Create cybersecurity principles landing page

[olpex]

Motivation

• Replace the simple starter HTML with a focused, professional landing page that communicates core cybersecurity principles and provides a clear call to action.
• Modernize the styling and layout to be responsive and visually consistent for a demonstration or marketing page.

Description

• Replaced index.html with a complete English landing page that adds a hero/nav with CTAs, a "Core Cybersecurity Principles" section with six cards, a quick security checklist section, and a footer.
• Reworked css/style.css to a new theme using CSS variables, improved typography, responsive container/grid, card styles, and button/hero styles.
• Updated the document metadata by setting lang="en" and adding meta tags for charset and viewport, and removed the previous placeholder span styling.
• Committed the changes with the message Create cybersecurity principles landing page.

Testing

• Verified the file diffs with git diff -- index.html css/style.css and inspected the updated files with nl -ba index.html and nl -ba css/style.css, which succeeded.
• Confirmed repository state with git status --short and created a commit using git add and git commit, which completed successfully.
• No automated test suite exists in this repository, so no unit or integration tests were run.

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Codex Task

[chatgpt-codex-connector]

💡 Codex Review

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Reviewed commit: e37537c17d

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[chatgpt-codex-connector]

Point download CTA to an actual resource

The “Download Free Guide” call-to-action currently uses href="#", which does not initiate any download and just navigates to the top of the page. In the checklist section this creates a broken user flow: users who click expecting a guide cannot complete the action, undermining the primary conversion goal of the landing page.

Useful? React with 👍 / 👎.

[gemini-code-assist]

Code Review

This pull request replaces a basic HTML/CSS template with a modern landing page for 'CyberShield,' detailing core cybersecurity principles. The changes introduce a comprehensive CSS structure with variables, a responsive grid, and a hero section. Feedback focuses on improving maintainability by replacing hardcoded colors and magic numbers with CSS variables, as well as enhancing navigation by converting the brand name into a functional link.

[gemini-code-assist]

To improve maintainability and theme consistency, it's best to declare all colors as CSS variables. Several colors are currently hardcoded in rules like .eyebrow, .subtitle, and .card. Please add these colors to the :root block and use the variables throughout the stylesheet. This also applies to color values within properties like box-shadow.

:root {
  --bg-dark: #0b1220;
  --bg-light: #f4f7fb;
  --text-main: #0f172a;
  --text-soft: #475569;
  --accent: #0ea5e9;
  --accent-strong: #0284c7;
  --white: #ffffff;
  --hero-eyebrow-text: #bae6fd;
  --hero-subtitle-text: #dbeafe;
  --hero-border-translucent: rgba(255, 255, 255, 0.35);
  --hero-border-translucent-strong: rgba(255, 255, 255, 0.45);
  --card-border: #e2e8f0;
  --card-shadow-color: rgba(15, 23, 42, 0.06);
  --section-accent-bg: #e0f2fe;
  --footer-text: #64748b;
}

[gemini-code-assist]

To support making the brand element a clickable link (as suggested in index.html), this style should be updated to remove the default link underline and ensure the color is correct.

.brand {
  font-weight: 800;
  letter-spacing: 0.5px;
  color: var(--white);
  text-decoration: none;
}

[gemini-code-assist]

The minimum card width 230px is a 'magic number'. It's better to define it as a CSS variable (e.g., --card-min-width: 230px;) in the :root selector for better maintainability, especially if this value might be used elsewhere or needs to be adjusted in the future.

[gemini-code-assist]

The brand name should be a link to the homepage for better usability and to follow web standards. I've added a corresponding style update suggestion in css/style.css.

Suggested change

	<div class="brand">CyberShield</div>
	<a class="brand" href="/">CyberShield</a>