/* =====================================================
   EDVIBE LABS · QUANTUM CORE v3.0
   GLOBAL SCIENCE PLATFORM · MOBILE-OPTIMIZED DESIGN
   ===================================================== */

/* ----- 1. RESET & BASE ----- */
* { 
    margin: 0; 
    padding: 0; 
    box-sizing: border-box; 
}

body {
    font-family: 'Inter', sans-serif;
    background: #0a0c12;
    background-image: 
        radial-gradient(circle at 20% 30%, rgba(0,242,255,0.03) 0%, transparent 25%),
        radial-gradient(circle at 80% 70%, rgba(77,140,255,0.03) 0%, transparent 30%),
        linear-gradient(rgba(0,242,255,0.02) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0,242,255,0.02) 1px, transparent 1px);
    background-size: 100% 100%, 100% 100%, 40px 40px, 40px 40px;
    color: #ffffff;
    line-height: 1.5;
    min-height: 100vh;
    position: relative;
}

/* ----- 2. ANIMATIONS ----- */
@keyframes neonPulse {
    0%, 100% { box-shadow: 0 0 5px rgba(0,242,255,0.3), 0 0 20px rgba(0,242,255,0.1); }
    50% { box-shadow: 0 0 15px rgba(0,242,255,0.5), 0 0 30px rgba(0,242,255,0.2); }
}

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

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

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

/* ----- 3. PARTICLES ----- */
.particle-field {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
}

.particle {
    position: absolute;
    width: 2px;
    height: 2px;
    background: rgba(0,242,255,0.3);
    box-shadow: 0 0 8px #00f2ff;
    border-radius: 50%;
    animation: float 15s linear infinite;
}

/* ----- 4. LAYOUT ----- */
.container {
    max-width: 1300px;
    margin: 0 auto;
    padding: 0 20px;
    position: relative;
    z-index: 10;
}

/* ----- 5. QUANTUM STATUS BAR ----- */
.quantum-status {
    background: rgba(10,12,18,0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(0,242,255,0.2);
    border-radius: 60px;
    padding: 12px 20px;
    margin: 20px 0 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.quantum-badge {
    color: #00f2ff;
    font-weight: 700;
    letter-spacing: 2px;
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 0.9rem;
}

.live-dot {
    width: 8px;
    height: 8px;
    background: #00f2ff;
    border-radius: 50%;
    box-shadow: 0 0 15px #00f2ff;
    animation: glowPulse 2s infinite;
}

/* ----- 6. NAVIGATION ----- */
.quantum-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 0;
    margin-bottom: 20px;
    border-bottom: 1px solid rgba(0,242,255,0.15);
    flex-wrap: wrap;
    gap: 15px;
}

.nav-logo h1 {
    font-size: 1.8rem;
    font-weight: 900;
    background: linear-gradient(145deg, #ffffff, #00f2ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    gap: 15px;
    align-items: center;
    flex-wrap: wrap;
}

.nav-link {
    color: rgba(255,255,255,0.8);
    text-decoration: none;
    font-weight: 600;
    font-size: 0.85rem;
    letter-spacing: 1px;
    padding: 8px 0;
    position: relative;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.nav-link:hover {
    color: #00f2ff;
}

.nav-link.active {
    color: #00f2ff;
    border-bottom: 2px solid #00f2ff;
}

.nav-link i {
    margin-right: 5px;
}

.auth-buttons {
    display: flex;
    gap: 8px;
}

.btn-login, .btn-register {
    padding: 6px 12px;
    border-radius: 30px;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.3s ease;
    font-size: 0.8rem;
    white-space: nowrap;
}

.btn-login {
    background: transparent;
    border: 1px solid #00f2ff;
    color: #00f2ff;
}

.btn-login:hover {
    background: rgba(0,242,255,0.1);
    box-shadow: 0 0 15px rgba(0,242,255,0.3);
}

.btn-register {
    background: linear-gradient(135deg, #00f2ff, #4d8cff);
    border: 1px solid rgba(255,255,255,0.2);
    color: #0a0c12;
}

.btn-register:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 20px rgba(0,242,255,0.4);
}

.user-menu {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.user-name {
    color: #00f2ff;
    font-weight: 600;
    font-size: 0.9rem;
}

