/* ===================================
   CSS Variables & Design System
   =================================== */
:root {
    /* Colors - Vibrant Dark Theme */
    --primary: #6366f1;
    --primary-light: #818cf8;
    --primary-dark: #4f46e5;
    --secondary: #ec4899;
    --secondary-light: #f472b6;
    --accent: #14b8a6;
    --accent-light: #2dd4bf;
    
    /* Background */
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-tertiary: #334155;
    --bg-glass: rgba(30, 41, 59, 0.7);
    
    /* Text */
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --text-muted: #94a3b8;
    
    /* Borders */
    --border-color: rgba(148, 163, 184, 0.2);
    --border-radius: 16px;
    --border-radius-sm: 8px;
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px rgba(99, 102, 241, 0.3);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    
    /* Typography */
    --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-size-sm: 0.875rem;
    --font-size-base: 1rem;
    --font-size-lg: 1.125rem;
    --font-size-xl: 1.5rem;
    --font-size-2xl: 2rem;
    --font-size-3xl: 2.5rem;
    
    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;
}

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

html {
    scroll-behavior: smooth;
}

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

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 50%, rgba(99, 102, 241, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(236, 72, 153, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(20, 184, 166, 0.1) 0%, transparent 50%);
    z-index: -1;
    animation: backgroundShift 20s ease infinite;
}

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

/* ===================================
   Typography
   =================================== */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-sm);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }

a {
    color: var(--primary-light);
    text-decoration: none;
    transition: color var(--transition-fast);
}

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

/* ===================================
   Layout
   =================================== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-lg);
}

.header {
    padding: var(--spacing-lg) 0;
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.header h1 {
    background: linear-gradient(135deg, var(--primary-light), var(--secondary-light));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-sm);
    animation: gradientShift 3s ease infinite;
}

@keyframes gradientShift {
    0%, 100% { filter: hue-rotate(0deg); }
    50% { filter: hue-rotate(20deg); }
}

.header p {
    color: var(--text-secondary);
    font-size: var(--font-size-lg);
}

/* ===================================
   Cards & Glassmorphism
   =================================== */
.card {
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg), var(--shadow-glow);
    border-color: rgba(99, 102, 241, 0.4);
}

.card-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    padding-bottom: var(--spacing-sm);
    border-bottom: 1px solid var(--border-color);
}

.card-icon {
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--border-radius-sm);
    font-size: 24px;
    flex-shrink: 0;
}

.card-title {
    font-size: var(--font-size-xl);
    margin: 0;
}

.card-description {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

/* ===================================
   Grid Layout
   =================================== */
.grid {
    display: grid;
    gap: var(--spacing-lg);
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

/* ===================================
   Buttons
   =================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.75rem 1.5rem;
    font-size: var(--font-size-base);
    font-weight: 600;
    border: none;
    border-radius: var(--border-radius-sm);
    cursor: pointer;
    transition: all var(--transition-base);
    text-decoration: none;
    white-space: nowrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), 0 0 20px rgba(99, 102, 241, 0.4);
}

.btn-secondary {
    background: var(--bg-secondary);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

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

.btn-success {
    background: linear-gradient(135deg, var(--accent), #059669);
    color: white;
}

.btn-success:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md), 0 0 20px rgba(20, 184, 166, 0.4);
}

.btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none !important;
}

.btn-group {
    display: flex;
    gap: var(--spacing-sm);
    flex-wrap: wrap;
}

/* ===================================
   Forms
   =================================== */
.form-group {
    margin-bottom: var(--spacing-md);
}

.form-label {
    display: block;
    margin-bottom: var(--spacing-xs);
    font-weight: 600;
    color: var(--text-primary);
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: var(--font-size-base);
    font-family: var(--font-family);
    color: var(--text-primary);
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    transition: all var(--transition-fast);
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.form-textarea {
    resize: vertical;
    min-height: 100px;
}

.form-range {
    width: 100%;
    height: 6px;
    background: var(--bg-secondary);
    border-radius: 3px;
    outline: none;
    -webkit-appearance: none;
}

.form-range::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    cursor: pointer;
    transition: all var(--transition-fast);
}

.form-range::-webkit-slider-thumb:hover {
    transform: scale(1.2);
    box-shadow: 0 0 10px rgba(99, 102, 241, 0.5);
}

