:root {
    /* Color Palette - Soft Glass */
    --bg-primary: #0f1419;
    --bg-secondary: #1a202c;
    --bg-tertiary: #252d42;
    --glass-light: rgba(255, 255, 255, 0.08);
    --glass-medium: rgba(255, 255, 255, 0.12);
    --glass-dark: rgba(255, 255, 255, 0.05);
    --glass-lighter: rgba(255, 255, 255, 0.15);
    
    /* Text Colors */
    --text-primary: #f8fafc;
    --text-secondary: #cbd5e1;
    --text-tertiary: #94a3b8;
    
    /* Borders */
    --border-glass: 1px solid rgba(255, 255, 255, 0.2);
    --border-subtle: 1px solid rgba(255, 255, 255, 0.1);
    
    /* Semantic Colors */
    --success: #10b981;
    --success-light: rgba(16, 185, 129, 0.15);
    --error: #ef4444;
    --error-light: rgba(239, 68, 68, 0.15);
    --warning: #f59e0b;
    --warning-light: rgba(245, 158, 11, 0.15);
    --info: #3b82f6;
    --info-light: rgba(59, 130, 246, 0.15);
    
    /* Shadow System - Soft Shadows */
    --shadow-xs: 0 1px 2px rgba(0, 0, 0, 0.05);
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.15);
    --shadow-xl: 0 20px 25px rgba(0, 0, 0, 0.2);
    --shadow-2xl: 0 25px 50px rgba(0, 0, 0, 0.25);
    
    /* Blur Values */
    --blur-sm: 8px;
    --blur-md: 16px;
    --blur-lg: 24px;
    --blur-xl: 32px;
}

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

/* ============================================
   Typography & Base Styles
   ============================================ */

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', sans-serif;
    background: linear-gradient(135deg, #0f1419 0%, #1a202c 50%, #2d3748 100%);
    color: var(--text-primary);
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

/* Animated Background - Subtle Floating Blobs */
.background-animation {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background: inherit;
    overflow: hidden;
}

.background-animation::before {
    content: '';
    position: absolute;
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, rgba(59, 130, 246, 0.06) 0%, transparent 70%);
    animation: float-slow 20s ease-in-out infinite;
    top: -150px;
    left: -150px;
    filter: blur(40px);
    pointer-events: none;
}

.background-animation::after {
    content: '';
    position: absolute;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(168, 85, 247, 0.05) 0%, transparent 70%);
    animation: float-slow 25s ease-in-out infinite reverse;
    bottom: -100px;
    right: -100px;
    filter: blur(40px);
    pointer-events: none;
}

@keyframes float-slow {
    0%, 100% { transform: translateY(0px) translateX(0px); }
    50% { transform: translateY(-40px) translateX(20px); }
}

/* ============================================
   Tags & Chips
   ============================================ */

.language-tag,
.level-chip {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.4rem 1rem;
    border-radius: 999px;
    font-size: 0.75rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    background: var(--glass-light);
    border: var(--border-subtle);
    color: var(--text-primary);
    margin-right: 0.4rem;
    backdrop-filter: blur(var(--blur-md));
    font-weight: 500;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.language-tag:hover {
    background: var(--glass-medium);
    border-color: rgba(255, 255, 255, 0.2);
    transform: translateY(-1px);
}

.level-chip {
    background: var(--info-light);
    border-color: rgba(59, 130, 246, 0.3);
    color: #60a5fa;
}

.level-chip.level-easy {
    background: var(--success-light);
    border-color: rgba(16, 185, 129, 0.3);
    color: #6ee7b7;
}

.level-chip.level-medium {
    background: var(--warning-light);
    border-color: rgba(245, 158, 11, 0.3);
    color: #fcd34d;
}

.level-chip.level-hard {
    background: var(--error-light);
    border-color: rgba(239, 68, 68, 0.3);
    color: #fca5a5;
}

.quiz-tags,
.challenge-tags,
.result-tags {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.5rem;
    flex-wrap: wrap;
}

/* ============================================
   Navigation
   ============================================ */