.btn-logout {
    padding: 6px 12px;
    background: rgba(255,77,109,0.1);
    border: 1px solid #ff4d6d;
    border-radius: 30px;
    color: #ff4d6d;
    text-decoration: none;
    font-size: 0.75rem;
    transition: all 0.3s ease;
    white-space: nowrap;
}

.btn-logout:hover {
    background: rgba(255,77,109,0.2);
    box-shadow: 0 0 15px rgba(255,77,109,0.3);
}

/* ----- 7. USER STATS PANEL ----- */
.user-quantum-panel {
    background: rgba(20,24,31,0.7);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(0,242,255,0.15);
    border-radius: 28px;
    padding: 20px;
    margin-bottom: 30px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 20px;
    flex-wrap: wrap;
}

.user-avatar {
    width: 50px;
    height: 50px;
    background: linear-gradient(145deg, #0a2472, #00f2ff);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    border: 2px solid #00f2ff;
    box-shadow: 0 0 25px rgba(0,242,255,0.3);
}

.user-stats {
    display: flex;
    gap: 20px;
    flex-wrap: wrap;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-value {
    font-size: 1.2rem;
    font-weight: 800;
    color: #00f2ff;
}

.stat-label {
    font-size: 0.65rem;
    color: rgba(255,255,255,0.6);
    letter-spacing: 1px;
}

.xp-bar-container {
    width: 200px;
    max-width: 100%;
}

.xp-bar-label {
    display: flex;
    justify-content: space-between;
    font-size: 0.7rem;
    color: rgba(255,255,255,0.6);
    margin-bottom: 5px;
}

.xp-bar-bg {
    width: 100%;
    height: 10px;
    background: rgba(0,242,255,0.1);
    border-radius: 20px;
    border: 1px solid rgba(0,242,255,0.2);
    overflow: hidden;
}

.xp-bar-fill {
    width: 0%;
    height: 100%;
    background: linear-gradient(90deg, #00f2ff, #4d8cff);
    border-radius: 20px;
    box-shadow: 0 0 20px #00f2ff;
    transition: width 0.5s ease;
}

/* ----- 8. HERO SECTION ----- */
.quantum-hero {
    display: grid;
    grid-template-columns: 1.5fr 1fr;
    gap: 30px;
    margin-bottom: 60px;
    align-items: center;
}

.hero-title {
    font-size: 2.8rem;
    font-weight: 900;
    line-height: 1.1;
    margin-bottom: 20px;
    background: linear-gradient(145deg, #ffffff, #00f2ff);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-subtitle {
    font-size: 1rem;
    color: rgba(255,255,255,0.7);
    margin-bottom: 30px;
}

.hero-stats {
    display: flex;
    gap: 30px;
    flex-wrap: wrap;
}

.hero-stat {
    display: flex;
    flex-direction: column;
}

.hero-stat-number {
    font-size: 1.8rem;
    font-weight: 800;
    color: #00f2ff;
}

.quantum-core {
    background: rgba(20,24,31,0.5);
    border: 1px solid rgba(0,242,255,0.3);
    border-radius: 30px;
    padding: 30px;
    position: relative;
    overflow: hidden;
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

.quantum-core::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: conic-gradient(transparent, rgba(0,242,255,0.1), transparent);
    animation: spin 10s linear infinite;
}

/* ----- 9. SUBJECT CARDS (HOME PAGE) ----- */
.subject-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 50px;
}

.subject-card {
    background: rgba(20,24,31,0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid rgba(0,242,255,0.15);
    border-radius: 30px;
    padding: 25px 15px;
    text-align: center;
    transition: all 0.3s cubic-bezier(0.2, 0.9, 0.4, 1);
    cursor: pointer;
    position: relative;
    overflow: hidden;
    text-decoration: none;
    display: block;
}

.subject-card:hover {
    border-color: #00f2ff;
    box-shadow: 0 0 40px rgba(0,242,255,0.2);
    transform: translateY(-5px);
}

.subject-icon {
    font-size: 2.5rem;
    margin-bottom: 15px;
}

.subject-title {
    font-size: 1.5rem;
    font-weight: 800;
    margin-bottom: 10px;
}

.subject-count {
    color: rgba(255,255,255,0.6);
    font-size: 0.8rem;
    letter-spacing: 1px;
}

.physics-card .subject-icon { color: #00f2ff; }
.chemistry-card .subject-icon { color: #4eff8c; }
.biology-card .subject-icon { color: #ff4d6d; }

