/* ===== CSS Reset & Base ===== */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary: #a855f7;
    --primary-dark: #7c3aed;
    --primary-glow: rgba(168, 85, 247, 0.4);
    --physics-color: #22d3ee;
    --physics-glow: rgba(34, 211, 238, 0.4);
    --chemistry-color: #f472b6;
    --chemistry-glow: rgba(244, 114, 182, 0.4);
    --maths-color: #fb923c;
    --maths-glow: rgba(251, 146, 60, 0.4);
    --bg-dark: #0a0a1a;
    --bg-card: rgba(26, 26, 46, 0.7);
    --bg-card-hover: rgba(34, 34, 58, 0.9);
    --text-primary: #ffffff;
    --text-secondary: #a0a0c0;
    --border-color: rgba(255, 255, 255, 0.08);
    --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
    --radius: 20px;
    --radius-sm: 12px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
    overflow-x: hidden;
}

/* ===== Animated Background ===== */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background:
        radial-gradient(ellipse at 20% 20%, rgba(168, 85, 247, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 20%, rgba(34, 211, 238, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(244, 114, 182, 0.06) 0%, transparent 50%),
        var(--bg-dark);
    animation: bgShift 20s ease-in-out infinite alternate;
}

@keyframes bgShift {
    0% { opacity: 1; }
    50% { opacity: 0.8; }
    100% { opacity: 1; }
}

/* ===== Floating Particles ===== */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    background-image:
        radial-gradient(2px 2px at 20% 30%, rgba(168, 85, 247, 0.3), transparent),
        radial-gradient(2px 2px at 40% 70%, rgba(34, 211, 238, 0.3), transparent),
        radial-gradient(2px 2px at 60% 40%, rgba(244, 114, 182, 0.2), transparent),
        radial-gradient(2px 2px at 80% 10%, rgba(251, 146, 60, 0.2), transparent),
        radial-gradient(1px 1px at 10% 90%, rgba(255, 255, 255, 0.2), transparent),
        radial-gradient(1px 1px at 70% 60%, rgba(255, 255, 255, 0.15), transparent),
        radial-gradient(1px 1px at 90% 80%, rgba(255, 255, 255, 0.15), transparent),
        radial-gradient(1px 1px at 50% 50%, rgba(255, 255, 255, 0.1), transparent);
    background-size: 200px 200px;
    animation: particles 40s linear infinite;
    pointer-events: none;
}

@keyframes particles {
    0% { transform: translateY(0); }
    100% { transform: translateY(-200px); }
}

/* ===== Header / Navbar ===== */
header {
    background: rgba(10, 10, 26, 0.85);
    backdrop-filter: blur(20px) saturate(1.5);
    -webkit-backdrop-filter: blur(20px) saturate(1.5);
    border-bottom: 1px solid var(--border-color);
    position: sticky;
    top: 0;
    z-index: 1000;
    box-shadow: 0 4px 30px rgba(0, 0, 0, 0.3);
}

.navbar {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0.6rem 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 0.8rem;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    flex-shrink: 1;
    min-width: 0;
}

.site-logo {
    height: 38px;
    width: auto;
    filter: drop-shadow(0 0 8px rgba(168, 85, 247, 0.3));
    transition: filter 0.3s ease;
}

.logo:hover .site-logo {
    filter: drop-shadow(0 0 12px rgba(168, 85, 247, 0.6));
}

.logo-text h1 {
    font-size: 1.1rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--physics-color), var(--primary), var(--chemistry-color), var(--maths-color));
    background-size: 300% 300%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 6s ease infinite;
    letter-spacing: -0.5px;
    line-height: 1.2;
}

.tagline {
    font-size: 0.55rem;
    color: var(--text-secondary);
    margin-top: -2px;
    letter-spacing: 1px;
    text-transform: uppercase;
    font-weight: 500;
}

.logo {
    display: flex;
    align-items: center;
    gap: 14px;
}

.site-logo {
    height: 48px;
    width: auto;
    filter: drop-shadow(0 0 8px rgba(168, 85, 247, 0.3));
    transition: filter 0.3s ease;
}

