar:hover {
        width: var(--sidebar-expanded);
    }

    .top-header {
        padding: 0 16px;
    }

    .header-logo span {
        display: none;
    }

    .quick-actions .quick-btn span {
        display: none;
    }

    .sheets-navigation {
        margin: 0 10px;
    }

    .shapes-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .canvas-toolbar {
        flex-direction: column;
        gap: 16px;
    }

    .toolbar-group {
        width: 100%;
        justify-content: space-between;
    }

    .dimension-grid {
        grid-template-columns: 1fr;
    }

    .stats-mini {
        flex-direction: column;
        gap: 10px;
    }

    .modal {
        width: 98%;
        margin: 10px;
    }
}

@media (max-width: 576px) {
    .right-panel {
        width: 100%;
    }

    .shapes-grid {
        grid-template-columns: 1fr;
    }

    .canvas-zone {
        padding: 10px;
    }

    .top-header {
        height: 50px;
    }

    .modal {
        margin: 5px;
        max-height: 95vh;
    }

    .modal-body {
        max-height: 50vh;
    }

    .multi-sheet-options {
        grid-template-columns: 1fr;
    }

    .summary-grid {
        grid-template-columns: 1fr;
    }
}

@keyframes slideInRight {
    from { transform: translateX(100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

@keyframes slideInLeft {
    from { transform: translateX(-100%); opacity: 0; }
    to { transform: translateX(0); opacity: 1; }
}

.empty-state {
    text-align: center;
    padding: 40px 20px;
    color: var(--text-secondary);
}

.empty-state i {
    font-size: 56px;
    margin-bottom: 16px;
    color: var(--border-color);
    opacity: 0.5;
}

.empty-state h4 {
    margin-bottom: 10px;
    color: var(--text-primary);
    font-size: 18px;
}

.empty-state p {
    font-size: 14px;
    max-width: 300px;
    margin: 0 auto;
}

*:focus {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

.menu-toggle {
    position: fixed;
    left: 10px;
    top: 70px;
    background: var(--primary-color);
    color: white;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 999;
    display: none;
}

.panel-tab-content {
    display: none;
    animation: fadeIn 0.3s ease;
}

.panel-tab-content.active {
    display: block;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(-5px); }
    to { opacity: 1; transform: translateY(0); }
}

#advancedStatsContent ul {
    margin: 10px 0 20px 20px;
    padding: 0;
}

#advancedStatsContent ul li {
    margin-bottom: 8px;
    padding: 5px 0;
    border-bottom: 1px solid var(--border-color);
}

#helpModal h4 {
    color: var(--primary-color);
    margin: 20px 0 10px 0;
    font-size: 16px;
}

#helpModal ul {
    margin-left: 20px;
    margin-bottom: 20px;
}

#helpModal ul li {
    margin-bottom: 8px;
    position: relative;
    padding-left: 5px;
}

.nav-item:hover {
    transform: translateX(3px);
}

.nav-item.active:hover {
    transform: none;
}