.physics-card .subject-title { color: #00f2ff; }
.chemistry-card .subject-title { color: #4eff8c; }
.biology-card .subject-title { color: #ff4d6d; }

/* ----- 10. FEATURED SECTION ----- */
.featured-section {
    background: rgba(20,24,31,0.5);
    border-radius: 30px;
    padding: 30px;
    margin-bottom: 50px;
    border: 1px solid rgba(0,242,255,0.1);
}

.section-title {
    font-size: 1.5rem;
    font-weight: 700;
    margin-bottom: 25px;
    display: flex;
    align-items: center;
    gap: 10px;
    flex-wrap: wrap;
}

.section-title i {
    color: #00f2ff;
}

.featured-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
}

.featured-item {
    background: rgba(10,12,18,0.6);
    border: 1px solid rgba(0,242,255,0.1);
    border-radius: 20px;
    padding: 20px;
    transition: all 0.3s ease;
}

.featured-item:hover {
    border-color: #00f2ff;
    box-shadow: 0 0 25px rgba(0,242,255,0.1);
}

/* ============ QUIZ INTERFACE STYLES ============ */

/* ----- 11. QUIZ SELECTION SCREEN ----- */
.quiz-selection-screen {
    background: rgba(20,24,31,0.7);
    backdrop-filter: blur(10px);
    border-radius: 32px;
    padding: 40px 30px;
    margin: 20px 0 40px;
    border: 1px solid rgba(0,242,255,0.1);
}

.quiz-selection-header {
    text-align: center;
    margin-bottom: 40px;
}

.subject-selection-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.subject-selection-card {
    background: rgba(255,255,255,0.03);
    border-radius: 24px;
    padding: 30px 20px;
    text-align: center;
    text-decoration: none;
    border: 1px solid rgba(255,255,255,0.05);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.subject-selection-card:hover {
    transform: translateY(-5px);
    border-color: currentColor;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.subject-selection-card.physics {
    color: #00f2ff;
}

.subject-selection-card.chemistry {
    color: #4eff8c;
}

.subject-selection-card.biology {
    color: #ff4d6d;
}

.subject-selection-card i {
    font-size: 3rem;
    margin-bottom: 20px;
    color: currentColor;
}

.subject-selection-card h4 {
    color: white;
    font-size: 1.2rem;
    margin-bottom: 10px;
}

.subject-selection-card p {
    color: rgba(255,255,255,0.6);
    font-size: 0.85rem;
    margin-bottom: 20px;
}

.start-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    background: rgba(255,255,255,0.05);
    border-radius: 40px;
    color: currentColor;
    font-size: 0.9rem;
    font-weight: 600;
    transition: all 0.3s ease;
}

.subject-selection-card:hover .start-badge {
    background: currentColor;
    color: #14181f;
}

.quiz-info-box {
    display: flex;
    justify-content: center;
    gap: 40px;
    flex-wrap: wrap;
    padding: 20px;
    background: rgba(255,255,255,0.02);
    border-radius: 60px;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 10px;
    color: rgba(255,255,255,0.8);
    font-size: 0.9rem;
}

.info-item i {
    font-size: 1.1rem;
}

/* ----- 12. ACTIVE QUIZ SCREEN ----- */
.active-quiz-screen {
    background: rgba(20,24,31,0.7);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: 32px;
    padding: 30px;
    margin: 20px 0 40px;
    border: 1px solid rgba(0,242,255,0.2);
    box-shadow: 0 20px 40px rgba(0,0,0,0.4);
}

.quiz-progress {
    margin-bottom: 30px;
}

.progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}

.subject-badge {
    padding: 8px 20px;
    border-radius: 40px;
    font-size: 0.9rem;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(0,242,255,0.1);
    border: 1px solid currentColor;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.question-counter {
    color: rgba(255,255,255,0.7);
    font-size: 0.9rem;
    font-weight: 600;
    background: rgba(255,255,255,0.05);
    padding: 6px 15px;
    border-radius: 30px;
}

.progress-bar-bg {
    width: 100%;
    height: 10px;
    background: rgba(255,255,255,0.1);
    border-radius: 20px;
    overflow: hidden;
    border: 1px solid rgba(0,242,255,0.2);
}

.progress-bar-fill {
    height: 100%;
    background: linear-gradient(90deg, #00f2ff, #4eff8c);
    border-radius: 20px;
    box-shadow: 0 0 15px #00f2ff;
    transition: width 0.5s ease;
}

