/* ==========================================================================
   Line Paper Generator Pro - Stylesheet
   A modern, accessible design with dark mode support
   ========================================================================== */

/* ==========================================================================
   1. CSS Custom Properties (Design Tokens)
   ========================================================================== */

:root {
    /* Typography */
    --font-display: 'Playfair Display', Georgia, serif;
    --font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'Space Mono', 'Fira Code', monospace;
    
    /* Font Sizes - Fluid Typography */
    --text-xs: clamp(0.7rem, 0.65rem + 0.25vw, 0.75rem);
    --text-sm: clamp(0.8rem, 0.75rem + 0.25vw, 0.875rem);
    --text-base: clamp(0.9rem, 0.85rem + 0.25vw, 1rem);
    --text-lg: clamp(1rem, 0.95rem + 0.25vw, 1.125rem);
    --text-xl: clamp(1.15rem, 1rem + 0.75vw, 1.375rem);
    --text-2xl: clamp(1.4rem, 1.2rem + 1vw, 1.75rem);
    --text-3xl: clamp(1.75rem, 1.5rem + 1.25vw, 2.25rem);
    --text-4xl: clamp(2.25rem, 1.75rem + 2.5vw, 3.5rem);
    
    /* Spacing */
    --space-1: 0.25rem;
    --space-2: 0.5rem;
    --space-3: 0.75rem;
    --space-4: 1rem;
    --space-5: 1.25rem;
    --space-6: 1.5rem;
    --space-8: 2rem;
    --space-10: 2.5rem;
    --space-12: 3rem;
    --space-16: 4rem;
    --space-20: 5rem;
    
    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.25rem;
    --radius-3xl: 1.5rem;
    --radius-full: 9999px;
    
    /* Shadows - Light Mode */
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-glow: 0 0 40px rgba(59, 130, 246, 0.15);
    --shadow-paper: 0 4px 24px rgba(0, 0, 0, 0.12), 0 0 0 1px rgba(0, 0, 0, 0.02);
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-spring: 500ms cubic-bezier(0.175, 0.885, 0.32, 1.275);
    
    /* Z-Index Scale */
    --z-base: 0;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 300;
    --z-toast: 400;
    --z-tooltip: 500;
    
    /* Light Mode Colors */
    --color-bg-primary: #f8fafc;
    --color-bg-secondary: #ffffff;
    --color-bg-tertiary: #f1f5f9;
    --color-bg-elevated: #ffffff;
    --color-bg-glass: rgba(255, 255, 255, 0.85);
    
    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-text-tertiary: #64748b;
    --color-text-muted: #94a3b8;
    --color-text-inverse: #ffffff;
    
    --color-border: #e2e8f0;
    --color-border-hover: #cbd5e1;
    --color-border-focus: #3b82f6;
    
    --color-accent-primary: #3b82f6;
    --color-accent-primary-hover: #2563eb;
    --color-accent-primary-light: rgba(59, 130, 246, 0.1);
    --color-accent-secondary: #8b5cf6;
    --color-accent-gradient: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
    
    --color-success: #10b981;
    --color-success-hover: #059669;
    --color-success-light: rgba(16, 185, 129, 0.1);
    
    --color-warning: #f59e0b;
    --color-danger: #ef4444;
    --color-danger-hover: #dc2626;
    
    /* Paper Preview */
    --color-paper: #ffffff;
    --color-paper-shadow: rgba(0, 0, 0, 0.15);
    
    /* Background Decorations */
    --bg-gradient: linear-gradient(135deg, #dbeafe 0%, #e0e7ff 50%, #fae8ff 100%);
    --bg-grid-color: rgba(59, 130, 246, 0.08);
    --bg-noise-opacity: 0.02;
}

/* Dark Mode Colors */
[data-theme="dark"] {
    --color-bg-primary: #0f172a;
    --color-bg-secondary: #1e293b;
    --color-bg-tertiary: #334155;
    --color-bg-elevated: #1e293b;
    --color-bg-glass: rgba(30, 41, 59, 0.9);
    
