:root {
    --primary: #4f46e5;
    --primary-hover: #4338ca;
    --primary-light: #eef2ff;
    --secondary: #64748b;
    --secondary-hover: #475569;
    --success: #10b981;
    --success-hover: #059669;
    --danger: #ef4444;
    --danger-hover: #dc2626;
    --warning: #f59e0b;
    --bg: #f8fafc;
    --surface: #ffffff;
    --border: #e2e8f0;
    --text: #1e293b;
    --text-muted: #64748b;
    --text-light: #94a3b8;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --radius: 12px;
    --radius-sm: 8px;
    --transition: all 0.2s ease;
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.app-header {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px 0;
    margin-bottom: 20px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--primary);
}

.logo i {
    font-size: 2rem;
}

/* Heading Section */
.heading-section {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.heading-display {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.heading-display h1 {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text);
    flex: 1;
}

.heading-actions {
    display: flex;
    gap: 8px;
}

.heading-form .input-group {
    display: flex;
    gap: 12px;
    align-items: center;
}

.heading-form input {
    flex: 1;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 1rem;
    font-family: inherit;
    transition: var(--transition);
}

.heading-form input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    font-family: inherit;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
}

.btn-sm {
    padding: 8px 12px;
    font-size: 0.8rem;
}

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

.btn-primary:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow);
}

.btn-secondary {
    background: var(--secondary);
    color: white;
}

.btn-secondary:hover {
    background: var(--secondary-hover);
}

.btn-success {
    background: var(--success);
    color: white;
}

.btn-success:hover {
    background: var(--success-hover);
    transform: translateY(-1px);
}

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

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

.btn-edit {
    background: var(--primary-light);
    color: var(--primary);
}

.btn-edit:hover {
    background: var(--primary);
    color: white;
}

.btn-delete {
    background: #fef2f2;
    color: var(--danger);
}

.btn-delete:hover {
    background: var(--danger);
    color: white;
}

/* Form Section */
.form-section {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 28px;
    margin-bottom: 24px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.section-title h2 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-title h2 i {
    color: var(--primary);
}

.form-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 24px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
}

.form-group.full-width {
    grid-column: 1 / -1;
}

.form-group label {
    font-size: 0.85rem;
    font-weight: 500;
    color: var(--text-muted);
    display: flex;
    align-items: center;
    gap: 6px;
}

.form-group label i {
    font-size: 0.75rem;
    color: var(--primary);
}

.form-group input,
.form-group textarea,
.form-group select {
    padding: 10px 14px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-family: inherit;
    transition: var(--transition);
    background: var(--surface);
}

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 80px;
}

/* Unit Suggestions */
.unit-group {
    position: relative;
}

.unit-suggestions {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--surface);
    border: 2px solid var(--primary);
    border-radius: var(--radius-sm);
    max-height: 200px;
    overflow-y: auto;
    z-index: 100;
    display: none;
    box-shadow: var(--shadow-lg);
}

.unit-suggestions.active {
    display: block;
}

.unit-suggestion-item {
    padding: 10px 14px;
    cursor: pointer;
    font-size: 0.85rem;
    transition: var(--transition);
    border-bottom: 1px solid var(--border);
}

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

.unit-suggestion-item:hover {
    background: var(--primary-light);
    color: var(--primary);
}

/* File Upload */
.file-upload-area {
    position: relative;
    border: 2px dashed var(--border);
    border-radius: var(--radius-sm);
    padding: 24px;
    text-align: center;
    transition: var(--transition);
    cursor: pointer;
}

.file-upload-area:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.file-upload-area input[type="file"] {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
    border: none;
    padding: 0;
}

.file-upload-placeholder {
    pointer-events: none;
}

.file-upload-placeholder i {
    font-size: 2rem;
    color: var(--text-light);
    margin-bottom: 8px;
}

.file-upload-placeholder p {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.file-upload-placeholder span {
    font-size: 0.75rem;
    color: var(--text-light);
}

.file-preview {
    display: flex;
    align-items: center;
    gap: 12px;
    pointer-events: auto;
}

.file-preview img {
    width: 60px;
    height: 60px;
    object-fit: cover;
    border-radius: var(--radius-sm);
    border: 2px solid var(--border);
}

.file-preview span {
    flex: 1;
    font-size: 0.85rem;
    color: var(--text);
    text-align: left;
    word-break: break-all;
}

.btn-remove-file {
    background: var(--danger);
    color: white;
    border: none;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    pointer-events: auto;
    position: relative;
    z-index: 5;
}

.btn-remove-file:hover {
    background: var(--danger-hover);
    transform: scale(1.1);
}

.form-actions {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
}

/* Items Section */
.items-section {
    background: var(--surface);
    border-radius: var(--radius);
    padding: 28px;
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--border);
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 20px;
    flex-wrap: wrap;
    gap: 16px;
}

.section-header h2 {
    font-size: 1.2rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 10px;
}

.section-header h2 i {
    color: var(--primary);
}

.section-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    flex-wrap: wrap;
}