.current-score {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 10px 25px;
    background: rgba(255,215,0,0.1);
    border: 1px solid #ffd700;
    border-radius: 40px;
    margin-bottom: 30px;
    color: #ffd700;
    font-weight: 700;
    font-size: 1rem;
}

.current-score i {
    font-size: 1.2rem;
}

.quiz-question-card {
    background: rgba(0,0,0,0.3);
    border: 1px solid rgba(0,242,255,0.2);
    border-radius: 28px;
    padding: 35px;
    margin-bottom: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.3);
}

.question-text {
    color: white;
    font-size: 1.3rem;
    font-weight: 600;
    line-height: 1.6;
    margin-bottom: 30px;
    padding-bottom: 25px;
    border-bottom: 1px solid rgba(0,242,255,0.2);
}

.options-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.quiz-option-btn {
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(0,242,255,0.2);
    border-radius: 20px;
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
    cursor: pointer;
    transition: all 0.3s ease;
    width: 100%;
    color: white;
    text-align: left;
    font-size: 1rem;
    position: relative;
    overflow: hidden;
}

.quiz-option-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(0,242,255,0.1), transparent);
    transition: left 0.5s ease;
}

.quiz-option-btn:hover::before {
    left: 100%;
}

.quiz-option-btn:hover {
    background: rgba(0,242,255,0.1);
    border-color: #00f2ff;
    transform: translateX(5px);
    box-shadow: 0 5px 20px rgba(0,242,255,0.2);
}

.quiz-option-btn.selected {
    background: rgba(0,242,255,0.15);
    border-color: #00f2ff;
    box-shadow: 0 0 30px rgba(0,242,255,0.3);
}

.option-letter {
    width: 45px;
    height: 45px;
    background: rgba(0,242,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 800;
    color: #00f2ff;
    font-size: 1.3rem;
    transition: all 0.3s ease;
    border: 1px solid rgba(0,242,255,0.3);
}

.quiz-option-btn:hover .option-letter {
    background: #00f2ff;
    color: #0a0c12;
    transform: scale(1.1);
}

.quiz-option-btn.selected .option-letter {
    background: #00f2ff;
    color: #0a0c12;
    box-shadow: 0 0 20px #00f2ff;
}

.option-text {
    flex: 1;
    font-size: 1rem;
    line-height: 1.5;
    font-weight: 500;
}

.quiz-controls {
    display: flex;
    justify-content: flex-end;
    margin-top: 20px;
}

.quit-quiz-btn {
    padding: 12px 30px;
    background: rgba(255,77,109,0.1);
    border: 1px solid #ff4d6d;
    border-radius: 40px;
    color: #ff4d6d;
    text-decoration: none;
    font-size: 0.95rem;
    font-weight: 600;
    transition: all 0.3s ease;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.quit-quiz-btn:hover {
    background: #ff4d6d;
    color: white;
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(255,77,109,0.3);
}

/* Physics specific colors for option letters */
.quiz-option-btn[value="A"]:hover .option-letter,
.quiz-option-btn[value="A"].selected .option-letter {
    background: #00f2ff;
}

.quiz-option-btn[value="B"]:hover .option-letter,
.quiz-option-btn[value="B"].selected .option-letter {
    background: #4eff8c;
}

.quiz-option-btn[value="C"]:hover .option-letter,
.quiz-option-btn[value="C"].selected .option-letter {
    background: #ff4d6d;
}

.quiz-option-btn[value="D"]:hover .option-letter,
.quiz-option-btn[value="D"].selected .option-letter {
    background: #ffd700;
}

/* ----- 13. QUIZ RESULTS SCREEN ----- */
.quiz-results-screen {
    background: rgba(20,24,31,0.7);
    backdrop-filter: blur(10px);
    border-radius: 32px;
    padding: 40px;
    margin: 20px 0 40px;
    border: 1px solid rgba(0,242,255,0.1);
}

.results-header {
    text-align: center;
    margin-bottom: 40px;
}

.results-circle {
    width: 200px;
    height: 200px;
    margin: 0 auto 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.circle-inner {
    width: 160px;
    height: 160px;
    background: #14181f;
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}

.percentage {
    font-size: 3rem;
    font-weight: 800;
    color: white;
    line-height: 1;
}

