/* ============================================
   PHYSICS LAB - HOMEPAGE STYLESHEET
   Futuristic Dark Theme with Neon Accents
   ============================================ */

:root {
    --bg-primary: #060a12;
    --bg-secondary: #0c1220;
    --bg-tertiary: #131b2e;
    --bg-card: #111a2d;
    --border-color: #1a2844;
    --border-glow: #7c4dff33;
    --text-primary: #e8eaed;
    --text-secondary: #8b95a5;
    --text-muted: #5a6577;
    --accent-primary: #7c4dff;
    --accent-cyan: #00e5ff;
    --accent-green: #76ff03;
    --accent-orange: #ff9100;
    --accent-pink: #ff4081;
    --accent-yellow: #ffd740;
    --accent-blue: #448aff;
    --danger: #ff1744;
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.5);
    --shadow-glow: 0 0 20px rgba(124,77,255,0.3);
    --shadow-glow-cyan: 0 0 15px rgba(0,229,255,0.3);
    --font-display: 'Orbitron', sans-serif;
    --font-body: 'Rajdhani', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    background: var(--bg-primary);
    color: var(--text-primary);
    overflow-x: hidden;
    line-height: 1.6;
}

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-secondary); }
::-webkit-scrollbar-thumb { background: var(--border-color); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--accent-primary); }

/* ---- PARTICLE BACKGROUND ---- */
#particle-canvas {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 0;
    pointer-events: none;
}

/* ---- NAVIGATION ---- */
#main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(6, 10, 18, 0.85);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    transition: all 0.3s ease;
}

#main-nav.scrolled {
    background: rgba(6, 10, 18, 0.95);
    box-shadow: 0 4px 30px rgba(0,0,0,0.5);
}

.nav-inner {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 40px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    font-size: 28px;
    filter: drop-shadow(0 0 8px rgba(124,77,255,0.6));
    animation: pulse-glow 2s ease-in-out infinite;
}

@keyframes pulse-glow {
    0%, 100% { filter: drop-shadow(0 0 8px rgba(124,77,255,0.4)); }
    50% { filter: drop-shadow(0 0 18px rgba(124,77,255,0.9)); }
}

.logo-text {
    font-family: var(--font-display);
    font-size: 20px;
    font-weight: 700;
    letter-spacing: 3px;
    color: var(--text-secondary);
}

.logo-highlight {
    color: var(--accent-primary);
    text-shadow: 0 0 12px rgba(124,77,255,0.5);
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.nav-link {
    padding: 8px 18px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 1px;
    text-transform: uppercase;
    border-radius: 6px;
    transition: all 0.2s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-primary);
    background: rgba(124,77,255,0.1);
}

.nav-link.circuit-link {
    border: 1px solid var(--accent-cyan);
    color: var(--accent-cyan);
    margin-left: 12px;
}

.nav-link.circuit-link:hover {
    background: rgba(0,229,255,0.1);
    box-shadow: var(--shadow-glow-cyan);
}

/* ---- HERO SECTION ---- */
#hero {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 100px 40px 60px;
    gap: 60px;
    max-width: 1400px;
    margin: 0 auto;
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.hero-badge {
    display: inline-block;
    padding: 6px 16px;
    font-family: var(--font-mono);
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--accent-primary);
    background: rgba(124,77,255,0.1);
    border: 1px solid rgba(124,77,255,0.3);
    border-radius: 20px;
    margin-bottom: 24px;
}

.hero-title {
    font-family: var(--font-display);
    font-size: 48px;
    font-weight: 900;
    line-height: 1.15;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.gradient-text {
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-cyan));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    line-height: 1.7;
    margin-bottom: 36px;
    max-width: 500px;
}

.hero-actions {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 14px 28px;
    border-radius: 10px;
    font-family: var(--font-body);
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    border: none;
}

.btn-primary {
    background: linear-gradient(135deg, var(--accent-primary), #651fff);
    color: white;
    box-shadow: 0 4px 20px rgba(124,77,255,0.4);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 30px rgba(124,77,255,0.6);
}

.btn-secondary {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

.btn-secondary:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    transform: translateY(-2px);
}

.btn-icon {
    font-size: 18px;
}

.hero-stats {
    display: flex;
    align-items: center;
    gap: 28px;
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.stat-number {
    font-family: var(--font-display);
    font-size: 36px;
    font-weight: 900;
    color: var(--accent-primary);
    text-shadow: 0 0 20px rgba(124,77,255,0.4);
}

.stat-number.special {
    background: linear-gradient(135deg, var(--accent-orange), var(--accent-pink));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 12px;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 2px;
    margin-top: 4px;
}

.stat-divider {
    width: 1px;
    height: 40px;
    background: var(--border-color);
}