.logo:hover .site-logo {
    filter: drop-shadow(0 0 12px rgba(168, 85, 247, 0.6));
}

.logo-text h1 {
    font-size: 1.6rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--physics-color), var(--primary), var(--chemistry-color), var(--maths-color));
    background-size: 300% 300%;
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: gradientShift 6s ease infinite;
    letter-spacing: -0.5px;
}

@keyframes gradientShift {
    0%, 100% { background-position: 0% 50%; }
    50% { background-position: 100% 50%; }
}

.tagline {
    font-size: 0.75rem;
    color: var(--text-secondary);
    margin-top: -4px;
    letter-spacing: 1px;
    text-transform: uppercase;
    font-weight: 500;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.menu-toggle span {
    width: 28px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: 0.3s;
}

.navbar-back-btn {
    padding: 0.45rem 1rem;
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.8rem;
    transition: all 0.3s ease;
    font-weight: 500;
    flex-shrink: 0;
    display: none;
}

.navbar-back-btn.visible {
    display: block;
}

.navbar-back-btn:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary);
    box-shadow: 0 0 15px var(--primary-glow);
}

/* ===== Hero Section ===== */
.hero-section {
    max-width: 1400px;
    margin: 0 auto;
    padding: 4rem 2rem 3rem;
    text-align: center;
    position: relative;
}

.hero-content h2 {
    font-size: 3rem;
    margin-bottom: 1rem;
    font-weight: 800;
    background: linear-gradient(135deg, #ffffff, #e0e0ff, var(--physics-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1.2;
    animation: heroFadeIn 1s ease-out;
}

@keyframes heroFadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.hero-content p {
    font-size: 1.2rem;
    color: var(--text-secondary);
    max-width: 650px;
    margin: 0 auto 3.5rem;
    animation: heroFadeIn 1s ease-out 0.2s both;
}

/* ===== Subject Cards ===== */
.subject-cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2.5rem;
    max-width: 1100px;
    margin: 0 auto;
}

.subject-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
    overflow: hidden;
    display: flex;
    flex-direction: column;
    animation: cardFloat 0.8s ease-out both;
}

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

@keyframes cardFloat {
    from { opacity: 0; transform: translateY(40px) scale(0.95); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    border-radius: var(--radius) var(--radius) 0 0;
    opacity: 0;
    transition: opacity 0.4s ease;
}

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

.subject-card[data-subject="physics"]::before {
    background: linear-gradient(90deg, transparent, var(--physics-color), transparent);
}

.subject-card[data-subject="chemistry"]::before {
    background: linear-gradient(90deg, transparent, var(--chemistry-color), transparent);
}

.subject-card[data-subject="maths"]::before {
    background: linear-gradient(90deg, transparent, var(--maths-color), transparent);
}

.subject-card::after {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
}

.subject-card[data-subject="physics"]::after {
    box-shadow: 0 0 40px var(--physics-glow), inset 0 0 40px rgba(34, 211, 238, 0.05);
}

.subject-card[data-subject="chemistry"]::after {
    box-shadow: 0 0 40px var(--chemistry-glow), inset 0 0 40px rgba(244, 114, 182, 0.05);
}

.subject-card[data-subject="maths"]::after {
    box-shadow: 0 0 40px var(--maths-glow), inset 0 0 40px rgba(251, 146, 60, 0.05);
}

.subject-card:hover {
    transform: translateY(-12px) scale(1.02);
    border-color: rgba(255, 255, 255, 0.15);
}

.subject-card:hover::after {
    opacity: 1;
}

.subject-card[data-subject="physics"]:hover {
    border-color: var(--physics-color);
}

.subject-card[data-subject="chemistry"]:hover {
    border-color: var(--chemistry-color);
}

.subject-card[data-subject="maths"]:hover {
    border-color: var(--maths-color);
}

.card-icon {
    width: 110px;
    height: 110px;
    margin: 0 auto 1.8rem;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    transition: transform 0.4s ease;
}

