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

:root {
    --primary-gradient: linear-gradient(135deg, #2c3e50 0%, #34495e 100%);
    --secondary-gradient: linear-gradient(135deg, #636e72 0%, #74b9ff 100%);
    --success-gradient: linear-gradient(135deg, #00b894 0%, #00cec9 100%);
    --danger-gradient: linear-gradient(135deg, #e17055 0%, #fdcb6e 100%);
    --warning-gradient: linear-gradient(135deg, #fdcb6e 0%, #e17055 100%);
    --accent-color: #74b9ff;
    
    --bg-primary: #0a0e27;
    --bg-secondary: #141835;
    --bg-card: rgba(255, 255, 255, 0.06);
    --bg-glass: rgba(255, 255, 255, 0.03);
    --text-primary: #e8eaed;
    --text-secondary: #9aa0a6;
    --text-muted: #70757a;
    --border-color: rgba(255, 255, 255, 0.08);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.2);
    --shadow-subtle: 0 2px 8px rgba(0, 0, 0, 0.1);
    --border-radius: 12px;
    --border-radius-lg: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Light Theme */
[data-theme="light"] {
    --primary-gradient: linear-gradient(135deg, #3498db 0%, #2980b9 100%);
    --secondary-gradient: linear-gradient(135deg, #74b9ff 0%, #0984e3 100%);
    --success-gradient: linear-gradient(135deg, #00b894 0%, #00cec9 100%);
    --danger-gradient: linear-gradient(135deg, #e17055 0%, #fdcb6e 100%);
    --warning-gradient: linear-gradient(135deg, #fdcb6e 0%, #e17055 100%);
    --accent-color: #3498db;
    
    --bg-primary: #f1f3f7;
    --bg-secondary: #ffffff;
    --bg-card: rgba(255, 255, 255, 0.95);
    --bg-glass: rgba(248, 250, 253, 0.8);
    --text-primary: #1a1a1a;
    --text-secondary: #4a5568;
    --text-muted: #718096;
    --border-color: rgba(74, 85, 104, 0.15);
    --shadow: 0 8px 32px rgba(74, 85, 104, 0.12);
    --shadow-subtle: 0 2px 8px rgba(74, 85, 104, 0.08);
}

[data-theme="light"] body {
    background: linear-gradient(135deg, #f1f3f7 0%, #e8f0fe 100%);
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(52, 152, 219, 0.08) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(116, 185, 255, 0.12) 0%, transparent 50%),
        radial-gradient(circle at 50% 50%, rgba(232, 240, 254, 0.3) 0%, transparent 70%);
}

body {
    font-family: 'Inter', 'Segoe UI', -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
    height: 100vh;
    font-weight: 400;
    line-height: 1.5;
    background-image: 
        radial-gradient(circle at 20% 80%, rgba(116, 185, 255, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(44, 62, 80, 0.05) 0%, transparent 50%);
}

.app-container {
    position: relative;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header Styles */
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 2rem;
    backdrop-filter: blur(20px);
    background: var(--bg-glass);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 100;
}

.logo {
    display: flex;
    align-items: center;
    gap: 1rem;
    cursor: pointer;
    transition: var(--transition);
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius-lg);
    position: relative;
    overflow: hidden;
}

.logo::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
    transition: left 0.5s ease;
}

.logo:hover::before {
    left: 100%;
}

.logo:hover {
    background: var(--bg-card);
    transform: translateY(-2px);
    box-shadow: var(--shadow-subtle);
}

.logo-icon {
    position: relative;
}

.brain-wrapper {
    position: relative;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.brain-wrapper i {
    font-size: 1.8rem;
    color: var(--accent-color);
    z-index: 2;
    position: relative;
}

.logo-pulse {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    border: 2px solid var(--accent-color);
    border-radius: 50%;
    opacity: 0.3;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0% { transform: translate(-50%, -50%) scale(0.8); opacity: 0.8; }
    50% { transform: translate(-50%, -50%) scale(1.2); opacity: 0.2; }
    100% { transform: translate(-50%, -50%) scale(1.4); opacity: 0; }
}