.score {
    color: rgba(255,255,255,0.6);
    font-size: 1rem;
    margin-top: 5px;
}

.results-stats {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 40px;
}

.result-stat {
    background: rgba(255,255,255,0.03);
    border-radius: 20px;
    padding: 20px;
    display: flex;
    align-items: center;
    gap: 15px;
}

.result-stat i {
    font-size: 2rem;
}

.result-stat .stat-label {
    color: rgba(255,255,255,0.5);
    font-size: 0.8rem;
    display: block;
}

.result-stat .stat-value {
    color: white;
    font-size: 1.5rem;
    font-weight: 700;
}

.results-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.results-btn {
    padding: 15px 30px;
    border-radius: 40px;
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 10px;
    transition: all 0.3s ease;
}

.results-btn.primary {
    background: linear-gradient(135deg, #00f2ff, #4eff8c);
    color: #14181f;
}

.results-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 30px rgba(0,242,255,0.3);
}

.results-btn.secondary {
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(0,242,255,0.3);
    color: #00f2ff;
}

.results-btn.secondary:hover {
    background: rgba(0,242,255,0.1);
}

.results-btn.tertiary {
    background: rgba(255,255,255,0.03);
    color: rgba(255,255,255,0.6);
}

.results-btn.tertiary:hover {
    background: rgba(255,255,255,0.05);
    color: white;
}

/* ----- 14. AUTH PAGES (LOGIN/REGISTER) ----- */
.auth-container {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 70vh;
    padding: 30px 0;
}

.auth-card {
    background: rgba(20,24,31,0.8);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid rgba(0,242,255,0.3);
    border-radius: 32px;
    padding: 40px 30px;
    width: 100%;
    max-width: 450px;
    box-shadow: 0 0 50px rgba(0,242,255,0.1);
}

.auth-title {
    font-size: 1.8rem;
    font-weight: 800;
    color: #00f2ff;
    margin-bottom: 10px;
    text-align: center;
}

.auth-subtitle {
    color: rgba(255,255,255,0.6);
    text-align: center;
    margin-bottom: 30px;
}

.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    color: rgba(255,255,255,0.8);
    margin-bottom: 6px;
    font-weight: 600;
    font-size: 0.85rem;
}

.form-input {
    width: 100%;
    padding: 14px 18px;
    background: rgba(10,12,18,0.6);
    border: 1px solid rgba(0,242,255,0.2);
    border-radius: 16px;
    color: white;
    font-size: 0.95rem;
    transition: all 0.3s ease;
}

.form-input:focus {
    outline: none;
    border-color: #00f2ff;
    box-shadow: 0 0 20px rgba(0,242,255,0.2);
    background: rgba(0,242,255,0.05);
}

.form-input::placeholder {
    color: rgba(255,255,255,0.3);
}

.auth-button {
    width: 100%;
    padding: 14px;
    background: linear-gradient(135deg, #00f2ff, #4d8cff);
    border: none;
    border-radius: 50px;
    color: #0a0c12;
    font-weight: 700;
    font-size: 0.95rem;
    letter-spacing: 1px;
    cursor: pointer;
    transition: all 0.3s ease;
    margin-top: 20px;
}

.auth-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 0 40px rgba(0,242,255,0.4);
}

.auth-footer {
    text-align: center;
    margin-top: 25px;
    color: rgba(255,255,255,0.5);
    font-size: 0.9rem;
}

.auth-footer a {
    color: #00f2ff;
    text-decoration: none;
    font-weight: 600;
}

.auth-footer a:hover {
    text-decoration: underline;
}

.error-message {
    background: rgba(255,77,109,0.1);
    border: 1px solid #ff4d6d;
    color: #ff4d6d;
    padding: 12px 18px;
    border-radius: 16px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

.success-message {
    background: rgba(78,255,140,0.1);
    border: 1px solid #4eff8c;
    color: #4eff8c;
    padding: 12px 18px;
    border-radius: 16px;
    margin-bottom: 20px;
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
}

/* ----- 15. ABOUT PAGE ----- */
.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
    margin-bottom: 40px;
}

.about-card {
    background: rgba(20,24,31,0.7);
    border: 1px solid rgba(0,242,255,0.15);
    border-radius: 28px;
    padding: 30px;
}

.team-section {
    margin-top: 40px;
}

.team-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 20px;
    margin-top: 25px;
}

