/* ========================================
   Text Case Converter - Styles
   Production-ready CSS with dark mode, 
   accessibility, and responsive design
   ======================================== */

:root {
    /* Light Mode Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #f0f1f4;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --text-tertiary: #999999;
    --border-color: #e0e0e0;
    --accent-color: #667eea;
    --accent-hover: #5568d3;
    --accent-light: #f0f2ff;
    --success-color: #10b981;
    --success-bg: #d1fae5;
    --error-color: #ef4444;
    --error-bg: #fee2e2;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);

    /* 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-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue', sans-serif;
    --font-mono: 'SF Mono', 'Monaco', 'Inconsolata', 'Fira Code', 'Source Code Pro', monospace;

    /* Transitions */
    --transition: all 0.3s ease;
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg-primary: #1a1a1a;
        --bg-secondary: #2a2a2a;
        --bg-tertiary: #3a3a3a;
        --text-primary: #ffffff;
        --text-secondary: #d0d0d0;
        --text-tertiary: #a0a0a0;
        --border-color: #404040;
        --accent-color: #7c8ff5;
        --accent-hover: #8b99ff;
        --accent-light: #2a2e5f;
        --success-bg: #064e3b;
        --error-bg: #7f1d1d;
        --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
        --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
        --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
    }
}

/* Force Light Mode */
[data-theme="light"] {
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-tertiary: #f0f1f4;
    --text-primary: #1a1a1a;
    --text-secondary: #666666;
    --text-tertiary: #999999;
    --border-color: #e0e0e0;
    --accent-color: #667eea;
    --accent-hover: #5568d3;
    --accent-light: #f0f2ff;
    --success-color: #10b981;
    --success-bg: #d1fae5;
    --error-color: #ef4444;
    --error-bg: #fee2e2;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

/* Force Dark Mode */
[data-theme="dark"] {
    --bg-primary: #1a1a1a;
    --bg-secondary: #2a2a2a;
    --bg-tertiary: #3a3a3a;
    --text-primary: #ffffff;
    --text-secondary: #d0d0d0;
    --text-tertiary: #a0a0a0;
    --border-color: #404040;
    --accent-color: #7c8ff5;
    --accent-hover: #8b99ff;
    --accent-light: #2a2e5f;
    --success-bg: #064e3b;
    --error-bg: #7f1d1d;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
}

/* ========================================
   Reset & Base Styles
   ======================================== */

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    transition: var(--transition);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Reduce motion for accessibility */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}

/* ========================================
   Typography
   ======================================== */

h1 {
    font-size: clamp(2rem, 5vw, 3.5rem);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h2 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    line-height: 1.3;
    margin-bottom: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 600;
    line-height: 1.4;
    margin-bottom: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
    line-height: 1.7;
}

ul, ol {
    margin-left: var(--spacing-lg);
    margin-bottom: var(--spacing-lg);
}

li {
    margin-bottom: var(--spacing-sm);
    color: var(--text-secondary);
}

/* ========================================
   Container & Layout
   ======================================== */

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

@media (max-width: 768px) {
    .container {
        padding: var(--spacing-md);
    }
}

/* ========================================
   Header
   ======================================== */

.header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: var(--spacing-2xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.header-content h1 {
    margin-bottom: var(--spacing-sm);
    background: linear-gradient(135deg, var(--accent-color) 0%, #7c8ff5 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tagline {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin: 0;
}

.theme-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 44px;
    height: 44px;
    border: 2px solid var(--border-color);
    background-color: var(--bg-secondary);
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: var(--transition);
    flex-shrink: 0;
    margin-left: var(--spacing-md);
}

.theme-toggle:hover {
    background-color: var(--accent-light);
    border-color: var(--accent-color);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

.theme-toggle svg {
    width: 20px;
    height: 20px;
    color: var(--accent-color);
    transition: var(--transition);
}

.sun-icon {
    display: block;
}

.moon-icon {
    display: none;
}

[data-theme="dark"] .sun-icon {
    display: none;
}

[data-theme="dark"] .moon-icon {
    display: block;
}

/* ========================================
   Input Section
   ======================================== */

.input-section {
    margin-bottom: var(--spacing-2xl);
}

.input-wrapper {
    background-color: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    transition: var(--transition);
}

.input-wrapper:focus-within {
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px var(--accent-light);
}

.input-label {
    display: block;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.input-container {
    position: relative;
}

