**Role:** You are a Frontend Artist who loves "The Imperfect Web." You specialize in using SVG filters and CSS `border-radius` manipulation to create organic, hand-drawn interfaces.
**Task:** Build a Hand-Drawn / Doodle style landing page for "SKETCH_PAD".
**[CONFIGURATION]**
- **[STYLE_NAME]:** Hand-Drawn / Doodle
- **[INDUSTRY]:** Creative Portfolio
- **[PROJECT_NAME]:** SKETCH_PAD
- **[TECH_STACK]:** HTML5 + Modern CSS3 (SVG Filters & Clip-path).
- **[PAGE_STRUCTURE]:** Notebook Nav, Doodled Hero, Sketchy Grid, Footer.
**Technical Requirements:**
1. **Global Variables (`:root`):**
- **Colors:** `--ink-black: #2b2b2b;`, `--paper-bg: #fdf6e3;` (Warm cream), `--marker-yellow: rgba(255, 255, 0, 0.4);`.
- **Fonts:** `--font-hand: 'Patrick Hand', 'Gochi Hand', cursive;`, `--font-marker: 'Permanent Marker', cursive;`.
- **Background:** Use a repeating CSS radial gradient to simulate "Dot Grid Paper" (`background-image: radial-gradient(#ccc 1px, transparent 1px); background-size: 20px 20px;`).
2. **Visual Effects (The "Doodle" Look):**
- **The "Squiggle" Filter (CRUCIAL):** Create an SVG filter in the HTML body to distort standard elements.
```html
<svg style="display: none;">
<filter id="wavy">
<feTurbulence type="fractalNoise" baseFrequency="0.02" numOctaves="5" result="noise" />
<feDisplacementMap in="SourceGraphic" in2="noise" scale="2" />
</filter>
</svg>
```
Apply `filter: url(#wavy);` to buttons or containers to make their edges rough.
- **Messy Borders:** Instead of `border: solid`, use `border-radius: 255px 15px 225px 15px / 15px 225px 15px 255px;` (random large/small values) to create wobbly box shapes.
- **Marker Highlight:** Create a `.highlight` class using `linear-gradient` that only covers the bottom half of the text and is slightly rotated (`transform: rotate(-1deg)`).
- **Box Shadow:** Use `box-shadow: 2px 2px 0px var(--ink-black);` (Solid offset) to look like a pen drawing.
3. **Layout Strategy:**
- **Playful Misalignment:** Use `transform: rotate()` randomly on grid items (e.g., `-2deg`, `1deg`, `3deg`) so nothing looks grid-locked.
- **Tape Effect:** Add a pseudo-element `::before` on top of images that looks like a piece of semi-transparent tape.
4. **Specific Components:**
- **Hero:** Main title uses the `--font-marker` font with a "Highlighter" background.
- **Buttons:** Apply a CSS `@keyframes` animation called `wiggle` that slightly changes the `border-radius` on hover to make it feel alive.
- **Scrollbar:** A thin, scribbly line style.
- The result should feel like a digital sketchbook.