gpt-oss-120b

We need to produce a self-contained HTML web demo for a Korean taco food truck called "Kimci Loco". The instructions: we must output exactly one fenced code block, containing the full HTML file. It must have inline CSS and JS. The page must be responsive from 1280x800 to 375px. Must show something meaningful on first paint. Can't use localStorage, etc. No network requests unless explicitly allowed, but not needed.

We need to design an attractive website that makes people want to come. Should include images? We can't load external images unless we embed base64-encoded images. We can embed a few base64 small images for decorative purposes (e.g., a taco icon, Korean flag, etc.). Possibly we could embed a background image of a food truck or some vector drawings. But to keep file size manageable, we can use simple CSS, icons from emoji or built-in fonts. Could embed some SVG icons inline.

We can have a hero section with large title "Kimchi Loco", tagline "Korean Tacos & Street Food". Use a background gradient or pattern. We can show some cards of menu items with images (probably embed small base64 JPEG or PNG). Or maybe use CSS shapes or inline SVG to represent tacos.

Could also have a map (but external network request to Google Maps would be disallowed). Could embed an iframe map with openstreetmap (embedding works) but requires network request to external map - the sandbox maybe blocks network? Not sure if allowed. The instructions say "except the CDN URLs explicitly allowed by the task". The task didn't mention any CDN; we likely should avoid network requests; but we could embed a static map image of a location using base64. That would be pretty heavy.

Better approach: create a simple appealing website with hero, sections: About, Menu, Location and Hours, Social Media, contact form (non-functional). Use CSS animations, parallax maybe.

Make sure everything looks good on load. Possibly have some subtle animation for text.

Also needs to be visible in screenshot after ~3 seconds. So we cannot have a "Click or press a key to start" overlay that blocks everything; it's only needed for games requiring keyboard. Here we don't need it.

So we can design with simple static content.

Let's plan structure:

<body>
<header class="hero">
  <h1>Kimchi Loco</h1>
  <p class="tagline">Korean Tacos & Street Food on Wheels</p>
  <a href="#menu" class="cta-button">Explore the Menu</a>
</header>

<section id="about">
  <h2>About Us</h2>
  <p>...story...</p>
</section>

<section id="menu">
  <h2>Menu</h2>
  <div class="menu-grid">
    <div class="menu-item">
      <img src="data:image/png;base64,..."> (Taco image)
      <h3>Kimchi Taco</h3>
      <p>Spicy kimchi, pork belly, crisp lettuce, and gochujang mayo in a soft tortilla.</p>
    </div>
    ... other items ...
  </div>
</section>

<section id="location">
  <h2>Find Us</h2>
  <p>We roam around ... <br>Currently at: <strong id="location-status">Park Central</strong></p>
  <script> maybe a simple animation of location change? Not needed.

</section>

<footer>
  <p>© 2026 Kimchi Loco | Follow us on Instagram <a href="https://instagram.com/kimchi_loco" target="_blank">...</a></p>
</footer>

Potential to embed small icons: Use inline SVG for Instagram icon, location pin. Use base64 for food photos.

We can embed maybe three menu items with small base64 images (maybe using a cartoon taco or some food). Could create simple icons via SVG: a taco shape. Could define an SVG shape for a taco. For simplicity, we could create a stylized taco using <svg> inside each menu-item. Use CSS for consistent colors.

Alternatively, use emojis like "🌮" for taco, "🥢" for Korean.

The requirement: "The page must look right in a 1280×800 viewport and adapt gracefully down to 375px wide. No horizontal scrollbar." So we need responsive CSS, media queries.

Make hero full-screen with background gradient maybe.

Use CSS variables for colors: brown, red, yellow.

Add animation: a subtle sliding in of elements.

The page should load quickly.

We need to include all content inline.

Now, define the HTML structure.

Also embed any fonts? Could embed Google Fonts via link (external CDN) but they might block external connections. However that line "except the CDN URLs explicitly allowed by the task". There's no allowance for external fonts. So best to avoid network requests. Use system fonts: 'Helvetica', Arial, sans-serif.

Potentially default to "Arial, Helvetica, sans-serif".

Add general CSS:

html,body, selects to remove margin, set box-sizing.

Define .hero { background: linear-gradient(135deg, #ff7e5f, #feb47b); color: white; text-align: center; padding: 4rem 1rem; }

Use .cta-button { display: inline-block; margin-top: 1rem; background-color: #fff; color: #ff7e5f; border-radius: 5px; padding: .75rem 1.5rem; text-decoration: none; font-weight: bold; transition: background-color .3s; }

:hover: background: #ffd6c5;

Make sections with padding.

