Responsive Single-price Grid Component (HTML-CSS)

Replace <h2> with <h1>, <h3> with <h2> and <h4> with <h3> to fix the accessibility issues.

To center .container on the page using flexbox or grid, add min-height:100vh; display: flex; align-items: center: justify-content: center; or min-height:100vh; display: grid place-items: center to the body.

To center .container on the page using flexbox:
body{
min-height: 100vh;
display: flex;
align-items: center;
justify-content: center;
}

To center .container on the page using grid:
body{
min-height: 100vh;
display: grid;
place-items: center;
}

Give .container a fixed max-width value, max-width:700px.

Use relative units like rem or em as unit for the padding, margin, width values and preferably rem for the font-size values, instead of using px which is an absolute unit. For more on CSS units Click here

Hope am helpful.

Well done for completing this challenge. HAPPY CODING