.team-member {
    text-align: center;
}

.team-avatar {
    width: 80px;
    height: 80px;
    background: rgba(0,242,255,0.05);
    border-radius: 50%;
    margin: 0 auto 15px;
    border: 1px solid #00f2ff;
    display: flex;
    align-items: center;
    justify-content: center;
}

.team-name {
    color: white;
    font-weight: 700;
    font-size: 1rem;
}

.team-location {
    color: rgba(255,255,255,0.5);
    font-size: 0.8rem;
}

/* ----- 16. RESEARCH/XP PAGE ----- */
.xp-dashboard {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 25px;
    margin-bottom: 40px;
}

.xp-card {
    background: rgba(20,24,31,0.7);
    border: 1px solid rgba(0,242,255,0.15);
    border-radius: 28px;
    padding: 25px;
}

.achievement-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 15px;
    margin-top: 20px;
}

.achievement-item {
    text-align: center;
}

.achievement-icon {
    width: 60px;
    height: 60px;
    background: rgba(0,242,255,0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 12px;
    border: 1px solid rgba(0,242,255,0.3);
    font-size: 1.5rem;
    color: #00f2ff;
}

.stat-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    font-size: 0.9rem;
}

/* ----- 17. NEON-7 MASCOT ----- */
.neon-mascot {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 999;
}

.mascot-speech {
    background: rgba(20,24,31,0.95);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border: 1px solid #00f2ff;
    padding: 12px 20px;
    border-radius: 25px 25px 4px 25px;
    margin-bottom: 12px;
    color: #00f2ff;
    font-weight: 600;
    box-shadow: 0 0 30px rgba(0,242,255,0.2);
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 0.9rem;
    max-width: 250px;
}

.mascot-avatar {
    width: 60px;
    height: 60px;
    background: linear-gradient(145deg, #0a0c12, #14181f);
    border: 2px solid #00f2ff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: #00f2ff;
    box-shadow: 0 0 30px rgba(0,242,255,0.3);
    position: relative;
    overflow: hidden;
    margin-left: auto;
}

.mascot-avatar::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: conic-gradient(transparent, rgba(0,242,255,0.2), transparent);
    animation: spin 8s linear infinite;
}

/* ----- 18. FOOTER ----- */
.quantum-footer {
    margin-top: 60px;
    padding: 40px 0 20px;
    border-top: 1px solid rgba(0,242,255,0.1);
}

.footer-grid {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 30px;
    margin-bottom: 30px;
}

.footer-logo {
    font-size: 1.3rem;
    font-weight: 800;
    color: white;
    margin-bottom: 12px;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-link {
    color: rgba(255,255,255,0.6);
    text-decoration: none;
    transition: color 0.3s ease;
    font-size: 0.9rem;
}

.footer-link:hover {
    color: #00f2ff;
}

.copyright {
    text-align: center;
    color: rgba(255,255,255,0.4);
    font-size: 0.7rem;
    padding-top: 20px;
    border-top: 1px solid rgba(0,242,255,0.05);
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-icon {
    color: rgba(255,255,255,0.4);
    transition: color 0.3s ease;
    font-size: 1.2rem;
}

.social-icon:hover {
    color: #00f2ff;
}

/* ----- 19. ANIMATIONS & UTILITIES ----- */
@keyframes correctFlash {
    0%, 100% { background: rgba(78,255,140,0.1); }
    50% { background: rgba(78,255,140,0.3); }
}

@keyframes wrongFlash {
    0%, 100% { background: rgba(255,77,109,0.1); }
    50% { background: rgba(255,77,109,0.3); }
}

.quiz-option-btn.correct {
    animation: correctFlash 0.5s ease;
    border-color: #4eff8c !important;
}

.quiz-option-btn.wrong {
    animation: wrongFlash 0.5s ease;
    border-color: #ff4d6d !important;
}

.quiz-timer {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 6px 15px;
    background: rgba(0,242,255,0.1);
    border-radius: 30px;
    color: #00f2ff;
    font-size: 0.9rem;
    font-weight: 600;
    margin-left: 15px;
}

.quiz-timer i {
    font-size: 0.9rem;
}

/* Fallback buttons style */
.fallback-buttons {
    text-align: center;
    margin-top: 30px;
    padding: 20px;
    background: rgba(255,255,255,0.02);
    border-radius: 60px;
}

