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

:root {
    /* Color Palette */
    --color-primary: #F8B195;
    --color-secondary: #F67280;
    --color-tertiary: #C06C84;
    --color-quaternary: #6C5B7B;
    --color-quinary: #355C7D;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    --gradient-secondary: linear-gradient(135deg, var(--color-secondary), var(--color-tertiary));
    --gradient-tertiary: linear-gradient(135deg, var(--color-tertiary), var(--color-quaternary));
    --gradient-quaternary: linear-gradient(135deg, var(--color-quaternary), var(--color-quinary));
    --gradient-background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    
    /* Light Theme */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-card: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #7f8c8d;
    --text-muted: #95a5a6;
    --border-color: #e9ecef;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.15);
    
    /* Typography */
    --font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    --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: 2rem;
    
    /* 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;
    
    /* Transitions */
    --transition-fast: 0.15s ease-in-out;
    --transition-normal: 0.3s ease-in-out;
    --transition-slow: 0.5s ease-in-out;
}

/* Dark Theme */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2d2d2d;
    --bg-card: #2d2d2d;
    --text-primary: #ffffff;
    --text-secondary: #b3b3b3;
    --text-muted: #888888;
    --border-color: #404040;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.4);
    --gradient-background: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
}

/* Base Styles */
html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    font-size: var(--font-size-base);
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--gradient-background);
    min-height: 100vh;
    transition: all var(--transition-normal);
}

/* App Container */
.app-container {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
.header {
    background: var(--gradient-primary);
    padding: var(--spacing-xl) var(--spacing-md);
    text-align: center;
    position: relative;
    box-shadow: var(--shadow);
}

.header__content {
    max-width: 1200px;
    margin: 0 auto;
    position: relative;
}

.header__title {
    font-size: var(--font-size-3xl);
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-sm);
    text-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.header__subtitle {
    font-size: var(--font-size-lg);
    color: rgba(255, 255, 255, 0.9);
    font-weight: 300;
}

/* Theme Toggle */
.theme-toggle {
    position: absolute;
    top: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.2);
    border: none;
    border-radius: var(--radius-lg);
    padding: var(--spacing-sm);
    cursor: pointer;
    transition: all var(--transition-normal);
    backdrop-filter: blur(10px);
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1);
}

.theme-toggle__icon {
    font-size: var(--font-size-xl);
    display: block;
}

/* Main Content */
.main {
    flex: 1;
    padding: var(--spacing-xl) var(--spacing-md);
    max-width: 1200px;
    margin: 0 auto;
    width: 100%;
}

/* Card Component */
.card {
    background: var(--bg-card);
    border-radius: var(--radius-xl);
    padding: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.card:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-2px);
}

.card__title {
    font-size: var(--font-size-2xl);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* Input Components */
.input-group {
    margin-bottom: var(--spacing-lg);
}

.input-group--small {
    flex: 1;
}

.input-group__label {
    display: block;
    font-weight: 500;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
    font-size: var(--font-size-sm);
}

.input-group__input,
.input-group__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(--bg-primary);
    color: var(--text-primary);
    transition: all var(--transition-normal);
}

.input-group__input:focus,
.input-group__select:focus {
    outline: none;
    border-color: var(--color-secondary);
    box-shadow: 0 0 0 3px rgba(246, 114, 128, 0.1);
}

.input-group__input::placeholder {
    color: var(--text-muted);
}

/* Time Configuration */
.time-config {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-lg);
}

.time-config__section {
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

.time-config__title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
}

.time-inputs {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
}

/* Financial Configuration */
.financial-config {
    padding: var(--spacing-lg);
    background: var(--gradient-quaternary);
    border-radius: var(--radius-lg);
    margin-bottom: var(--spacing-lg);
}

.financial-config__title {
    font-size: var(--font-size-lg);
    font-weight: 600;
    color: white;
    margin-bottom: var(--spacing-md);
}

.financial-config .input-group__label {
    color: rgba(255, 255, 255, 0.9);
}

.financial-config .input-group__input {
    background: rgba(255, 255, 255, 0.1);
    border-color: rgba(255, 255, 255, 0.2);
    color: white;
    backdrop-filter: blur(10px);
}

.financial-config .input-group__input::placeholder {
    color: rgba(255, 255, 255, 0.6);
}

.financial-config .input-group__input:focus {
    border-color: rgba(255, 255, 255, 0.5);
    background: rgba(255, 255, 255, 0.2);
}

/* Buttons */
.action-buttons {
    display: flex;
    gap: var(--spacing-md);
    flex-wrap: wrap;
}

.btn {
    padding: var(--spacing-md) var(--spacing-lg);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--font-size-base);
    font-weight: 500;
    cursor: pointer;
    transition: all var(--transition-normal);
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-sm);
    text-decoration: none;
    min-height: 48px;
}

.btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.btn--primary {
    background: var(--gradient-secondary);
    color: white;
    box-shadow: 0 4px 15px rgba(246, 114, 128, 0.3);
}

.btn--primary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(246, 114, 128, 0.4);
}