.navbar {
    background: linear-gradient(180deg, rgba(15, 23, 42, 0.4) 0%, rgba(15, 23, 42, 0.2) 100%);
    backdrop-filter: blur(var(--blur-xl));
    border-bottom: var(--border-subtle);
    padding: 1rem 2rem;
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

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

.nav-logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    text-decoration: none;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    letter-spacing: -0.02em;
}

.nav-logo:hover {
    transform: scale(1.02);
    color: #60a5fa;
}

.nav-links {
    display: flex;
    gap: 2.5rem;
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    font-weight: 500;
    font-size: 0.95rem;
}

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

.logout-btn {
    padding: 0.6rem 1.5rem;
    background: var(--glass-light);
    backdrop-filter: blur(var(--blur-md));
    border: var(--border-glass);
    border-radius: 999px;
    color: var(--text-primary);
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    cursor: pointer;
    font-weight: 500;
    font-size: 0.9rem;
}

.logout-btn:hover {
    background: var(--glass-medium);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* ============================================
   Flash Messages
   ============================================ */

.flash-messages {
    position: fixed;
    top: 100px;
    right: 20px;
    z-index: 1001;
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.flash-message {
    padding: 1.2rem 1.5rem;
    border-radius: 16px;
    backdrop-filter: blur(var(--blur-lg));
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;
    min-width: 320px;
    animation: slideInRight 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow-lg);
    border: var(--border-subtle);
}

.flash-success {
    background: linear-gradient(135deg, rgba(16, 185, 129, 0.15) 0%, rgba(16, 185, 129, 0.08) 100%);
    border-color: rgba(16, 185, 129, 0.3);
    color: #6ee7b7;
}

.flash-error {
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.15) 0%, rgba(239, 68, 68, 0.08) 100%);
    border-color: rgba(239, 68, 68, 0.3);
    color: #fca5a5;
}

.flash-close {
    background: none;
    border: none;
    color: inherit;
    font-size: 1.5rem;
    cursor: pointer;
    transition: transform 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    opacity: 0.7;
}

.flash-close:hover {
    transform: scale(1.1);
    opacity: 1;
}

@keyframes slideInRight {
    from {
        transform: translateX(400px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

/* ============================================
   Main Content & Layout
   ============================================ */

.main-content {
    min-height: calc(100vh - 80px);
    padding: 2.5rem;
}

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

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

/* ============================================
   Glass Card Effect
   ============================================ */

.glass-card {
    position: relative;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.08) 0%, rgba(255, 255, 255, 0.05) 100%);
    backdrop-filter: blur(var(--blur-xl));
    border: var(--border-glass);
    border-radius: 20px;
    padding: 2rem;
    box-shadow: var(--shadow-lg);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    overflow: hidden;
}

.glass-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255, 255, 255, 0.08) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
}

.glass-card:hover {
    border-color: rgba(255, 255, 255, 0.3);
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.2), inset 0 1px 1px rgba(255, 255, 255, 0.1);
    transform: translateY(-4px);
}

.glass-card:hover::before {
    opacity: 0.5;
}

.card-hover {
    cursor: pointer;
}

.card-hover:hover {
    transform: translateY(-8px);
}

/* ============================================
   Landing Page
   ============================================ */

.landing-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    position: relative;
    overflow: hidden;
    padding: 2rem;
}

.landing-content {
    text-align: center;
    z-index: 1;
    animation: fadeInUp 0.8s cubic-bezier(0.4, 0, 0.2, 1);
}

.landing-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 1rem;
    flex-wrap: wrap;
    letter-spacing: -0.02em;
}

.title-word {
    color: var(--text-primary);
    background: linear-gradient(135deg, #60a5fa 0%, #a78bfa 50%, #f472b6 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.title-separator {
    color: #60a5fa;
    font-size: 2.5rem;
    animation: gentle-pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

.landing-subtitle {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 3rem;
    animation: fadeIn 1s cubic-bezier(0.4, 0, 0.2, 1) 0.2s backwards;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.landing-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeIn 1s cubic-bezier(0.4, 0, 0.2, 1) 0.4s backwards;
}

