/* ============================================
   UNIFIED DESIGN SYSTEM
   ============================================ */

:root {
    /* Color Palette - Modern & Professional */
    --primary: #00d4aa;
    --primary-dark: #00b894;
    --primary-light: #00f5d4;
    
    --secondary: #667eea;
    --secondary-dark: #5568d3;
    --secondary-light: #7c8ff0;
    
    --accent: #ff6b6b;
    --accent-dark: #ee5a6f;
    --accent-light: #ff8787;
    
    --success: #51cf66;
    --warning: #ffd93d;
    --error: #ff6b6b;
    --info: #4dabf7;
    
    /* Background Colors */
    --bg-primary: #0a0e27;
    --bg-secondary: #141b2d;
    --bg-tertiary: #1a2332;
    --bg-card: rgba(255, 255, 255, 0.05);
    --bg-card-hover: rgba(255, 255, 255, 0.08);
    
    /* Text Colors */
    --text-primary: #ffffff;
    --text-secondary: #b8c5d6;
    --text-tertiary: #8b9dc3;
    --text-muted: #6b7a99;
    
    /* Border Colors */
    --border-primary: rgba(255, 255, 255, 0.1);
    --border-secondary: rgba(255, 255, 255, 0.15);
    --border-accent: rgba(0, 212, 170, 0.3);
    
    /* 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-xl: 0 16px 48px rgba(0, 0, 0, 0.4);
    --shadow-glow: 0 0 20px rgba(0, 212, 170, 0.3);
    
    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    
    /* Border Radius */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-xl: 2rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 0.15s ease;
    --transition-base: 0.3s ease;
    --transition-slow: 0.5s ease;
    
    /* Typography */
    --font-primary: 'Share Tech', sans-serif;
    --font-mono: 'Share Tech Mono', monospace;
    
    /* Z-index layers */
    --z-base: 1;
    --z-dropdown: 100;
    --z-sticky: 200;
    --z-modal: 300;
    --z-tooltip: 400;
}

/* ============================================
   GLOBAL RESET & BASE STYLES
   ============================================ */

* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

/* ============================================
   TYPOGRAPHY SYSTEM
   ============================================ */

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-primary);
    font-weight: 600;
    line-height: 1.2;
    margin: 0 0 var(--spacing-md) 0;
    color: var(--text-primary);
}

h1 {
    font-size: clamp(2rem, 5vw, 3rem);
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

h2 {
    font-size: clamp(1.5rem, 4vw, 2rem);
    color: var(--primary);
}

h3 {
    font-size: clamp(1.25rem, 3vw, 1.5rem);
}

h4 {
    font-size: clamp(1.1rem, 2.5vw, 1.25rem);
}

p {
    margin: 0 0 var(--spacing-sm) 0;
    color: var(--text-secondary);
}

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

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

/* ============================================
   COMPONENT SYSTEM
   ============================================ */

/* Card Component */
.card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-md);
    padding: var(--spacing-lg);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.card:hover {
    background: var(--bg-card-hover);
    border-color: var(--border-secondary);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

/* Button Component */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-family: var(--font-primary);
    font-size: 1rem;
    font-weight: 600;
    border: none;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 4px 15px rgba(0, 212, 170, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 212, 170, 0.4);
}

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

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

/* Input Component */
.input {
    width: 100%;
    padding: var(--spacing-sm) var(--spacing-md);
    font-family: var(--font-mono);
    font-size: 1rem;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-primary);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    transition: all var(--transition-base);
}

.input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(0, 212, 170, 0.1);
}

/* Badge Component */
.badge {
    display: inline-flex;
    align-items: center;
    padding: 0.25rem 0.75rem;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-full);
    background: var(--bg-card);
    border: 1px solid var(--border-primary);
    color: var(--text-secondary);
}

.badge-primary {
    background: rgba(0, 212, 170, 0.2);
    border-color: var(--primary);
    color: var(--primary);
}

.badge-success {
    background: rgba(81, 207, 102, 0.2);
    border-color: var(--success);
    color: var(--success);
}

/* Progress Bar Component */
.progress {
    width: 100%;
    height: 8px;
    background: var(--bg-tertiary);
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    border-radius: var(--radius-full);
    transition: width var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.progress-fill::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.3), transparent);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

/* Section Component */
.section {
    margin-bottom: var(--spacing-xl);
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-lg);
    padding-bottom: var(--spacing-sm);
    border-bottom: 2px solid var(--border-primary);
}

