/* ============================================
   CSS Variables & Theme Configuration
   ============================================ */
:root {
    /* Primary Colors */
    --primary-color: #667eea;
    --primary-dark: #5568d3;
    --primary-light: #7c93f0;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    
    /* Status Colors */
    --success-color: #48bb78;
    --error-color: #f56565;
    --warning-color: #ed8936;
    --info-color: #4299e1;
    
    /* Neutral Colors - Light Mode */
    --bg-primary: #ffffff;
    --bg-secondary: #f7fafc;
    --bg-tertiary: #edf2f7;
    --text-primary: #1a202c;
    --text-secondary: #4a5568;
    --text-tertiary: #718096;
    --border-color: #e2e8f0;
    --border-hover: #cbd5e0;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.15);
    --shadow-hover: 0 15px 40px rgba(102, 126, 234, 0.2);
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-success: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    --gradient-bg: linear-gradient(135deg, #f7fafc 0%, #ffffff 100%);
    
    /* Transitions */
    --transition-fast: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: all 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Spacing */
    --space-xs: 0.25rem;
    --space-sm: 0.5rem;
    --space-md: 1rem;
    --space-lg: 1.5rem;
    --space-xl: 2rem;
    --space-2xl: 3rem;
    
    /* Border Radius */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-full: 9999px;
    
    /* Fonts */
    --font-sans: 'Poppins', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'Fira Code', 'Courier New', monospace;
}

/* Dark Theme */
[data-theme="dark"] {
    --primary-color: #7c93f0;
    --primary-dark: #667eea;
    --primary-light: #96a9f7;
    --secondary-color: #a855f7;
    --accent-color: #f093fb;
    
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --info-color: #3b82f6;
    
    --bg-primary: #1a202c;
    --bg-secondary: #2d3748;
    --bg-tertiary: #4a5568;
    --text-primary: #f7fafc;
    --text-secondary: #e2e8f0;
    --text-tertiary: #cbd5e0;
    --border-color: #4a5568;
    --border-hover: #718096;
    
    --shadow-sm: 0 2px 4px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 10px 30px rgba(0, 0, 0, 0.5);
    --shadow-xl: 0 20px 50px rgba(0, 0, 0, 0.6);
    --shadow-hover: 0 15px 40px rgba(124, 147, 240, 0.3);
    
    --gradient-bg: linear-gradient(135deg, #1a202c 0%, #2d3748 100%);
}

/* ============================================
   Reset & Base Styles
   ============================================ */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

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

.guide-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--primary-color);
}

.guide-icon {
    width: 60px;
    height: 60px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--space-md);
}

.guide-title {
    font-size: 1.25rem;
    margin-bottom: var(--space-sm);
}

.guide-text {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    margin-bottom: var(--space-md);
}

.guide-example {
    font-family: var(--font-mono);
    font-size: 0.875rem;
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-primary);
    border-radius: var(--radius-sm);
    border-left: 3px solid var(--primary-color);
}

/* ============================================
   Calculator Dock
   ============================================ */
.calc-toggle {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 60px;
    height: 60px;
    border-radius: 50%;
    background: var(--gradient-primary);
    color: white;
    border: none;
    font-size: 1.75rem;
    cursor: pointer;
    box-shadow: var(--shadow-lg);
    transition: var(--transition-base);
    z-index: 998;
    animation: bounce 2s ease-in-out infinite;
}

.calc-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-xl);
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.calc-dock {
    position: fixed;
    bottom: 2rem;
    right: -350px;
    width: 320px;
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--space-lg);
    transition: right 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 999;
    border: 2px solid var(--border-color);
}

.calc-dock.open {
    right: 2rem;
}

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

.calc-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.calc-close {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-secondary);
    border: none;
    color: var(--text-primary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.calc-close:hover {
    background: var(--error-color);
    color: white;
    transform: rotate(90deg);
}

.calc-display {
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-md);
    text-align: right;
    font-size: 1.75rem;
    font-family: var(--font-mono);
    margin-bottom: var(--space-md);
    min-height: 60px;
    word-break: break-all;
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: flex-end;
}

.calc-buttons {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-sm);
}

.calc-btn {
    padding: var(--space-lg);
    border: none;
    border-radius: var(--radius-md);
    background: var(--bg-secondary);
    color: var(--text-primary);
    font-size: 1.25rem;
    cursor: pointer;
    transition: var(--transition-fast);
    font-weight: 600;
    border: 2px solid var(--border-color);
}

