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

:root {
    --bg: #0a0d12;
    --surface: #111520;
    --card: #151b27;
    --border: #1e2840;
    --accent: #3affc0;
    --accent2: #4f9dff;
    --accent3: #ff6b6b;
    --text: #e8edf5;
    --muted: #7a8ba6;
    --font-head: 'Syne', sans-serif;
    --font-body: 'DM Sans', sans-serif;
}

html { scroll-behavior: smooth; }

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-body);
    font-weight: 300;
    line-height: 1.7;
    overflow-x: hidden;
}

/* ── NAV ── */
nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 1.2rem 4rem;
    background: rgba(10, 13, 18, 0.85);
    backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
}

.nav-logo {
    font-family: var(--font-head);
    font-weight: 800;
    font-size: 1.2rem;
    letter-spacing: -0.5px;
    color: var(--text);
    text-decoration: none;
}

.nav-logo span { color: var(--accent); }

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
}

.nav-links a {
    color: var(--muted);
    text-decoration: none;
    font-size: 0.88rem;
    font-weight: 400;
    letter-spacing: 0.5px;
    transition: color 0.2s;
}

.nav-links a:hover, .nav-links a.active { color: var(--accent); }

/* ── HERO ── */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 8rem 4rem 4rem;
    position: relative;
    overflow: hidden;
}

/* spine glow orbs */
.hero::before {
    content: '';
    position: absolute;
    top: 10%; right: -10%;
    width: 600px; height: 600px;
    background: radial-gradient(circle, rgba(58,255,192,0.07) 0%, transparent 70%);
    pointer-events: none;
}

.hero::after {
    content: '';
    position: absolute;
    bottom: 5%; left: -5%;
    width: 500px; height: 500px;
    background: radial-gradient(circle, rgba(79,157,255,0.06) 0%, transparent 70%);
    pointer-events: none;
}

.hero-eyebrow {
    font-family: var(--font-head);
    font-size: 0.75rem;
    font-weight: 600;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 1.5rem;
    opacity: 0;
    animation: fadeUp 0.7s 0.1s ease forwards;
}

.hero-title {
    font-family: var(--font-head);
    font-size: clamp(3.5rem, 8vw, 7rem);
    font-weight: 800;
    line-height: 0.95;
    letter-spacing: -3px;
    color: var(--text);
    max-width: 800px;
    margin-bottom: 2rem;
    opacity: 0;
    animation: fadeUp 0.7s 0.25s ease forwards;
}

.hero-title .line2 {
    color: transparent;
    -webkit-text-stroke: 1.5px var(--accent);
}

.hero-desc {
    font-size: 1.15rem;
    color: var(--muted);
    max-width: 520px;
    line-height: 1.8;
    margin-bottom: 3rem;
    opacity: 0;
    animation: fadeUp 0.7s 0.4s ease forwards;
}

.hero-cta {
    display: inline-flex;
    align-items: center;
    gap: 0.6rem;
    background: var(--accent);
    color: #0a0d12;
    font-family: var(--font-head);
    font-weight: 700;
    font-size: 0.9rem;
    letter-spacing: 0.5px;
    padding: 0.9rem 2rem;
    border: none;
    cursor: pointer;
    text-decoration: none;
    transition: transform 0.2s, box-shadow 0.2s;
    opacity: 0;
    animation: fadeUp 0.7s 0.55s ease forwards;
}

.hero-cta:hover {
    transform: translateY(-2px);
    box-shadow: 0 12px 40px rgba(58,255,192,0.25);
}

.hero-cta svg { transition: transform 0.2s; }
.hero-cta:hover svg { transform: translateX(4px); }

/* ── SPINE ILLUSTRATION ── */
.hero-visual {
    position: absolute;
    right: 4rem;
    top: 50%;
    transform: translateY(-50%);
    opacity: 0;
    animation: fadeIn 1s 0.6s ease forwards;
}

.spine-track {
    width: 4px;
    height: 340px;
    background: linear-gradient(to bottom, var(--accent), var(--accent2));
    border-radius: 2px;
    position: relative;
    margin: 0 auto;
    box-shadow: 0 0 20px rgba(58,255,192,0.3);
}

.vertebra {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 28px;
    height: 10px;
    background: var(--card);
    border: 1.5px solid var(--accent);
    border-radius: 3px;
}

.vertebra::before {
    content: '';
    position: absolute;
    left: 50%; top: 50%;
    transform: translate(-50%, -50%);
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    opacity: 0.6;
}

.sensor-dot {
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
    width: 18px; height: 18px;
    background: var(--accent);
    border-radius: 50%;
    box-shadow: 0 0 16px var(--accent), 0 0 32px rgba(58,255,192,0.4);
    animation: pulse 2s infinite;
}

.sensor-dot.bottom { background: var(--accent2); box-shadow: 0 0 16px var(--accent2), 0 0 32px rgba(79,157,255,0.4); }

.sensor-label {
    position: absolute;
    right: calc(100% + 20px);
    top: 50%;
    transform: translateY(-50%);
    font-family: var(--font-head);
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 1.5px;
    text-transform: uppercase;
    color: var(--accent);
    white-space: nowrap;
}

.sensor-label.bottom-label { color: var(--accent2); }

.sensor-line {
    position: absolute;
    right: calc(100% + 10px);
    top: 50%;
    width: 10px;
    height: 1px;
    background: var(--accent);
}

