:root {
    --primary: #4a90e2;
    --success: #7ed321;
    --danger: #d0021b;
    --bg-light: #f5f5f5;
    --bg-white: #ffffff;
    --text-dark: #333333;
    --text-light: #666666;
    --border: #e0e0e0;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    background-color: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.6;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 1rem;
}

header {
    text-align: center;
    margin-bottom: 2rem;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border);
}

header h1 {
    font-size: 1.8rem;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.tabs {
    display: flex;
    border-bottom: 2px solid var(--border);
    margin-bottom: 1.5rem;
}

.tab {
    flex: 1;
    padding: 0.75rem;
    text-align: center;
    background: none;
    border: none;
    font-size: 1rem;
    cursor: pointer;
    position: relative;
    color: var(--text-light);
    transition: all 0.3s ease;
}

.tab.active {
    color: var(--primary);
    border-bottom: 3px solid var(--primary);
}

.tab:hover:not(.active) {
    color: var(--text-dark);
    background-color: rgba(0,0,0,0.02);
}

.transaction-form {
    display: flex;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
}

.transaction-form input[type="text"],
.transaction-form input[type="number"] {
    flex: 1 1 200px;
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: 4px;
    font-size: 1rem;
    min-width: 0;
}

.transaction-form button {
    flex: 0 0 auto;
    padding: 0.75rem 1.5rem;
    background: var(--primary);
    color: white;
    border: none;
    border-radius: 4px;
    font-size: 1rem;
    cursor: pointer;
    transition: background 0.2s ease;
}

.transaction-form button:hover {
    background: #357ab8;
}

.transaction-list {
    list-style: none;
}

.transaction-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    border-bottom: 1px solid var(--border);
    background: var(--bg-white);
    margin-bottom: 0.5rem;
    border-radius: 4px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.1);
}

.transaction-item.completed {
    opacity: 0.7;
}

.transaction-description {
    flex: 1;
    min-width: 0;
    word-wrap: break-word;
}

.transaction-amount {
    font-weight: bold;
    min-width: 80px;
    text-align: right;
}

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

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

.transaction-actions {
    display: flex;
    gap: 0.5rem;
}

.action-btn {
    padding: 0.25rem 0.5rem;
    border: none;
    border-radius: 3px;
    cursor: pointer;
    font-size: 0.875rem;
    transition: all 0.2s ease;
}

.edit-btn {
    background: #ffc107;
    color: #212529;
}

.edit-btn:hover {
    background: #e0a800;
}

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

.delete-btn:hover {
    background: #a70219;
}

.balance {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--bg-white);
    border-radius: 4px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    font-size: 1.25rem;
    font-weight: bold;
}

.balance span:first-child {
    color: var(--text-light);
}

#total-balance {
    color: var(--primary);
}

/* Responsive */
@media (max-width: 480px) {
    .container {
        padding: 0.5rem;
    }
    
    .transaction-form {
        flex-direction: column;
    }
    
    .transaction-form input,
    .transaction-form button {
        width: 100%;
    }
    
    .transaction-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.75rem;
    }
    
    .transaction-amount {
        text-align: left;
        width: 100%;
    }
    
    .transaction-actions {
        align-self: flex-end;
    }
}