    --color-text-primary: #f8fafc;
    --color-text-secondary: #cbd5e1;
    --color-text-tertiary: #94a3b8;
    --color-text-muted: #64748b;
    --color-text-inverse: #0f172a;
    
    --color-border: #334155;
    --color-border-hover: #475569;
    --color-border-focus: #60a5fa;
    
    --color-accent-primary: #60a5fa;
    --color-accent-primary-hover: #3b82f6;
    --color-accent-primary-light: rgba(96, 165, 250, 0.15);
    
    --color-success-light: rgba(16, 185, 129, 0.15);
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -2px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4), 0 4px 6px -4px rgba(0, 0, 0, 0.3);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.4), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(96, 165, 250, 0.2);
    --shadow-paper: 0 4px 24px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(255, 255, 255, 0.05);
    
    --color-paper: #ffffff;
    --color-paper-shadow: rgba(0, 0, 0, 0.5);
    
    --bg-gradient: linear-gradient(135deg, #1e293b 0%, #0f172a 50%, #1e1b4b 100%);
    --bg-grid-color: rgba(96, 165, 250, 0.05);
    --bg-noise-opacity: 0.03;
}

/* ==========================================================================
   2. Base Styles & Reset
   ========================================================================== */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--font-body);
    font-size: var(--text-base);
    line-height: 1.6;
    color: var(--color-text-primary);
    background: var(--color-bg-primary);
    min-height: 100vh;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Focus Styles */
:focus-visible {
    outline: 2px solid var(--color-border-focus);
    outline-offset: 2px;
}

:focus:not(:focus-visible) {
    outline: none;
}

/* Selection */
::selection {
    background: var(--color-accent-primary);
    color: var(--color-text-inverse);
}

/* Scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--color-bg-tertiary);
}

::-webkit-scrollbar-thumb {
    background: var(--color-border-hover);
    border-radius: var(--radius-full);
    border: 2px solid var(--color-bg-tertiary);
}

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

/* ==========================================================================
   3. Layout
   ========================================================================== */

.app-container {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Background Decoration */
.bg-decoration {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: -1;
    overflow: hidden;
}

.bg-grid {
    position: absolute;
    inset: 0;
    background-image: 
        linear-gradient(var(--bg-grid-color) 1px, transparent 1px),
        linear-gradient(90deg, var(--bg-grid-color) 1px, transparent 1px);
    background-size: 60px 60px;
    opacity: 0.8;
}

.bg-glow {
    position: absolute;
    width: 600px;
    height: 600px;
    border-radius: 50%;
    filter: blur(100px);
    opacity: 0.4;
    animation: glow-float 20s ease-in-out infinite;
}

.bg-glow-1 {
    top: -200px;
    right: -200px;
    background: var(--color-accent-primary);
}

.bg-glow-2 {
    bottom: -200px;
    left: -200px;
    background: var(--color-accent-secondary);
    animation-delay: -10s;
}

@keyframes glow-float {
    0%, 100% { transform: translate(0, 0) scale(1); }
    33% { transform: translate(30px, 30px) scale(1.1); }
    66% { transform: translate(-20px, 20px) scale(0.95); }
}

.bg-noise {
    position: absolute;
    inset: 0;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    opacity: var(--bg-noise-opacity);
}

/* Main Content Layout */
.main-content {
    flex: 1;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: var(--space-8);
    padding: var(--space-8);
    max-width: 1800px;
    margin: 0 auto;
    width: 100%;
}

@media (max-width: 1200px) {
    .main-content {
        grid-template-columns: 1fr;
        padding: var(--space-6);
        gap: var(--space-6);
    }
}

@media (max-width: 640px) {
    .main-content {
        padding: var(--space-4);
        gap: var(--space-4);
    }
}

/* ==========================================================================
   4. Theme Toggle
   ========================================================================== */