.logo-text {
    display: flex;
    flex-direction: column;
    gap: 0.1rem;
}

.brand-name {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.02em;
    line-height: 1;
}

.brand-tagline {
    font-size: 0.75rem;
    color: var(--text-secondary);
    font-weight: 500;
    letter-spacing: 0.05em;
    font-style: italic;
    position: relative;
    overflow: hidden;
}

.brand-tagline::after {
    content: '|';
    animation: blink 1s infinite;
    font-style: normal;
    font-weight: 300;
}

@keyframes blink {
    0%, 50% { opacity: 1; }
    51%, 100% { opacity: 0; }
}

.header-controls {
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.progress-indicator {
    position: relative;
    display: none;
}

.progress-indicator.active {
    display: block;
}

.progress-ring {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
}

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

.progress-ring-circle {
    stroke-dasharray: 87.96;
    stroke-dashoffset: 87.96;
    transition: stroke-dashoffset 0.3s ease;
    opacity: 0.3;
}

.progress-text {
    position: absolute;
    font-size: 0.7rem;
    font-weight: 600;
    color: var(--accent-color);
}

.theme-toggle {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    min-width: 44px;
    min-height: 44px;
}

.sound-toggle {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    cursor: pointer;
    transition: var(--transition);
    color: var(--text-primary);
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    min-width: 44px;
    min-height: 44px;
}

.toggle-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: var(--accent-color);
    opacity: 0;
    transition: var(--transition);
}

.theme-toggle:hover .toggle-bg {
    opacity: 0.1;
}

.sound-toggle:hover .toggle-bg {
    opacity: 0.1;
}

.theme-toggle:hover {
    background: var(--bg-secondary);
    border-color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-subtle);
}

.sound-toggle:hover {
    background: var(--bg-secondary);
    border-color: var(--accent-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-subtle);
}

.theme-toggle i {
    font-size: 1.1rem;
    z-index: 2;
    position: relative;
    transition: var(--transition);
}

.sound-toggle i {
    font-size: 1.1rem;
    z-index: 2;
    position: relative;
    transition: var(--transition);
}

.theme-toggle:hover i {
    transform: scale(1.1);
    color: var(--accent-color);
}

.sound-toggle:hover i {
    transform: scale(1.1);
    color: var(--accent-color);
}

.sound-toggle.muted i {
    color: var(--text-muted);
}

.score-display {
    display: flex;
    align-items: center;
    gap: 1rem;
    background: var(--bg-card);
    padding: 0.75rem 1.25rem;
    border-radius: var(--border-radius-lg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-subtle);
    position: relative;
}

.score-icon {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
}

.score-icon i {
    color: var(--accent-color);
    font-size: 1.2rem;
    z-index: 2;
    position: relative;
}

.score-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 24px;
    height: 24px;
    background: var(--accent-color);
    border-radius: 50%;
    opacity: 0.2;
    filter: blur(8px);
    animation: glow 2s ease-in-out infinite alternate;
}

@keyframes glow {
    from { transform: translate(-50%, -50%) scale(0.8); opacity: 0.2; }
    to { transform: translate(-50%, -50%) scale(1.2); opacity: 0.4; }
}

.score-info {
    display: flex;
    flex-direction: column;
    gap: 0.1rem;
}

.score-label {
    font-size: 0.65rem;
    color: var(--text-secondary);
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
    line-height: 1;
}

.score-value {
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--text-primary);
    line-height: 1;
}

/* Main Content */
.main-content {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
    min-height: calc(100vh - 120px);
    overflow: hidden;
}

.screen {
    display: none;
    width: 100%;
    max-width: 1200px;
    animation: slideIn 0.6s ease-out;
}

.screen.active {
    display: block;
}

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

/* Welcome Screen */
.welcome-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem;
}

.welcome-hero {
    display: flex;
    align-items: center;
    gap: 3rem;
    margin-bottom: 4rem;
    background: var(--bg-card);
    padding: 3rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    backdrop-filter: blur(20px);
}