Define .menu-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 1.5rem; margin-top: 1rem; }

Define menu-item card with border radius, box shadow, text align.

Use CSS pseudo-element to show a small taco icon.

Better: Use <svg> for taco icon directly inside each menu item.

Let's generate a simple taco SVG shape: It could be a taco outline shape: a semi-circle with some filling. Or could use simple shapes: a half-ellipse filled with orange; separate random shapes for lettuce and sauce. But fine.

Simplify: Use an emoji as "🌮". Could use <span class="emoji">🌮</span> style.

Ok.

Add a "Map" static representation: use an SVG of a simple pin on a simplified location map: just an empty circle with location pin.

Better: Use an image from a placeholder. Might risk external request.

We can embed base64 image: maybe a small map snippet with a location pin.

But we can simply provide text: "We’ll be at the downtown Farmers Market every Saturday from 12-5pm!" 

So we can skip map.

Now includes social icons: Instagram, Facebook, Twitter with inline SVG.

Define <a class="social" href="#"> <svg> ... </svg> </a>.

All in one.

Add flicker effect: maybe small animation on hero tagline.

Make sure not too heavy.

Now ensure the page has visible content on load. All good.

Test for any possible JavaScript. Might not need any JavaScript. Could add a small script to animate the hero tagline using CSS keyframes but that can be pure CSS.

But to make the site more interesting, we could have a simple "carousel" of images for menu items, maybe using JavaScript to rotate images automatically.

But keep minimal.

I think a static responsive site works.

Now produce HTML code.

Consider also a "subscribe" form with dummy input field; no need for form submission.

All good.

Now also ensure no horizontal scrollbars; set max-width for container elements.

Use <div class="container"> with width: 100%; max-width: 1200px; margin: auto; padding.

Now plan actual HTML:

<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Kimchi Loco - Korean Taco Food Truck</title>
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    ... CSS ...
  </style>
</head>
<body>
<header class="hero">
  <div class="container">
    <h1>Kimchi Loco</h1>
    <p class="tagline">Korean Tacos & Street Food on Wheels</p>
    <a href="#menu" class="cta-button">Explore the Menu</a>
  </div>
</header>

<section id="about" class="section">
  <div class="container">
    <h2>About Us</h2>
    <p>...</p>
  </div>
</section>

<section id="menu" class="section">
  <div class="container">
    <h2>Menu</h2>
    <div class="menu-grid">
      <div class="menu-item">
        <div class="icon">🌮</div>
        <h3>Kimchi Taco</h3>
        <p>Spicy kimchi, juicy pork belly, crisp lettuce, and gochujang mayo wrapped in a soft tortilla.</p>
      </div>
      <div class="menu-item">
        <div class="icon">🥢</div>
        <h3>Fried Chicken & Kimchi Sliders</h3>
        <p>Crispy Korean fried chicken with tangy kimchi on mini brioche buns.</p>
      </div>
      <div class="menu-item">
        <div class "icon">🍚</div>   // but we need proper syntax.
      </div>
    </div>
  </div>
</section>

<section id="location" class="section">
  <div class="container">
    <h2>Find Us</h2>
    <p>Catch us at the <strong>Downtown Farmers Market</strong> every Saturday from 12 pm – 5 pm. Follow us on social media for daily updates on our location!</p>
  </div>
</section>

<footer class="footer">
  <div class="container">
    <p>© 2026 Kimchi Loco. All rights reserved.</p>
    <div class="social-icons">
      <a href="#" aria-label="Instagram">
        <svg ... > ... </svg>
      </a>
      <a href="#" aria-label="Twitter">
        <svg ... > ... </svg>
      </a>
    </div>
  </div>
</footer>
</body>
</html>

Now includes CSS class .container, .section.

Add CSS for responsiveness: Use fluid grid for .menu-grid.

Add CSS for icons: .menu-item .icon { font-size: 3rem; margin-bottom: .5rem; }

Use default font-family.

Add optional CSS animation: .hero h1 { animation: fadeInUp 1s ease-out; }

Define keyframes.

Add CSS for .cta-button hover.

Add universal box-sizing.

Add "touch no scroll" for small screens.

Ok.

Potential JavaScript: maybe a small scroll-to-top button? Not needed.

Better to include decorative background: maybe a subtle pattern using CSS for hero: repeating radial pattern.

But optional.

Now base64 images: not necessary.

Better to embed a small image for the food truck or small picture: We can embed one small base64 image for hero: a stylized food truck silhouette at bottom.

Simplify: just gradient.

Now ensure the page looks good on first paint: hero with title and tagline visible.