.theme-toggle {
    position: fixed;
    top: var(--space-6);
    right: var(--space-6);
    z-index: var(--z-sticky);
    width: 48px;
    height: 48px;
    border-radius: var(--radius-full);
    border: 2px solid var(--color-border);
    background: var(--color-bg-glass);
    backdrop-filter: blur(10px);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--transition-base);
    box-shadow: var(--shadow-lg);
}

.theme-toggle:hover {
    border-color: var(--color-accent-primary);
    transform: scale(1.05);
    box-shadow: var(--shadow-xl);
}

.theme-toggle svg {
    width: 22px;
    height: 22px;
    color: var(--color-text-secondary);
    transition: var(--transition-base);
}

.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

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

@media (max-width: 640px) {
    .theme-toggle {
        top: var(--space-4);
        right: var(--space-4);
        width: 42px;
        height: 42px;
    }
}

/* ==========================================================================
   5. Header
   ========================================================================== */

.header {
    text-align: center;
    padding: var(--space-12) var(--space-8) var(--space-8);
    background: var(--color-bg-glass);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
}

.header-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--space-2);
    padding: var(--space-2) var(--space-4);
    background: var(--color-accent-primary-light);
    border: 1px solid var(--color-accent-primary);
    border-radius: var(--radius-full);
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-accent-primary);
    margin-bottom: var(--space-6);
    animation: badge-glow 2s ease-in-out infinite;
}

@keyframes badge-glow {
    0%, 100% { box-shadow: 0 0 10px var(--color-accent-primary-light); }
    50% { box-shadow: 0 0 20px var(--color-accent-primary-light); }
}

.badge-icon {
    font-size: var(--text-base);
}

.header-title {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-4);
    margin-bottom: var(--space-4);
}

.title-icon {
    font-size: var(--text-4xl);
    animation: icon-bounce 2s ease-in-out infinite;
}

@keyframes icon-bounce {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    25% { transform: translateY(-5px) rotate(-5deg); }
    75% { transform: translateY(-5px) rotate(5deg); }
}

.title-text {
    font-family: var(--font-display);
    font-size: var(--text-4xl);
    font-weight: 800;
    color: var(--color-text-primary);
    letter-spacing: -0.02em;
}

.title-accent {
    background: var(--color-accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.header-subtitle {
    font-size: var(--text-lg);
    color: var(--color-text-secondary);
    max-width: 600px;
    margin: 0 auto var(--space-8);
    line-height: 1.7;
}

.header-subtitle strong {
    color: var(--color-accent-primary);
    font-weight: 600;
}

.header-stats {
    display: inline-flex;
    align-items: center;
    gap: var(--space-6);
    padding: var(--space-4) var(--space-8);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-md);
}

.stat {
    text-align: center;
}

.stat-number {
    display: block;
    font-family: var(--font-mono);
    font-size: var(--text-2xl);
    font-weight: 700;
    color: var(--color-accent-primary);
    line-height: 1.2;
}

.stat-label {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--color-border);
}

@media (max-width: 640px) {
    .header {
        padding: var(--space-16) var(--space-4) var(--space-6);
    }
    
    .header-title {
        flex-direction: column;
        gap: var(--space-2);
    }
    
    .title-icon {
        font-size: var(--text-3xl);
    }
    
    .header-stats {
        flex-wrap: wrap;
        justify-content: center;
        gap: var(--space-4);
        padding: var(--space-3) var(--space-4);
    }
    
    .stat-divider {
        display: none;
    }
}

/* ==========================================================================
   6. Controls Panel
   ========================================================================== */

.controls-panel {
    background: var(--color-bg-secondary);
    border-radius: var(--radius-3xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
}

.control-section {
    padding: var(--space-6);
    border-bottom: 1px solid var(--color-border);
}

.control-section:last-child {
    border-bottom: none;
}

.section-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-5);
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: var(--text-xl);
    font-weight: 700;
    color: var(--color-text-primary);
}

.section-icon {
    font-size: var(--text-2xl);
}

.section-hint {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    font-family: var(--font-mono);
}

/* Paper Type Cards */
.paper-types-container {
    display: flex;
    flex-direction: column;
    gap: var(--space-6);
}