.hero-icon {
    flex-shrink: 0;
}

.icon-layers {
    position: relative;
    width: 120px;
    height: 120px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.main-icon {
    font-size: 4rem;
    color: var(--accent-color);
    z-index: 3;
    position: relative;
}

.icon-bg {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80px;
    height: 80px;
    background: var(--accent-color);
    border-radius: 50%;
    opacity: 0.1;
    z-index: 1;
}

.icon-ring {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 100px;
    height: 100px;
    border: 2px solid var(--accent-color);
    border-radius: 50%;
    opacity: 0.3;
    z-index: 2;
    animation: rotate 8s linear infinite;
}

@keyframes rotate {
    from { transform: translate(-50%, -50%) rotate(0deg); }
    to { transform: translate(-50%, -50%) rotate(360deg); }
}

.hero-content {
    flex: 1;
}

.hero-title {
    margin-bottom: 1.5rem;
}

.title-main {
    display: block;
    font-size: 3rem;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.04em;
    line-height: 0.9;
    margin-bottom: 0.5rem;
}

.title-sub {
    display: block;
    font-size: 2rem;
    font-weight: 400;
    color: var(--accent-color);
    letter-spacing: -0.02em;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--text-secondary);
    line-height: 1.6;
    max-width: 500px;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
    margin-bottom: 2.5rem;
}

.stat-item {
    background: var(--bg-glass);
    padding: 1.25rem;
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.stat-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    background: var(--bg-card);
}

.stat-item i {
    display: block;
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--accent-color);
    opacity: 0.8;
}

.stat-item span {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-secondary);
}

.start-btn {
    background: var(--accent-color);
    border: none;
    padding: 1rem 2.5rem;
    border-radius: var(--border-radius);
    color: white;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin: 0 auto;
    box-shadow: var(--shadow-subtle);
}

.start-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    background: #5dade2;
}

/* Quiz Screen */
.quiz-container {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.progress-container {
    flex: 1;
    min-width: 200px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: var(--success-gradient);
    border-radius: 10px;
    transition: width 0.3s ease;
    width: 10%;
}

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

.timer {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--bg-card);
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    color: var(--text-primary);
    font-weight: 500;
    box-shadow: var(--shadow-subtle);
    border: 1px solid var(--border-color);
}

.question-card {
    background: var(--bg-glass);
    border-radius: var(--border-radius);
    padding: 2rem;
    border: 1px solid var(--border-color);
}

.question-card h2 {
    font-size: 1.375rem;
    font-weight: 500;
    margin-bottom: 2rem;
    line-height: 1.5;
    color: var(--text-primary);
    letter-spacing: -0.01em;
}

.options-container {
    display: grid;
    gap: 1rem;
}

.option {
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 1rem 1.5rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 1rem;
    font-weight: 400;
}

.option:hover {
    background: var(--bg-card);
    border-color: var(--accent-color);
    transform: translateX(3px);
}

.option.selected {
    background: var(--accent-color);
    border-color: var(--accent-color);
    color: white;
    box-shadow: var(--shadow-subtle);
}

.option.correct {
    background: var(--success-gradient);
    border-color: transparent;
    animation: correctAnswer 0.4s ease;
}

.option.wrong {
    background: var(--danger-gradient);
    border-color: transparent;
    animation: wrongAnswer 0.4s ease;
}

@keyframes correctAnswer {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

@keyframes wrongAnswer {
    0% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
    100% { transform: translateX(0); }
}

.option-letter {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    flex-shrink: 0;
}

/* Results Screen */
.results-card {
    background: var(--bg-card);
    backdrop-filter: blur(20px);
    border-radius: var(--border-radius-lg);
    padding: 3rem;
    text-align: center;
    box-shadow: var(--shadow);
    border: 1px solid var(--border-color);
}

.results-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
    color: var(--accent-color);
    opacity: 0.9;
}

.results-card h1 {
    font-size: 2.25rem;
    font-weight: 600;
    margin-bottom: 2rem;
    color: var(--text-primary);
    letter-spacing: -0.03em;
}