Spacing: adjust.

Write CSS with media queries for small screens: .hero padding, .cta-button size.

Make the container margin: auto; padding: 0 1rem.

Use max-width: 1150px.

Now implement.

Potential improvements: Use scroll effect: sticky header for nav? Not needed.

Now fill in content for About: "Kimchi Loco blends the bold flavors of Korean cuisine with the hand-held convenience of tacos..."

Menu items: at least 4-5 items with icons.

Define these items:

1. Kimchi Taco
2. Bulgogi Beef Taco
3. Spicy Pork & Kimchi Tostada
4. Korean Fried Chicken Slider
5. Sweet Potato & Kimchi Quesadilla

Use emojis: 🌮 for taco, 🐖 for pork, 🐮 for beef, 🍗 for chicken, 🍠 for sweet potato.

Also could use 🍚 for rice.

For each item, an icon.

Now layout.

Add CSS for .menu-item: border: 1px solid #e0e0e0, border-radius: .5rem, padding: .75rem, text-align: center, background: white; box-shadow: 0 2px 5px rgba(0,0,0,.1); transition transform.

Hover effect: transform: translateY(-5px); box-shadow stronger.

Make .menu-item an interactive card.

Make .menu-item a:hover.

Now implement CSS.

Now code.

Select icons as emojis; define .icon class.

Add a small decorative border-top on sections.

Now generate final HTML.

Will also include meta description maybe.

Now writing the final code:

We'll produce HTML using proper indentation.

Potential challenges:

- Need to embed inline SVG for social icons. Let's create simple Instagram icon using inline path. Could copy known simple path for Instagram. However we need to avoid mistakes: we want minimal code.

Simplify: Use emoji like 📸 for Instagram. But not as nice? But okay.

We can use simple text: "IG" styled.

But for visual, maybe we can use pure CSS icons like <div class="social-icon">IG</div>. But we can embed simple path: For Instagram: <svg viewBox="0 0 24 24" width="24" height="24" fill="currentColor"><path d="..." /></svg>. Could copy path from typical glyph.

Simplify: Use Font Awesome's free icons but requires external CSS. Not allowed.

Better to embed simple i.e., using 2-circled shapes.

Alternative: Use minimal inline SVG shapes.

Let's look at typical Instagram icon: a rounded square with a small circle in the top left and a dot. The path can be approximated.

But to avoid complexity, just use text with style: "instagram" as a link.

We'll use <a href="#" class="social-link">Instagram</a> style.

Better to have small icons for social: maybe small images via base64; but perhaps not needed.

Thus we can skip icons to simplify.

But provide social handle: Instagram: @kimchi_loco.

Ok.

Now ensure site has no network request: All internal only.

Now fill about text.

Add maybe a code for the background to add subtle pattern using repeating-linear-gradient.

Ok.

Now we need to ensure it's all valid.

Now incorporate forms; we could have a sign-up form for updates. Form doesn't need to submit; will be purely UI.

Add a section #subscribe: input and button.

But simplest: keep it minimal.

Now final HTML.

Let's assemble.

We'll write the code.

Be careful to use correct closing tags.

We'll embed some CSS variables for colors: --primary: #ff7e5f; --secondary: #feb47b; --accent: #ff543e; These are orange/red.

Use background gradient: linear-gradient(to right, var(--primary), var(--secondary)).

Set hero background.

Add CSS for .cta-button.

Alright.

Now finalize.

Potential features:

- The hero tagline could slide in from bottom: keyframe slideUp.

- Use transition for .menu-item.

- Use hover effect for .cta-button.

Make page responsive: For small screens, reduce hero padding.

Define media query @media (max-width: 600px) to adjust.

Now code.

Add <meta charset="UTF-8">, <title>Kimchi Loco - Korean Taco Food Truck</title>.

Add <meta name="description" content="Kimchi Loco serves bold Korean tacos from a vibrant food truck. Find us at local markets and enjoy flavors that will make you loco for kimchi!">

Add <meta name="viewport" content="width=device-width, initial-scale=1">

Ok.

Now code.

Will produce as a full HTML file.

Check for any missing closing tags.

Will use standard skeleton.

Double-check that all sections are inside .container.

Add appropriate classes.

Now let's produce final code.

Potential to embed a small background image of a truck using base64: We can create a tiny PNG with a food truck silhouette (maybe found online). But doing that is time-consuming. Better to skip.

Okay.

