* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            -webkit-tap-highlight-color: transparent;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px 10px;
            padding-bottom: env(safe-area-inset-bottom);
        }

        .container {
            max-width: 450px;
            margin: 0 auto;
        }

        .pwa-banner {
            background: #48bb78;
            color: white;
            padding: 12px;
            border-radius: 12px;
            margin-bottom: 15px;
            display: none;
            align-items: center;
            gap: 10px;
            animation: slideDown 0.3s ease-out;
        }

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

        .pwa-banner.show {
            display: flex;
        }

        .pwa-banner button {
            background: white;
            color: #48bb78;
            border: none;
            padding: 8px 16px;
            border-radius: 8px;
            font-weight: 600;
            cursor: pointer;
        }

        .header {
            background: white;
            border-radius: 20px 20px 0 0;
            padding: 25px 20px;
            box-shadow: 0 -5px 20px rgba(0,0,0,0.1);
        }

        .header h1 {
            font-size: 24px;
            color: #2d3748;
            margin-bottom: 8px;
        }

        .month-selector {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-top: 15px;
            background: #f7fafc;
            padding: 12px;
            border-radius: 12px;
        }

        .month-selector button {
            background: #667eea;
            color: white;
            border: none;
            width: 36px;
            height: 36px;
            border-radius: 50%;
            font-size: 18px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .month-selector button:hover {
            background: #5a67d8;
            transform: scale(1.1);
        }

        .month-selector button:active {
            transform: scale(0.95);
        }

        .month-display {
            font-size: 18px;
            font-weight: 600;
            color: #2d3748;
        }

        .stats {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 10px;
            margin-top: 15px;
        }

        .stat-card {
            background: white;
            padding: 12px;
            border-radius: 12px;
            text-align: center;
            border: 2px solid #e2e8f0;
        }

        .stat-number {
            font-size: 24px;
            font-weight: bold;
            margin-bottom: 4px;
        }

        .stat-label {
            font-size: 12px;
            color: #718096;
            text-transform: uppercase;
        }

        .stat-card.paid {
            border-color: #48bb78;
            background: #f0fff4;
        }

        .stat-card.paid .stat-number {
            color: #48bb78;
        }

        .stat-card.unpaid {
            border-color: #f56565;
            background: #fff5f5;
        }

        .stat-card.unpaid .stat-number {
            color: #f56565;
        }

        .stat-card.null {
            border-color: #cbd5e0;
            background: #f7fafc;
        }

        .stat-card.null .stat-number {
            color: #a0aec0;
        }

        .main-content {
            background: white;
            border-radius: 0 0 20px 20px;
            padding: 20px;
            margin-top: 2px;
            box-shadow: 0 10px 25px rgba(0,0,0,0.1);
        }

        .add-card-btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 12px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            margin-bottom: 20px;
        }

        .add-card-btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(102, 126, 234, 0.4);
        }

        .add-card-btn:active {
            transform: translateY(0);
        }

        .search-box {
            margin-bottom: 15px;
        }

        .search-box input {
            width: 100%;
            padding: 12px 15px;
            border: 2px solid #e2e8f0;
            border-radius: 12px;
            font-size: 16px;
            transition: all 0.3s;
            background: white;
        }

        .search-box input:focus {
            outline: none;
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .search-box input::placeholder {
            color: #a0aec0;
        }

        .filter-options {
            display: flex;
            gap: 10px;
            margin-bottom: 20px;
        }

        .filter-btn {
            flex: 1;
            padding: 10px;
            border: 2px solid #e2e8f0;
            background: white;
            border-radius: 8px;
            font-size: 14px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .filter-btn.active {
            background: #667eea;
            color: white;
            border-color: #667eea;
        }

        .cards-list {
            display: flex;
            flex-direction: column;
            gap: 12px;
        }

        .card-item {
            background: white;
            border: 2px solid #e2e8f0;
            border-radius: 12px;
            padding: 15px;
            transition: all 0.3s;
            animation: slideIn 0.3s ease-out;
        }

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

        .card-item:hover {
            border-color: #cbd5e0;
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
        }

        .card-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 12px;
        }

        .card-name {
            font-size: 16px;
            font-weight: 600;
            color: #2d3748;
            flex: 1;
        }

