:root {
    --primary-color: #00f2fe;
    --secondary-color: #4facfe;
    --bg-color: #0f172a;
    --text-color: #f1f5f9;
    --text-muted: #94a3b8;
    --glass-bg: rgba(255, 255, 255, 0.05);
    --glass-border: rgba(255, 255, 255, 0.1);
    --glass-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Outfit', sans-serif;
}

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
    background-image:
        radial-gradient(at 0% 0%, hsla(253, 16%, 7%, 1) 0, transparent 50%),
        radial-gradient(at 50% 0%, hsla(225, 39%, 30%, 1) 0, transparent 50%),
        radial-gradient(at 100% 0%, hsla(339, 49%, 30%, 1) 0, transparent 50%);
    min-height: 100vh;
}

/* Glassmorphism Utilities */
.glass-nav {
    background: rgba(15, 23, 42, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--glass-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border: 1px solid var(--glass-border);
    border-radius: 1rem;
    padding: 2rem;
    box-shadow: var(--glass-shadow);
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.glass-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 100%;
    background: radial-gradient(800px circle at var(--mouse-x, 50%) var(--mouse-y, -10%), rgba(255, 255, 255, 0.06), transparent 40%);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
    z-index: 1;
}

.glass-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: 0 20px 40px -10px rgba(0, 0, 0, 0.5);
    border-color: rgba(255, 255, 255, 0.2);
}

.glass-card:hover::before {
    opacity: 1;
}

/* Navbar */
.navbar {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--primary-color);
    text-decoration: none;
    letter-spacing: -0.025em;
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-weight: 500;
    transition: color 0.2s;
}

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

/* Hero Section */
.hero {
    max-width: 800px;
    margin: 6rem auto 4rem;
    text-align: center;
    padding: 0 2rem;
}

.hero h1 {
    font-size: 4rem;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-muted);
    margin-bottom: 2.5rem;
}

.cta-buttons {
    display: flex;
    justify-content: center;
    gap: 1rem;
    flex-wrap: wrap;
}

.btn-primary {
    background: linear-gradient(135deg, var(--secondary-color), var(--primary-color));
    color: #000;
    padding: 0.75rem 2rem;
    border-radius: 2rem;
    text-decoration: none;
    font-weight: 600;
    transition: transform 0.2s, opacity 0.2s;
    border: none;
    cursor: pointer;
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--text-color);
    padding: 0.75rem 2rem;
    border-radius: 2rem;
    text-decoration: none;
    font-weight: 600;
    border: 1px solid var(--glass-border);
    transition: background 0.2s;
    display: flex;
    align-items: center;
}

.btn-primary:hover {
    opacity: 0.9;
    transform: scale(1.05);
}

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

/* Features */
.features {
    max-width: 1200px;
    margin: 4rem auto;
    padding: 0 2rem;
}

.features h2,
.topics h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
}

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

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

/* Topics */
.topics {
    max-width: 1200px;
    margin: 4rem auto;
    padding: 0 2rem;
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.topic-card {
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 1rem;
}

.topic-info h3 {
    margin-bottom: 0.25rem;
}

/* Quiz UI */
.quiz-container {
    max-width: 800px;
    margin: 4rem auto;
    padding: 0 1rem;
}

.question-text {
    font-size: 1.5rem;
    font-weight: 600;
    margin: 2rem 0;
}

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

.option-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--glass-border);
    padding: 1rem;
    border-radius: 0.75rem;
    color: var(--text-color);
    text-align: left;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all 0.2s;
}

.option-btn:hover:not(:disabled) {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary-color);
}

.option-btn:disabled {
    cursor: default;
    opacity: 0.7;
}

.option-btn.correct {
    background: rgba(34, 197, 94, 0.2);
    border-color: #22c55e;
    color: #4ade80;
}

.option-btn.wrong {
    background: rgba(239, 68, 68, 0.2);
    border-color: #ef4444;
    color: #f87171;
}

.quiz-header {
    border-bottom: 1px solid var(--glass-border);
    padding-bottom: 1rem;
    margin-bottom: 1rem;
}

.progress-bar {
    height: 6px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 3px;
    margin-top: 1rem;
    overflow: hidden;
}

.progress {
    height: 100%;
    background: var(--primary-color);
    width: 0%;
    transition: width 0.3s ease;
}

.score-circle {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    border: 4px solid var(--primary-color);
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 2.5rem;
    font-weight: bold;
    margin: 2rem auto;
    background: var(--glass-bg);
}

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

/* Footer */
footer {
    border-top: 1px solid var(--glass-border);
    margin-top: 4rem;
    padding: 3rem 2rem;
    text-align: center;
    background: rgba(15, 23, 42, 0.5);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-bottom: 1.5rem;
}

.footer-links a {
    color: var(--text-muted);
    text-decoration: none;
}

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

/* Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .navbar {
        flex-direction: column;
        gap: 1rem;
    }

    .nav-links {
        gap: 1rem;
        font-size: 0.9rem;
    }
}
/* =========================================
   UNIVERSAL RESPONSIVE BLOCK 
   (Appended globally for consistency)
   ========================================= */

/* Tablet View (max-width: 1024px) */
@media (max-width: 1024px) {
    .section { padding-left: 2rem; padding-right: 2rem; }
    .hero { padding-left: 2rem; padding-right: 2rem; }
    .hero h1 { font-size: 2.8rem; }
    .stats-bar { gap: 2rem; }
}

/* Mobile & Small Tablet (max-width: 768px) */
@media (max-width: 768px) {
  /* Standardize mobile flow and touch targets (min 44px) */
  .navbar-menu a, .footer a, .footer-col a, .btn, .card a, .nav-links a {
    min-height: 44px;
    display: inline-flex;
    align-items: center;
  }
  .footer a, .footer-col a {
    padding: 8px 0;
  }

    .hero h1 { font-size: clamp(2rem, 6vw, 2.5rem); }
    .hero-subtitle { font-size: 1rem; }
    
    .nav-links {
        position: fixed;
        top: 68px;
        left: 0;
        width: 100%;
        background: var(--bg-dark, #0f172a);
        padding: 1.5rem;
        flex-direction: column;
        border-bottom: 1px solid var(--glass-border, rgba(255, 255, 255, 0.08));
        transform: translateY(-150%);
        transition: 0.3s;
        gap: 1.2rem;
        z-index: 999;
    }
    .nav-links.open { transform: translateY(0); }
    .menu-toggle { display: flex; }
    
    .stats-bar { gap: 1rem; flex-wrap: wrap; }
    .stat-item { flex: 1 1 40%; }
    
    .section { padding: 4rem 1.5rem; }
    .mock-grid, .feature-grid { grid-template-columns: 1fr; }
    
    .btn-group { flex-direction: column; width: 100%; }
    .btn-group .btn-primary, .btn-group .btn-secondary, 
    .btn-group .btn-indigo, .btn-group .btn-green { 
        width: 100%; text-align: center; justify-content: center; margin-bottom: 0.5rem;
    }
}

/* Small Mobile View (max-width: 480px) */
@media (max-width: 480px) {
    .hero { padding: 5rem 1rem 3rem; }
    .hero h1 { font-size: clamp(1.8rem, 8vw, 2.2rem); }
    .action-btn { min-width: 100%; }
    .stat-item { flex: 1 1 100%; }
    .section { padding: 3rem 1rem; }
    
    .overlay-container { max-height: 95vh; border-radius: 12px; }
    .overlay-body { padding: 1.25rem; }
    .score-circle { width: 100px; height: 100px; font-size: 1.8rem; }
}