.btn--secondary {
    background: var(--gradient-tertiary);
    color: white;
    box-shadow: 0 4px 15px rgba(192, 108, 132, 0.3);
}

.btn--secondary:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(192, 108, 132, 0.4);
}

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

.btn--tertiary:hover {
    background: var(--border-color);
    transform: translateY(-1px);
}

/* Results Section */
.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-xl);
}

.result-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg);
    background: var(--gradient-primary);
    border-radius: var(--radius-lg);
    color: white;
    box-shadow: 0 4px 15px rgba(248, 177, 149, 0.3);
}

.result-item__icon {
    font-size: var(--font-size-2xl);
    opacity: 0.9;
}

.result-item__content {
    display: flex;
    flex-direction: column;
}

.result-item__label {
    font-size: var(--font-size-sm);
    opacity: 0.9;
    font-weight: 400;
}

.result-item__value {
    font-size: var(--font-size-lg);
    font-weight: 600;
}

/* Summary Stats */
.summary-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.stat-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-xl);
    background: var(--gradient-tertiary);
    border-radius: var(--radius-lg);
    color: white;
    box-shadow: 0 4px 15px rgba(192, 108, 132, 0.3);
}

.stat-card__icon {
    font-size: var(--font-size-3xl);
    opacity: 0.9;
}

.stat-card__content {
    display: flex;
    flex-direction: column;
}

.stat-card__label {
    font-size: var(--font-size-sm);
    opacity: 0.9;
    font-weight: 400;
}

.stat-card__value {
    font-size: var(--font-size-2xl);
    font-weight: 700;
}

/* Charts Section */
.chart-container {
    display: flex;
    justify-content: center;
    margin-bottom: var(--spacing-lg);
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
}

#savingsChart {
    max-width: 100%;
    height: auto;
}

.chart-legend {
    display: flex;
    justify-content: center;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

.legend-item {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--font-size-sm);
}

.legend-color {
    width: 16px;
    height: 16px;
    border-radius: var(--radius-sm);
}

/* Saved Simulations */
.saved-simulations {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-md);
}

.empty-state {
    text-align: center;
    color: var(--text-muted);
    font-style: italic;
    padding: var(--spacing-xl);
}

.simulation-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border-color);
    transition: all var(--transition-normal);
}

.simulation-item:hover {
    box-shadow: var(--shadow);
    transform: translateY(-1px);
}

.simulation-info {
    flex: 1;
}

.simulation-name {
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.simulation-details {
    font-size: var(--font-size-sm);
    color: var(--text-secondary);
}

.simulation-actions {
    display: flex;
    gap: var(--spacing-sm);
}

.btn--small {
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-sm);
    min-height: 36px;
}

/* Footer */
.footer {
    background: var(--gradient-quaternary);
    padding: var(--spacing-lg) var(--spacing-md);
    text-align: center;
    margin-top: auto;
}

.footer__content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer__text {
    color: white;
    font-size: var(--font-size-sm);
}

.footer__link {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    transition: color var(--transition-normal);
}

.footer__link:hover {
    color: white;
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .header__title {
        font-size: var(--font-size-2xl);
    }
    
    .header__subtitle {
        font-size: var(--font-size-base);
    }
    
    .theme-toggle {
        position: static;
        margin-top: var(--spacing-md);
    }
    
    .main {
        padding: var(--spacing-lg) var(--spacing-md);
    }
    
    .card {
        padding: var(--spacing-lg);
    }
    
    .time-config {
        grid-template-columns: 1fr;
        gap: var(--spacing-lg);
    }
    
    .time-inputs {
        flex-direction: column;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
    
    .results-grid {
        grid-template-columns: 1fr;
    }
    
    .summary-stats {
        grid-template-columns: 1fr;
    }
    
    .simulation-item {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
    }
    
    .simulation-actions {
        width: 100%;
        justify-content: flex-end;
    }
}

@media (max-width: 480px) {
    .card__title {
        font-size: var(--font-size-xl);
    }
    
    .time-config__section {
        padding: var(--spacing-md);
    }
    
    .financial-config {
        padding: var(--spacing-md);
    }
    
    .result-item,
    .stat-card {
        padding: var(--spacing-md);
    }
    
    .chart-container {
        padding: var(--spacing-md);
    }
}

/* Accessibility */
@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

/* Focus styles for keyboard navigation */
.btn:focus,
.input-group__input:focus,
.input-group__select:focus,
.theme-toggle:focus {
    outline: 2px solid var(--color-secondary);
    outline-offset: 2px;
}

/* High contrast mode support */
@media (prefers-contrast: high) {
    :root {
        --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
        --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.4);
    }
    
    .card {
        border-width: 2px;
    }
    
    .input-group__input,
    .input-group__select {
        border-width: 2px;
    }
}

/* Print styles */
@media print {
    .theme-toggle,
    .action-buttons,
    .simulation-actions {
        display: none;
    }
    
    .card {
        box-shadow: none;
        border: 1px solid #000;
        break-inside: avoid;
    }
    
    .header {
        background: none;
        color: #000;
    }
    
    .header__title,
    .header__subtitle {
        color: #000;
    }
}