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

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

@keyframes gentle-pulse {
    0%, 100% { opacity: 0.7; }
    50% { opacity: 1; }
}

/* ============================================
   Buttons
   ============================================ */

.btn {
    padding: 0.85rem 2rem;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    text-decoration: none;
    display: inline-block;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
    letter-spacing: -0.01em;
}

.btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.2) 0%, rgba(255, 255, 255, 0) 100%);
    opacity: 0;
    transition: opacity 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    pointer-events: none;
}

.btn-primary {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.9) 0%, rgba(99, 102, 241, 0.9) 100%);
    color: var(--text-primary);
    border: 1px solid rgba(59, 130, 246, 0.5);
    backdrop-filter: blur(var(--blur-sm));
    box-shadow: 0 4px 15px rgba(59, 130, 246, 0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(59, 130, 246, 0.4);
    border-color: rgba(59, 130, 246, 0.8);
}

.btn-primary:hover::before {
    opacity: 1;
}

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

.btn-secondary {
    background: linear-gradient(135deg, var(--glass-light) 0%, var(--glass-dark) 100%);
    color: var(--text-primary);
    border: var(--border-glass);
    backdrop-filter: blur(var(--blur-md));
    box-shadow: var(--shadow-sm);
}

.btn-secondary:hover {
    background: linear-gradient(135deg, var(--glass-medium) 0%, var(--glass-light) 100%);
    border-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(0, 0, 0, 0.15);
}

.btn-secondary:hover::before {
    opacity: 0.8;
}

.btn-block {
    width: 100%;
    text-align: center;
}

.btn-small {
    padding: 0.5rem 1.2rem;
    font-size: 0.9rem;
    border-radius: 10px;
}

/* ============================================
   Authentication Pages
   ============================================ */

.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 80px);
    padding: 2rem;
}

.auth-card {
    width: 100%;
    max-width: 420px;
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.auth-title {
    font-size: 2rem;
    margin-bottom: 2.5rem;
    text-align: center;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.auth-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.6rem;
}

.form-group label {
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.95rem;
}

.form-input {
    padding: 0.9rem 1.2rem;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);
    border: var(--border-subtle);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(var(--blur-sm));
}

.form-input::placeholder {
    color: var(--text-tertiary);
}

.form-input:focus {
    outline: none;
    border-color: rgba(59, 130, 246, 0.5);
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.08) 0%, rgba(255, 255, 255, 0.04) 100%);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1), inset 0 1px 2px rgba(255, 255, 255, 0.1);
}

.auth-switch {
    text-align: center;
    margin-top: 2rem;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.auth-switch a {
    color: #60a5fa;
    text-decoration: none;
    transition: color 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    font-weight: 600;
}

.auth-switch a:hover {
    color: #93c5fd;
}

/* ============================================
   Dashboard
   ============================================ */

.dashboard-header {
    text-align: center;
    margin-bottom: 3rem;
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.dashboard-title {
    font-size: 2.5rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.dashboard-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.stat-card {
    text-align: center;
    padding: 2.5rem 2rem;
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    animation-fill-mode: both;
}

.stat-card:nth-child(1) { animation-delay: 0.1s; }
.stat-card:nth-child(2) { animation-delay: 0.2s; }
.stat-card:nth-child(3) { animation-delay: 0.3s; }

.stat-icon {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.stat-value {
    font-size: 2.2rem;
    font-weight: 700;
    color: #60a5fa;
    margin-bottom: 0.5rem;
    letter-spacing: -0.02em;
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 500;
}

.action-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.action-card {
    text-align: center;
    padding: 2.5rem;
    text-decoration: none;
    color: inherit;
    display: block;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.action-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
}

.action-card h3 {
    font-size: 1.4rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

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

.recent-section {
    margin-top: 3rem;
}

.section-title {
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.recent-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.recent-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.recent-item:hover {
    background: var(--glass-dark);
    border-radius: 12px;
}

.recent-info h4 {
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 600;
}

.recent-date {
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.recent-score {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.score-value {
    font-size: 1.4rem;
    font-weight: 700;
    color: #60a5fa;
}