.score-circle {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    background: var(--bg-card);
    border: 2px solid var(--accent-color);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 2rem;
    box-shadow: var(--shadow);
    position: relative;
}

.score-inner {
    text-align: center;
}

.score-inner #final-score {
    font-size: 2.5rem;
    font-weight: 600;
    display: block;
    color: var(--accent-color);
}

.score-total {
    font-size: 1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}

.stat {
    background: rgba(255, 255, 255, 0.05);
    padding: 1rem;
    border-radius: 15px;
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.stat i {
    display: block;
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.stat:nth-child(1) i { color: var(--accent-color); }
.stat:nth-child(2) i { color: #e17055; }
.stat:nth-child(3) i { color: #00b894; }

.results-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

.retry-btn, .share-btn {
    background: var(--accent-color);
    border: none;
    padding: 0.875rem 1.75rem;
    border-radius: var(--border-radius);
    color: white;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    box-shadow: var(--shadow-subtle);
}

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

.retry-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    background: #5dade2;
}

.share-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow);
    background: var(--bg-glass);
}



/* Light theme specific card styling */
[data-theme="light"] .welcome-card,
[data-theme="light"] .quiz-container,
[data-theme="light"] .results-card {
    background: rgba(255, 255, 255, 0.9);
    border: 1px solid rgba(74, 85, 104, 0.12);
    box-shadow: 0 10px 40px rgba(74, 85, 104, 0.1);
}

[data-theme="light"] .question-card {
    background: rgba(248, 250, 253, 0.7);
    border: 1px solid rgba(74, 85, 104, 0.1);
}

[data-theme="light"] .option {
    background: rgba(248, 250, 253, 0.8);
    border: 1px solid rgba(74, 85, 104, 0.12);
}

[data-theme="light"] .option:hover {
    background: rgba(255, 255, 255, 0.9);
    border-color: var(--accent-color);
    box-shadow: 0 4px 12px rgba(52, 152, 219, 0.15);
}

[data-theme="light"] .stat-item {
    background: rgba(248, 250, 253, 0.8);
    border: 1px solid rgba(74, 85, 104, 0.1);
}

[data-theme="light"] .stat-item:hover {
    background: rgba(255, 255, 255, 0.9);
    box-shadow: 0 6px 20px rgba(74, 85, 104, 0.1);
}



@keyframes float {
    0%, 100% {
        transform: translateY(0px);
        opacity: 0.1;
    }
    50% {
        transform: translateY(-10px);
        opacity: 0.3;
    }
}

/* Responsive Design */
@media (max-width: 768px) {
    .header {
        padding: 1rem;
    }
    
    .brand-name {
        font-size: 1.2rem;
    }
    
    .brand-tagline {
        font-size: 0.65rem;
    }
    
    .header-controls {
        gap: 1rem;
    }
    
    .progress-indicator {
        display: none;
    }
    
    .theme-toggle {
        width: 40px;
        height: 40px;
        padding: 0.625rem;
    }
    
    .welcome-container {
        padding: 1rem;
    }
    
    .welcome-hero {
        flex-direction: column;
        text-align: center;
        gap: 2rem;
        padding: 2rem;
    }
    
    .title-main {
        font-size: 2.2rem;
    }
    
    .title-sub {
        font-size: 1.5rem;
    }
    
    .features-showcase {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        margin-bottom: 3rem;
    }
    
    .feature-card {
        padding: 1.5rem;
    }
    
    .quick-stats {
        gap: 0.8rem;
        padding: 2rem 1rem;
        max-width: 100%;
        width: 100%;
        flex-direction: row;
        flex-wrap: nowrap;
        display: flex;
        justify-content: space-around;
        align-items: center;
        overflow: visible;
    }
    
    .stat {
        padding: 0;
        flex: 1 1 33.333%;
        text-align: center;
        display: flex;
        flex-direction: column;
        align-items: center;
        min-width: 0;
        max-width: 33.333%;
    }
    