.paper-category {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
}

.category-title {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-tertiary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.paper-types-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
    gap: var(--space-3);
}

.paper-type-card {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: var(--space-4) var(--space-3);
    background: var(--color-bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: var(--transition-base);
    text-align: center;
    font-family: inherit;
    color: inherit;
}

.paper-type-card:hover {
    border-color: var(--color-border-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.paper-type-card.active {
    background: var(--color-accent-primary-light);
    border-color: var(--color-accent-primary);
    box-shadow: var(--shadow-glow);
}

.card-icon {
    font-size: var(--text-2xl);
    margin-bottom: var(--space-2);
    transition: var(--transition-base);
}

.paper-type-card.active .card-icon {
    transform: scale(1.1);
}

.card-name {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: var(--space-1);
}

.card-desc {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
}

.card-shortcut {
    position: absolute;
    top: var(--space-2);
    right: var(--space-2);
    width: 20px;
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    opacity: 0;
    transition: var(--transition-base);
}

.paper-type-card:hover .card-shortcut {
    opacity: 1;
}

/* Settings Grid */
.settings-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
}

@media (max-width: 640px) {
    .settings-grid {
        grid-template-columns: 1fr;
    }
}

.setting-group {
    display: flex;
    flex-direction: column;
    gap: var(--space-2);
}

.setting-group.hidden {
    display: none;
}

.setting-label {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
}

.setting-value {
    font-family: var(--font-mono);
    color: var(--color-accent-primary);
}

/* Select Wrapper */
.select-wrapper {
    position: relative;
}

.setting-select {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    padding-right: var(--space-10);
    background: var(--color-bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--radius-lg);
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-primary);
    cursor: pointer;
    appearance: none;
    transition: var(--transition-base);
}

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

.setting-select:focus {
    border-color: var(--color-border-focus);
    box-shadow: 0 0 0 3px var(--color-accent-primary-light);
}

.select-icon {
    position: absolute;
    right: var(--space-3);
    top: 50%;
    transform: translateY(-50%);
    width: 18px;
    height: 18px;
    color: var(--color-text-muted);
    pointer-events: none;
}

/* Color Picker */
.color-picker-wrapper {
    display: flex;
    gap: var(--space-2);
}

.color-input {
    width: 48px;
    height: 42px;
    border: 2px solid var(--color-border);
    border-radius: var(--radius-lg);
    cursor: pointer;
    padding: 2px;
    background: var(--color-bg-secondary);
}

.color-input::-webkit-color-swatch-wrapper {
    padding: 0;
}

.color-input::-webkit-color-swatch {
    border: none;
    border-radius: var(--radius-md);
}

.color-select {
    flex: 1;
}

/* Toggle Group */
.toggle-group {
    display: flex;
    gap: var(--space-2);
}

.toggle-group.triple {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
}

.toggle-btn {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-4);
    background: var(--color-bg-tertiary);
    border: 2px solid transparent;
    border-radius: var(--radius-lg);
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--transition-base);
}

.toggle-btn svg {
    width: 16px;
    height: 16px;
}

.toggle-btn:hover {
    border-color: var(--color-border-hover);
    color: var(--color-text-primary);
}

.toggle-btn.active {
    background: var(--color-accent-primary-light);
    border-color: var(--color-accent-primary);
    color: var(--color-accent-primary);
}

/* Slider */
.slider-wrapper {
    position: relative;
    padding: var(--space-2) 0;
}

.slider {
    width: 100%;
    height: 6px;
    border-radius: var(--radius-full);
    background: var(--color-bg-tertiary);
    appearance: none;
    cursor: pointer;
}

.slider::-webkit-slider-thumb {
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--color-accent-primary);
    border: 3px solid var(--color-bg-secondary);
    box-shadow: var(--shadow-md);
    cursor: pointer;
    transition: var(--transition-base);
}

.slider::-webkit-slider-thumb:hover {
    transform: scale(1.15);
    box-shadow: var(--shadow-lg);
}