/* ============================================
   Page Headers
   ============================================ */

.page-header {
    text-align: center;
    margin-bottom: 3rem;
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 0.8rem;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.page-header p {
    color: var(--text-secondary);
    font-size: 1.1rem;
}

/* ============================================
   Quiz & Challenge Cards
   ============================================ */

.quiz-grid,
.challenge-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 2rem;
}

.quiz-card,
.challenge-card {
    display: flex;
    flex-direction: column;
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.quiz-header,
.challenge-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    margin-bottom: 1rem;
    gap: 1rem;
}

.quiz-header h3,
.challenge-header h3 {
    font-size: 1.3rem;
    color: var(--text-primary);
    flex: 1;
    font-weight: 600;
    letter-spacing: -0.01em;
}

.difficulty-badge {
    padding: 0.35rem 0.85rem;
    border-radius: 20px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    white-space: nowrap;
}

.difficulty-easy {
    background: var(--success-light);
    color: #6ee7b7;
    border: 1px solid rgba(16, 185, 129, 0.4);
}

.difficulty-medium {
    background: var(--warning-light);
    color: #fcd34d;
    border: 1px solid rgba(245, 158, 11, 0.4);
}

.difficulty-hard {
    background: var(--error-light);
    color: #fca5a5;
    border: 1px solid rgba(239, 68, 68, 0.4);
}

.quiz-description,
.challenge-description {
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
    flex: 1;
    font-size: 0.95rem;
    line-height: 1.6;
}

.quiz-meta {
    display: flex;
    gap: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-tertiary);
    font-size: 0.85rem;
}

.challenge-examples {
    margin: 1.5rem 0;
    padding: 1.25rem;
    background: var(--glass-dark);
    border: var(--border-subtle);
    border-radius: 12px;
}

.example-item {
    margin: 0.5rem 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.example-item code {
    color: #60a5fa;
    background: rgba(59, 130, 246, 0.1);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
}

/* ============================================
   Quiz Selection & Forms
   ============================================ */

.quiz-select-container {
    animation: fadeInUp 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.quiz-select-form {
    margin-top: 2rem;
    padding: 2.5rem;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

.select-section {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.section-heading {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 1rem;
}

.section-heading h3 {
    margin: 0;
    font-size: 1rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-secondary);
    font-weight: 700;
}

.section-hint {
    font-size: 0.8rem;
    color: var(--text-tertiary);
}

.language-grid,
.level-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 0.75rem;
}

.language-pill,
.level-badge {
    position: relative;
    cursor: pointer;
    border-radius: 12px;
    padding: 0.85rem 1.2rem;
    border: var(--border-subtle);
    background: var(--glass-dark);
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-transform: uppercase;
    letter-spacing: 0.08em;
    font-weight: 600;
    font-size: 0.8rem;
}

.language-pill .pill-label,
.level-badge .badge-label {
    color: var(--text-primary);
}

.language-pill input,
.level-badge input {
    display: none;
}

.language-pill:hover,
.level-badge:hover {
    border-color: rgba(255, 255, 255, 0.3);
    background: var(--glass-light);
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

.language-pill.active,
.level-badge.active {
    border-color: rgba(59, 130, 246, 0.5);
    background: rgba(59, 130, 246, 0.15);
    color: #60a5fa;
}

.level-badge.level-easy.active {
    border-color: rgba(16, 185, 129, 0.5);
    background: rgba(16, 185, 129, 0.15);
    color: #6ee7b7;
}

.level-badge.level-medium.active {
    border-color: rgba(245, 158, 11, 0.5);
    background: rgba(245, 158, 11, 0.15);
    color: #fcd34d;
}

.level-badge.level-hard.active {
    border-color: rgba(239, 68, 68, 0.5);
    background: rgba(239, 68, 68, 0.15);
    color: #fca5a5;
}

.selected-quiz-panel {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.08) 0%, rgba(255, 255, 255, 0.04) 100%);
    border: var(--border-subtle);
    border-radius: 16px;
    padding: 2rem;
    backdrop-filter: blur(var(--blur-md));
}

