/**
 * Professional Design System
 * 
 * Ultra-modern, professional design with premium aesthetics
 *
 * @package Coursee
 * @since 1.0.0
 */

/* ============================================
   DESIGN TOKENS & VARIABLES
   ============================================ */
:root {
    /* Colors - Professional Palette */
    --color-primary: #6366f1;
    --color-primary-dark: #4f46e5;
    --color-primary-light: #818cf8;
    --color-primary-lighter: #c7d2fe;
    --color-secondary: #ec4899;
    --color-accent: #f59e0b;
    --color-success: #10b981;
    --color-error: #ef4444;
    --color-warning: #f59e0b;
    --color-info: #3b82f6;
    
    /* Neutrals */
    --color-gray-50: #f9fafb;
    --color-gray-100: #f3f4f6;
    --color-gray-200: #e5e7eb;
    --color-gray-300: #d1d5db;
    --color-gray-400: #9ca3af;
    --color-gray-500: #6b7280;
    --color-gray-600: #4b5563;
    --color-gray-700: #374151;
    --color-gray-800: #1f2937;
    --color-gray-900: #111827;
    
    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-secondary: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    --gradient-accent: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    --gradient-success: linear-gradient(135deg, #10b981 0%, #059669 100%);
    --gradient-dark: linear-gradient(135deg, #1f2937 0%, #111827 100%);
    --gradient-glass: linear-gradient(135deg, rgba(255, 255, 255, 0.1) 0%, rgba(255, 255, 255, 0.05) 100%);
    
    /* Shadows - Professional Depth */
    --shadow-xs: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 2px 4px 0 rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.06);
    --shadow-colored: 0 10px 30px -5px rgba(99, 102, 241, 0.3);
    
    /* Typography */
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --font-display: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
    --font-mono: "SF Mono", Monaco, "Cascadia Code", "Roboto Mono", Consolas, monospace;
    
    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 1.875rem;
    --text-4xl: 2.25rem;
    --text-5xl: 3rem;
    
    --font-weight-light: 300;
    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;
    --font-weight-extrabold: 800;
    
    /* 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: 1.5rem;
    --radius-full: 9999px;
    
    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 600ms cubic-bezier(0.68, -0.55, 0.265, 1.55);
    
    /* Z-Index Scale */
    --z-dropdown: 1000;
    --z-sticky: 1020;
    --z-fixed: 1030;
    --z-modal-backdrop: 1040;
    --z-modal: 1050;
    --z-popover: 1060;
    --z-tooltip: 1070;
}

/* ============================================
   GLOBAL ENHANCEMENTS
   ============================================ */
* {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: 1.7;
    color: var(--color-gray-800);
    background: var(--color-gray-50);
    overflow-x: hidden;
}

/* ============================================
   PROFESSIONAL BUTTONS
   ============================================ */
.button,
button.button,
input[type="submit"],
input[type="button"] {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--space-2);
    padding: var(--space-3) var(--space-6);
    font-family: var(--font-display);
    font-size: var(--text-sm);
    font-weight: var(--font-weight-semibold);
    line-height: 1.5;
    text-decoration: none;
    border: none;
    border-radius: var(--radius-lg);
    cursor: pointer;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    background: var(--color-primary);
    color: white;
}

.button::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.3);
    transform: translate(-50%, -50%);
    transition: width 0.6s, height 0.6s;
}

.button:hover::before {
    width: 300px;
    height: 300px;
}

.button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
    background: var(--color-primary-dark);
}

.button:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

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

.button-primary:hover {
    background: var(--gradient-primary);
    box-shadow: var(--shadow-xl), var(--shadow-colored);
    transform: translateY(-3px) scale(1.02);
}

.button-secondary {
    background: var(--color-gray-100);
    color: var(--color-gray-800);
}

.button-secondary:hover {
    background: var(--color-gray-200);
    color: var(--color-gray-900);
}

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

.button-outline:hover {
    background: var(--color-primary);
    color: white;
}

.button-large {
    padding: var(--space-4) var(--space-8);
    font-size: var(--text-base);
}

.button-small {
    padding: var(--space-2) var(--space-4);
    font-size: var(--text-xs);
}

/* ============================================
   PROFESSIONAL CARDS
   ============================================ */
.card,
.course-item,
.stat-card,
.quiz-question {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    padding: var(--space-6);
    transition: all var(--transition-base);
    border: 1px solid var(--color-gray-200);
    position: relative;
    overflow: hidden;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform var(--transition-base);
}

.card:hover::before {
    transform: scaleX(1);
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-xl);
    border-color: var(--color-primary-lighter);
}