.slider::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--color-accent-primary);
    border: 3px solid var(--color-bg-secondary);
    box-shadow: var(--shadow-md);
    cursor: pointer;
}

/* Action Buttons */
.actions-section {
    background: var(--color-bg-tertiary);
}

.action-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: var(--space-3);
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-5);
    border: 2px solid transparent;
    border-radius: var(--radius-xl);
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition-base);
    text-decoration: none;
}

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

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

.btn-primary {
    background: var(--color-accent-gradient);
    color: white;
    box-shadow: var(--shadow-md), 0 0 20px var(--color-accent-primary-light);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg), 0 0 30px var(--color-accent-primary-light);
}

.btn-success {
    background: var(--color-success);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-success:hover {
    background: var(--color-success-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover {
    border-color: var(--color-accent-primary);
    color: var(--color-accent-primary);
    transform: translateY(-2px);
}

.actions-hint {
    margin-top: var(--space-4);
    font-size: var(--text-xs);
    color: var(--color-text-muted);
    text-align: center;
}

.actions-hint kbd {
    display: inline-block;
    padding: var(--space-1) var(--space-2);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: var(--text-xs);
}

@media (max-width: 640px) {
    .action-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
}

/* ==========================================================================
   7. Preview Section
   ========================================================================== */

.preview-section {
    display: flex;
    flex-direction: column;
    background: var(--color-bg-secondary);
    border-radius: var(--radius-3xl);
    border: 1px solid var(--color-border);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
}

.preview-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-4) var(--space-6);
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-tertiary);
}

.preview-title {
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--color-text-primary);
}

.preview-info {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    font-size: var(--text-sm);
    font-family: var(--font-mono);
    color: var(--color-text-muted);
}

.preview-divider {
    color: var(--color-border);
}

.preview-container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: var(--space-8);
    background: 
        repeating-linear-gradient(
            45deg,
            var(--color-bg-tertiary),
            var(--color-bg-tertiary) 10px,
            var(--color-bg-secondary) 10px,
            var(--color-bg-secondary) 20px
        );
    overflow: auto;
    min-height: 500px;
}

.preview-wrapper {
    position: relative;
    max-width: 100%;
    max-height: 100%;
    transition: transform var(--transition-slow);
}

.preview-loading {
    position: absolute;
    inset: 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    background: var(--color-bg-glass);
    backdrop-filter: blur(5px);
    border-radius: var(--radius-lg);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
    z-index: 10;
}

.preview-loading.visible {
    opacity: 1;
    visibility: visible;
}

.loading-spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--color-border);
    border-top-color: var(--color-accent-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.preview-loading span {
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-secondary);
}

#paperCanvas {
    display: block;
    max-width: 100%;
    height: auto;
    background: var(--color-paper);
    box-shadow: var(--shadow-paper);
    border-radius: 2px;
}

/* Zoom Controls */
.preview-zoom {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    border-top: 1px solid var(--color-border);
    background: var(--color-bg-tertiary);
}

.zoom-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: var(--transition-base);
}

.zoom-btn:hover {
    border-color: var(--color-accent-primary);
    color: var(--color-accent-primary);
}

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

.zoom-level {
    min-width: 60px;
    text-align: center;
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    color: var(--color-text-muted);
}

/* ==========================================================================
   8. Footer
   ========================================================================== */

.footer {
    padding: var(--space-6) var(--space-8);
    background: var(--color-bg-glass);
    backdrop-filter: blur(20px);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1800px;
    margin: 0 auto;
    flex-wrap: wrap;
    gap: var(--space-4);
}

.footer-brand {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: var(--transition-base);
}

.footer-brand:hover {
    color: var(--color-text-primary);
}

.footer-brand strong {
    color: var(--color-accent-primary);
}

.heart {
    display: inline-block;
    color: var(--color-danger);
    animation: heartbeat 1.5s ease-in-out infinite;
}

@keyframes heartbeat {
    0%, 50%, 100% { transform: scale(1); }
    25%, 75% { transform: scale(1.2); }
}

