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

:root {
    /* High contrast colors for accessibility */
    --color-primary: #0066cc;
    --color-primary-dark: #0052a3;
    --color-secondary: #666666;
    --color-text: #000000;
    --color-text-light: #333333;
    --color-background: #ffffff;
    --color-border: #000000;
    --color-focus: #0066cc;
    --color-focus-outline: #0066cc;
    --color-error: #cc0000;
    --color-success: #006600;
    --color-result-bg: #f5f5f5;
    --color-result-border: #000000;
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Typography */
    --font-size-base: 1rem;
    --font-size-lg: 1.25rem;
    --font-size-xl: 1.5rem;
    --font-size-xxl: 2rem;
    --line-height-base: 1.5;
    
    /* Border radius */
    --border-radius: 0.5rem;
    
    /* Focus outline */
    --focus-outline-width: 3px;
    --focus-outline-offset: 2px;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    font-size: var(--font-size-base);
    line-height: var(--line-height-base);
    color: var(--color-text);
    background-color: var(--color-background);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    padding: var(--spacing-md);
}

.container {
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    flex: 1;
}

/* Accessibility Controls */
.accessibility-controls {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
    justify-content: center;
    align-items: flex-start;
    padding: var(--spacing-md);
    background-color: var(--color-result-bg);
    border-radius: var(--border-radius);
    border: 1px solid var(--color-border);
}

.control-group {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
    flex: 0 1 auto;
    min-width: 160px;
    max-width: 200px;
}

.control-label {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--color-text);
    white-space: nowrap;
    text-align: center;
}

.control-select {
    flex: 1;
    padding: 0.75rem;
    font-size: var(--font-size-base);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    background-color: var(--color-background);
    color: var(--color-text);
    min-height: 44px;
    cursor: pointer;
    transition: all 0.2s ease;
    text-align: center;
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23000' d='M6 9L1 4h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 0.75rem center;
    padding-right: 2.5rem;
}

.control-select:hover {
    border-color: var(--color-primary);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.control-select:focus {
    outline: var(--focus-outline-width) solid var(--color-focus-outline);
    outline-offset: var(--focus-outline-offset);
    border-color: var(--color-focus);
}

.control-select:hover {
    border-color: var(--color-primary);
}

/* Header Styles */
header {
    text-align: center;
    margin-bottom: var(--spacing-md);
}

h1 {
    font-size: var(--font-size-xxl);
    margin-bottom: 0.25rem;
    color: var(--color-text);
}

.subtitle {
    font-size: var(--font-size-lg);
    color: var(--color-text-light);
    margin-bottom: 0;
}

/* Form Styles */
form {
    background-color: var(--color-background);
    padding: var(--spacing-lg);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    margin-bottom: var(--spacing-lg);
    margin-top: var(--spacing-sm);
}

/* Currency Selection */
.currency-selection {
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-sm) var(--spacing-md);
    margin-bottom: var(--spacing-md);
    background-color: var(--color-background);
}

.currency-selection legend {
    font-size: var(--font-size-base);
    font-weight: bold;
    padding: 0 var(--spacing-xs);
    color: var(--color-text);
}

.radio-group {
    display: flex;
    flex-direction: row;
    gap: var(--spacing-md);
    margin-top: var(--spacing-xs);
    flex-wrap: wrap;
}

.radio-label {
    display: flex;
    align-items: center;
    cursor: pointer;
    padding: var(--spacing-xs) var(--spacing-sm);
    border: 2px solid transparent;
    border-radius: var(--border-radius);
    transition: background-color 0.2s;
    min-height: 44px; /* Minimum touch target size */
    flex: 0 1 auto;
}

.radio-label:hover {
    background-color: var(--color-result-bg);
}

.radio-label input[type="radio"] {
    width: 24px;
    height: 24px;
    margin-right: var(--spacing-sm);
    cursor: pointer;
    accent-color: var(--color-primary);
    flex-shrink: 0;
}

.radio-label input[type="radio"]:focus {
    outline: var(--focus-outline-width) solid var(--color-focus-outline);
    outline-offset: var(--focus-outline-offset);
    border-radius: 50%;
}

.radio-label span {
    font-size: var(--font-size-base);
    color: var(--color-text);
}

