/* CSS Variables for Theme Management */
:root {
    /* Light Theme Colors */
    --primary-color: #4F46E5;
    --primary-light: #6366F1;
    --primary-dark: #4338CA;
    
    --success-color: #10B981;
    --success-light: #34D399;
    --success-dark: #059669;
    
    --danger-color: #EF4444;
    --danger-light: #F87171;
    --danger-dark: #DC2626;
    
    --warning-color: #F59E0B;
    --warning-light: #FBBF24;
    
    --background-primary: #FFFFFF;
    --background-secondary: #F8FAFC;
    --background-tertiary: #F1F5F9;
    
    --text-primary: #1E293B;
    --text-secondary: #64748B;
    --text-muted: #94A3B8;
    
    --border-color: #E2E8F0;
    --shadow-color: rgba(0, 0, 0, 0.1);
    --shadow-hover: rgba(0, 0, 0, 0.15);
    
    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    /* Typography */
    --font-size-xs: 0.75rem;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.5rem;
    --font-size-3xl: 1.875rem;
    --font-size-4xl: 2.25rem;
}

/* Dark Theme */
[data-theme="dark"] {
    --background-primary: #0F172A;
    --background-secondary: #1E293B;
    --background-tertiary: #334155;
    
    --text-primary: #F8FAFC;
    --text-secondary: #CBD5E1;
    --text-muted: #94A3B8;
    
    --border-color: #334155;
    --shadow-color: rgba(0, 0, 0, 0.3);
    --shadow-hover: rgba(0, 0, 0, 0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--background-secondary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.app-container {
    min-height: 100vh;
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
.header {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    padding: var(--spacing-lg) var(--spacing-md);
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 4px 6px var(--shadow-color);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.app-title {
    font-size: var(--font-size-2xl);
    font-weight: 700;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.header-controls {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
}

.theme-toggle,
.nav-btn {
    background: rgba(255, 255, 255, 0.2);
    border: none;
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-size: var(--font-size-sm);
}

.theme-toggle:hover,
.nav-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

/* Balance Section */
.balance-section {
    padding: var(--spacing-xl) var(--spacing-md);
    background: var(--background-primary);
}

.balance-card {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.balance-card h2 {
    font-size: var(--font-size-lg);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.balance-amount {
    font-size: var(--font-size-4xl);
    font-weight: 700;
    color: var(--primary-color);
    text-shadow: 0 2px 4px var(--shadow-color);
}

.balance-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xl);
}

.balance-item {
    background: var(--background-secondary);
    padding: var(--spacing-lg);
    border-radius: var(--radius-xl);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    border: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

.balance-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px var(--shadow-hover);
}

.balance-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: var(--font-size-xl);
    color: white;
}

.balance-item.income .balance-icon {
    background: linear-gradient(135deg, var(--success-color), var(--success-light));
}

.balance-item.expense .balance-icon {
    background: linear-gradient(135deg, var(--danger-color), var(--danger-light));
}

.balance-info {
    display: flex;
    flex-direction: column;
}

.balance-label {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
    font-weight: 500;
}

.balance-value {
    font-size: var(--font-size-xl);
    font-weight: 700;
    margin-top: var(--spacing-xs);
}

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

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

/* Main Content */
.main-content {
    flex: 1;
    padding: var(--spacing-xl) var(--spacing-md);
    background: var(--background-secondary);
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.section-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

/* Form Styles */
.transaction-form {
    background: var(--background-primary);
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 6px var(--shadow-color);
    margin-bottom: var(--spacing-2xl);
}

.form-group {
    margin-bottom: var(--spacing-lg);
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
}

label {
    display: block;
    margin-bottom: var(--spacing-sm);
    font-weight: 600;
    color: var(--text-primary);
    font-size: var(--font-size-sm);
}

input,
select {
    width: 100%;
    padding: var(--spacing-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    background: var(--background-primary);
    color: var(--text-primary);
    transition: all 0.3s ease;
}

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

/* Transaction Type Radio Buttons */
.transaction-type {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.radio-label {
    cursor: pointer;
    margin-bottom: 0;
}

.radio-label input[type="radio"] {
    display: none;
}

.radio-custom {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    border: 2px solid var(--border-color);
    background: var(--background-secondary);
    font-weight: 600;
    transition: all 0.3s ease;
}

.radio-custom:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px var(--shadow-hover);
}

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

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

.radio-label input[type="radio"]:checked + .income-radio {
    background: var(--success-color);
    color: white;
    border-color: var(--success-color);
}

.radio-label input[type="radio"]:checked + .expense-radio {
    background: var(--danger-color);
    color: white;
    border-color: var(--danger-color);
}

/* Buttons */
.btn-primary,
.btn-secondary,
.btn-danger {
    padding: var(--spacing-md) var(--spacing-xl);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-light));
    color: white;
    width: 100%;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(79, 70, 229, 0.3);
}

.btn-secondary {
    background: var(--background-secondary);
    color: var(--text-primary);
    border: 2px solid var(--border-color);
}

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

.btn-danger {
    background: linear-gradient(135deg, var(--danger-color), var(--danger-light));
    color: white;
}

.btn-danger:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(239, 68, 68, 0.3);
}

/* Filter Controls */
.filter-controls {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