.input-textarea {
    width: 100%;
    padding: var(--spacing-md);
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    resize: vertical;
    transition: var(--transition);
    min-height: 120px;
    max-height: 300px;
}

.input-textarea:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px var(--accent-light);
}

.input-textarea::placeholder {
    color: var(--text-tertiary);
}

.clear-btn {
    position: absolute;
    top: var(--spacing-md);
    right: var(--spacing-md);
    width: 36px;
    height: 36px;
    padding: 0;
    background-color: var(--error-bg);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--error-color);
    transition: var(--transition);
    opacity: 0;
}

.input-textarea:not(:placeholder-shown) ~ .clear-btn {
    opacity: 1;
}

.clear-btn:hover {
    background-color: var(--error-color);
    color: white;
}

.clear-btn:focus-visible {
    outline: 2px solid var(--error-color);
    outline-offset: 2px;
}

.clear-btn svg {
    width: 20px;
    height: 20px;
}

.char-count {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    margin-top: var(--spacing-sm);
    text-align: right;
}

/* ========================================
   Advertisement Placeholders
   ======================================== */

.ad-placeholder {
    background-color: var(--bg-secondary);
    border: 2px dashed var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    text-align: center;
    color: var(--text-tertiary);
    margin: var(--spacing-2xl) 0;
    min-height: 100px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ad-placeholder small {
    font-size: 0.875rem;
}

/* ========================================
   Output Section
   ======================================== */

.output-section {
    margin-bottom: var(--spacing-2xl);
}

.output-section h2 {
    margin-top: 0;
}

.variants-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: var(--spacing-lg);
}

@media (max-width: 768px) {
    .variants-grid {
        grid-template-columns: 1fr;
    }
}

.variant-card {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-lg);
    transition: var(--transition);
    display: flex;
    flex-direction: column;
}

.variant-card:hover {
    border-color: var(--accent-color);
    box-shadow: var(--shadow-md);
}

.variant-header {
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
}

.variant-header h3 {
    font-size: 1.25rem;
    margin: 0 0 var(--spacing-xs) 0;
    color: var(--accent-color);
    font-weight: 700;
}

.variant-desc {
    font-size: 0.875rem;
    color: var(--text-tertiary);
    font-weight: 400;
}

.variant-content {
    flex: 1;
    margin-bottom: var(--spacing-md);
    min-height: 100px;
    display: flex;
    align-items: center;
}

.variant-output {
    width: 100%;
    font-family: var(--font-mono);
    font-size: 0.95rem;
    line-height: 1.5;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    margin: 0;
    word-break: break-all;
    white-space: pre-wrap;
    overflow-x: auto;
    max-height: 120px;
    overflow-y: auto;
}

.variant-output:empty::before {
    content: "Your converted text will appear here...";
    color: var(--text-tertiary);
    font-style: italic;
}

.copy-btn {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-size: 1rem;
    font-weight: 600;
    color: white;
    background-color: var(--accent-color);
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
}

.copy-btn:hover {
    background-color: var(--accent-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.copy-btn:active {
    transform: translateY(0);
}

.copy-btn:focus-visible {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

.copy-btn.copied {
    background-color: var(--success-color);
}

.copy-btn svg {
    width: 18px;
    height: 18px;
}

/* ========================================
   Info Section
   ======================================== */

.info-section,
.author-section,
.legal-section {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    padding: var(--spacing-2xl);
    margin-top: var(--spacing-2xl);
}

.info-section p {
    margin-bottom: var(--spacing-md);
}

.author-section h2 {
    margin-top: 0;
}

.updated-date {
    color: var(--text-tertiary);
    font-size: 0.875rem;
    font-weight: 600;
}

.examples-table-wrapper {
    overflow-x: auto;
    margin-bottom: var(--spacing-lg);
}

.examples-table {
    width: 100%;
    border-collapse: collapse;
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.examples-table th,
.examples-table td {
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--border-color);
    text-align: left;
    vertical-align: top;
}

.examples-table th {
    color: var(--text-primary);
    background-color: var(--bg-tertiary);
}

.examples-table td {
    color: var(--text-secondary);
}

.info-section ul {
    margin-left: var(--spacing-lg);
}

.info-section li {
    margin-bottom: var(--spacing-md);
}

.legal-section {
    max-width: 900px;
    margin-left: auto;
    margin-right: auto;
}

.legal-section h2:first-child {
    margin-top: 0;
}

.legal-section a,
.site-footer a {
    color: var(--accent-color);
    font-weight: 600;
    text-decoration: none;
}