.subject-card:hover .card-icon {
    transform: scale(1.1) rotate(5deg);
}

.physics-bg {
    background: radial-gradient(circle, rgba(34, 211, 238, 0.2), rgba(34, 211, 238, 0.05));
    box-shadow: 0 0 30px rgba(34, 211, 238, 0.15);
}

.chemistry-bg {
    background: radial-gradient(circle, rgba(244, 114, 182, 0.2), rgba(244, 114, 182, 0.05));
    box-shadow: 0 0 30px rgba(244, 114, 182, 0.15);
}

.maths-bg {
    background: radial-gradient(circle, rgba(251, 146, 60, 0.2), rgba(251, 146, 60, 0.05));
    box-shadow: 0 0 30px rgba(251, 146, 60, 0.15);
}

.card-icon svg {
    width: 65px;
    height: 65px;
    transition: transform 0.4s ease;
}

.subject-card:hover .card-icon svg {
    transform: scale(1.1);
}

.subject-card h3 {
    font-size: 1.6rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.subject-card[data-subject="physics"] h3 {
    color: var(--physics-color);
}

.subject-card[data-subject="chemistry"] h3 {
    color: var(--chemistry-color);
}

.subject-card[data-subject="maths"] h3 {
    color: var(--maths-color);
}

.subject-card p {
    color: var(--text-secondary);
    margin-bottom: 1.8rem;
    font-size: 0.95rem;
    flex-grow: 1;
}

.explore-btn {
    padding: 0.75rem 2.5rem;
    border: 2px solid var(--primary);
    background: transparent;
    color: var(--text-primary);
    border-radius: 50px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    position: relative;
}

.explore-btn:hover {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    border-color: transparent;
    box-shadow: 0 0 25px var(--primary-glow);
    transform: scale(1.05);
}

/* ===== Subject Section ===== */
.subject-section {
    max-width: 1400px;
    margin: 0 auto;
    padding: 2.5rem 2rem;
}

.back-btn {
    padding: 0.7rem 1.8rem;
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    color: var(--text-primary);
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.95rem;
    margin-bottom: 2rem;
    transition: all 0.3s ease;
    font-weight: 500;
}

.back-btn:hover {
    background: var(--bg-card-hover);
    border-color: var(--primary);
    box-shadow: 0 0 20px var(--primary-glow);
    transform: translateX(-5px);
}

.subject-section h2 {
    font-size: 2.2rem;
    margin-bottom: 2.5rem;
    padding-bottom: 1.2rem;
    border-bottom: 2px solid var(--border-color);
    font-weight: 800;
    position: relative;
}

#physicsSection h2 {
    border-bottom-color: var(--physics-color);
    color: var(--physics-color);
}

#chemistrySection h2 {
    border-bottom-color: var(--chemistry-color);
    color: var(--chemistry-color);
}

#mathsSection h2 {
    border-bottom-color: var(--maths-color);
    color: var(--maths-color);
}

/* ===== Simulation Grid ===== */
.simulation-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
}

.sim-card {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    overflow: hidden;
    cursor: pointer;
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
}

.sim-card::before {
    content: '';
    position: absolute;
    inset: 0;
    border-radius: var(--radius);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
    z-index: 1;
}

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

#physicsSection .sim-card:hover::before {
    box-shadow: 0 0 30px var(--physics-glow), inset 0 0 30px rgba(34, 211, 238, 0.03);
}

#chemistrySection .sim-card:hover::before {
    box-shadow: 0 0 30px var(--chemistry-glow), inset 0 0 30px rgba(244, 114, 182, 0.03);
}

#mathsSection .sim-card:hover::before {
    box-shadow: 0 0 30px var(--maths-glow), inset 0 0 30px rgba(251, 146, 60, 0.03);
}

.sim-card:hover {
    transform: translateY(-8px) scale(1.02);
    border-color: rgba(255, 255, 255, 0.15);
}

.sim-card.inactive {
    cursor: not-allowed;
    opacity: 0.45;
    pointer-events: none;
    filter: grayscale(0.5);
}