/* Input Fields */
.input-row {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-md);
    flex-wrap: wrap;
}

.input-group {
    flex: 1;
    min-width: 200px;
    margin-bottom: 0;
}

.input-label {
    display: block;
    font-size: var(--font-size-base);
    font-weight: bold;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text);
}

.required {
    color: var(--color-error);
    margin-left: 0.25rem;
}

input[type="number"] {
    width: 100%;
    padding: var(--spacing-sm);
    font-size: var(--font-size-lg);
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    background-color: var(--color-background);
    color: var(--color-text);
    min-height: 44px; /* Minimum touch target size */
    transition: border-color 0.2s;
}

input[type="number"]:focus {
    outline: var(--focus-outline-width) solid var(--color-focus-outline);
    outline-offset: var(--focus-outline-offset);
    border-color: var(--color-focus);
}

input[type="number"]:user-invalid {
    border-color: var(--color-error);
}

input[type="number"]::placeholder {
    color: var(--color-secondary);
    opacity: 0.7;
}

/* Button Styles */
.button-group {
    display: flex;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    flex-wrap: wrap;
}

.btn {
    flex: 1;
    min-width: 120px;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: var(--font-size-base);
    font-weight: bold;
    border: 2px solid var(--color-border);
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.2s;
    min-height: 44px; /* Minimum touch target size */
    text-align: center;
}

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

.btn-primary:hover,
.btn-primary:focus {
    background-color: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    outline: var(--focus-outline-width) solid var(--color-focus-outline);
    outline-offset: var(--focus-outline-offset);
}

.btn-secondary {
    background-color: var(--color-background);
    color: var(--color-text);
    border-color: var(--color-border);
}

.btn-secondary:hover,
.btn-secondary:focus {
    background-color: var(--color-result-bg);
    outline: var(--focus-outline-width) solid var(--color-focus-outline);
    outline-offset: var(--focus-outline-offset);
}

.btn:active {
    transform: scale(0.98);
}

/* Results Section */
.results-section {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
}

.result-card {
    background-color: var(--color-result-bg);
    border: 2px solid var(--color-result-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    text-align: center;
}

.result-title {
    font-size: var(--font-size-base);
    font-weight: bold;
    margin-bottom: var(--spacing-sm);
    color: var(--color-text);
}

.result-value {
    font-size: var(--font-size-xl);
    font-weight: bold;
    color: var(--color-text);
    min-height: 2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

.result-value:not(:empty) {
    color: var(--color-success);
}

/* Error Messages */
.error-container {
    margin-top: var(--spacing-md);
    padding: var(--spacing-sm);
    background-color: #ffebee;
    border: 2px solid var(--color-error);
    border-radius: var(--border-radius);
    color: var(--color-error);
    font-weight: bold;
    display: none;
}

.error-container:not(:empty) {
    display: block;
}

.error-container p {
    margin: 0;
}

/* Info Section */
.info-section {
    background-color: var(--color-result-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius);
    padding: var(--spacing-md);
    margin-bottom: var(--spacing-lg);
    text-align: center;
}

.exchange-rate-info {
    font-size: var(--font-size-base);
    color: var(--color-text);
    margin: 0;
}

/* Footer */
footer {
    text-align: center;
    padding: var(--spacing-md);
    border-top: 1px solid var(--color-border);
    margin-top: var(--spacing-lg);
}

.accessibility-info {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin: 0 0 var(--spacing-xs) 0;
}

.footer-credit {
    font-size: 0.875rem;
    color: var(--color-text-light);
    margin: 0;
}

.footer-credit a {
    color: var(--color-primary);
    text-decoration: none;
    font-weight: 600;
    transition: color 0.2s ease;
}

.footer-credit a:hover,
.footer-credit a:focus {
    color: var(--color-primary-dark);
    text-decoration: underline;
    outline: 2px solid var(--color-focus);
    outline-offset: 2px;
}

/* Screen Reader Only */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

/* Responsive Design - Mobile First */
@media (max-width: 599px) {
    .accessibility-controls {
        padding: var(--spacing-sm);
        gap: var(--spacing-sm);
    }
    