.legal-section a:hover,
.site-footer a:hover {
    color: var(--accent-hover);
    text-decoration: underline;
}

/* ========================================
   Footer
   ======================================== */

.site-footer {
    margin-top: var(--spacing-2xl);
    border-top: 1px solid var(--border-color);
    background-color: var(--bg-secondary);
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: var(--spacing-md);
}

.footer-content p {
    margin: 0;
    font-size: 0.95rem;
}

.footer-nav {
    display: flex;
    gap: var(--spacing-lg);
    flex-wrap: wrap;
}

/* ========================================
   Toast Notification
   ======================================== */

.toast {
    position: fixed;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    background-color: var(--text-primary);
    color: var(--bg-primary);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    font-size: 0.95rem;
    font-weight: 500;
    opacity: 0;
    transform: translateY(100px) scale(0.9);
    transition: var(--transition);
    pointer-events: none;
    z-index: 1000;
}

.toast.show {
    opacity: 1;
    transform: translateY(0) scale(1);
    pointer-events: auto;
}

.cookie-consent {
    position: fixed;
    left: var(--spacing-lg);
    right: var(--spacing-lg);
    bottom: var(--spacing-lg);
    z-index: 1100;
    max-width: 760px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background-color: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
}

.cookie-consent p {
    margin: 0;
    font-size: 0.95rem;
}

.cookie-consent a {
    color: var(--accent-color);
    font-weight: 600;
}

.cookie-consent button {
    flex-shrink: 0;
    padding: var(--spacing-sm) var(--spacing-md);
    color: white;
    background-color: var(--accent-color);
    border: 0;
    border-radius: var(--radius-md);
    cursor: pointer;
    font-weight: 700;
}

.cookie-consent button:hover {
    background-color: var(--accent-hover);
}

@media (max-width: 480px) {
    .toast {
        left: var(--spacing-lg);
        right: var(--spacing-lg);
        bottom: var(--spacing-lg);
    }

    .cookie-consent {
        flex-direction: column;
        align-items: flex-start;
    }
}

/* ========================================
   Accessibility
   ======================================== */

/* Focus visible styles for keyboard navigation */
:focus-visible {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* Skip to main content link */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background-color: var(--accent-color);
    color: white;
    padding: var(--spacing-sm) var(--spacing-md);
    text-decoration: none;
    z-index: 100;
    border-radius: var(--radius-md);
}

.skip-link:focus {
    top: var(--spacing-md);
}

/* Reduce motion animations */
@media (prefers-reduced-motion: reduce) {
    .theme-toggle,
    .variant-card,
    .copy-btn,
    .toast {
        transition: none;
    }
}

/* High contrast mode support */
@media (prefers-contrast: more) {
    body {
        border: 1px solid var(--text-primary);
    }

    .variant-card,
    .input-wrapper {
        border-width: 2px;
    }
}

/* ========================================
   Responsive Design
   ======================================== */

@media (max-width: 640px) {
    :root {
        --spacing-lg: 1rem;
        --spacing-xl: 1.5rem;
        --spacing-2xl: 2rem;
    }

    .header {
        flex-direction: column;
        align-items: flex-start;
    }

    .theme-toggle {
        margin-left: 0;
        margin-top: var(--spacing-md);
        align-self: flex-start;
    }

    h1 {
        font-size: 1.75rem;
    }

    h2 {
        font-size: 1.5rem;
    }

    .variant-output {
        font-size: 0.85rem;
        padding: var(--spacing-sm);
    }

    .info-section,
    .legal-section {
        padding: var(--spacing-lg);
    }

    .footer-content {
        align-items: flex-start;
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .container {
        padding: var(--spacing-md);
    }

    .header-content h1 {
        font-size: 1.5rem;
    }

    .tagline {
        font-size: 1rem;
    }

    .variants-grid {
        gap: var(--spacing-md);
    }

    .variant-card {
        padding: var(--spacing-md);
    }

    .copy-btn {
        padding: var(--spacing-sm);
        font-size: 0.95rem;
    }
}

/* ========================================
   Print Styles
   ======================================== */

@media print {
    .header,
    .input-section,
    .ad-placeholder,
    .info-section,
    .copy-btn,
    .clear-btn,
    .theme-toggle {
        display: none;
    }

    .variant-output {
        page-break-inside: avoid;
    }
}