.calc-btn:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
}

.calc-btn:active {
    transform: scale(0.95);
}

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

.calc-btn.operator:hover {
    background: var(--primary-dark);
}

.calc-btn.equals {
    background: var(--success-color);
    color: white;
    grid-column: span 2;
    border-color: var(--success-color);
}

.calc-btn.equals:hover {
    background: #38a169;
}

.calc-btn.clear {
    background: var(--error-color);
    color: white;
    grid-column: span 4;
    border-color: var(--error-color);
}

.calc-btn.clear:hover {
    background: #e53e3e;
}

/* ============================================
   Toast Notification
   ============================================ */
.toast {
    position: fixed;
    bottom: -100px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--text-primary);
    color: var(--bg-primary);
    padding: var(--space-md) var(--space-xl);
    border-radius: var(--radius-full);
    box-shadow: var(--shadow-xl);
    display: flex;
    align-items: center;
    gap: var(--space-md);
    transition: bottom 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 9999;
    font-weight: 500;
}

.toast.show {
    bottom: 2rem;
}

.toast-icon {
    width: 24px;
    height: 24px;
    background: var(--success-color);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.875rem;
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--bg-primary);
    border-top: 2px solid var(--border-color);
    padding: var(--space-2xl) var(--space-xl);
    margin-top: var(--space-2xl);
}

.footer-container {
    max-width: 1400px;
    margin: 0 auto;
}

.footer-content {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    flex-wrap: wrap;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
}

.footer-brand {
    max-width: 400px;
}

.footer-description {
    color: var(--text-secondary);
    margin-top: var(--space-sm);
    line-height: 1.6;
}

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

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: var(--transition-fast);
    font-weight: 500;
}

.footer-links a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    text-align: center;
    padding-top: var(--space-xl);
    border-top: 1px solid var(--border-color);
    color: var(--text-tertiary);
    font-size: 0.875rem;
}

.footer-bottom p {
    margin-bottom: var(--space-xs);
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    .container {
        padding: var(--space-md);
    }
    
    .card {
        padding: var(--space-lg);
    }
}

@media (max-width: 768px) {
    .navbar {
        padding: var(--space-md);
    }
    
    .mobile-toggle {
        display: flex;
    }
    
    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--bg-primary);
        flex-direction: column;
        padding: var(--space-lg);
        box-shadow: var(--shadow-lg);
        transform: translateY(-100%);
        opacity: 0;
        pointer-events: none;
        transition: var(--transition-base);
        border-bottom: 2px solid var(--border-color);
    }
    
    .nav-links.active {
        transform: translateY(0);
        opacity: 1;
        pointer-events: all;
    }
    
    .hero {
        padding: var(--space-xl) var(--space-md);
    }
    
    .hero-stats {
        gap: var(--space-lg);
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .conversion-display {
        flex-direction: column;
        gap: var(--space-md);
    }
    
    .conversion-arrow {
        transform: rotate(90deg);
    }
    
    .base-grid {
        grid-template-columns: 1fr;
    }
    
    .btn-group {
        flex-direction: column;
        width: 100%;
    }
    
    .btn {
        width: 100%;
    }
    
    .code-type-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .guide-grid {
        grid-template-columns: 1fr;
    }
    
    .calc-toggle {
        bottom: 1rem;
        right: 1rem;
        width: 50px;
        height: 50px;
        font-size: 1.5rem;
    }
    
    .calc-dock {
        width: calc(100% - 2rem);
        right: -100%;
    }
    
    .calc-dock.open {
        right: 1rem;
    }
    
    .footer-content {
        flex-direction: column;
        text-align: center;
    }
    
    .footer-links {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }
    
    .hero-subtitle {
        font-size: 0.95rem;
    }
    
    .card {
        padding: var(--space-md);
        border-radius: var(--radius-md);
    }
    
    .card-title {
        font-size: 1.5rem;
    }
    
    .result-value {
        font-size: 1.25rem;
    }
    
    .code-type-grid {
        grid-template-columns: 1fr;
    }
    
    .code-result-value {
        font-size: 1.25rem;
    }
    
    .calc-buttons {
        gap: var(--space-xs);
    }
    
    .calc-btn {
        padding: var(--space-md);
        font-size: 1.1rem;
    }
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .navbar,
    .calc-toggle,
    .calc-dock,
    .toast,
    .footer {
        display: none;
    }
    