.fallback-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 12px 25px;
    margin: 0 10px 10px;
    border-radius: 40px;
    text-decoration: none;
    font-weight: 600;
    transition: all 0.3s ease;
}

.fallback-btn.physics {
    background: rgba(0,242,255,0.1);
    color: #00f2ff;
    border: 1px solid #00f2ff;
}

.fallback-btn.chemistry {
    background: rgba(78,255,140,0.1);
    color: #4eff8c;
    border: 1px solid #4eff8c;
}

.fallback-btn.biology {
    background: rgba(255,77,109,0.1);
    color: #ff4d6d;
    border: 1px solid #ff4d6d;
}

.fallback-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 20px rgba(0,242,255,0.2);
}

/* ----- 20. ADVANCED LAB STYLES (NEW) ----- */
.advanced-lab-container {
    max-width: 900px;
    margin: 0 auto;
}

.advanced-header {
    text-align: center;
    margin-bottom: 40px;
}

.advanced-badge {
    display: inline-block;
    background: linear-gradient(135deg, #ff4d6d, #ff8c42);
    color: white;
    padding: 8px 20px;
    border-radius: 40px;
    font-weight: 700;
    font-size: 1rem;
    margin-bottom: 20px;
    letter-spacing: 1px;
}

.advanced-filters {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 12px 25px;
    border-radius: 40px;
    background: rgba(255,255,255,0.03);
    border: 1px solid rgba(255,255,255,0.1);
    color: white;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
}

.filter-btn:hover {
    background: rgba(0,242,255,0.1);
    border-color: #00f2ff;
    transform: translateY(-2px);
}

.question-type-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 40px 0;
}

.type-card {
    background: rgba(255,255,255,0.03);
    border-radius: 20px;
    padding: 25px;
    text-align: center;
    border: 1px solid rgba(255,255,255,0.05);
    transition: all 0.3s ease;
    text-decoration: none;
    display: block;
}

.type-card:hover {
    transform: translateY(-5px);
    border-color: #00f2ff;
    background: rgba(0,242,255,0.05);
}

.type-card i {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: #00f2ff;
}

.type-card h4 {
    color: white;
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.type-card p {
    color: rgba(255,255,255,0.6);
    font-size: 0.8rem;
    margin-bottom: 15px;
}

.type-badge {
    display: inline-block;
    padding: 5px 15px;
    background: rgba(255,77,109,0.2);
    border-radius: 40px;
    color: #ff4d6d;
    font-size: 0.8rem;
    font-weight: 700;
}

.advanced-question-card {
    background: rgba(20,24,31,0.8);
    border-radius: 30px;
    padding: 30px;
    border: 1px solid rgba(255,255,255,0.1);
    backdrop-filter: blur(10px);
    margin-bottom: 25px;
}

.question-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 20px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.marks-badge {
    background: linear-gradient(135deg, #00f2ff, #4eff8c);
    color: #14181f;
    padding: 8px 20px;
    border-radius: 40px;
    font-weight: 800;
    font-size: 1.1rem;
}

.question-topic {
    color: #ff4d6d;
    font-weight: 600;
    font-size: 0.9rem;
}

.essay-editor {
    width: 100%;
    padding: 20px;
    background: rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 16px;
    color: white;
    font-size: 1rem;
    line-height: 1.6;
    resize: vertical;
    min-height: 200px;
    margin: 20px 0;
}

.essay-editor:focus {
    outline: none;
    border-color: #00f2ff;
}

.word-counter {
    text-align: right;
    font-size: 0.85rem;
    color: rgba(255,255,255,0.6);
    margin-top: 8px;
    margin-bottom: 20px;
}

.numerical-input-group {
    display: flex;
    gap: 15px;
    align-items: center;
    background: rgba(0,0,0,0.3);
    padding: 15px;
    border-radius: 16px;
    border: 1px solid rgba(255,255,255,0.1);
    margin: 20px 0;
}

.numerical-input {
    flex: 1;
    padding: 15px;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 12px;
    color: white;
    font-size: 1.1rem;
}

.numerical-input:focus {
    outline: none;
    border-color: #00f2ff;
}

.unit-select {
    padding: 15px;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 12px;
    color: white;
    min-width: 120px;
}

.formula-hint {
    background: rgba(0,242,255,0.1);
    border-left: 4px solid #00f2ff;
    padding: 15px;
    border-radius: 8px;
    margin: 20px 0;
    font-family: monospace;
    font-size: 1rem;
    color: #00f2ff;
}