    .control-group {
        min-width: 100%;
        max-width: 100%;
    }
    
    .control-label {
        font-size: 0.85rem;
    }
}

@media (min-width: 600px) {
    .results-section {
        grid-template-columns: 1fr 1fr;
    }
    
    .button-group {
        flex-wrap: nowrap;
    }
    
    .input-row {
        flex-wrap: nowrap;
    }
}

@media (min-width: 768px) {
    body {
        padding: var(--spacing-lg);
    }
    
    h1 {
        font-size: 2.5rem;
    }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
    :root {
        --color-border: #000000;
        --color-text: #000000;
        --color-background: #ffffff;
        --focus-outline-width: 4px;
    }
    
    .btn {
        border-width: 3px;
    }
    
    input[type="number"] {
        border-width: 3px;
    }
}

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

/* Text Scaling Support - up to 200% */
@media (min-width: 1px) {
    html {
        font-size: 100%;
    }
}

/* Color Theme - Light Theme (Default) */
body.theme-light {
    --color-primary: #0066cc;
    --color-primary-dark: #0052a3;
    --color-secondary: #666666;
    --color-text: #000000;
    --color-text-light: #333333;
    --color-background: #ffffff;
    --color-border: #000000;
    --color-focus: #0066cc;
    --color-focus-outline: #0066cc;
    --color-error: #cc0000;
    --color-success: #006600;
    --color-result-bg: #f5f5f5;
    --color-result-border: #000000;
}

/* Color Theme - Dark Theme */
body.theme-dark {
    --color-primary: #4da6ff;
    --color-primary-dark: #3399ff;
    --color-secondary: #999999;
    --color-text: #ffffff;
    --color-text-light: #e0e0e0;
    --color-background: #1a1a1a;
    --color-border: #ffffff;
    --color-focus: #4da6ff;
    --color-focus-outline: #4da6ff;
    --color-error: #ff6666;
    --color-success: #66ff66;
    --color-result-bg: #2d2d2d;
    --color-result-border: #ffffff;
}

/* Auto theme - use OS preference */
@media (prefers-color-scheme: dark) {
    body:not(.theme-light):not(.theme-dark) {
        --color-primary: #4da6ff;
        --color-primary-dark: #3399ff;
        --color-secondary: #999999;
        --color-text: #ffffff;
        --color-text-light: #e0e0e0;
        --color-background: #1a1a1a;
        --color-border: #ffffff;
        --color-focus: #4da6ff;
        --color-focus-outline: #4da6ff;
        --color-error: #ff6666;
        --color-success: #66ff66;
        --color-result-bg: #2d2d2d;
        --color-result-border: #ffffff;
    }
}

@media (prefers-color-scheme: light) {
    body:not(.theme-light):not(.theme-dark) {
        --color-primary: #0066cc;
        --color-primary-dark: #0052a3;
        --color-secondary: #666666;
        --color-text: #000000;
        --color-text-light: #333333;
        --color-background: #ffffff;
        --color-border: #000000;
        --color-focus: #0066cc;
        --color-focus-outline: #0066cc;
        --color-error: #cc0000;
        --color-success: #006600;
        --color-result-bg: #f5f5f5;
        --color-result-border: #000000;
    }
}

/* Contrast Themes - High Contrast (Blue/Black/White) */
body.contrast-high {
    --color-primary: #0066ff;
    --color-primary-dark: #0052cc;
    --color-text: #000000;
    --color-text-light: #000000;
    --color-background: #ffffff;
    --color-border: #0066ff;
    --color-focus: #0066ff;
    --color-focus-outline: #0066ff;
    --color-error: #ff0000;
    --color-success: #008000;
    --color-result-bg: #e6f2ff;
    --color-result-border: #0066ff;
    --focus-outline-width: 4px;
}

body.contrast-high .btn-primary {
    background-color: #0066ff;
    color: #ffffff;
    border-color: #0066ff;
    border-width: 3px;
    font-weight: bold;
}

body.contrast-high .btn-primary:hover,
body.contrast-high .btn-primary:focus {
    background-color: #0052cc;
    border-color: #0052cc;
    outline: 4px solid #0066ff;
    outline-offset: 2px;
}

body.contrast-high .btn-secondary {
    background-color: #ffffff;
    color: #0066ff;
    border-color: #0066ff;
    border-width: 3px;
    font-weight: bold;
}