/* Hero Visual */
.hero-visual {
    position: relative;
    flex-shrink: 0;
}

#hero-sim {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.hero-sim-label {
    text-align: center;
    font-family: var(--font-mono);
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 12px;
    letter-spacing: 1px;
}

/* ---- SECTION COMMON ---- */
.section-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 100px 40px;
    position: relative;
    z-index: 1;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-badge {
    display: inline-block;
    padding: 4px 14px;
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 600;
    letter-spacing: 3px;
    color: var(--accent-cyan);
    background: rgba(0,229,255,0.08);
    border: 1px solid rgba(0,229,255,0.2);
    border-radius: 16px;
    margin-bottom: 16px;
}

.section-title {
    font-family: var(--font-display);
    font-size: 36px;
    font-weight: 900;
    margin-bottom: 12px;
}

.section-subtitle {
    font-size: 16px;
    color: var(--text-secondary);
    max-width: 500px;
    margin: 0 auto;
}

/* ---- CATEGORY FILTER ---- */
.category-filter {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    margin-bottom: 48px;
}

.filter-btn {
    padding: 8px 20px;
    border: 1px solid var(--border-color);
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border-radius: 20px;
    cursor: pointer;
    font-family: var(--font-body);
    font-size: 14px;
    font-weight: 600;
    letter-spacing: 0.5px;
    transition: all 0.3s ease;
}

.filter-btn:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
}

.filter-btn.active {
    background: var(--accent-primary);
    border-color: var(--accent-primary);
    color: white;
    box-shadow: 0 2px 12px rgba(124,77,255,0.4);
}

/* ---- SIMULATION CARDS GRID ---- */
.sim-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 28px;
}

.sim-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    overflow: hidden;
    transition: all 0.4s ease;
    cursor: default;
}

.sim-card:hover {
    border-color: rgba(124,77,255,0.5);
    transform: translateY(-6px);
    box-shadow: 0 12px 40px rgba(0,0,0,0.4), 0 0 30px rgba(124,77,255,0.15);
}

.card-glow {
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle at 50% 50%, rgba(124,77,255,0.06) 0%, transparent 60%);
    opacity: 0;
    transition: opacity 0.4s ease;
    pointer-events: none;
}

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

.card-icon-wrap {
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--border-color);
    background: rgba(0,0,0,0.2);
}

.card-canvas {
    display: block;
    width: 100%;
    height: 160px;
}

.card-body {
    padding: 20px;
}

.card-category {
    font-family: var(--font-mono);
    font-size: 10px;
    font-weight: 600;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent-primary);
    margin-bottom: 8px;
}

.card-title {
    font-family: var(--font-display);
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: 1px;
}

.card-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 14px;
}

.card-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 16px;
}

.tag {
    padding: 3px 10px;
    font-size: 11px;
    font-weight: 600;
    color: var(--text-muted);
    background: rgba(255,255,255,0.04);
    border: 1px solid rgba(255,255,255,0.06);
    border-radius: 12px;
    letter-spacing: 0.5px;
}

.card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 14px;
    border-top: 1px solid rgba(255,255,255,0.05);
}

.card-formula {
    font-family: var(--font-mono);
    font-size: 13px;
    color: var(--accent-cyan);
    opacity: 0.7;
}

.card-btn {
    padding: 8px 20px;
    background: linear-gradient(135deg, var(--accent-primary), #651fff);
    color: white;
    border: none;
    border-radius: 8px;
    font-family: var(--font-body);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    letter-spacing: 0.5px;
}

.card-btn:hover {
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(124,77,255,0.5);
}

/* Card hidden by filter */
.sim-card.hidden {
    display: none;
}

/* ---- COMING SOON OVERLAY ---- */
.sim-card.coming-soon {
    position: relative;
}

.sim-card.coming-soon::after {
    content: 'COMING SOON';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(6, 10, 18, 0.7);
    backdrop-filter: blur(2px);
    font-family: var(--font-display);
    font-size: 18px;
    font-weight: 700;
    letter-spacing: 4px;
    color: rgba(255,255,255,0.25);
    border-radius: 16px;
    z-index: 10;
    pointer-events: none;
    transition: all 0.3s ease;
}

.sim-card.coming-soon:hover::after {
    background: rgba(6, 10, 18, 0.55);
    color: rgba(124,77,255,0.5);
    text-shadow: 0 0 20px rgba(124,77,255,0.3);
}

.coming-soon-btn {
    background: var(--bg-tertiary) !important;
    color: var(--text-muted) !important;
    cursor: not-allowed !important;
    box-shadow: none !important;
    border: 1px solid var(--border-color) !important;
}

.coming-soon-btn:hover {
    transform: none !important;
    box-shadow: none !important;
}

/* ---- AVAILABLE NOW CARD ---- */
.sim-card.available-now {
    border-color: rgba(0,229,255,0.4);
    box-shadow: 0 0 30px rgba(0,229,255,0.1);
    order: -1;
}