.footer-links {
    display: flex;
    gap: var(--space-6);
}

.footer-link {
    display: flex;
    align-items: center;
    gap: var(--space-2);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-muted);
    text-decoration: none;
    transition: var(--transition-base);
}

.footer-link:hover {
    color: var(--color-accent-primary);
    transform: translateY(-2px);
}

.footer-link svg {
    width: 18px;
    height: 18px;
}

@media (max-width: 640px) {
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        gap: var(--space-4);
    }
}

/* ==========================================================================
   9. Modal
   ========================================================================== */

.modal-overlay {
    position: fixed;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.5);
    backdrop-filter: blur(4px);
    z-index: var(--z-modal);
    opacity: 0;
    visibility: hidden;
    transition: var(--transition-base);
}

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

.modal {
    width: 90%;
    max-width: 480px;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-2xl);
    transform: scale(0.95) translateY(10px);
    transition: var(--transition-base);
}

.modal-overlay.visible .modal {
    transform: scale(1) translateY(0);
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: var(--space-5) var(--space-6);
    border-bottom: 1px solid var(--color-border);
}

.modal-header h3 {
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--color-text-primary);
}

.modal-close {
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--color-bg-tertiary);
    border: none;
    border-radius: var(--radius-md);
    font-size: var(--text-xl);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: var(--transition-base);
}

.modal-close:hover {
    background: var(--color-danger);
    color: white;
}

.modal-body {
    padding: var(--space-6);
}

.shortcut-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-3);
}

.shortcut-item {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-3);
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-lg);
}

.shortcut-item kbd {
    min-width: 32px;
    padding: var(--space-1) var(--space-2);
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    font-family: var(--font-mono);
    font-size: var(--text-sm);
    font-weight: 700;
    text-align: center;
    color: var(--color-accent-primary);
}

.shortcut-item span {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

/* ==========================================================================
   10. Follow Modal
   ========================================================================== */

.follow-overlay {
    background: rgba(0, 0, 0, 0.75);
    backdrop-filter: blur(8px);
}

.follow-modal {
    max-width: 480px;
    text-align: center;
    padding: 0;
    overflow: hidden;
    animation: modal-bounce-in 0.5s cubic-bezier(0.68, -0.55, 0.265, 1.55);
}

@keyframes modal-bounce-in {
    0% { transform: scale(0.3) translateY(-50px); opacity: 0; }
    50% { transform: scale(1.05); }
    100% { transform: scale(1) translateY(0); opacity: 1; }
}

.follow-modal .modal-close {
    position: absolute;
    top: var(--space-4);
    right: var(--space-4);
    z-index: 10;
    opacity: 0.5;
    transition: var(--transition-base);
}

.follow-modal .modal-close:enabled {
    opacity: 1;
}

.follow-modal .modal-close:disabled {
    cursor: not-allowed;
    background: var(--color-bg-tertiary);
    color: var(--color-text-muted);
}

.follow-content {
    padding: var(--space-10) var(--space-6) var(--space-6);
}

.follow-icon-wrapper {
    position: relative;
    display: inline-block;
    margin-bottom: var(--space-5);
}

.follow-icon {
    font-size: 4.5rem;
    display: inline-block;
    animation: bounce-pulse 2s ease-in-out infinite;
}

@keyframes bounce-pulse {
    0%, 100% { transform: scale(1) rotate(0deg); }
    25% { transform: scale(1.15) rotate(-10deg); }
    50% { transform: scale(1.1) rotate(10deg); }
    75% { transform: scale(1.15) rotate(-5deg); }
}

.follow-sparkles {
    position: absolute;
    top: -10px;
    right: -10px;
    font-size: 1.5rem;
    animation: sparkle-rotate 3s linear infinite;
}

@keyframes sparkle-rotate {
    0%, 100% { transform: rotate(0deg) scale(1); opacity: 1; }
    25% { transform: rotate(90deg) scale(1.2); opacity: 0.8; }
    50% { transform: rotate(180deg) scale(1); opacity: 1; }
    75% { transform: rotate(270deg) scale(1.2); opacity: 0.8; }
}

