Simplest CSS to put inline for a single-page website

Ended up stealing from… shamefully, i cannot find where i was stealing this from. I feel like i eventually ended up on a list of simple design examples and i don’t remember if they were pure CSS zen-garden style or for some static site generator.

::placeholder {
	color: #191919;
}

a.intro-link, a.restaurant-link {
   	text-decoration: none;
    border-bottom: 3px solid #191919;
    -webkit-transition: border 400ms ease;
    -moz-transition: border 400ms ease;
    -ms-transition: border 400ms ease;
    -o-transition: border 400ms ease;
    transition: border 400ms ease;
}

a.book-link {
   	text-decoration: none;
    border-bottom: 3px solid #ff647e;
    -webkit-transition: border 400ms ease;
    -moz-transition: border 400ms ease;
    -ms-transition: border 400ms ease;
    -o-transition: border 400ms ease;
    transition: border 400ms ease;
}

a.intro-book-link {
   	text-decoration: none;
    border-bottom: 3px solid #f5a623;
    -webkit-transition: border 400ms ease;
    -moz-transition: border 400ms ease;
    -ms-transition: border 400ms ease;
    -o-transition: border 400ms ease;
    transition: border 400ms ease;
}

a.intro-link:hover, a.restaurant-link:hover, a.book-link:hover, a.intro-book-link:hover {
	border-bottom: 3px solid transparent;
}

@media only screen and (max-width: 767px) {
	a.intro-link, a.restaurant-link {
   		text-decoration: none;
    	border-bottom: 2px solid #191919;
    	-webkit-transition: border 400ms ease;
    	-moz-transition: border 400ms ease;
    	-ms-transition: border 400ms ease;
    	-o-transition: border 400ms ease;
    	transition: border 400ms ease;
	}

  	a.book-link {
   		text-decoration: none;
    	border-bottom: 2px solid #ff647e;
    	-webkit-transition: border 400ms ease;
    	-moz-transition: border 400ms ease;
    	-ms-transition: border 400ms ease;
    	-o-transition: border 400ms ease;
    	transition: border 400ms ease;
	}
  a.intro-book-link {
   		text-decoration: none;
    	border-bottom: 2px solid #f5a623;
    	-webkit-transition: border 400ms ease;
    	-moz-transition: border 400ms ease;
    	-ms-transition: border 400ms ease;
    	-o-transition: border 400ms ease;
    	transition: border 400ms ease;
	}

	a.intro-link:hover, a.restaurant-link:hover, a.book-link:hover, a.intro-book-link:hover {
		border-bottom: 2px solid transparent;
	}
}

.content {
	font-family: Calibri, Candara, Segoe, Segoe UI, Optima, Arial, sans-serif;
  font-size: 1.1rem;
  line-height: 1.6rem;
  max-width: 70rem;
  padding-left: 4rem;
  padding-right: 4rem;
  margin-left: auto;
  margin-right: auto;
}

.content h1, .content h2, .content h3, .content h4, .content h5, .content h6 {
  font-family: Times New Roman, serif;
}

.content img.large {
  display: block;
  width: 80%;
  margin-left: auto;
  margin-right: auto;
}

.content img.small {
  max-width: 25rem;
}

.content .right {
  float: right;
}

All that between unadorned <style> </style> tags in the HTML head.