    .stat-number {
        font-size: 1.5rem;
        margin-bottom: 0.5rem;
    }
    
    .stat-label {
        font-size: 0.65rem;
        white-space: nowrap;
    }
    
    .stat-divider {
        height: 40px;
        width: 1px;
        flex-shrink: 0;
    }
    
    .quiz-container, .results-card {
        padding: 2rem 1.5rem;
    }
    
    .quiz-header {
        flex-direction: column;
        align-items: stretch;
    }
    
    .timer {
        align-self: center;
    }
    
    .results-actions {
        flex-direction: column;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 1rem;
    }
    
    .quick-stats {
        gap: 0.5rem;
        padding: 1.5rem 0.75rem;
        display: flex;
        justify-content: space-around;
        align-items: center;
        flex-wrap: nowrap;
        width: 100%;
        overflow: visible;
    }
    
    .stat {
        padding: 0;
        flex: 1 1 33.333%;
        text-align: center;
        display: flex;
        flex-direction: column;
        align-items: center;
        min-width: 0;
        max-width: 33.333%;
    }
    
    .stat-number {
        font-size: 1.4rem;
        margin-bottom: 0.4rem;
    }
    
    .stat-label {
        font-size: 0.65rem;
        white-space: nowrap;
    }
    
    .stat-divider {
        height: 35px;
        width: 1px;
        flex-shrink: 0;
    }
    
    .question-card h2 {
        font-size: 1.3rem;
    }
    
    .option {
        padding: 0.8rem 1rem;
    }
    
    .score-circle {
        width: 120px;
        height: 120px;
    }
    
    .score-inner #final-score {
        font-size: 2.5rem;
    }
}

.features-showcase {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
    margin-bottom: 4rem;
}

.feature-card {
    background: var(--bg-glass);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-lg);
    padding: 2rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.05), transparent);
    transition: left 0.6s ease;
}

.feature-card:hover::before {
    left: 100%;
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow);
    background: var(--bg-card);
}

.feature-icon {
    position: relative;
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.5rem;
}

.feature-icon i {
    font-size: 2rem;
    color: var(--accent-color);
    z-index: 2;
    position: relative;
}

.feature-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 40px;
    height: 40px;
    background: var(--accent-color);
    border-radius: 50%;
    opacity: 0.15;
    filter: blur(12px);
    animation: glow 3s ease-in-out infinite alternate;
}

.feature-content h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 0.5rem;
    letter-spacing: -0.01em;
}

.feature-content p {
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.5;
    margin-bottom: 1rem;
}

.feature-badge {
    display: inline-block;
    background: var(--accent-color);
    color: white;
    padding: 0.4rem 0.8rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.02em;
    text-transform: uppercase;
}

.action-section {
    text-align: center;
}

.start-btn.primary {
    background: var(--accent-color);
    border: none;
    padding: 1.25rem 3rem;
    border-radius: var(--border-radius-lg);
    color: white;
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
}

.start-btn.primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 12px 40px rgba(52, 152, 219, 0.3);
    background: #2980b9;
}

.btn-text {
    position: relative;
    z-index: 2;
}

.btn-icon {
    position: relative;
    z-index: 2;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 24px;
    height: 24px;
    background: rgba(255,255,255,0.2);
    border-radius: 50%;
    transition: var(--transition);
}

.start-btn.primary:hover .btn-icon {
    transform: translateX(4px);
}

.btn-shimmer {
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.6s ease;
}

.start-btn.primary:hover .btn-shimmer {
    left: 100%;
}

.quick-stats {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1.5rem;
    background: var(--bg-glass);
    padding: 3rem 3.5rem;
    border-radius: var(--border-radius-lg);
    border: 1px solid var(--border-color);
    max-width: 650px;
    margin: 0 auto;
}

.stat {
    text-align: center;
    flex: 1;
    padding: 0 1.25rem;
}

.stat-number {
    display: block;
    font-size: 2.2rem;
    font-weight: 700;
    color: var(--accent-color);
    line-height: 1;
    margin-bottom: 0.75rem;
}

.stat-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    line-height: 1.2;
    white-space: nowrap;
}