.card-header {
    margin-bottom: var(--space-4);
    padding-bottom: var(--space-4);
    border-bottom: 1px solid var(--color-gray-200);
}

.card-title {
    font-size: var(--text-xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-gray-900);
    margin: 0;
    line-height: 1.3;
}

.card-body {
    color: var(--color-gray-600);
    line-height: 1.7;
}

.card-footer {
    margin-top: var(--space-4);
    padding-top: var(--space-4);
    border-top: 1px solid var(--color-gray-200);
}

/* ============================================
   GLASSMORPHISM EFFECTS
   ============================================ */
.glass {
    background: rgba(255, 255, 255, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.3);
    box-shadow: var(--shadow-lg);
}

.glass-dark {
    background: rgba(31, 41, 55, 0.7);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    color: white;
}

/* ============================================
   PROFESSIONAL FORMS
   ============================================ */
input[type="text"],
input[type="email"],
input[type="password"],
input[type="number"],
input[type="date"],
input[type="datetime-local"],
textarea,
select {
    width: 100%;
    padding: var(--space-3) var(--space-4);
    font-family: var(--font-sans);
    font-size: var(--text-base);
    line-height: 1.5;
    color: var(--color-gray-900);
    background: white;
    border: 2px solid var(--color-gray-300);
    border-radius: var(--radius-lg);
    transition: all var(--transition-fast);
    box-shadow: var(--shadow-sm);
}

input:focus,
textarea:focus,
select:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1), var(--shadow-md);
    transform: translateY(-1px);
}

input::placeholder,
textarea::placeholder {
    color: var(--color-gray-400);
}

.form-group {
    margin-bottom: var(--space-5);
}

.form-label {
    display: block;
    font-size: var(--text-sm);
    font-weight: var(--font-weight-semibold);
    color: var(--color-gray-700);
    margin-bottom: var(--space-2);
}

.form-description {
    font-size: var(--text-xs);
    color: var(--color-gray-500);
    margin-top: var(--space-1);
}

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

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

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

@keyframes shimmer {
    0% {
        background-position: -1000px 0;
    }
    100% {
        background-position: 1000px 0;
    }
}

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

@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.5;
    }
}

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

.slide-in {
    animation: slideIn 0.4s ease-out;
}

.scale-in {
    animation: scaleIn 0.3s ease-out;
}

.float {
    animation: float 3s ease-in-out infinite;
}

.pulse {
    animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

/* ============================================
   PROFESSIONAL HEADER
   ============================================ */
.site-header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    box-shadow: var(--shadow-sm);
    border-bottom: 1px solid var(--color-gray-200);
    padding: var(--space-4) 0;
    position: sticky;
    top: 0;
    z-index: var(--z-sticky);
    transition: all var(--transition-base);
}

.site-header.scrolled {
    padding: var(--space-3) 0;
    box-shadow: var(--shadow-md);
}

.site-title {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: var(--font-weight-extrabold);
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    letter-spacing: -0.5px;
    margin: 0;
}

.site-title a {
    text-decoration: none;
    transition: transform var(--transition-base);
}

.site-title a:hover {
    transform: scale(1.05);
}

/* ============================================
   PROFESSIONAL NAVIGATION - PREMIUM HOVER EFFECTS
   ============================================ */
.main-navigation {
    display: flex;
    align-items: center;
}

.main-navigation ul {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    gap: var(--space-1);
    align-items: center;
}

.main-navigation li {
    position: relative;
    margin: 0;
}

.main-navigation a {
    position: relative;
    display: inline-flex;
    align-items: center;
    padding: var(--space-3) var(--space-5);
    font-weight: var(--font-weight-semibold);
    font-size: var(--text-sm);
    color: var(--color-gray-700);
    text-decoration: none;
    border-radius: var(--radius-lg);
    transition: all var(--transition-base);
    overflow: hidden;
    z-index: 1;
}

/* Animated background on hover */
.main-navigation a::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--gradient-primary);
    opacity: 0;
    transform: scale(0.8);
    transform-origin: center;
    transition: all var(--transition-base);
    z-index: -1;
    border-radius: var(--radius-lg);
}

/* Underline effect */
.main-navigation a::after {
    content: '';
    position: absolute;
    bottom: var(--space-2);
    left: 50%;
    width: 0;
    height: 3px;
    background: var(--gradient-primary);
    border-radius: var(--radius-full);
    transform: translateX(-50%);
    transition: width var(--transition-base) cubic-bezier(0.4, 0, 0.2, 1);
    z-index: 2;
}

/* Hover state - premium effect */
.main-navigation a:hover {
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(99, 102, 241, 0.3);
}