Now final HTML:

Let's write:

```html
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Kimchi Loco – Korean Taco Food Truck</title>
  <meta name="description" content="Kimchi Loco serves bold Korean tacos from a vibrant food truck. Find us at local markets and enjoy flavors that will make you loco for kimchi!">
  <meta name="viewport" content="width=device-width, initial-scale=1">
  <style>
    :root {
      --primary: #ff7e5f;
      --secondary: #feb47b;
      --dark: #2c2c2c;
      --light: #fff;
      --accent: #ff543e;
      --bg-gradient: linear-gradient(135deg, var(--primary), var(--secondary));
    }
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html, body {
      font-family: -apple-system, BlinkMacSystemFont, "Helvetica Neue", Helvetica, Arial, sans-serif;
      color: var(--dark);
      line-height: 1.6;
      scroll-behavior: smooth;
    }
    body {
      background: #f9f9f9;
    }
    .container {
      width: 100%;
      max-width: 1150px;
      margin: 0 auto;
      padding: 0 1rem;
    }
    header.hero {
      background: var(--bg-gradient);
      color: var(--light);
      text-align: center;
      padding: 5rem 1rem 4rem;
      position: relative;
      overflow: hidden;
    }
    header.hero::after {
      content: "";
      position: absolute;
      bottom: -30px;
      left: 0;
      width: 100%;
      height: 80px;
      background: var(--light);
      border-radius: 50% 50% 0 0;
      transform: scaleX(2);
    }
    header.hero h1 {
      font-size: 3rem;
      margin-bottom: .5rem;
      animation: fadeInUp 1s ease-out forwards;
    }
    header.hero .tagline {
      font-size: 1.25rem;
      margin-bottom: 1.5rem;
      opacity: 0;
      animation: fadeInUp 1.2s ease-out forwards;
      animation-delay: .2s;
    }
    .cta-button {
      display: inline-block;
      background: var(--light);
      color: var(--primary);
      padding: .75rem 1.5rem;
      border-radius: 30px;
      text-decoration: none;
      font-weight: bold;
      font-size: 1rem;
      transition: background .3s, color .3s, transform .2s;
      opacity: 0;
      animation: fadeInUp 1.4s ease-out forwards;
      animation-delay: .4s;
    }
    .cta-button:hover {
      background: var(--accent);
      color: var(--light);
      transform: translateY(-3px);
    }
    section.section {
      padding: 3rem 0;
    }
    section.section h2 {
      text-align: center;
      font-size: 2rem;
      margin-bottom: 1.5rem;
      position: relative;
    }
    section.section h2::after {
      content: "";
      width: 60px;
      height: 3px;
      background: var(--primary);
      position: absolute;
      left: 50%;
      bottom: -10px;
      transform: translateX(-50%);
    }
    #about p, #location p {
      max-width: 800px;
      margin: 0 auto;
      font-size: 1.1rem;
      text-align: center;
    }
    .menu-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
      gap: 2rem;
      margin-top: 2rem;
    }
    .menu-item {
      background: var(--light);
      padding: 1.5rem;
      border-radius: .75rem;
      box-shadow: 0 2px 5px rgba(0,0,0,.1);
      text-align: center;
      transition: transform .2s, box-shadow .2s;
    }
    .menu-item:hover {
      transform: translateY(-5px);
      box-shadow: 0 8px 15px rgba(0,0,0,.15);
    }
    .menu-item .icon {
      font-size: 3rem;
      margin-bottom: .75rem;
    }
    .menu-item h3 {
      margin-bottom: .5rem;
      font-size: 1.25rem;
      color: var(--primary);
    }
    .menu-item p {
      font-size: .95rem;
      color: #555;
    }
    footer.footer {
      background: var(--dark);
      color: var(--light);
      text-align: center;
      padding: 2rem 1rem;
    }
    .social-icons {
      margin-top: .75rem;
    }
    .social-icons a {
      color: var(--light);
      margin: 0 .5rem;
      text-decoration: none;
      font-size: 1.2rem;
      transition: color .2s;
    }
    .social-icons a:hover {
      color: var(--secondary);
    }
    /* Animations */
    @keyframes fadeInUp {
      from {
        opacity: 0;
        transform: translateY(20px);
      }
      to {
        opacity: 1;
        transform: translateY(0);
      }
    }
    /* Responsive tweaks */
    @media (max-width: 600px) {
      header.hero {
        padding: 3rem 1rem 2.5rem;
      }
      header.hero h1 {
        font-size: 2.2rem;
      }
      header.hero .tagline {
        font-size: 1rem;
      }
      .cta-button {
        font-size: .9rem;
        padding: .6rem 1.2rem;
      }
    }
  </style>
</head>
<body>
  <header class="hero">
    <div class="container">
      <h1>Kimchi Loco</h1>
      <p class="tagline">Korean Tacos &amp; Street Food on Wheels</p>
      <a href="#menu" class="cta-button">Explore the Menu</a>
    </div>
  </header>

  <section id="about" class="section">
    <div class="container">
      <h2>About Us</h2>
      <p>At Kimchi Loco we mash up the fiery zest of Korean cuisine with the handheld joy of tacos. From our sizzling pork belly kimchi taco to crunchy bulgogi beef bites, every dish is a burst of flavor that’ll have you shouting “Loco for kimchi!” Catch us rolling through the city’s best markets and festivals.</p>
    </div>
  </section>

  <section id="menu" class="section">
    <div class="container">
      <h2>Our Menu</h2>
      <div class="menu-grid">
        <div class="menu-item">
          <div class="icon">🌮</div>
          <h3>Kimchi Taco</h3>
          <p>Spicy kimchi, juicy pork belly, crisp lettuce, and gochujang mayo wrapped in a soft tortilla.</p>
        </div>
        <div class="menu-item">
          <div class="icon">🥩</div>
          <h3>Bulgogi Beef Taco</h3>
          <p>Marinated Korean BBQ beef, pickled radish, sesame seeds, and a drizzle of soy‑sesame sauce.</p>
        </div>
        <div class="menu-item">
          <div class="icon">🐖</div>
          <h3>Spicy Pork &amp; Kimchi Tostada</h3>
          <p>Crispy corn tostada piled with pork, kimchi, avocado, and a splash of hot chili oil.</p>
        </div>
        <div class="menu-item">
          <div class="icon">🍗</div>
          <h3>Korean Fried Chicken Slider</h3>
          <p>Golden double‑fried chicken, sweet &amp; spicy glaze, pickled cabbage on buttery brioche.</p>
        </div>
        <div class="menu-item">
          <div class="icon">🍠</div>
          <h3>Sweet Potato Kimchi Quesadilla</h3>
          <p>Roasted sweet potato, kimchi, melted mozzarella, and a hint of gochujang inside a crisp tortilla.</p>
        </div>
      </div>
    </div>
  </section>

  <section id="location" class="section">
    <div class="container">
      <h2>Find Us</h2>
      <p>We roll into the <strong>Downtown Farmers Market</strong> every Saturday from 12 pm – 5 pm. Follow us on Instagram @kimchi_loco for daily location updates and special pop‑up events!</p>
    </div>
  </section>

  <footer class="footer">
    <div class="container">
      <p>© 2026 Kimchi Loco. All rights reserved.</p>
      <div class="social-icons">
        <a href="https://instagram.com/kimchi_loco" target="_blank" aria-label="Instagram">📸 Instagram</a>
        <a href="#" target="_blank" aria-label="Twitter">🐦 Twitter</a>
      </div>
    </div>
  </footer>
</body>
</html>
```

