Fixes part of #4177: Dark mode Topic Activity Part 4 (Practice Tab)

[MohitGupta121]

Explanation

Fixes part of #4177: Dark mode Topic Activity Part 4 (Practice Tab)

Dark Mode Mockup:-

• https://xd.adobe.com/view/c05e9343-60f6-4c11-84ac-c756b75b940f-950d/screen/f403add1-079a-4202-9975-efe04c076290/specs/
• https://xd.adobe.com/view/c05e9343-60f6-4c11-84ac-c756b75b940f-950d/screen/33f22169-7db1-4a28-84e3-8a6cb3be2f4d/specs/

Default	Dark Mode

Essential Checklist

• The PR title and explanation each start with "Fix #bugnum: " (If this PR fixes part of an issue, prefix the title with "Fix part of #bugnum: ...".)
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[MohitGupta121]

@rt4914 please first merge #4571 after that merge this one, as background color that we using is already in the past PR that's why.

[MohitGupta121]

@rt4914 I use the color from last PR and make that background color common for Topics Fragments. Can you please review it now.

[rt4914]

@MohitGupta121 PTAL, Thanks.

[MohitGupta121]

Done @rt4914 can you please now review it.

[rt4914]

LGTM, Thanks.