.sensor-line.bottom-line { background: var(--accent2); }

/* ── SECTION ── */
section {
    padding: 6rem 4rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-label {
    font-family: var(--font-head);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 3px;
    text-transform: uppercase;
    color: var(--accent2);
    margin-bottom: 1rem;
}

.section-title {
    font-family: var(--font-head);
    font-size: clamp(2rem, 4vw, 3.2rem);
    font-weight: 800;
    letter-spacing: -1.5px;
    line-height: 1.1;
    margin-bottom: 1.5rem;
}

/* ── HOW IT WORKS ── */
.how-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5px;
    margin-top: 4rem;
    border: 1.5px solid var(--border);
}

.step-card {
    background: var(--card);
    padding: 3rem;
    position: relative;
    overflow: hidden;
    transition: background 0.3s;
}

.step-card:hover { background: #1a2235; }

.step-card::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 3px; height: 100%;
    background: transparent;
    transition: background 0.3s;
}

.step-card:hover::before { background: var(--accent); }

.step-number {
    font-family: var(--font-head);
    font-size: 4rem;
    font-weight: 800;
    letter-spacing: -3px;
    color: var(--border);
    line-height: 1;
    margin-bottom: 1.5rem;
    transition: color 0.3s;
}

.step-card:hover .step-number { color: rgba(58,255,192,0.15); }

.step-icon {
    width: 44px; height: 44px;
    background: rgba(58,255,192,0.08);
    border: 1px solid rgba(58,255,192,0.2);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1.2rem;
}

.step-card:nth-child(2) .step-icon { background: rgba(79,157,255,0.08); border-color: rgba(79,157,255,0.2); }
.step-card:nth-child(3) .step-icon { background: rgba(255,107,107,0.08); border-color: rgba(255,107,107,0.2); }
.step-card:nth-child(4) .step-icon { background: rgba(58,255,192,0.08); border-color: rgba(58,255,192,0.2); }

.step-title {
    font-family: var(--font-head);
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 0.8rem;
    letter-spacing: -0.5px;
}

.step-desc {
    font-size: 0.92rem;
    color: var(--muted);
    line-height: 1.75;
}

/* ── PROBLEM/SOLUTION ── */
.ps-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    align-items: start;
    margin-top: 2rem;
}

.ps-block {
    padding: 2.5rem;
    border: 1px solid var(--border);
    background: var(--card);
    position: relative;
}

.ps-block::after {
    content: attr(data-label);
    position: absolute;
    top: -0.6rem; left: 2rem;
    background: var(--bg);
    padding: 0 0.6rem;
    font-family: var(--font-head);
    font-size: 0.68rem;
    font-weight: 700;
    letter-spacing: 2px;
    text-transform: uppercase;
    color: var(--accent3);
}

.ps-block.solution::after { color: var(--accent); }

.ps-block h3 {
    font-family: var(--font-head);
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -0.5px;
    margin-bottom: 1rem;
}

.ps-block p {
    font-size: 0.93rem;
    color: var(--muted);
    line-height: 1.8;
}

/* ── STATS BAR ── */
.stats-bar {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    border: 1px solid var(--border);
    margin-top: 5rem;
}

.stat-item {
    padding: 2.5rem;
    text-align: center;
    border-right: 1px solid var(--border);
}

.stat-item:last-child { border-right: none; }

.stat-number {
    font-family: var(--font-head);
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -2px;
    color: var(--accent);
    line-height: 1;
    margin-bottom: 0.5rem;
}

.stat-label {
    font-size: 0.82rem;
    color: var(--muted);
    text-transform: uppercase;
    letter-spacing: 1.5px;
    font-weight: 500;
}

/* ── FOOTER ── */
footer {
    border-top: 1px solid var(--border);
    padding: 2rem 4rem;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

footer span { font-size: 0.82rem; color: var(--muted); }

.footer-links {
    display: flex;
    gap: 1.5rem;
}

.footer-links a {
    font-size: 0.82rem;
    color: var(--muted);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* ── ANIMATIONS ── */
@keyframes fadeUp {
    from { opacity: 0; transform: translateY(24px); }
    to   { opacity: 1; transform: translateY(0); }
}

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

@keyframes pulse {
    0%, 100% { box-shadow: 0 0 16px currentColor, 0 0 32px rgba(58,255,192,0.3); }
    50%       { box-shadow: 0 0 24px currentColor, 0 0 48px rgba(58,255,192,0.6); }
}

/* ── DIVIDER ── */
.divider {
    width: 100%;
    height: 1px;
    background: linear-gradient(to right, transparent, var(--border), transparent);
    margin: 0 4rem;
}

/* ── SCROLL REVEAL ── */
.reveal {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.7s ease, transform 0.7s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

@media (max-width: 900px) {
    nav { padding: 1rem 1.5rem; }
    .nav-links { display: none; }
    .hero { padding: 7rem 1.5rem 3rem; }
    .hero-visual { display: none; }
    .how-grid { grid-template-columns: 1fr; }
    .ps-wrapper { grid-template-columns: 1fr; }
    .stats-bar { grid-template-columns: 1fr; }
    .stat-item { border-right: none; border-bottom: 1px solid var(--border); }
    section { padding: 4rem 1.5rem; }
    footer { padding: 1.5rem; flex-direction: column; gap: 1rem; text-align: center; }
}