That would be the output.

Now check for any errors:

- In .menu-item a, not needed.

- Ensure HTML is valid: all tags properly closed.

Potential missing <meta name="viewport"> included.

CSS uses some custom variables defined.

No JS needed.

Should be fully responsive.

Will they require a screenshot after 3 seconds? The page shows hero and menu etc immediate, so visible.

No interactive overlay.

All fine.

Edge Cases: The hero background gradient with pseudo after: bottom shape. Might be fine.

Let's examine CSS for header.hero::after: height 80px; border-radius: 50% 50% 0 0; transform: scaleX(2); That will create a decorative shape.

Ok.

Now text and layout appear immediate.

Testing: Should look fine on small screens.

Now test final code in mind:

<!DOCTYPE html>
<html lang="en">
<head>
  ...
  <style>
    ...
  </style>
</head>
<body> ... etc

One subtle bug: In the `menu-item` .icon in the 5th menu-item, I wrote `<div class "icon">` incorrectly (typo). Let's correct that. It should be `<div class="icon">`.

I need to verify all `<div class="icon">` lines are correct.

Let's list them:

- For "Kimchi Taco": `<div class="icon">🌮</div>` correct.

- For "Bulgogi Beef Taco": `<div class="icon">🥩</div>` correct.

- For "Spicy Pork & Kimchi Tostada": `<div class="icon">🐖</div>` correct.

- For "Korean Fried Chicken Slider": `<div class="icon">🍗</div>` correct.

- For "Sweet Potato Kimchi Quesadilla": had `<div class "icon">` missing equals; need to correct.

Make sure all corrections are applied.

Check for any missing closing tags: All sections have closing `</section>`. The <footer> closed.

Check that the <a href="#" aria-label="Twitter"> contains no extra spaces.

Ok.

Now produce final answer containing the code block exactly.