:root {
    --primary-color: #4361ee;
    --secondary-color: #3a0ca3;
    --success-color: #4cc9f0;
    --danger-color: #f72585;
    --warning-color: #f8961e;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --gray-color: #6c757d;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f5f7fb;
    color: var(--dark-color);
    line-height: 1.6;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

.header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.header-title {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.header-subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.summary-cards {
    display: flex;
    justify-content: space-between;
    margin: 20px 0;
    gap: 15px;
}

.summary-card {
    background: white;
    padding: 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
    flex: 1;
}

.summary-title {
    font-size: 0.9rem;
    color: var(--gray-color);
    margin-bottom: 10px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.summary-amount {
    font-size: 1.8rem;
    font-weight: bold;
}

.balance-amount {
    color: var(--primary-color);
}

.income-amount {
    color: var(--success-color);
}

.expense-amount {
    color: var(--danger-color);
}

.form-container {
    background: white;
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    margin-bottom: 30px;
}

.form-title {
    margin-bottom: 20px;
    color: var(--dark-color);
    font-size: 1.5rem;
}

.expense-form {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

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

.form-label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
}

.form-input, .form-select {
    width: 100%;
    padding: 12px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-size: 1rem;
    transition: var(--transition);
}

.form-input:focus, .form-select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(67, 97, 238, 0.2);
}

.btn {
    padding: 12px 20px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1rem;
    font-weight: 500;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

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

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

.btn-danger {
    background-color: var(--danger-color);
    color: white;
    padding: 6px 12px;
    font-size: 0.9rem;
}

.btn-danger:hover {
    background-color: #d1145a;
}

.transactions-container {
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    overflow: hidden;
}

.transactions-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    background-color: var(--light-color);
    border-bottom: 1px solid #ddd;
}

.transactions-title {
    font-size: 1.5rem;
    color: var(--dark-color);
}

.filter-controls {
    display: flex;
    gap: 10px;
}

.filter-btn {
    padding: 8px 16px;
    background-color: white;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn.active, .filter-btn:hover {
    background-color: var(--primary-color);
    color: white;
    border-color: var(--primary-color);
}

.transactions-list {
    max-height: 400px;
    overflow-y: auto;
}

.transaction-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid #eee;
    transition: var(--transition);
}

.transaction-item:hover {
    background-color: #f9f9f9;
}

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

.transaction-details {
    display: flex;
    flex-direction: column;
    flex: 1;
}

.transaction-description {
    font-weight: 500;
    margin-bottom: 5px;
}

.transaction-meta {
    display: flex;
    gap: 15px;
    font-size: 0.85rem;
    color: var(--gray-color);
}

.transaction-category {
    background-color: var(--light-color);
    padding: 2px 8px;
    border-radius: 12px;
    font-size: 0.75rem;
}

.transaction-amount {
    font-weight: bold;
    font-size: 1.1rem;
    margin-right: 15px;
}

.income {
    color: var(--success-color);
}

.expense {
    color: var(--danger-color);
}

.transaction-actions {
    display: flex;
    gap: 10px;
}

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

@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header-title {
        font-size: 2rem;
    }
    
    .summary-cards {
        flex-direction: column;
    }
    
    .expense-form {
        grid-template-columns: 1fr;
    }
    
    .transactions-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
    }
    
    .transaction-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
    
    .transaction-actions {
        align-self: flex-end;
    }
}