.sim-card.available-now:hover {
    border-color: rgba(0,229,255,0.7);
    box-shadow: 0 12px 40px rgba(0,0,0,0.4), 0 0 40px rgba(0,229,255,0.2);
}

.available-badge {
    display: inline-block;
    padding: 4px 12px;
    font-family: var(--font-mono);
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 2px;
    color: #00e5ff;
    background: rgba(0,229,255,0.1);
    border: 1px solid rgba(0,229,255,0.3);
    border-radius: 12px;
    margin-bottom: 8px;
    animation: available-pulse 2s ease-in-out infinite;
}

@keyframes available-pulse {
    0%, 100% { box-shadow: 0 0 8px rgba(0,229,255,0.2); }
    50% { box-shadow: 0 0 16px rgba(0,229,255,0.5); }
}

.available-btn {
    background: linear-gradient(135deg, #00b8d4, #00e5ff) !important;
    text-decoration: none;
    display: inline-block;
    color: #0a0e17 !important;
    font-weight: 700 !important;
}

.available-btn:hover {
    box-shadow: 0 4px 20px rgba(0,229,255,0.5) !important;
}

.card-canvas-placeholder {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    height: 160px;
    background: rgba(0,229,255,0.03);
}

.card-canvas-placeholder svg {
    display: block;
    width: 100%;
    height: 100%;
}

/* ---- FEATURES GRID ---- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 24px;
}

.feature-card {
    padding: 32px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    transition: all 0.3s ease;
}

.feature-card:hover {
    border-color: rgba(124,77,255,0.3);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 36px;
    margin-bottom: 16px;
    display: block;
}

.feature-card h3 {
    font-family: var(--font-display);
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: 1px;
}

.feature-card p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ---- ABOUT SECTION ---- */
.about-content {
    display: flex;
    gap: 60px;
    align-items: center;
}

.about-text {
    flex: 1;
}

.about-text p {
    font-size: 16px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 16px;
}

.about-links {
    display: flex;
    gap: 16px;
    margin-top: 24px;
}

.about-link {
    padding: 10px 20px;
    color: var(--text-secondary);
    text-decoration: none;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-weight: 600;
    transition: all 0.2s ease;
}

.about-link:hover {
    border-color: var(--accent-primary);
    color: var(--accent-primary);
    background: rgba(124,77,255,0.08);
}

/* Floating equations */
.about-equations {
    flex: 1;
    position: relative;
    height: 300px;
}

.equation-float {
    position: absolute;
    font-family: var(--font-mono);
    font-size: 18px;
    color: var(--accent-primary);
    opacity: 0.15;
    left: var(--x);
    top: var(--y);
    animation: float-eq 6s ease-in-out infinite;
    animation-delay: var(--delay);
    white-space: nowrap;
}

@keyframes float-eq {
    0%, 100% { transform: translateY(0px); opacity: 0.15; }
    50% { transform: translateY(-15px); opacity: 0.35; }
}

/* ---- FOOTER ---- */
#site-footer {
    position: relative;
    z-index: 1;
    border-top: 1px solid var(--border-color);
    background: var(--bg-secondary);
}

.footer-inner {
    max-width: 1400px;
    margin: 0 auto;
    padding: 32px 40px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.footer-text {
    font-size: 13px;
    color: var(--text-muted);
}

.footer-links {
    display: flex;
    align-items: center;
    gap: 8px;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 13px;
    transition: color 0.2s;
}

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

.footer-sep {
    color: var(--text-muted);
}

/* ---- RESPONSIVE ---- */
@media (max-width: 1024px) {
    #hero {
        flex-direction: column;
        text-align: center;
        padding-top: 120px;
    }
    .hero-content {
        max-width: 100%;
    }
    .hero-subtitle {
        margin-left: auto;
        margin-right: auto;
    }
    .hero-actions {
        justify-content: center;
    }
    .hero-stats {
        justify-content: center;
    }
    .about-content {
        flex-direction: column;
    }
    .about-equations {
        display: none;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 32px;
    }
    .section-title {
        font-size: 28px;
    }
    .nav-inner {
        padding: 0 20px;
    }
    .section-container {
        padding: 60px 20px;
    }
    #hero {
        padding: 100px 20px 40px;
    }
    .hero-visual {
        width: 100%;
    }
    #hero-sim {
        width: 100%;
        height: auto;
    }
    .footer-inner {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }
    .sim-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 26px;
    }
    .hero-actions {
        flex-direction: column;
        align-items: center;
    }
    .hero-stats {
        flex-direction: column;
        gap: 16px;
    }
    .stat-divider {
        width: 40px;
        height: 1px;
    }
    .nav-links {
        display: none;
    }
}