.form-range::-moz-range-thumb {
    width: 20px;
    height: 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 50%;
    cursor: pointer;
    border: none;
}

.checkbox-group {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-md);
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    cursor: pointer;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    accent-color: var(--primary);
}

/* File Upload */
.file-upload {
    position: relative;
    display: inline-block;
    width: 100%;
}

.file-upload-input {
    position: absolute;
    opacity: 0;
    width: 100%;
    height: 100%;
    cursor: pointer;
}

.file-upload-label {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-xl);
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    background: var(--bg-secondary);
    cursor: pointer;
    transition: all var(--transition-base);
}

.file-upload-label:hover {
    border-color: var(--primary);
    background: var(--bg-tertiary);
}

.file-upload-icon {
    font-size: 48px;
    color: var(--primary);
}

/* ===================================
   Alerts & Messages
   =================================== */
.alert {
    padding: var(--spacing-md);
    border-radius: var(--border-radius-sm);
    margin-bottom: var(--spacing-md);
    border-left: 4px solid;
}

.alert-success {
    background: rgba(20, 184, 166, 0.1);
    border-color: var(--accent);
    color: var(--accent-light);
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border-color: #ef4444;
    color: #fca5a5;
}

.alert-info {
    background: rgba(99, 102, 241, 0.1);
    border-color: var(--primary);
    color: var(--primary-light);
}

/* ===================================
   Utility Classes
   =================================== */
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: var(--spacing-sm); }
.mb-2 { margin-bottom: var(--spacing-md); }
.mb-3 { margin-bottom: var(--spacing-lg); }
.mt-1 { margin-top: var(--spacing-sm); }
.mt-2 { margin-top: var(--spacing-md); }
.mt-3 { margin-top: var(--spacing-lg); }

.flex { display: flex; }
.flex-column { flex-direction: column; }
.align-center { align-items: center; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.gap-1 { gap: var(--spacing-sm); }
.gap-2 { gap: var(--spacing-md); }

.w-full { width: 100%; }

/* ===================================
   Loading Spinner
   =================================== */
.spinner {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 0.8s linear infinite;
}

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

/* ===================================
   Responsive Design
   =================================== */
@media (max-width: 768px) {
    :root {
        --font-size-3xl: 2rem;
        --font-size-2xl: 1.5rem;
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
    }
    
    .container {
        padding: var(--spacing-sm);
    }
    
    .grid {
        grid-template-columns: 1fr;
    }
    
    .btn-group {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
}

/* ===================================
   Navigation Menu
   =================================== */
.nav-menu {
    display: flex;
    justify-content: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-xl);
    flex-wrap: wrap;
}

.nav-link {
    padding: 0.75rem 1.5rem;
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    color: var(--text-primary);
    font-weight: 600;
    transition: all var(--transition-base);
}

.nav-link:hover,
.nav-link.active {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-color: var(--primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

/* ===================================
   Tool-Specific Styles
   =================================== */
.result-box {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-sm);
    padding: var(--spacing-md);
    margin: var(--spacing-md) 0;
    font-family: 'Courier New', monospace;
    font-size: var(--font-size-lg);
    word-break: break-all;
    position: relative;
}

.copy-btn {
    position: absolute;
    top: var(--spacing-sm);
    right: var(--spacing-sm);
    padding: 0.5rem 1rem;
    font-size: var(--font-size-sm);
}

.strength-meter {
    height: 8px;
    background: var(--bg-secondary);
    border-radius: 4px;
    overflow: hidden;
    margin-top: var(--spacing-sm);
}

.strength-bar {
    height: 100%;
    transition: all var(--transition-base);
    border-radius: 4px;
}

.strength-weak { 
    width: 25%; 
    background: linear-gradient(90deg, #ef4444, #f87171);
}

.strength-medium { 
    width: 50%; 
    background: linear-gradient(90deg, #f59e0b, #fbbf24);
}

.strength-strong { 
    width: 75%; 
    background: linear-gradient(90deg, #10b981, #34d399);
}

.strength-very-strong { 
    width: 100%; 
    background: linear-gradient(90deg, var(--accent), var(--accent-light));
}

.comparison-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: var(--spacing-md);
}

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

.comparison-table th {
    background: var(--bg-secondary);
    font-weight: 600;
    color: var(--primary-light);
}

.comparison-table tr:hover {
    background: var(--bg-secondary);
}