Stillmind

Create a fullscreen cinematic hero section for a mindfulness/focus app called "Lumora" using React, Tailwind CSS, and Lucide React icons.

## Font

Use **Instrument Serif** (Google Fonts, italic for the logo). Load it in index.html:
```
<link rel="preconnect" href="https://fonts.googleapis.com">
<link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
<link href="https://fonts.googleapis.com/css2?family=Instrument+Serif:ital@0;1&display=swap" rel="stylesheet">
```

Set `font-family: 'Instrument Serif', serif` on html/body. Use `system-ui, sans-serif` inline for body text (subtext, buttons, stats, video labels).

---

## Background Video Layer

Stack 4 fullscreen looping videos absolutely positioned. Only the active one has `opacity-100`; others have `opacity-0`. Transition opacity over 1000ms ease-in-out. Videos autoPlay, muted, loop, playsInline.

**Video URLs (in order):**
1. `https://assets.motionin.app/imports/25f8d1c02b4e9ef918582551.mp4`
2. `https://assets.motionin.app/imports/0fc5e45d6f32eb56035ed351.mp4`
3. `https://assets.motionin.app/imports/3c382bfa55ac95ecb879daad.mp4`
4. `https://assets.motionin.app/imports/eaeb0307fb96d3550de4f0fd.mp4`

**Labels:** Golden Hour, Still Water, Deep Woods, Quiet Dawn

---

## Transparent PNG Overlay (z-index 1)

Place this image over the videos as an absolutely positioned overlay covering the full viewport:
```
https://assets.motionin.app/imports/1646c5d57c33afea3704f088.png
```

Apply a continuous "train-bob" animation: translateY oscillates between 0 and -6px over 3s ease-in-out infinite, with a constant scale(1.03) to prevent edges from showing during the motion.

---

## Liquid Glass Effect (CSS class `.liquid-glass`)

```css
.liquid-glass {
  background: rgba(255, 255, 255, 0.01);
  background-blend-mode: luminosity;
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  border: none;
  box-shadow: inset 0 1px 1px rgba(255, 255, 255, 0.1);
  position: relative;
  overflow: hidden;
}
```

With a `::before` pseudo-element for a subtle gradient border:
```css
.liquid-glass::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1.4px;
  background: linear-gradient(180deg,
    rgba(255,255,255,0.45) 0%, rgba(255,255,255,0.15) 20%,
    rgba(255,255,255,0) 40%, rgba(255,255,255,0) 60%,
    rgba(255,255,255,0.15) 80%, rgba(255,255,255,0.45) 100%);
  -webkit-mask: linear-gradient(#fff 0 0) content-box, linear-gradient(#fff 0 0);
  -webkit-mask-composite: xor;
  mask-composite: exclude;
  pointer-events: none;
}
```

---

## Content Layer (z-index 2) - Flex Column Full Height

### Navigation (top)
- Left: "Lumora" in white, italic, text-xl (sm:text-2xl)
- Right (desktop md+): A `.liquid-glass` pill containing nav links ("How It Works", "Features", "Pricing", "Community") in white/90 text-sm with hover to white, plus a solid white "Get Started" button at the end
- Right (mobile): A `.liquid-glass` rounded hamburger button using Lucide `Menu`/`X` icons with a crossfade rotation animation (300ms). The Menu icon rotates out 90deg and scales to 75%; the X icon rotates in from -90deg

### Mobile Menu Overlay (fixed, z-50)
- Backdrop: `bg-black/60 backdrop-blur-sm`
- Centered fullscreen panel with staggered entrance (each link delays 50ms more: 100ms, 150ms, 200ms, 250ms, 300ms)
- Links: white text-3xl, translate-y-4 to 0 on open
- "Get Started" button at bottom with scale animation
- Cubic-bezier easing: `cubic-bezier(0.4,0,0.2,1)`, duration 500ms

### Hero Content (centered, below nav)
- **Badge**: `.liquid-glass` rounded-full pill with text "Over 10,000 minds already finding their clarity"
- **Heading**: "Clarity in an Endlessly / Noisy Universe" (line break after "Endlessly"). Sizes: text-4xl / sm:text-5xl / md:text-7xl / lg:text-[5.5rem], leading-[1.1], max-w-4xl
- **Subtext**: "Rise above the chaos of pings, infinite scrolling, and relentless demands. Discover how to protect your presence and create with intention." max-w-xl, leading-relaxed
- **Email Input**: `.liquid-glass` rounded-full pill containing a text input ("Your Best Email") and a solid white "Get Early Access" button. Max-width 320px on mobile, sm:max-w-sm
- **Video Switcher**: Row of 4 text buttons with labels. Active button has solid color + bottom border. Inactive buttons are 50% opacity with transparent border, hover to 80%

### Dark Mode for "Deep Woods" (3rd video, index 2)
When the 3rd video is active, all hero content (badge, heading, subtext, input, video switcher) transitions to dark color `#182C41` with 700ms duration. The navbar and bottom stats remain white always.

### Bottom Stats (pushed to bottom via flex-1 spacer)
- Row of stats separated by `|` dividers (hidden on mobile): "60+ Deep Sessions", "12,000+ Creators", "4.8 User Satisfaction", "Intentional-First Design"
- text-white/70, text-xs sm:text-sm, system-ui font

---

## Video Switching Logic
- Track `activeVideo` state (default 0) and `isTransitioning` boolean
- On click, if not already active and not mid-transition, set new active video and start a 1000ms cooldown (matching the CSS crossfade duration)
- During cooldown, ignore additional clicks

---

## Responsive Behavior
- Mobile: Smaller text sizes, tighter padding, hamburger nav, stats wrap naturally
- Tablet/Desktop: Larger heading, more padding, inline nav pill, stats with pipe separators

---

## Section Container
```html
<section className="relative w-full h-screen overflow-hidden bg-black">
```

Black background prevents flash before videos load. Everything is a single viewport-height section with no scroll.

---

That's the complete specification. The entire app lives in a single `App.tsx` component with the CSS in `index.css`.