.stat-divider {
    width: 1px;
    height: 50px;
    background: var(--border-color);
    opacity: 0.3;
    flex-shrink: 0;
}

/* Creative personality touches */
.welcome-container {
    position: relative;
}



/* Glitch effect for developer personality */
.brand-name:hover {
    animation: glitch 0.3s ease-in-out;
}

@keyframes glitch {
    0% { transform: translateX(0); }
    20% { transform: translateX(-2px); }
    40% { transform: translateX(2px); }
    60% { transform: translateX(-1px); }
    80% { transform: translateX(1px); }
    100% { transform: translateX(0); }
}



/* Hidden dev signature */
.logo:active::after {
    content: 'Built by @YourName 👨‍💻';
    position: absolute;
    top: 100%;
    left: 0;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
    white-space: nowrap;
    box-shadow: var(--shadow);
    z-index: 1000;
}

/* Breathing animation for more life */
.hero-icon {
    animation: breathe 4s ease-in-out infinite;
}

@keyframes breathe {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}



/* Screen shake for wrong answers */
@keyframes shake {
    0%, 100% { transform: translateX(0); }
    10% { transform: translateX(-5px); }
    20% { transform: translateX(5px); }
    30% { transform: translateX(-5px); }
    40% { transform: translateX(5px); }
    50% { transform: translateX(-3px); }
    60% { transform: translateX(3px); }
    70% { transform: translateX(-2px); }
    80% { transform: translateX(2px); }
    90% { transform: translateX(-1px); }
}

/* Add some randomness to feature cards */
.feature-card:nth-child(1) {
    animation-delay: 0.1s;
}

.feature-card:nth-child(2) {
    animation-delay: 0.2s;
}

.feature-card:nth-child(3) {
    animation-delay: 0.3s;
}

/* Dynamic glow effect */
.start-btn.primary:hover {
    animation: dynamicGlow 2s ease-in-out infinite;
}

@keyframes dynamicGlow {
    0%, 100% { 
        box-shadow: var(--shadow), 0 0 20px rgba(102, 126, 234, 0.3);
    }
    50% { 
        box-shadow: var(--shadow), 0 0 30px rgba(102, 126, 234, 0.5);
    }
}

/* Loading message animations */
@keyframes loadingPulse {
    0% { 
        transform: translate(-50%, -50%) scale(0.8); 
        opacity: 0; 
    }
    50% { 
        transform: translate(-50%, -50%) scale(1.05); 
    }
    100% { 
        transform: translate(-50%, -50%) scale(1); 
        opacity: 1; 
    }
}

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

@keyframes notificationSlide {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.8) translateY(-20px);
    }
    100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1) translateY(0);
    }
}

/* Notification styles */
.notification {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    padding: 1rem 2rem;
    border-radius: 12px;
    font-size: 1.1rem;
    font-weight: 600;
    z-index: 1000;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
    backdrop-filter: blur(10px);
    color: white;
}

.notification.success {
    background: linear-gradient(135deg, #00b894, #00cec9);
}

.notification.wrong {
    background: linear-gradient(135deg, #e17055, #fdcb6e);
}

.notification.timeout {
    background: linear-gradient(135deg, #74b9ff, #0984e3);
}

.notification.encouragement {
    background: linear-gradient(135deg, #6c5ce7, #a29bfe);
}

/* Enhanced option hover effects */
.option:hover {
    transform: translateY(-2px) scale(1.02);
    box-shadow: 0 8px 25px rgba(116, 185, 255, 0.2);
}

.option:active {
    transform: translateY(0) scale(0.98);
}

/* Add pulse animation to timer when low */
.timer.warning {
    animation: timerPulse 1s infinite;
}

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

/* Enhanced score animation */
.score-display:hover .score-glow {
    opacity: 1;
    transform: scale(1.2);
}

/* Add celebration effect for correct answers */
@keyframes celebrate {
    0% { transform: scale(1); }
    25% { transform: scale(1.1) rotate(5deg); }
    50% { transform: scale(1.2) rotate(-5deg); }
    75% { transform: scale(1.1) rotate(3deg); }
    100% { transform: scale(1) rotate(0deg); }
}