    .card {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #000;
    }
    
    .btn {
        display: none;
    }
}

/* ============================================
   Accessibility
   ============================================ */
.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

*:focus-visible {
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

/* ============================================
   Loading Animation
   ============================================ */
.loading {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(102, 126, 234, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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

/* ============================================
   Utility Classes
   ============================================ */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.mt-1 { margin-top: var(--space-xs); }
.mt-2 { margin-top: var(--space-sm); }
.mt-3 { margin-top: var(--space-md); }
.mt-4 { margin-top: var(--space-lg); }

.mb-1 { margin-bottom: var(--space-xs); }
.mb-2 { margin-bottom: var(--space-sm); }
.mb-3 { margin-bottom: var(--space-md); }
.mb-4 { margin-bottom: var(--space-lg); }

.p-1 { padding: var(--space-xs); }
.p-2 { padding: var(--space-sm); }
.p-3 { padding: var(--space-md); }
.p-4 { padding: var(--space-lg); }

.hidden { display: none !important; }
.flex { display: flex; }
.grid { display: grid; }

/* ============================================
   Smooth Scrollbar
   ============================================ */
::-webkit-scrollbar {
    width: 12px;
    height: 12px;
}

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

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: var(--radius-full);
    border: 3px solid var(--bg-secondary);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--primary-dark);
}

/* ============================================
   Selection
   ============================================ */
::selection {
    background: var(--primary-color);
    color: white;
}

::-moz-selection {
    background: var(--primary-color);
    color: white;
}

/* Prevent horizontal scrolling */
html {
    overflow-x: hidden;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.2;
    color: var(--text-primary);
}

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

/* ============================================
   Navbar
   ============================================ */
.navbar {
    background: var(--bg-primary);
    padding: var(--space-md) var(--space-xl);
    box-shadow: var(--shadow-md);
    position: sticky;
    top: 0;
    z-index: 1000;
    transition: var(--transition-base);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
}

.navbar.scrolled {
    padding: var(--space-sm) var(--space-xl);
    box-shadow: var(--shadow-lg);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    font-size: 1.5rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition-fast);
}

.logo:hover {
    transform: scale(1.05);
}

.logo-icon {
    font-size: 2rem;
    animation: float 3s ease-in-out infinite;
}

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

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

.nav-menu {
    display: flex;
    align-items: center;
    gap: var(--space-xl);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: var(--space-xl);
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: var(--transition-fast);
    position: relative;
    padding: var(--space-sm) 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient-primary);
    transition: var(--transition-fast);
}

.nav-link:hover, .nav-link.active {
    color: var(--primary-color);
}

.nav-link:hover::after, .nav-link.active::after {
    width: 100%;
}

.nav-actions {
    display: flex;
    align-items: center;
    gap: var(--space-md);
}

.theme-toggle {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    padding: var(--space-sm) var(--space-md);
    border-radius: var(--radius-full);
    cursor: pointer;
    font-size: 1.25rem;
    transition: var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    transform: rotate(180deg);
    border-color: var(--primary-color);
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 4px;
    background: transparent;
    border: none;
    cursor: pointer;
    padding: var(--space-sm);
}

.mobile-toggle span {
    width: 24px;
    height: 3px;
    background: var(--text-primary);
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    padding: var(--space-2xl) var(--space-xl);
    text-align: center;
    background: var(--bg-primary);
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(102, 126, 234, 0.05) 0%, transparent 70%);
    animation: pulse 10s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.5; }
    50% { transform: scale(1.1); opacity: 0.8; }
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
    margin: 0 auto;
}

.hero-title {
    font-size: clamp(2rem, 5vw, 3.5rem);
    margin-bottom: var(--space-md);
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    margin-bottom: var(--space-xl);
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: var(--space-2xl);
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-top: var(--space-xs);
}

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

/* ============================================
   Container & Layout
   ============================================ */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: var(--space-xl);
}

/* ============================================
   Card Component
   ============================================ */
.card {
    background: var(--bg-primary);
    border-radius: var(--radius-xl);
    padding: var(--space-xl);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--space-xl);
    transition: var(--transition-base);
    border: 1px solid var(--border-color);
    animation: fadeIn 0.6s ease-out;
}