.missing-quiz {
    color: var(--text-tertiary);
    font-style: italic;
    font-size: 0.95rem;
}

.quiz-meta {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.meta-stats {
    display: flex;
    gap: 1.5rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.btn-start {
    align-self: flex-end;
    position: relative;
    margin-top: 1.5rem;
}

.btn-start:hover {
    transform: translateY(-2px);
}

/* ============================================
   Quiz & Coding Pages
   ============================================ */

.quiz-container {
    max-width: 900px;
    margin: 0 auto;
}

.quiz-header-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding: 1.5rem 2rem;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.08) 0%, rgba(255, 255, 255, 0.04) 100%);
    backdrop-filter: blur(var(--blur-lg));
    border: var(--border-subtle);
    border-radius: 16px;
    box-shadow: var(--shadow-sm);
}

.quiz-info h2 {
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.question-counter {
    color: var(--text-tertiary);
    font-size: 0.9rem;
}

.timer-container {
    display: flex;
    align-items: center;
}

.timer {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: linear-gradient(135deg, rgba(239, 68, 68, 0.15) 0%, rgba(239, 68, 68, 0.08) 100%);
    border: 1px solid rgba(239, 68, 68, 0.3);
    border-radius: 10px;
    color: #fca5a5;
    font-size: 1rem;
    font-weight: 700;
    backdrop-filter: blur(var(--blur-sm));
}

.question-container {
    margin-bottom: 2rem;
}

.question-text {
    margin-bottom: 2rem;
}

.question-text h3 {
    font-size: 1.4rem;
    line-height: 1.7;
    color: var(--text-primary);
    font-weight: 600;
}

.options-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    margin-bottom: 2rem;
}

.option-item {
    display: flex;
    align-items: center;
    padding: 1.2rem 1.5rem;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);
    border: var(--border-subtle);
    border-radius: 12px;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(var(--blur-sm));
}

.option-item:hover {
    border-color: rgba(59, 130, 246, 0.4);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.08) 0%, rgba(59, 130, 246, 0.03) 100%);
    transform: translateX(4px);
}

.option-item.selected {
    border-color: rgba(59, 130, 246, 0.6);
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.15) 0%, rgba(59, 130, 246, 0.08) 100%);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1), inset 0 1px 2px rgba(255, 255, 255, 0.1);
}

.option-item input[type="radio"] {
    margin-right: 1rem;
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: #60a5fa;
}

.option-label {
    font-weight: 700;
    color: #60a5fa;
    margin-right: 0.5rem;
}

.option-text {
    flex: 1;
    color: var(--text-primary);
}

.question-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
}

/* ============================================
   Results Page
   ============================================ */

.result-container {
    max-width: 1200px;
    margin: 0 auto;
}

.result-header {
    text-align: center;
    margin-bottom: 3rem;
}

.result-header h1 {
    font-size: 2.2rem;
    margin-bottom: 0.5rem;
    color: var(--text-primary);
    font-weight: 700;
    letter-spacing: -0.02em;
}

.result-subtitle {
    color: var(--text-secondary);
    font-size: 1rem;
}

.result-stats {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
    margin-bottom: 3rem;
}

.score-circle {
    display: flex;
    justify-content: center;
    align-items: center;
    padding: 2rem;
}

.score-ring {
    position: relative;
    width: 180px;
    height: 180px;
}

.progress-ring {
    transform: rotate(-90deg);
}

.progress-ring-circle {
    fill: none;
    stroke: #60a5fa;
    stroke-width: 8;
    stroke-linecap: round;
}

.score-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}

.score-value {
    font-size: 2.8rem;
    font-weight: 700;
    color: #60a5fa;
}

.score-total {
    font-size: 1.2rem;
    color: var(--text-secondary);
}

.score-percentage {
    font-size: 1rem;
    color: var(--text-tertiary);
    margin-top: 0.5rem;
}

.stats-breakdown {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.stat-item {
    display: flex;
    align-items: center;
    gap: 1.5rem;
    padding: 1.5rem;
    background: var(--glass-dark);
    border-radius: 12px;
    border: var(--border-subtle);
}