.main-navigation a:hover::before {
    opacity: 1;
    transform: scale(1);
}

.main-navigation a:hover::after {
    width: calc(100% - var(--space-6));
    background: rgba(255, 255, 255, 0.4);
}

/* Active/Current state */
.main-navigation .current-menu-item > a,
.main-navigation .current_page_item > a {
    color: white;
    background: var(--gradient-primary);
    box-shadow: var(--shadow-md);
}

.main-navigation .current-menu-item > a::before,
.main-navigation .current_page_item > a::before {
    opacity: 1;
    transform: scale(1);
}

.main-navigation .current-menu-item > a::after,
.main-navigation .current_page_item > a::after {
    width: 0;
}

/* Submenu support */
.main-navigation .sub-menu {
    position: absolute;
    top: 100%;
    left: 0;
    min-width: 220px;
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-xl);
    padding: var(--space-2);
    margin-top: var(--space-2);
    opacity: 0;
    visibility: hidden;
    transform: translateY(-10px);
    transition: all var(--transition-base);
    z-index: 1000;
    border: 1px solid var(--color-gray-200);
}

.main-navigation li:hover > .sub-menu {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.main-navigation .sub-menu a {
    padding: var(--space-3) var(--space-4);
    border-radius: var(--radius-md);
    color: var(--color-gray-700);
    font-weight: var(--font-weight-medium);
}

.main-navigation .sub-menu a::after {
    display: none;
}

.main-navigation .sub-menu a:hover {
    background: var(--color-gray-100);
    color: var(--color-primary);
    transform: translateX(4px);
    box-shadow: none;
}

.main-navigation .sub-menu a:hover::before {
    display: none;
}

/* ============================================
   PROFESSIONAL TYPOGRAPHY
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-display);
    font-weight: var(--font-weight-bold);
    line-height: 1.2;
    color: var(--color-gray-900);
    margin-top: 0;
}

h1 {
    font-size: var(--text-4xl);
    font-weight: var(--font-weight-extrabold);
    letter-spacing: -1px;
}

h2 {
    font-size: var(--text-3xl);
    font-weight: var(--font-weight-bold);
    letter-spacing: -0.5px;
}

h3 {
    font-size: var(--text-2xl);
}

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

/* ============================================
   PROFESSIONAL PROGRESS BARS
   ============================================ */
.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--color-gray-200);
    border-radius: var(--radius-full);
    overflow: hidden;
    position: relative;
}

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

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

/* ============================================
   PROFESSIONAL BADGES & TAGS
   ============================================ */
.badge {
    display: inline-flex;
    align-items: center;
    padding: var(--space-1) var(--space-3);
    font-size: var(--text-xs);
    font-weight: var(--font-weight-semibold);
    border-radius: var(--radius-full);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.badge-success {
    background: var(--color-success);
    color: white;
}

.badge-warning {
    background: var(--color-warning);
    color: white;
}

.badge-error {
    background: var(--color-error);
    color: white;
}

.badge-info {
    background: var(--color-info);
    color: white;
}

.badge-primary {
    background: var(--gradient-primary);
    color: white;
}

/* ============================================
   PROFESSIONAL ALERTS
   ============================================ */
.alert {
    padding: var(--space-4);
    border-radius: var(--radius-lg);
    border-left: 4px solid;
    margin-bottom: var(--space-4);
    box-shadow: var(--shadow-sm);
}

.alert-success {
    background: rgba(16, 185, 129, 0.1);
    border-color: var(--color-success);
    color: #065f46;
}

.alert-error {
    background: rgba(239, 68, 68, 0.1);
    border-color: var(--color-error);
    color: #991b1b;
}

.alert-warning {
    background: rgba(245, 158, 11, 0.1);
    border-color: var(--color-warning);
    color: #92400e;
}

.alert-info {
    background: rgba(59, 130, 246, 0.1);
    border-color: var(--color-info);
    color: #1e40af;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */
@media (max-width: 768px) {
    :root {
        --text-4xl: 2rem;
        --text-3xl: 1.75rem;
        --text-2xl: 1.5rem;
    }
    
    .card {
        padding: var(--space-4);
    }
    
    .button {
        width: 100%;
        justify-content: center;
    }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */
.text-gradient {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.shadow-colored {
    box-shadow: var(--shadow-colored);
}

.hover-lift {
    transition: transform var(--transition-base);
}

.hover-lift:hover {
    transform: translateY(-4px);
}

.glow {
    box-shadow: 0 0 20px rgba(99, 102, 241, 0.3);
}

.glow:hover {
    box-shadow: 0 0 30px rgba(99, 102, 241, 0.5);
}