.sim-card.inactive::after {
    content: 'Coming Soon';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(0, 0, 0, 0.85);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    color: #fdcb6e;
    padding: 0.6rem 1.5rem;
    border-radius: 8px;
    font-weight: 700;
    font-size: 0.95rem;
    z-index: 10;
    border: 1px solid rgba(253, 203, 110, 0.3);
    letter-spacing: 1px;
}

.sim-card:hover .sim-thumbnail canvas {
    filter: brightness(1.15) contrast(1.05);
}

.sim-thumbnail {
    width: 100%;
    height: 180px;
    overflow: hidden;
    background: #0d0d20;
    position: relative;
}

.sim-thumbnail::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 40px;
    background: linear-gradient(transparent, #0d0d20);
    pointer-events: none;
}

.sim-thumbnail canvas {
    width: 100%;
    height: 100%;
    display: block;
    transition: filter 0.3s, transform 0.3s;
}

.sim-info {
    padding: 1.3rem;
    position: relative;
    z-index: 2;
}

.sim-info h3 {
    font-size: 1.15rem;
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.sim-info p {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-bottom: 0.8rem;
    line-height: 1.5;
}

.sim-tag {
    display: inline-block;
    padding: 0.3rem 0.9rem;
    border-radius: 50px;
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 0.5px;
}

#physicsSection .sim-tag {
    background: rgba(34, 211, 238, 0.12);
    color: var(--physics-color);
    border: 1px solid rgba(34, 211, 238, 0.2);
}

#chemistrySection .sim-tag {
    background: rgba(244, 114, 182, 0.12);
    color: var(--chemistry-color);
    border: 1px solid rgba(244, 114, 182, 0.2);
}

#mathsSection .sim-tag {
    background: rgba(251, 146, 60, 0.12);
    color: var(--maths-color);
    border: 1px solid rgba(251, 146, 60, 0.2);
}

.sim-dropdown {
    width: 100%;
    padding: 0.7rem;
    margin-top: 0.8rem;
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.15), rgba(168, 85, 247, 0.15));
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 2px solid rgba(34, 211, 238, 0.5);
    color: var(--text-primary);
    border-radius: 8px;
    font-size: 0.85rem;
    cursor: pointer;
    transition: all 0.3s ease;
    animation: dropdownPulse 2s ease-in-out infinite;
}

@keyframes dropdownPulse {
    0%, 100% { box-shadow: 0 0 10px rgba(34, 211, 238, 0.2); }
    50% { box-shadow: 0 0 20px rgba(34, 211, 238, 0.4); }
}

.sim-dropdown:hover, .sim-dropdown:focus {
    border-color: var(--physics-color);
    outline: none;
    box-shadow: 0 0 25px rgba(34, 211, 238, 0.3);
    background: linear-gradient(135deg, rgba(34, 211, 238, 0.25), rgba(168, 85, 247, 0.25));
}

.sim-dropdown option {
    background: var(--bg-dark);
    color: var(--text-primary);
}

/* ===== Hidden utility ===== */
.hidden {
    display: none !important;
}

/* ===== Simulation Page Styles ===== */
.sim-page {
    max-width: 100%;
    margin: 0 auto;
    padding: 0;
}

.sim-page-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid var(--border-color);
}

.sim-page-header h2 {
    font-size: 1.8rem;
    font-weight: 800;
}

.sim-container {
    display: grid;
    grid-template-columns: 1fr 340px;
    gap: 2rem;
}

.canvas-wrapper {
    background: rgba(13, 13, 32, 0.9);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border-radius: var(--radius);
    border: 1px solid var(--border-color);
    overflow: hidden;
    box-shadow: var(--shadow);
    position: relative;
}

.canvas-wrapper::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: linear-gradient(90deg, transparent, var(--primary), transparent);
    z-index: 1;
}