        .card-due {
            font-size: 12px;
            color: #718096;
            margin-left: 10px;
            margin-right: 15px;
        }

        .card-actions {
            display: flex;
            gap: 6px;
        }

        .edit-btn {
            background: #4299e1;
            color: white;
            border: none;
            padding: 6px 12px;
            border-radius: 6px;
            font-size: 12px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .edit-btn:hover {
            background: #3182ce;
        }

        .delete-btn {
            background: #f56565;
            color: white;
            border: none;
            padding: 6px 12px;
            border-radius: 6px;
            font-size: 12px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .delete-btn:hover {
            background: #e53e3e;
        }

        .status-buttons {
            display: flex;
            gap: 8px;
        }

        .status-btn {
            flex: 1;
            padding: 10px;
            border: 2px solid #e2e8f0;
            background: white;
            border-radius: 8px;
            font-size: 14px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.3s;
        }

        .status-btn:hover {
            transform: translateY(-2px);
        }

        .status-btn.paid {
            background: #48bb78;
            color: white;
            border-color: #48bb78;
        }

        .status-btn.unpaid {
            background: #f56565;
            color: white;
            border-color: #f56565;
        }

        .status-btn.null {
            background: #a0aec0;
            color: white;
            border-color: #a0aec0;
        }

        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            right: 0;
            bottom: 0;
            background: rgba(0,0,0,0.5);
            z-index: 1000;
            animation: fadeIn 0.3s;
        }

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

        .modal.active {
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }

        .modal-content {
            background: white;
            border-radius: 20px;
            padding: 25px;
            width: 100%;
            max-width: 400px;
            animation: slideUp 0.3s;
        }

        @keyframes slideUp {
            from {
                transform: translateY(50px);
                opacity: 0;
            }
            to {
                transform: translateY(0);
                opacity: 1;
            }
        }

        .modal-header {
            font-size: 20px;
            font-weight: 600;
            margin-bottom: 20px;
            color: #2d3748;
        }

        .form-group {
            margin-bottom: 15px;
        }

        .form-group label {
            display: block;
            margin-bottom: 5px;
            font-size: 14px;
            color: #4a5568;
            font-weight: 500;
        }

        .form-group input {
            width: 100%;
            padding: 12px;
            border: 2px solid #e2e8f0;
            border-radius: 8px;
            font-size: 16px;
            transition: all 0.3s;
        }

        .form-group input:focus {
            outline: none;
            border-color: #667eea;
            box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
        }

        .modal-buttons {
            display: flex;
            gap: 10px;
            margin-top: 20px;
        }

        .modal-buttons button {
            flex: 1;
            padding: 12px;
            border-radius: 8px;
            font-size: 16px;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.3s;
            border: none;
        }

        .btn-save {
            background: #48bb78;
            color: white;
        }

        .btn-save:hover {
            background: #38a169;
        }

        .btn-cancel {
            background: #e2e8f0;
            color: #4a5568;
        }

        .btn-cancel:hover {
            background: #cbd5e0;
        }

        .empty-state {
            text-align: center;
            padding: 40px;
            color: #718096;
        }

        .empty-state svg {
            width: 80px;
            height: 80px;
            margin-bottom: 20px;
            opacity: 0.5;
        }

        .backup-section {
            margin-top: 20px;
            padding-top: 20px;
            border-top: 2px solid #e2e8f0;
        }

        .backup-buttons {
            display: flex;
            gap: 10px;
        }

        .backup-buttons button {
            flex: 1;
            padding: 12px;
            border: 2px solid #e2e8f0;
            background: white;
            border-radius: 8px;
            font-size: 14px;
            cursor: pointer;
            transition: all 0.3s;
        }

        .backup-buttons button:hover {
            background: #f7fafc;
            border-color: #cbd5e0;
        }

        .offline-badge {
            position: fixed;
            bottom: 20px;
            left: 50%;
            transform: translateX(-50%);
            background: #ed8936;
            color: white;
            padding: 8px 16px;
            border-radius: 20px;
            font-size: 12px;
            display: none;
            z-index: 1001;
            animation: slideUp 0.3s ease-out;
        }

        .offline-badge.show {
            display: block;
        }