Build This Scroll Website with NEW Grok 4.5

Video. youtube.com/watch?v=kM7cHTf-RAg · id kM7cHTf-RAg · 12:42 · reviewed 02-08-2026.

In one line. A Grok 4.5 test inside Cursor; the keeper is the blend-mode trick that melts a black-background video into a black page — plus a handful of taste corrections he applies that match our anti-slop rules.

The process he shows

Start bare in Cursor with Grok 4.5 (high fast). First prompt: "build a website for a fictional AI-driven car company, four to five sections, keep the background pure black, I'll add images later — don't worry about them." Content first, assets later.
Restyle with a transplant prompt. He copies a design prompt from motionsites.ai (his prompt shop) and says: "I will send you a prompt for an unrelated website. Do not implement it. Keep our structure, name, copy, sections. Just apply the new design." Same style-transplant move as his Kimi video.
Melt a video into the page with blending mode "exclusion". He drops a stock motionsites video into the hero: "add this video as the background… and apply to it blending mode of exclusion." The video's own black is not the page's black; the CSS blend mode makes it disappear into the page. He proves it in Figma first: paste a frame of the video over the page background, cycle blend modes, see that exclusion blends naturally — then asks the coding model for the same CSS property.
Edit by screenshot-pointing. Every layout fix is a screenshot of the section plus a plain sentence: "remove the stroke around this section", "center align this text", "move this text inside the image".
Full-bleed with gradient fades. "Make it take the full width of the page, no paddings… from the bottom and from the top add a gradient from our background color to transparent" — the seamless bleed we already hold as the bottom-fade rule.
Tame a second video. Saturation zero, opacity 70 percent, blending mode exclusion — a foreign-colored video forced into the page's palette.
Taste corrections, by hand. Two videos side by side are distracting: move one section down, delete the near-duplicate section. "AI models like to add strokes and borders — not a great design practice": remove them. Stat numbers stealing attention from the headline: shrink them 20 percent, "the main thing in web design is hierarchy."
Fill empty cards. On an image card he adds two big numbers (headline-size) with four-to-five-word captions, and a white logo made in Figma, top-aligned.
Scale to remaining pages in max mode. "In the navbar there are two links, model and experience. Build those pages with the same font styles and design direction we already established, four to six sections each." Then a quick mobile check by narrowing the window.

What is genuinely new for us

mix-blend-mode: exclusion to melt video into the page. Our doctrine melts video with a scrim plus a bottom gradient fade; the blend mode is a second, different tool — it makes a video's mismatched black background vanish into a pure-black page with one CSS property. Real technique, model-independent.
Test the blend mode in Figma before prompting. Paste a video frame over the page color, cycle blend modes, name the winner in the prompt. Cheap certainty instead of prompt roulette. (Any layer editor works; Figma is his habit.)
Desaturate + dim to force a foreign video into the palette (saturation 0, opacity ~70 percent, blend exclusion). A one-line recipe for using a video whose colors do not match.
His stroke rule said plainly. "AI models like to add strokes/borders" — matches our anti-slop rules; his fix (ask for their removal in the same breath as any new section) is a good reflex.

What we skip and why

Grok 4.5 and Cursor. Model-and-editor test; our stack is Claude and Codex, and every prompt shown works there.
Copying assets from other companies' sites (he lifts an xAI background "just for the concept"). Fine for his demo, never for our public pages — we generate our own assets in one style.
The transplant prompt and scale-by-established-style. Already captured in the Kimi digest (sUeTik8Sf4o); no need to hold it twice.
Bottom/top gradient bleed. Already doctrine (motion-design.md §3, video under the page).

Fold-in candidates

Blend-mode exclusion melt — one bullet on the technique shelf: melt a black-background video into a dark page with mix-blend-mode: exclusion; test the mode on a frame in a layer editor first → motion-design.md §3.
Foreign-video taming recipe — saturation 0 + opacity ~70 percent + blend mode, one line under the same bullet → motion-design.md §3.

Deserves a full reference page with frames

No. One technique carries the video, and it is one CSS property plus one Figma habit — the digest and the §3 fold-in hold it fully. The rest repeats moves we already decoded.