.card:hover {
    box-shadow: var(--shadow-hover);
    transform: translateY(-5px);
}

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

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

.card-title {
    font-size: 1.75rem;
    display: flex;
    align-items: center;
    gap: var(--space-sm);
    margin-bottom: var(--space-sm);
}

.title-icon {
    font-size: 2rem;
}

.card-description {
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.card-body {
    position: relative;
}

/* ============================================
   Conversion Display
   ============================================ */
.conversion-display {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-xl);
    margin-bottom: var(--space-xl);
    padding: var(--space-lg);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
    flex-wrap: wrap;
}

.base-badge {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
    padding: var(--space-md) var(--space-lg);
    background: var(--bg-primary);
    border-radius: var(--radius-md);
    border: 2px solid var(--border-color);
    transition: var(--transition-base);
    min-width: 120px;
}

.base-badge:hover {
    border-color: var(--primary-color);
    transform: scale(1.05);
}

.badge-label {
    font-size: 0.75rem;
    color: var(--text-tertiary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.badge-value {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--primary-color);
}

.conversion-arrow {
    color: var(--primary-color);
    animation: slideRight 2s ease-in-out infinite;
}

@keyframes slideRight {
    0%, 100% { transform: translateX(0); }
    50% { transform: translateX(5px); }
}

/* ============================================
   Form Elements
   ============================================ */
.input-group {
    margin-bottom: var(--space-lg);
}

.input-label {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: var(--space-sm);
    font-weight: 500;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.input-field, .select-field {
    width: 100%;
    padding: var(--space-md);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-family: var(--font-sans);
    background: var(--bg-secondary);
    color: var(--text-primary);
    transition: var(--transition-fast);
}

.input-field:focus, .select-field:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 4px rgba(102, 126, 234, 0.1);
}

.input-field.error {
    border-color: var(--error-color);
    animation: shake 0.4s;
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-8px); }
    75% { transform: translateX(8px); }
}

.code-input {
    font-family: var(--font-mono);
    font-size: 1.1rem;
    letter-spacing: 2px;
}

.input-action-btn {
    position: absolute;
    right: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
    background: var(--bg-primary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: var(--transition-fast);
    font-size: 1rem;
}

.input-action-btn:hover {
    background: var(--primary-color);
    border-color: var(--primary-color);
    transform: scale(1.1);
}

.error-message {
    color: var(--error-color);
    font-size: 0.875rem;
    margin-top: var(--space-xs);
    display: none;
    animation: fadeInDown 0.3s ease-out;
}

.error-message.show {
    display: block;
}

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

.input-hint {
    font-size: 0.85rem;
    color: var(--text-tertiary);
    margin-top: var(--space-xs);
    display: flex;
    align-items: center;
    gap: var(--space-xs);
}

.input-hint::before {
    content: '💡';
}

/* ============================================
   Tooltip
   ============================================ */
.tooltip {
    position: relative;
    display: inline-flex;
}

.help-icon {
    width: 18px;
    height: 18px;
    background: var(--primary-color);
    color: white;
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.7rem;
    font-weight: bold;
    cursor: help;
    transition: var(--transition-fast);
}

.help-icon:hover {
    transform: scale(1.2);
    background: var(--primary-dark);
}

.tooltip-text {
    visibility: hidden;
    background: var(--text-primary);
    color: var(--bg-primary);
    text-align: center;
    border-radius: var(--radius-md);
    padding: var(--space-sm) var(--space-md);
    position: absolute;
    z-index: 1000;
    bottom: 150%;
    left: 50%;
    transform: translateX(-50%);
    white-space: nowrap;
    opacity: 0;
    transition: var(--transition-fast);
    font-size: 0.85rem;
    box-shadow: var(--shadow-lg);
}

.tooltip-text::after {
    content: '';
    position: absolute;
    top: 100%;
    left: 50%;
    margin-left: -5px;
    border-width: 5px;
    border-style: solid;
    border-color: var(--text-primary) transparent transparent transparent;
}

.tooltip:hover .tooltip-text {
    visibility: visible;
    opacity: 1;
}

/* ============================================
   Grid Layouts
   ============================================ */
.base-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--space-lg);
    margin-bottom: var(--space-lg);
}