.canvas-wrapper canvas {
    width: 100%;
    display: block;
}

.controls-panel {
    background: var(--bg-card);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius);
    padding: 1.5rem;
    max-height: 75vh;
    overflow-y: auto;
    box-shadow: var(--shadow);
    position: sticky;
    top: 90px;
}

.controls-panel::-webkit-scrollbar {
    width: 6px;
}

.controls-panel::-webkit-scrollbar-track {
    background: transparent;
}

.controls-panel::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 3px;
}

.controls-panel h3 {
    font-size: 1.15rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.8rem;
    border-bottom: 1px solid var(--border-color);
    font-weight: 700;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.control-group {
    margin-bottom: 1.5rem;
}

.control-group label {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
    font-size: 0.88rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.control-group label span.value {
    color: var(--primary);
    font-weight: 700;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

.control-group input[type="range"] {
    width: 100%;
    height: 6px;
    -webkit-appearance: none;
    appearance: none;
    background: linear-gradient(90deg, var(--primary), var(--border-color));
    border-radius: 3px;
    outline: none;
    cursor: pointer;
}

.control-group input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    border: 3px solid #fff;
    box-shadow: 0 0 10px var(--primary-glow);
    transition: transform 0.2s ease;
}

.control-group input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.2);
}

.control-group input[type="range"]::-moz-range-thumb {
    width: 18px;
    height: 18px;
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    border: 3px solid #fff;
    box-shadow: 0 0 10px var(--primary-glow);
}

.sim-buttons {
    display: flex;
    gap: 0.8rem;
    margin-top: 2rem;
}

.sim-btn {
    flex: 1;
    padding: 0.75rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.sim-btn::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, rgba(255,255,255,0.1), transparent);
    opacity: 0;
    transition: opacity 0.3s;
}

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

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

.sim-btn.primary {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    box-shadow: 0 4px 15px var(--primary-glow);
}

.sim-btn.primary:hover {
    box-shadow: 0 6px 25px var(--primary-glow);
}

.sim-btn.secondary {
    background: rgba(255, 255, 255, 0.05);
    color: var(--text-primary);
    border: 1px solid var(--border-color);
}

.sim-btn.secondary:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary);
}

.info-box {
    background: rgba(168, 85, 247, 0.08);
    border: 1px solid rgba(168, 85, 247, 0.2);
    border-radius: var(--radius-sm);
    padding: 1.2rem;
    margin-top: 1.5rem;
    font-size: 0.85rem;
    color: var(--text-secondary);
    line-height: 1.7;
}

.info-box strong {
    color: var(--primary);
}

/* Fullscreen button */
.fs-btn {
    margin: 0;
    width: 160px;
    text-align: center;
    flex-shrink: 0;
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    padding: 0.6rem 1rem;
    border-radius: 10px;
    font-size: 0.85rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px var(--primary-glow);
}

.fs-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 25px var(--primary-glow);
}

/* Stats panel */
.stats-panel {
    background: var(--bg-card);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-sm);
    padding: 1rem;
    margin-top: 1rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.6rem;
    box-shadow: var(--shadow);
}

.stat-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
    padding: 0.3rem 0.5rem;
    border-radius: 6px;
    background: rgba(255, 255, 255, 0.02);
}

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

.stat-item .val {
    color: var(--physics-color);
    font-weight: 700;
    font-family: 'Courier New', monospace;
}

#mathsSection ~ .sim-page .stat-item .val,
.maths-sim .stat-item .val {
    color: var(--maths-color);
}

.chemistry-sim .stat-item .val {
    color: var(--chemistry-color);
}

/* ===== Footer ===== */
footer {
    text-align: center;
    padding: 2.5rem 2rem;
    margin-top: 3rem;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
    font-size: 0.9rem;
    background: rgba(10, 10, 26, 0.5);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .simulation-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .sim-container {
        grid-template-columns: 1fr;
    }

    .controls-panel {
        max-height: none;
        position: static;
    }
}

@media (max-width: 768px) {
    .subject-cards {
        grid-template-columns: 1fr;
        max-width: 400px;
    }