.stat-icon {
    width: 50px;
    height: 50px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 700;
    flex-shrink: 0;
}

.stat-icon.correct {
    background: var(--success-light);
    color: #6ee7b7;
    border: 2px solid rgba(16, 185, 129, 0.4);
}

.stat-icon.wrong {
    background: var(--error-light);
    color: #fca5a5;
    border: 2px solid rgba(239, 68, 68, 0.4);
}

.stat-icon.unanswered {
    background: rgba(148, 163, 184, 0.1);
    color: var(--text-tertiary);
    border: 2px solid rgba(148, 163, 184, 0.3);
}

.stat-details {
    flex: 1;
}

.stat-number {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-primary);
}

.stat-label {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-top: 0.3rem;
}

.results-table-container {
    margin-bottom: 2rem;
}

.table-title {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    font-weight: 700;
}

.results-table {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.result-row {
    padding: 1.5rem;
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.05) 0%, rgba(255, 255, 255, 0.02) 100%);
    border: var(--border-subtle);
    border-radius: 12px;
    border-left: 4px solid;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.result-row:hover {
    background: linear-gradient(135deg, rgba(255, 255, 255, 0.08) 0%, rgba(255, 255, 255, 0.04) 100%);
    border-color: rgba(255, 255, 255, 0.15);
}

.result-row.correct-row {
    border-left-color: rgba(16, 185, 129, 0.5);
}

.result-row.wrong-row {
    border-left-color: rgba(239, 68, 68, 0.5);
}

.result-question {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.question-number {
    font-weight: 700;
    color: #60a5fa;
    min-width: 40px;
}

.result-answers {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.answer-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
    flex-wrap: wrap;
}

.answer-label {
    color: var(--text-tertiary);
    min-width: 120px;
    font-weight: 500;
    font-size: 0.9rem;
}

.answer-value {
    padding: 0.5rem 0.75rem;
    border-radius: 8px;
    font-weight: normal;
    flex: 1;
    min-width: 250px;
    word-wrap: break-word;
    overflow-wrap: break-word;
    font-size: 0.9rem;
}

.answer-value.correct {
    background: var(--success-light);
    color: #6ee7b7;
    border: 1px solid rgba(16, 185, 129, 0.3);
}

.answer-value.wrong {
    background: var(--error-light);
    color: #fca5a5;
    border: 1px solid rgba(239, 68, 68, 0.3);
}

.result-actions {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
    margin-top: 2rem;
}

/* ============================================
   Coding Challenge
   ============================================ */

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

.coding-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}

.coding-description {
    max-height: calc(100vh - 200px);
    overflow-y: auto;
    padding-right: 1rem;
}

.coding-description::-webkit-scrollbar {
    width: 6px;
}

.coding-description::-webkit-scrollbar-track {
    background: transparent;
}

.coding-description::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.15);
    border-radius: 3px;
}

.coding-description::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.25);
}

.challenge-meta {
    margin: 1rem 0;
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

.challenge-content {
    margin-top: 1.5rem;
}

.challenge-content p {
    line-height: 1.8;
    color: var(--text-secondary);
    margin-bottom: 1.5rem;
}

.challenge-examples {
    margin-top: 2rem;
}

.challenge-examples h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-weight: 700;
}

.example-box {
    background: var(--glass-dark);
    padding: 1.25rem;
    border-radius: 12px;
    border: var(--border-subtle);
    margin-bottom: 1rem;
}

.example-row {
    margin: 0.5rem 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.example-row code {
    color: #60a5fa;
    background: rgba(59, 130, 246, 0.1);
    padding: 0.25rem 0.6rem;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.85rem;
}

.coding-editor {
    display: flex;
    flex-direction: column;
}

.editor-header h3 {
    color: var(--text-primary);
    margin-bottom: 1rem;
    font-weight: 700;
}