/* Container Component */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

.container-narrow {
    max-width: 900px;
}

.container-wide {
    max-width: 1400px;
}

/* Grid System */
.grid {
    display: grid;
    gap: var(--spacing-md);
}

.grid-2 {
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
}

.grid-3 {
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
}

/* Flex Utilities */
.flex {
    display: flex;
}

.flex-col {
    flex-direction: column;
}

.flex-center {
    align-items: center;
    justify-content: center;
}

.flex-between {
    justify-content: space-between;
}

.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }
.gap-lg { gap: var(--spacing-lg); }

/* Spacing Utilities */
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }

.p-sm { padding: var(--spacing-sm); }
.p-md { padding: var(--spacing-md); }
.p-lg { padding: var(--spacing-lg); }

/* Text Utilities */
.text-center { text-align: center; }
.text-left { text-align: left; }
.text-right { text-align: right; }

.text-primary { color: var(--text-primary); }
.text-secondary { color: var(--text-secondary); }
.text-tertiary { color: var(--text-tertiary); }
.text-muted { color: var(--text-muted); }

.text-gradient {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* Glass Morphism Effect */
.glass {
    background: rgba(255, 255, 255, 0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.glass-strong {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

/* Glow Effects */
.glow {
    box-shadow: var(--shadow-glow);
}

.glow-primary {
    box-shadow: 0 0 20px rgba(0, 212, 170, 0.4);
}

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

@keyframes slideInLeft {
    from {
        opacity: 0;
        transform: translateX(-30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

@keyframes slideInRight {
    from {
        opacity: 0;
        transform: translateX(30px);
    }
    to {
        opacity: 1;
        transform: translateX(0);
    }
}

.animate-fadeIn {
    animation: fadeIn 0.6s ease-out;
}

.animate-slideInLeft {
    animation: slideInLeft 0.6s ease-out;
}

.animate-slideInRight {
    animation: slideInRight 0.6s ease-out;
}

/* Responsive Breakpoints */
@media (max-width: 768px) {
    :root {
        --spacing-md: 1rem;
        --spacing-lg: 1.5rem;
        --spacing-xl: 2rem;
    }
    
    .container {
        padding: 0 var(--spacing-sm);
    }
    
    .grid-2,
    .grid-3 {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   LIGHT THEME
   ============================================ */

.light-theme {
    /* Background Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f5f7fa;
    --bg-tertiary: #e8ecf1;
    --bg-card: rgba(0, 0, 0, 0.03);
    --bg-card-hover: rgba(0, 0, 0, 0.05);
    
    /* Text Colors */
    --text-primary: #1a1a2e;
    --text-secondary: #4a5568;
    --text-tertiary: #718096;
    --text-muted: #a0aec0;
    
    /* Border Colors */
    --border-primary: rgba(0, 0, 0, 0.1);
    --border-secondary: rgba(0, 0, 0, 0.15);
    --border-accent: rgba(0, 212, 170, 0.3);
    
    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 16px 48px rgba(0, 0, 0, 0.2);
}

.light-theme body {
    background: linear-gradient(180deg, #ffffff 0%, #f5f7fa 50%, #ffffff 100%);
}

.light-theme body::before {
    background: 
        radial-gradient(circle at 20% 30%, rgba(0, 212, 170, 0.05), transparent 50%),
        radial-gradient(circle at 80% 70%, rgba(102, 126, 234, 0.05), transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(255, 107, 107, 0.03), transparent 50%);
}

.light-theme .card,
.light-theme .lesson-card,
.light-theme section {
    background: rgba(255, 255, 255, 0.8);
    border-color: rgba(0, 0, 0, 0.1);
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.05);
}

.light-theme .card:hover,
.light-theme .lesson-card:hover {
    box-shadow: 0 4px 16px rgba(0, 0, 0, 0.1);
}

.light-theme .top-navbar {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.95), rgba(245, 247, 250, 0.95));
    border-bottom-color: rgba(0, 0, 0, 0.1);
}

.light-theme .search-input {
    background: rgba(255, 255, 255, 0.9);
    border-color: rgba(0, 0, 0, 0.15);
    color: var(--text-primary);
}

.light-theme .search-results {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.98), rgba(245, 247, 250, 0.98));
    border-color: rgba(0, 0, 0, 0.1);
}

/* Print Styles */
@media print {
    * {
        background: white !important;
        color: black !important;
        box-shadow: none !important;
    }
}