body.contrast-high .btn-secondary:hover,
body.contrast-high .btn-secondary:focus {
    background-color: #e6f2ff;
    border-color: #0052cc;
    outline: 4px solid #0066ff;
    outline-offset: 2px;
}

body.contrast-high input[type="number"],
body.contrast-high .control-select {
    border-width: 3px;
    border-color: #0066ff;
    font-weight: bold;
}

body.contrast-high input[type="number"]:focus,
body.contrast-high .control-select:focus {
    border-color: #0066ff;
    outline: 4px solid #0066ff;
    outline-offset: 2px;
}

body.contrast-high .result-card {
    border-width: 3px;
    border-color: #0066ff;
    background-color: #e6f2ff;
}

body.contrast-high .result-value {
    font-weight: bold;
    font-size: 1.5rem;
    color: #000000;
}

body.contrast-high .radio-label {
    border: 2px solid #0066ff;
}

body.contrast-high .radio-label:hover {
    background-color: #e6f2ff;
    border-color: #0052cc;
}

/* Contrast Themes - Ultra High Contrast (Pure Black/White) */
body.contrast-ultra {
    --color-primary: #000000;
    --color-primary-dark: #000000;
    --color-text: #000000;
    --color-text-light: #000000;
    --color-background: #ffffff;
    --color-border: #000000;
    --color-focus: #000000;
    --color-focus-outline: #000000;
    --color-error: #000000;
    --color-success: #000000;
    --color-result-bg: #ffffff;
    --color-result-border: #000000;
    --focus-outline-width: 5px;
}

body.contrast-ultra .btn-primary {
    background-color: #000000;
    color: #ffffff;
    border-color: #000000;
    border-width: 4px;
    font-weight: 900;
    font-size: 1.1rem;
}

body.contrast-ultra .btn-primary:hover,
body.contrast-ultra .btn-primary:focus {
    background-color: #000000;
    color: #ffffff;
    border-color: #000000;
    outline: 5px solid #000000;
    outline-offset: 3px;
}

body.contrast-ultra .btn-secondary {
    background-color: #ffffff;
    color: #000000;
    border-color: #000000;
    border-width: 4px;
    font-weight: 900;
    font-size: 1.1rem;
}

body.contrast-ultra .btn-secondary:hover,
body.contrast-ultra .btn-secondary:focus {
    background-color: #ffffff;
    color: #000000;
    border-color: #000000;
    outline: 5px solid #000000;
    outline-offset: 3px;
}

body.contrast-ultra input[type="number"],
body.contrast-ultra .control-select {
    border-width: 4px;
    border-color: #000000;
    font-weight: 900;
    font-size: 1.1rem;
}

body.contrast-ultra input[type="number"]:focus,
body.contrast-ultra .control-select:focus {
    border-color: #000000;
    outline: 5px solid #000000;
    outline-offset: 3px;
}

body.contrast-ultra .result-card {
    border-width: 4px;
    border-color: #000000;
    background-color: #ffffff;
}

body.contrast-ultra .result-value {
    font-weight: 900;
    font-size: 2rem;
    color: #000000;
}

body.contrast-ultra .result-title {
    font-weight: 900;
    font-size: 1.5rem;
    color: #000000;
}

body.contrast-ultra .radio-label {
    border: 3px solid #000000;
    font-weight: 900;
}

body.contrast-ultra .radio-label:hover {
    background-color: #ffffff;
    border-color: #000000;
    outline: 3px solid #000000;
    outline-offset: 2px;
}

body.contrast-ultra .radio-label input[type="radio"]:checked + span {
    font-weight: 900;
}

body.contrast-ultra h1,
body.contrast-ultra h2,
body.contrast-ultra h3 {
    font-weight: 900;
    color: #000000;
}

body.contrast-ultra .accessibility-controls {
    border: 3px solid #000000;
    padding: var(--spacing-md);
    background-color: #ffffff;
}

body.contrast-ultra .control-label {
    font-weight: 900;
    color: #000000;
}

/* Print Styles */
@media print {
    .button-group,
    .error-container,
    footer {
        display: none;
    }
    
    form {
        border: 1px solid var(--color-border);
    }
}