.follow-modal h3 {
    font-family: var(--font-display);
    font-size: var(--text-3xl);
    font-weight: 800;
    color: var(--color-text-primary);
    margin-bottom: var(--space-4);
    line-height: 1.2;
}

.follow-message-container {
    margin-bottom: var(--space-8);
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.follow-message {
    font-size: var(--text-base);
    color: var(--color-text-secondary);
    line-height: 1.7;
    animation: message-fade-in 0.4s ease;
}

@keyframes message-fade-in {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.follow-message strong {
    color: var(--color-accent-primary);
    font-weight: 700;
}

.follow-message .highlight {
    background: linear-gradient(135deg, var(--color-accent-primary) 0%, var(--color-accent-secondary) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
}

.follow-message .emoji {
    display: inline-block;
    animation: bounce-small 2s ease-in-out infinite;
}

@keyframes bounce-small {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

.follow-buttons {
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    margin-bottom: var(--space-6);
}

.follow-btn {
    display: flex;
    align-items: center;
    gap: var(--space-4);
    padding: var(--space-4) var(--space-5);
    border-radius: var(--radius-xl);
    font-size: var(--text-sm);
    font-weight: 600;
    text-decoration: none;
    text-align: left;
    transition: var(--transition-base);
    position: relative;
    overflow: hidden;
}

.follow-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.follow-btn:hover::before {
    left: 100%;
}

.follow-btn svg {
    width: 24px;
    height: 24px;
    flex-shrink: 0;
}

.follow-btn span {
    display: flex;
    flex-direction: column;
    gap: 2px;
    flex: 1;
}

.follow-btn strong {
    font-size: var(--text-base);
    font-weight: 700;
    display: block;
}

.follow-btn small {
    font-size: var(--text-xs);
    opacity: 0.9;
    font-weight: 400;
}

.follow-btn:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: var(--shadow-xl);
}

.follow-btn-primary {
    animation: pulse-primary 2s ease-in-out infinite;
}

@keyframes pulse-primary {
    0%, 100% { box-shadow: 0 0 0 0 rgba(0, 0, 0, 0.3); }
    50% { box-shadow: 0 0 0 8px rgba(0, 0, 0, 0); }
}

.follow-btn.twitter {
    background: #000000;
    color: #ffffff;
    border: 2px solid #1d9bf0;
}

.follow-btn.twitter:hover {
    background: #1a1a1a;
    border-color: #1d9bf0;
    box-shadow: 0 0 20px rgba(29, 155, 240, 0.4), var(--shadow-xl);
}

.follow-btn.github {
    background: #24292e;
    color: #ffffff;
    border: 2px solid #444d56;
}

.follow-btn.github:hover {
    background: #2f363d;
    border-color: #586069;
    box-shadow: 0 0 20px rgba(88, 96, 105, 0.4), var(--shadow-xl);
}

.follow-btn.linkedin {
    background: #0a66c2;
    color: #ffffff;
    border: 2px solid #0a66c2;
}

.follow-btn.linkedin:hover {
    background: #004182;
    border-color: #0077b5;
    box-shadow: 0 0 20px rgba(10, 102, 194, 0.4), var(--shadow-xl);
}

.follow-actions {
    margin-bottom: var(--space-5);
}

.btn-continue {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-3);
    padding: var(--space-4) var(--space-6);
    background: var(--color-accent-gradient);
    border: none;
    border-radius: var(--radius-xl);
    font-family: inherit;
    font-size: var(--text-base);
    font-weight: 700;
    color: white;
    cursor: pointer;
    transition: var(--transition-base);
    box-shadow: var(--shadow-lg);
    animation: pulse-continue 2s ease-in-out infinite;
}

@keyframes pulse-continue {
    0%, 100% { transform: scale(1); box-shadow: var(--shadow-lg); }
    50% { transform: scale(1.02); box-shadow: var(--shadow-xl), 0 0 20px rgba(59, 130, 246, 0.5); }
}