.step-input {
    width: 100%;
    padding: 15px;
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 12px;
    color: white;
    margin: 15px 0;
    resize: vertical;
}

.results-breakdown {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin: 30px 0;
}

.result-item {
    background: rgba(255,255,255,0.03);
    border-radius: 16px;
    padding: 20px;
    text-align: center;
}

.result-score {
    font-size: 2.5rem;
    font-weight: 800;
    color: #00f2ff;
    margin-bottom: 5px;
}

.feedback-list {
    list-style: none;
    padding: 0;
    text-align: left;
    margin-top: 15px;
}

.feedback-list li {
    padding: 8px 12px;
    margin: 5px 0;
    border-radius: 8px;
    font-size: 0.9rem;
}

.feedback-list li.success {
    background: rgba(78,255,140,0.1);
    color: #4eff8c;
}

.feedback-list li.warning {
    background: rgba(255,77,109,0.1);
    color: #ff4d6d;
}

.rubric-preview {
    background: rgba(255,255,255,0.02);
    border-radius: 16px;
    padding: 20px;
    margin: 20px 0;
}

.rubric-item {
    display: flex;
    justify-content: space-between;
    padding: 10px 0;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

/* ----- 21. RESPONSIVE DESIGN ----- */
@media (max-width: 1024px) {
    .hero-title { font-size: 2.5rem; }
    .subject-grid { gap: 15px; }
    .subject-title { font-size: 1.3rem; }
}

@media (max-width: 900px) {
    .subject-grid,
    .featured-grid,
    .xp-dashboard,
    .about-grid,
    .footer-grid,
    .team-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 768px) {
    .container { padding: 0 15px; }
    
    .quantum-hero {
        grid-template-columns: 1fr;
    }
    
    .hero-title { font-size: 2.2rem; }
    
    .quantum-nav {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .nav-links {
        width: 100%;
        justify-content: space-between;
    }
    
    .user-quantum-panel {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .user-info {
        width: 100%;
    }
    
    .xp-bar-container {
        width: 100%;
    }
    
    .subject-grid,
    .featured-grid,
    .xp-dashboard,
    .about-grid,
    .footer-grid,
    .team-grid {
        grid-template-columns: 1fr;
    }
    
    .options-grid {
        grid-template-columns: 1fr;
    }
    
    .results-stats {
        grid-template-columns: 1fr;
    }
    
    .quiz-info-box {
        flex-direction: column;
        align-items: flex-start;
        gap: 15px;
        border-radius: 24px;
    }
    
    .results-actions {
        flex-direction: column;
    }
    
    .results-btn {
        width: 100%;
        justify-content: center;
    }
    
    .active-quiz-screen {
        padding: 20px;
    }
    
    .quiz-question-card {
        padding: 25px;
    }
    
    .question-text {
        font-size: 1.1rem;
    }
    
    .progress-header {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .option-letter {
        width: 35px;
        height: 35px;
        font-size: 1.1rem;
    }
    
    .option-text {
        font-size: 0.9rem;
    }
    
    .achievement-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        gap: 25px;
    }
}

@media (max-width: 480px) {
    .hero-title { font-size: 1.8rem; }
    
    .nav-links { 
        gap: 8px;
        justify-content: flex-start;
    }
    
    .nav-link { 
        font-size: 0.75rem;
        padding: 6px 0;
    }
    
    .nav-link span { display: none; }
    .nav-link i { margin-right: 0; }
    
    .auth-buttons {
        width: 100%;
        justify-content: center;
        margin-top: 5px;
    }
    
    .btn-login, .btn-register {
        padding: 6px 16px;
        font-size: 0.8rem;
    }
    
    .auth-card { 
        padding: 25px 20px; 
    }
    
    .quiz-card {
        padding: 20px;
    }
    
    .quiz-question {
        font-size: 1.1rem;
    }
    
    .mascot-speech {
        max-width: 200px;
        font-size: 0.8rem;
    }
    
    .neon-mascot {
        bottom: 10px;
        right: 10px;
    }
    
    .quiz-question-card {
        padding: 20px;
    }
    
    .quiz-option-btn {
        padding: 15px;
    }
    
    .current-score {
        width: 100%;
        justify-content: center;
    }
    
    .quit-quiz-btn {
        width: 100%;
        justify-content: center;
    }
}