.code-type-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-md);
}

.guide-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: var(--space-lg);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-sm);
    padding: var(--space-md) var(--space-xl);
    border: none;
    border-radius: var(--radius-md);
    font-size: 1rem;
    font-weight: 600;
    font-family: var(--font-sans);
    cursor: pointer;
    transition: var(--transition-base);
    white-space: nowrap;
}

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

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

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

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

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

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

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

.btn-sm {
    padding: var(--space-sm) var(--space-md);
    font-size: 0.875rem;
}

.btn-icon {
    font-size: 1.2rem;
}

.btn-group {
    display: flex;
    gap: var(--space-md);
    flex-wrap: wrap;
    justify-content: center;
    margin-top: var(--space-lg);
}

.icon-btn {
    padding: var(--space-sm);
    background: transparent;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: var(--transition-fast);
    display: flex;
    align-items: center;
    justify-content: center;
}

.icon-btn:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
    transform: scale(1.1);
}

.code-type-btn {
    padding: var(--space-md);
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: var(--transition-base);
    text-align: center;
}

.code-type-btn:hover {
    border-color: var(--primary-color);
    transform: translateY(-3px);
}

.code-type-btn.active {
    background: var(--gradient-primary);
    border-color: transparent;
    color: white;
}

.code-icon {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: var(--space-xs);
}

.code-name {
    font-size: 0.875rem;
    font-weight: 500;
}

/* ============================================
   Result Sections
   ============================================ */
.result-section {
    margin-top: var(--space-xl);
}

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

.result-title {
    font-size: 1.25rem;
    font-weight: 600;
}

.result-actions {
    display: flex;
    gap: var(--space-sm);
}

.result-box {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: var(--space-lg);
    position: relative;
    min-height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.result-value {
    font-size: clamp(1.25rem, 3vw, 1.75rem);
    font-weight: 600;
    color: var(--primary-color);
    font-family: var(--font-mono);
    word-break: break-all;
    text-align: center;
    line-height: 1.5;
}

.batch-results {
    margin-top: var(--space-lg);
    animation: fadeIn 0.5s ease-out;
}

.batch-results h3 {
    margin-bottom: var(--space-md);
    color: var(--text-secondary);
}

.batch-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--space-md);
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-sm);
    border-left: 4px solid var(--primary-color);
    transition: var(--transition-fast);
}

.batch-item:hover {
    background: var(--bg-tertiary);
    transform: translateX(5px);
}

.code-results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--space-md);
    margin-top: var(--space-xl);
}

.code-result-item {
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-md);
    text-align: center;
    border: 2px solid var(--border-color);
    transition: var(--transition-base);
}

.code-result-item:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.code-result-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: var(--space-sm);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.code-result-value {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--primary-color);
    font-family: var(--font-mono);
    word-break: break-all;
}

/* ============================================
   History Section
   ============================================ */
.history-section {
    max-height: 500px;
    overflow-y: auto;
    padding-right: var(--space-sm);
}

.history-section::-webkit-scrollbar {
    width: 8px;
}

.history-section::-webkit-scrollbar-track {
    background: var(--bg-secondary);
    border-radius: var(--radius-full);
}

.history-section::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: var(--radius-full);
}

.history-item {
    background: var(--bg-secondary);
    padding: var(--space-md);
    border-radius: var(--radius-md);
    margin-bottom: var(--space-sm);
    border-left: 4px solid var(--primary-color);
    transition: var(--transition-fast);
    animation: slideInLeft 0.4s ease-out;
}

.history-item:hover {
    background: var(--bg-tertiary);
    transform: translateX(5px);
}

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-20px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.history-empty {
    text-align: center;
    padding: var(--space-2xl);
    color: var(--text-secondary);
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: var(--space-md);
    opacity: 0.5;
}

.empty-text {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: var(--space-sm);
}

.empty-subtext {
    font-size: 0.95rem;
}

/* ============================================
   Export Section
   ============================================ */
.export-section {
    margin-top: var(--space-xl);
    padding-top: var(--space-xl);
    border-top: 2px solid var(--border-color);
}

.export-title {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: var(--space-md);
    color: var(--text-secondary);
}

/* ============================================
   Guide Section
   ============================================ */
.guide-item {
    background: var(--bg-secondary);
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
    border: 2px solid var(--border-color);
    transition: var(--transition-base);
}

/* NOTE: The original file appeared truncated beyond this point. */
/* Restored a minimal closing for `.guide-item` to fix syntax errors. */