Hi @SamuraiArtGuy,
HTML
- Do not use lower levels to decrease heading font size:
<h1 class="white">Miyamoto Musashi</h1>
<h3 class="white normal zero-spacing">Japan's Greatest Swordsman</h3>
MDN documentation:
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Heading_Elements
Do not use lower levels to decrease heading font size: use the CSS font-size property instead.Avoid skipping heading levels: always start from <h1>
, next use <h2>
and so on.
http://w3c.github.io/html/sections.html#the-h1-h2-h3-h4-h5-and-h6-elements
h2–h6 elements must not be used to markup subheadings, subtitles, alternative titles and taglines unless intended to be the heading for a new section or subsection. Instead use the markup patterns in the §4.13 Common idioms without dedicated elements section of the specification.
Common Idioms
https://www.w3.org/TR/html5/common-idioms-without-dedicated-elements.html#common-idioms-without-dedicated-elements
- The ‘align’ attribute is no longer valid on the
<img>
element and should not be used
<img class="img-responsive m-b-5" src="https://www.fantastic-realities.com/projects/codecamp/images/miyamoto-musashi-by-tigerjordan.jpg" align="right" alt="The Iconic Musahi">
MDN documentation:
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Img
Attributes
align Deprecated since HTML4.01, obsolete since HTML5
CSS
Unexpected unknown property “line-spacing”
( maybe you can use: line-height )
body {
...
line-spacing: 125%;
}
MDN documentation:
https://developer.mozilla.org/en-US/docs/Web/CSS/line-height
The line-height CSS property sets the amount of space used for lines, such as in text.
Unexpected unknown property “background-opacity”
( maybe you can use: opacity)
#top_banner {
...
background-opacity: 0.3;
}
MDN documentation:
https://developer.mozilla.org/en-US/docs/Web/CSS/background
The property is a shorthand that sets the following properties in a single declaration:
background-clip,
background-color,
background-image,
background-origin,
background-position,
background-repeat,
background-size,
and background-attachment
MDN documentation:
https://developer.mozilla.org/en-US/docs/Web/CSS/opacity
The opacity CSS property specifies the level of transparency of an element, that is, the degree to which the content behind the element is visible.
Cheers and happy coding 
note:
- Tool used:
- Codepen’s html inspector
- Codepen’s css linter