.option.correct {
    animation: celebrate 0.6s ease;
}

.option.wrong {
    animation: shake 0.5s ease;
} 

@keyframes confettiFall {
    0% {
        transform: translateY(-10px) rotate(0deg);
        opacity: 1;
    }
    100% {
        transform: translateY(100vh) rotate(720deg);
        opacity: 0;
    }
}

/* Enhanced quiz card hover effect */
.question-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 15px 40px rgba(116, 185, 255, 0.15);
}

/* More engaging welcome screen animations */
.welcome-hero {
    animation: gentleFloat 6s ease-in-out infinite;
}

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

/* Personalized result message styling */
#personal-message {
    background: var(--bg-glass);
    border-radius: var(--border-radius);
    padding: 1rem 1.5rem;
    border-left: 4px solid var(--accent-color);
    margin: 1.5rem 0;
    font-style: italic;
    animation: slideInFromBottom 0.5s ease;
}

@keyframes slideInFromBottom {
    0% {
        opacity: 0;
        transform: translateY(20px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Enhanced button interactions */
.start-btn.primary:hover .btn-icon {
    animation: bounceIcon 0.6s ease;
}

@keyframes bounceIcon {
    0%, 100% { transform: translateX(0); }
    50% { transform: translateX(10px); }
}

/* Loading state for transitions */
.screen {
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

.screen:not(.active) {
    pointer-events: none;
}

/* Enhanced progress ring animation */
.progress-ring-circle {
    transition: stroke-dashoffset 0.5s ease, opacity 0.3s ease;
}

/* Better focus states for accessibility */
.option:focus,
.start-btn:focus,
.theme-toggle:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* Animated background elements */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: 
        radial-gradient(circle at 20% 80%, rgba(116, 185, 255, 0.03) 0%, transparent 50%),
        radial-gradient(circle at 80% 20%, rgba(44, 62, 80, 0.05) 0%, transparent 50%);
    animation: backgroundFloat 20s ease-in-out infinite;
    pointer-events: none;
    z-index: -1;
}

@keyframes backgroundFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(-10px, -5px) scale(1.02); }
} 

@keyframes particleExplosion {
    0% {
        transform: translate(-50%, -50%) scale(1);
        opacity: 1;
    }
    100% {
        transform: translate(-50%, -50%) translate(calc(cos(var(--angle)) * 100px), calc(sin(var(--angle)) * 100px)) scale(0);
        opacity: 0;
    }
}

@keyframes gentlePulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.02); }
}

@keyframes subtleShake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-3px); }
    75% { transform: translateX(3px); }
}

/* Enhanced option selection feedback */
.option {
    position: relative;
    overflow: hidden;
}

.option::after {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.1), transparent);
    transition: left 0.5s ease;
}

.option:hover::after {
    left: 100%;
}

/* Enhanced timer visual feedback */
.timer {
    position: relative;
    overflow: hidden;
}

.timer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: radial-gradient(circle, transparent 30%, var(--accent-color) 70%);
    opacity: 0;
    transform: scale(0);
    transition: all 0.3s ease;
}

.timer.warning::before {
    opacity: 0.1;
    transform: scale(1);
    animation: timerWarning 1s ease infinite;
}

@keyframes timerWarning {
    0%, 100% { opacity: 0.1; transform: scale(1); }
    50% { opacity: 0.3; transform: scale(1.1); }
}

/* Enhanced score display feedback */
.score-display {
    position: relative;
}

.score-display::before {
    content: '';
    position: absolute;
    top: -5px;
    left: -5px;
    right: -5px;
    bottom: -5px;
    background: linear-gradient(45deg, var(--accent-color), transparent, var(--accent-color));
    border-radius: inherit;
    opacity: 0;
    animation: scoreGlow 2s ease infinite;
    z-index: -1;
}

@keyframes scoreGlow {
    0%, 100% { opacity: 0; transform: scale(0.95); }
    50% { opacity: 0.3; transform: scale(1.05); }
}