fix: roadmap page not adapting to light theme

[AribaRazi]

Pull Request Summary

Fix light/dark theme inconsistency across various roadmap pages (AIML,DSA,BLOCKCHAIN etc.) . Several elements were using hardcoded dark color values instead of CSS variables, causing them to remain dark even when the light theme was active. Fixes #255

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Changes Introduced

1. Replaced hardcoded .section-header background gradient with var(--timeline-card-bg) so roadmap cards correctly switch between dark and light themes
2. Added [data-theme="light"] overrides for .section-title, .section-description, and .section-content li to ensure readable text in light mode
3. Fixed .roadmap-hero background by replacing hardcoded #0f172a dark gradient with a light-mode override using linear-gradient(135deg, #f1f5f9 0%, #e2e8f0 100%)
4. Fixed hero h1 which used -webkit-text-fill-color: transparent with a white gradient, making it invisible in light mode — replaced with color: var(--text-main) and added light-mode gradient override
5. Added [data-theme="light"] override for .hero-progress-card to show white background with proper shadow

Screenshots

BEFORE CHANGES:

AFTER CHANGES

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Checklist

Please ensure the following before requesting review:

• Code follows project conventions and best practices.
• Feature or fix works correctly on both mobile and desktop.
• No new console errors or accessibility regressions.
• Documentation updated if applicable.
• Visuals attached for UI-related updates.

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Additional Notes

All fixes are CSS-only — no HTML or JavaScript was modified. Light mode and dark mode have been manually verified across the hero section, timeline cards, progress bars, and navigation.

[github-actions]

📥 Pull Request Received

Thank you for your contribution to College Daddy. Your pull request has been received and is currently under review.

🔗 Linked Issues

• [Bug]: Light Theme Not Applied Consistently on AI/ML Roadmap Page (Roadmap Section Remains Dark) #255: [Bug]: Light Theme Not Applied Consistently on AI/ML Roadmap Page (Roadmap Section Remains Dark)

✅ Pre-Merge Checklist

Please ensure the following requirements are met:

• Changes adhere to contribution guidelines
• Related issues are referenced in description
• All changes tested and verified locally
• Code follows project standards

👤 Reviewer Assigned

@mugenkyou has been assigned to review this pull request.

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[github-actions]

🎉 Pull Request Merged Successfully

Contributor: @AribaRazi

Your pull request has been successfully merged into the main codebase. Thank you for your valuable contribution to College Daddy.

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