.code-editor {
    width: 100%;
    padding: 1.2rem;
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.6) 0%, rgba(15, 23, 42, 0.4) 100%);
    border: var(--border-subtle);
    border-radius: 12px;
    color: var(--text-primary);
    font-family: 'Courier New', 'Monaco', monospace;
    font-size: 0.9rem;
    line-height: 1.6;
    resize: vertical;
    min-height: 300px;
    margin-bottom: 1rem;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    backdrop-filter: blur(var(--blur-sm));
}

.code-editor::placeholder {
    color: var(--text-tertiary);
}

.code-editor:focus {
    outline: none;
    border-color: rgba(59, 130, 246, 0.5);
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.8) 0%, rgba(15, 23, 42, 0.6) 100%);
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.1), inset 0 1px 2px rgba(255, 255, 255, 0.05);
}

.editor-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 1rem;
}

.output-area {
    min-height: 120px;
    padding: 1.2rem;
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.6) 0%, rgba(15, 23, 42, 0.4) 100%);
    border: var(--border-subtle);
    border-radius: 12px;
    font-family: 'Courier New', 'Monaco', monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    color: var(--text-secondary);
    backdrop-filter: blur(var(--blur-sm));
    overflow-y: auto;
}

.output-info {
    color: var(--text-tertiary);
}

.output-error {
    color: #fca5a5;
}

/* ============================================
   Utilities
   ============================================ */

.empty-state {
    text-align: center;
    padding: 3rem 2rem;
    margin-top: 2rem;
    border: var(--border-subtle);
    border-radius: 16px;
    background: var(--glass-dark);
}

.empty-state p {
    color: var(--text-secondary);
}

.catalog-grid {
    margin-top: 1.5rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 1.5rem;
}

.catalog-card {
    padding: 1.5rem;
    min-height: 200px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

.catalog-card.highlight {
    border: 1px solid rgba(59, 130, 246, 0.4);
    box-shadow: 0 0 0 1px rgba(59, 130, 246, 0.2), 0 8px 20px rgba(59, 130, 246, 0.1);
}

.catalog-head {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}

.catalog-meta {
    display: flex;
    justify-content: space-between;
    margin-top: 1rem;
    font-size: 0.85rem;
    color: var(--text-tertiary);
}

.filter-panel {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
    padding: 2rem;
    background: var(--glass-dark);
    border-radius: 16px;
    border: var(--border-subtle);
}

.filter-group label {
    display: block;
    margin-bottom: 0.75rem;
    font-size: 0.85rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-secondary);
    font-weight: 600;
}

.filter-actions {
    display: flex;
    align-items: flex-end;
    gap: 0.75rem;
}

/* ============================================
   Responsive Design
   ============================================ */

@media (max-width: 1024px) {
    .coding-layout {
        grid-template-columns: 1fr;
    }
    
    .result-stats {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .main-content {
        padding: 1.5rem;
    }
    
    .navbar {
        padding: 0.75rem 1.5rem;
    }
    
    .nav-links {
        gap: 1.5rem;
        font-size: 0.85rem;
    }
    
    .landing-title {
        font-size: 2.2rem;
    }
    
    .dashboard-title {
        font-size: 1.8rem;
    }
    
    .stats-grid {
        grid-template-columns: 1fr;
    }
    
    .action-cards {
        grid-template-columns: 1fr;
    }
    
    .quiz-grid,
    .challenge-grid {
        grid-template-columns: 1fr;
    }
    
    .quiz-header-bar {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .recent-item {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .flash-messages {
        right: 10px;
        left: 10px;
    }
    
    .flash-message {
        min-width: auto;
    }
}

@media (max-width: 480px) {
    .landing-title {
        font-size: 1.8rem;
    }
    
    .landing-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
    }
    
    .page-header h1 {
        font-size: 1.8rem;
    }
    
    .auth-card {
        max-width: 100%;
    }
    
    .quiz-grid,
    .challenge-grid,
    .stats-grid,
    .action-cards {
        grid-template-columns: 1fr;
    }
}

/* ============================================
   Print Styles
   ============================================ */

@media print {
    .navbar,
    .flash-messages,
    .btn-start,
    .question-nav {
        display: none;
    }
    
    .glass-card {
        box-shadow: none;
        border: 1px solid #ddd;
    }
}