.btn-continue:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: var(--shadow-2xl), 0 0 30px rgba(59, 130, 246, 0.6);
}

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

.follow-footer {
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: var(--space-4);
    border-top: 1px solid var(--color-border);
}

.follow-count {
    font-size: var(--text-xs);
    font-family: var(--font-mono);
    color: var(--color-text-muted);
    font-weight: 600;
    padding: var(--space-1) var(--space-3);
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-full);
}

.follow-skip {
    background: none;
    border: none;
    font-family: inherit;
    font-size: var(--text-sm);
    font-weight: 600;
    color: var(--color-text-muted);
    cursor: pointer;
    padding: var(--space-2) var(--space-4);
    border-radius: var(--radius-md);
    transition: var(--transition-base);
}

.follow-skip:hover:not(:disabled) {
    color: var(--color-text-primary);
    background: var(--color-bg-tertiary);
}

.follow-skip:disabled {
    cursor: not-allowed;
    opacity: 0.5;
}

/* ==========================================================================
   11. Toast Notifications
   ========================================================================== */

.toast-container {
    position: fixed;
    bottom: var(--space-6);
    right: var(--space-6);
    display: flex;
    flex-direction: column;
    gap: var(--space-3);
    z-index: var(--z-toast);
}

.toast {
    display: flex;
    align-items: center;
    gap: var(--space-3);
    padding: var(--space-4) var(--space-5);
    background: var(--color-bg-elevated);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    animation: toast-in 0.3s ease forwards;
    min-width: 280px;
    max-width: 400px;
}

.toast.removing {
    animation: toast-out 0.3s ease forwards;
}

@keyframes toast-in {
    from {
        opacity: 0;
        transform: translateX(100%) scale(0.9);
    }
    to {
        opacity: 1;
        transform: translateX(0) scale(1);
    }
}

@keyframes toast-out {
    to {
        opacity: 0;
        transform: translateX(100%) scale(0.9);
    }
}

.toast-icon {
    font-size: var(--text-xl);
}

.toast-content {
    flex: 1;
}

.toast-title {
    font-size: var(--text-sm);
    font-weight: 700;
    color: var(--color-text-primary);
}

.toast-message {
    font-size: var(--text-xs);
    color: var(--color-text-muted);
}

.toast-close {
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: var(--radius-sm);
    color: var(--color-text-muted);
    cursor: pointer;
    transition: var(--transition-base);
}

.toast-close:hover {
    background: var(--color-bg-tertiary);
    color: var(--color-text-primary);
}

.toast.success {
    border-left: 4px solid var(--color-success);
}

.toast.error {
    border-left: 4px solid var(--color-danger);
}

.toast.warning {
    border-left: 4px solid var(--color-warning);
}

/* ==========================================================================
   12. Print Styles
   ========================================================================== */

@media print {
    *,
    *::before,
    *::after {
        background: transparent !important;
        color: black !important;
        box-shadow: none !important;
        text-shadow: none !important;
    }
    
    body {
        margin: 0;
        padding: 0;
    }
    
    .header,
    .controls-panel,
    .theme-toggle,
    .footer,
    .preview-header,
    .preview-zoom,
    .toast-container,
    .modal-overlay,
    .bg-decoration {
        display: none !important;
    }
    
    .app-container,
    .main-content,
    .preview-section,
    .preview-container {
        all: unset;
        display: block;
        width: 100%;
        height: auto;
    }
    
    .preview-container {
        background: white !important;
        padding: 0 !important;
    }
    
    .preview-wrapper {
        transform: none !important;
    }
    
    #paperCanvas {
        width: 100% !important;
        max-width: none !important;
        height: auto !important;
        box-shadow: none !important;
        border-radius: 0 !important;
        page-break-after: always;
    }
    
    @page {
        margin: 0;
        size: auto;
    }
}

/* ==========================================================================
   13. Utility Classes
   ========================================================================== */

.hidden {
    display: none !important;
}

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

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