fix(docs-website): fix dark theme behaviour - I39

[apoorvsxna]

Closes #39

Fixed inconsistent behaviour of the elements mentioned in the issue, when switching the display theme (light to dark, or back).

Changes

• Changed the styling of feature icons so that their colors adjust when switching themes.
• Included an image for the Accord Project logo in the navbar for use in the dark theme.

Screenshots or Video

• Before-

• After-

Author Checklist

• [x]  Ensure you provide a DCO sign-off for your commits using the --signoff option of git commit.
• [x]  Vital features and changes captured in unit and/or integration tests
• [x]  Commits messages follow AP format
• [x]  Merging to main from fork:branchname

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[apoorvsxna]

HI @DianaLease. Could you please review this PR? Thanks.

[DianaLease]

@mttrbrts @dselman Can one of you review/merge? Looks like I don't have write access in this repo.