    .simulation-grid {
        grid-template-columns: 1fr;
    }

    .hero-content h2 {
        font-size: 2rem;
    }

    .navbar {
        padding: 1rem;
    }

    .logo-text h1 {
        font-size: 1.3rem;
    }

    .menu-toggle {
        display: flex;
    }

    .hero-section {
        padding: 3rem 1.5rem 2rem;
    }

    .subject-section {
        padding: 2rem 1.5rem;
    }

    .sim-page {
        padding: 1rem;
    }
}

@media (max-width: 480px) {
    .hero-section {
        padding: 2rem 1rem;
    }

    .subject-section {
        padding: 1.5rem 1rem;
    }

    .sim-page {
        padding: 0.8rem;
    }

    .hero-content h2 {
        font-size: 1.6rem;
    }
}

/* ===== Hide Scrollbars ===== */
html, body {
    overflow-x: hidden;
    -ms-overflow-style: none;
    scrollbar-width: none;
}

body::-webkit-scrollbar,
html::-webkit-scrollbar {
    display: none;
}

/* Allow scroll only on subject sections with simulation pages */
.hero-section,
.subject-section,
.sim-page {
    overflow-y: auto;
    scrollbar-width: none;
}

.hero-section::-webkit-scrollbar,
.subject-section::-webkit-scrollbar,
.sim-page::-webkit-scrollbar {
    display: none;
}

body::-webkit-scrollbar,
html::-webkit-scrollbar {
    display: none;
}

.controls-panel::-webkit-scrollbar {
    width: 4px;
}

.controls-panel::-webkit-scrollbar-track {
    background: transparent;
}

.controls-panel::-webkit-scrollbar-thumb {
    background: rgba(168, 85, 247, 0.3);
    border-radius: 2px;
}

.controls-panel::-webkit-scrollbar-thumb:hover {
    background: rgba(168, 85, 247, 0.5);
}

/* ===== Reduced Motion ===== */
@media (prefers-reduced-motion: reduce) {
    .subject-card,
    .sim-card,
    .explore-btn,
    .back-btn,
    .sim-btn,
    .sim-thumbnail canvas,
    .menu-toggle span {
        transition: none !important;
        animation: none !important;
    }

    .subject-card:hover {
        transform: none;
    }

    .sim-card:hover {
        transform: none;
    }

    html {
        scroll-behavior: auto;
    }

    body::before, body::after {
        animation: none !important;
    }
}

/* ===== Info Modal ===== */
.info-btn {
    background: none;
    border: 2px solid rgba(168, 85, 247, 0.5);
    color: #a855f7;
    font-size: 1.2rem;
    padding: 0.4rem 0.7rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s;
    flex-shrink: 0;
}
.info-btn:hover {
    background: rgba(168, 85, 247, 0.15);
    border-color: #a855f7;
    box-shadow: 0 0 10px rgba(168, 85, 247, 0.3);
}
.modal-overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0,0,0,0.7);
    backdrop-filter: blur(5px);
    z-index: 9999;
    justify-content: center;
    align-items: center;
}
.modal-overlay.active {
    display: flex;
}
.modal-content {
    background: linear-gradient(135deg, #0a0a1a, #1a1a3a);
    border: 2px solid rgba(168, 85, 247, 0.4);
    border-radius: 16px;
    padding: 2rem;
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: 0 0 30px rgba(168, 85, 247, 0.3);
}
.modal-content h2 {
    font-size: 1.3rem;
    margin-bottom: 1rem;
    color: #a855f7;
}
.learn-list {
    list-style: none;
    padding: 0;
    margin: 0 0 1.5rem 0;
}
.learn-list li {
    padding: 0.5rem 0;
    border-bottom: 1px solid rgba(255,255,255,0.05);
    color: var(--text-primary);
    font-size: 0.95rem;
    line-height: 1.5;
}
.learn-list li:last-child {
    border-bottom: none;
}
.modal-close {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.6rem 1.5rem;
    border-radius: 8px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    transition: opacity 0.3s;
}
.modal-close:hover {
    opacity: 0.85;
}