* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            min-height: 100vh;
            padding: 20px;
        }
        
        .container {
            max-width: 1200px;
            margin: 0 auto;
            background: white;
            border-radius: 20px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
            overflow: hidden;
        }
        
        .header {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 30px;
            text-align: center;
        }
        
        .header h1 {
            font-size: 2.5em;
            margin-bottom: 10px;
        }
        
        .balance-section {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            padding: 30px;
            background: #f8f9fa;
        }
        
        .balance-card {
            background: white;
            padding: 20px;
            border-radius: 15px;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
            text-align: center;
            transition: transform 0.3s;
        }
        
        .balance-card:hover {
            transform: translateY(-5px);
        }
        
        .balance-card h3 {
            color: #666;
            font-size: 0.9em;
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 10px;
        }
        
        .balance-card p {
            font-size: 2em;
            font-weight: bold;
        }
        
        .balance-card.total p {
            color: #667eea;
        }
        
        .balance-card.income p {
            color: #10b981;
        }
        
        .balance-card.expense p {
            color: #ef4444;
        }
        
        .main-content {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 30px;
            padding: 30px;
        }
        
        .form-section,
        .chart-section {
            background: white;
        }
        
        .form-section h2,
        .chart-section h2 {
            color: #333;
            margin-bottom: 20px;
            font-size: 1.5em;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            color: #666;
            margin-bottom: 8px;
            font-weight: 600;
        }
        
        .form-group input,
        .form-group select {
            width: 100%;
            padding: 12px;
            border: 2px solid #e5e7eb;
            border-radius: 8px;
            font-size: 1em;
            transition: border-color 0.3s;
        }
        
        .form-group input:focus,
        .form-group select:focus {
            outline: none;
            border-color: #667eea;
        }
        
        .form-group input.error,
        .form-group select.error {
            border-color: #ef4444;
        }
        
        .error-message {
            color: #ef4444;
            font-size: 0.85em;
            margin-top: 5px;
            display: none;
        }
        
        .btn {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            border: none;
            border-radius: 8px;
            font-size: 1.1em;
            font-weight: 600;
            cursor: pointer;
            transition: transform 0.2s;
        }
        
        .btn:hover {
            transform: scale(1.02);
        }
        
        .btn:active {
            transform: scale(0.98);
        }
        
        .transactions-section {
            padding: 30px;
        }
        
        .transactions-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 20px;
            flex-wrap: wrap;
            gap: 15px;
        }
        
        .transactions-header h2 {
            color: #333;
            font-size: 1.5em;
        }
        
        .filters {
            display: flex;
            gap: 10px;
            flex-wrap: wrap;
        }
        
        .filter-btn {
            padding: 8px 16px;
            border: 2px solid #667eea;
            background: white;
            color: #667eea;
            border-radius: 20px;
            cursor: pointer;
            transition: all 0.3s;
            font-weight: 600;
        }
        
        .filter-btn.active {
            background: #667eea;
            color: white;
        }
        
        .sort-select {
            padding: 8px 16px;
            border: 2px solid #e5e7eb;
            border-radius: 20px;
            cursor: pointer;
        }
        
        .transactions-list {
            max-height: 500px;
            overflow-y: auto;
        }
        
        .transaction-item {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px;
            background: #f8f9fa;
            border-radius: 10px;
            margin-bottom: 10px;
            border-left: 4px solid;
            transition: transform 0.2s;
        }
        
        .transaction-item:hover {
            transform: translateX(5px);
        }
        
        .transaction-item.income {
            border-left-color: #10b981;
        }
        
        .transaction-item.expense {
            border-left-color: #ef4444;
        }
        
        .transaction-info {
            flex: 1;
        }
        
        .transaction-description {
            font-weight: 600;
            color: #333;
            margin-bottom: 5px;
        }
        
        .transaction-date {
            font-size: 0.85em;
            color: #666;
        }
        
        .transaction-amount {
            font-size: 1.2em;
            font-weight: bold;
            margin-right: 10px;
        }
        
        .transaction-amount.income {
            color: #10b981;
        }
        
        .transaction-amount.expense {
            color: #ef4444;
        }
        
        .delete-btn {
            background: #ef4444;
            color: white;
            border: none;
            padding: 8px 12px;
            border-radius: 5px;
            cursor: pointer;
            transition: background 0.3s;
        }
        
        .delete-btn:hover {
            background: #dc2626;
        }
        
        .empty-state {
            text-align: center;
            padding: 40px;
            color: #999;
        }
        
        .empty-state svg {
            width: 100px;
            height: 100px;
            margin-bottom: 20px;
            opacity: 0.3;
        }
        
        .footer {
            background: #f8f9fa;
            padding: 30px;
            text-align: center;
            color: #666;
            border-top: 1px solid #e5e7eb;
        }
        
        .footer p {
            margin: 5px 0;
        }
        
        .footer p:first-child {
            font-weight: 600;
            color: #333;
        }
        
        .month-header {
            background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
            color: white;
            padding: 15px 20px;
            border-radius: 10px;
            margin-bottom: 15px;
            margin-top: 20px;
        }
        
        .month-header:first-child {
            margin-top: 0;
        }
        
        .month-header h3 {
            margin: 0 0 10px 0;
            font-size: 1.3em;
        }
        
        .month-summary {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
            font-size: 0.9em;
        }
        
        .month-summary span {
            background: rgba(255, 255, 255, 0.2);
            padding: 5px 12px;
            border-radius: 15px;
            font-weight: 600;
        }
        
        @media (max-width: 968px) {
            .main-content {
                grid-template-columns: 1fr;
            }
        }
        
        @media (max-width: 640px) {
            .header h1 {
                font-size: 1.8em;
            }
            .balance-card p {
                font-size: 1.5em;
            }
            .transactions-header {
                flex-direction: column;
                align-items: flex-start;
            }
        }