Hey Tariq, there is no backend or admin panel as this is a HTML template so there are only html, CSS and JavaScript files.
If you want to edit the colors,
Edit CSS files assets >> CSS >> theme-styles.css
There you would see the color codes like this which you can replace with your own codes.
:root {
--color-bg: #ffffff;
--color-primary: #2a2a2a;
--color-secondar: #f2b705;
--color-dark-heading: #2a2a2a;
--color-light-heading: #f2b705;
--text-heading-color: #101010;
--light-text-color: #333333;
--gray-bg-color: #f0f5f9;
--gray-bg-one-color: #e0dede;
--white-text-color: #fff;
--section-color: #f0f5f9;
--info-two: #679ac2;
--info-three: #80abcc;
--border-color: #f2b705;
/* roots for responsive font size */
--fs-16: 1rem;
--fs-18: 1.1rem;
--fs-20: clamp(1rem, 1vw + 1rem, 1.25rem);
--fs-22: clamp(1rem, 1vw + 1rem, 1.375rem);
--fs-30: clamp(1rem, 1vw + 1rem, 1.85rem);
--fs-36: clamp(1.5rem, 2vw + 1rem, 2.25rem);
--fs-47: clamp(1.75rem, 9vw + 1rem, 2.938rem);
--fs-55: clamp(1.75rem, 9vw + 1rem, 3.438rem);
--fs-xl: clamp(1.75rem, 4vw + 1rem, 3.75rem);
}