.filter-select {
    padding: var(--spacing-sm) var(--spacing-md);
    border-radius: var(--radius-md);
    border: 2px solid var(--border-color);
    background: var(--background-primary);
    color: var(--text-primary);
    font-size: var(--font-size-sm);
    min-width: 120px;
}

/* Transactions List */
.transactions-list {
    background: var(--background-primary);
    border-radius: var(--radius-xl);
    border: 1px solid var(--border-color);
    overflow: hidden;
}

.no-transactions {
    text-align: center;
    padding: var(--spacing-2xl);
    color: var(--text-muted);
}

.no-transactions i {
    font-size: var(--font-size-4xl);
    margin-bottom: var(--spacing-md);
    color: var(--text-muted);
}

.no-transactions p {
    font-size: var(--font-size-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
}

.transaction-item {
    display: flex;
    align-items: center;
    padding: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
    cursor: pointer;
}

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

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

.transaction-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: var(--spacing-md);
    font-size: var(--font-size-lg);
    color: white;
}

.transaction-item.income .transaction-icon {
    background: linear-gradient(135deg, var(--success-color), var(--success-light));
}

.transaction-item.expense .transaction-icon {
    background: linear-gradient(135deg, var(--danger-color), var(--danger-light));
}

.transaction-details {
    flex: 1;
    min-width: 0;
}

.transaction-description {
    font-weight: 600;
    font-size: var(--font-size-base);
    margin-bottom: var(--spacing-xs);
    color: var(--text-primary);
}

.transaction-meta {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.transaction-category {
    background: var(--background-tertiary);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    font-size: var(--font-size-xs);
    font-weight: 500;
}

.transaction-amount {
    font-size: var(--font-size-lg);
    font-weight: 700;
    margin-left: var(--spacing-md);
}

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

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

.transaction-actions {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-left: var(--spacing-md);
}

.action-btn {
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
    font-size: var(--font-size-sm);
}

.delete-btn {
    background: rgba(239, 68, 68, 0.1);
    color: var(--danger-color);
}

.delete-btn:hover {
    background: var(--danger-color);
    color: white;
    transform: scale(1.1);
}

/* Toast Notification */
.toast {
    position: fixed;
    bottom: var(--spacing-xl);
    left: 50%;
    transform: translateX(-50%) translateY(100px);
    background: var(--success-color);
    color: white;
    padding: var(--spacing-md) var(--spacing-xl);
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-weight: 600;
    box-shadow: 0 8px 25px rgba(16, 185, 129, 0.3);
    z-index: 1000;
    transition: all 0.3s ease;
}

.toast.show {
    transform: translateX(-50%) translateY(0);
}

/* Modal */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal-overlay.show {
    opacity: 1;
    visibility: visible;
}

.modal {
    background: var(--background-primary);
    border-radius: var(--radius-xl);
    max-width: 400px;
    width: 90%;
    box-shadow: 0 20px 25px rgba(0, 0, 0, 0.3);
    transform: scale(0.9);
    transition: all 0.3s ease;
}

.modal-overlay.show .modal {
    transform: scale(1);
}

.modal-header {
    padding: var(--spacing-xl) var(--spacing-xl) 0;
}

.modal-header h3 {
    font-size: var(--font-size-xl);
    font-weight: 600;
    color: var(--text-primary);
}

.modal-body {
    padding: var(--spacing-lg) var(--spacing-xl);
}

.modal-body p {
    color: var(--text-secondary);
    line-height: 1.6;
}

.modal-actions {
    padding: 0 var(--spacing-xl) var(--spacing-xl);
    display: flex;
    gap: var(--spacing-md);
    justify-content: flex-end;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: var(--spacing-md);
    }
    
    .app-title {
        font-size: var(--font-size-xl);
    }
    
    .header-controls {
        gap: var(--spacing-sm);
    }
    
    .nav-btn span {
        display: none;
    }
    
    .balance-section {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .balance-amount {
        font-size: var(--font-size-3xl);
    }
    
    .balance-grid {
        grid-template-columns: 1fr;
        gap: var(--spacing-sm);
    }
    
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .transaction-type {
        grid-template-columns: 1fr;
    }
    
    .section-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .filter-controls {
        width: 100%;
    }
    
    .filter-select {
        flex: 1;
        min-width: 0;
    }
    
    .transaction-item {
        padding: var(--spacing-md);
    }
    
    .transaction-meta {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-xs);
    }
    
    .transaction-actions {
        margin-left: 0;
        margin-top: var(--spacing-sm);
    }
    
    .modal {
        margin: var(--spacing-md);
    }
    
    .modal-actions {
        flex-direction: column-reverse;
    }
}

@media (max-width: 480px) {
    .balance-item {
        flex-direction: column;
        text-align: center;
        gap: var(--spacing-sm);
    }
    
    .transaction-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
    }
    
    .transaction-icon {
        margin-right: 0;
    }
    
    .transaction-amount {
        margin-left: 0;
        align-self: flex-end;
    }
}

/* Animation Classes */
.fade-in {
    animation: fadeIn 0.3s ease-in;
}

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

.slide-up {
    animation: slideUp 0.3s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

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

/* Hidden class for view toggle */
.hidden {
    display: none !important;
}