.sort-control {
    display: flex;
    align-items: center;
    gap: 8px;
}

.sort-control label {
    color: var(--text-muted);
}

.sort-control select {
    padding: 8px 12px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 0.8rem;
    font-family: inherit;
    cursor: pointer;
    background: var(--surface);
}

.sort-control select:focus {
    outline: none;
    border-color: var(--primary);
}

/* Item Cards */
.items-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.item-card {
    display: grid;
    grid-template-columns: auto 1fr auto;
    gap: 16px;
    align-items: center;
    padding: 16px;
    background: var(--bg);
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.item-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow);
    transform: translateY(-1px);
}

.item-card-image {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    background: var(--border);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.item-card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.item-card-image .no-image {
    color: var(--text-light);
    font-size: 1.2rem;
}

.item-card-info {
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-width: 0;
}

.item-card-info h3 {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.item-card-details {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 0.8rem;
}

.item-detail-badge {
    background: var(--primary-light);
    color: var(--primary);
    padding: 2px 8px;
    border-radius: 4px;
    font-weight: 500;
}

.item-detail-badge.qty {
    background: #ecfdf5;
    color: var(--success);
}

.item-card-remarks {
    font-size: 0.8rem;
    color: var(--text-muted);
    font-style: italic;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.item-card-actions {
    display: flex;
    gap: 8px;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 48px 20px;
    color: var(--text-light);
}

.empty-state i {
    font-size: 3rem;
    margin-bottom: 12px;
    opacity: 0.5;
}

.empty-state p {
    font-size: 1.1rem;
    font-weight: 500;
    margin-bottom: 4px;
    color: var(--text-muted);
}

.empty-state span {
    font-size: 0.85rem;
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    padding: 20px;
    animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.modal-content {
    background: var(--surface);
    border-radius: var(--radius);
    width: 100%;
    max-height: 90vh;
    display: flex;
    flex-direction: column;
    box-shadow: var(--shadow-lg);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from { transform: translateY(20px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.preview-modal {
    max-width: 900px;
}

.edit-modal {
    max-width: 700px;
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    border-bottom: 1px solid var(--border);
}

.modal-header h3 {
    font-size: 1.1rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 8px;
}

.modal-header h3 i {
    color: var(--primary);
}

.btn-close {
    background: none;
    border: none;
    font-size: 1.2rem;
    color: var(--text-muted);
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    transition: var(--transition);
}

.btn-close:hover {
    background: var(--bg);
    color: var(--text);
}

.modal-body {
    padding: 24px;
    overflow-y: auto;
    flex: 1;
}

.modal-footer {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
    padding: 16px 24px;
    border-top: 1px solid var(--border);
    flex-wrap: wrap;
}

/* Preview Table */
.preview-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.85rem;
}

.preview-table th,
.preview-table td {
    border: 1px solid var(--border);
    padding: 10px 12px;
    text-align: left;
    vertical-align: middle;
}

.preview-table th {
    background: var(--primary);
    color: white;
    font-weight: 600;
    font-size: 0.8rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.preview-table tr:nth-child(even) {
    background: var(--bg);
}

.preview-table tr:hover {
    background: var(--primary-light);
}

.preview-table img {
    max-width: 60px;
    max-height: 60px;
    object-fit: contain;
    border-radius: 4px;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 30px;
    right: 30px;
    background: var(--text);
    color: white;
    padding: 14px 24px;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 500;
    box-shadow: var(--shadow-lg);
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 2000;
    display: flex;
    align-items: center;
    gap: 10px;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

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

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

.toast.info {
    background: var(--primary);
}

/* Responsive */
@media (max-width: 768px) {
    .app-container {
        padding: 12px;
    }

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

    .heading-form .input-group {
        flex-direction: column;
    }

    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .section-controls {
        width: 100%;
        justify-content: space-between;
    }

    .item-card {
        grid-template-columns: 1fr;
        text-align: center;
    }

    .item-card-image {
        margin: 0 auto;
    }

    .item-card-actions {
        justify-content: center;
    }

    .item-card-details {
        justify-content: center;
    }

    .form-actions {
        flex-direction: column;
    }

    .form-actions .btn {
        width: 100%;
        justify-content: center;
    }

    .modal-footer {
        flex-direction: column;
    }

    .modal-footer .btn {
        width: 100%;
        justify-content: center;
    }

    .heading-display {
        flex-direction: column;
        text-align: center;
    }

    .export-controls {
        width: 100%;
    }

    .export-controls .btn {
        width: 100%;
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .logo {
        font-size: 1.4rem;
    }

    .form-section,
    .items-section,
    .heading-section {
        padding: 16px;
    }

    .item-card {
        padding: 12px;
    }

    .preview-table {
        font-size: 0.7rem;
    }

    .preview-table th,
    .preview-table td {
        padding: 6px 8px;
    }
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 6px;
}

::-webkit-scrollbar-track {
    background: var(--bg);
}

::-webkit-scrollbar-thumb {
    background: var(--border);
    border-radius: 3px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-light);
}