style.css

/******************************/
/****** General Styles ********/
/******************************/

/*h1, h2, h3, h4 { ... }*/
/*ul { ... }*/
/*blockquote { ... }*/
/* || Typography */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
  }
 
  /*Clear the flow*/
  .row::after {
    content: "";
    clear: both;
    display: table;
  }

html{
  display: flex;
  justify-content: center;
}

body{
  /*margin: auto 0; /*Normalizing CSS - test with other browsers*/
  display: flex; /*flex || inline-flex*/
  flex-direction: column; /* row || column || row-reverse || column-reverse*/
  flex-wrap: nowrap; /*nowrap || wrap || wrap-reverse*/
  /*flex-flow: column nowrap;*/ /*<'flex-direction'> || <'flex-wrap'>*/
  /*justify-content: flex-start*/ ; /*flex-start | flex-end | center | space-between | space-around | space-evenly | start | end | left | right ... + safe | unsafe*/
  /*align-items: stretch ;*//*stretch | flex-start | flex-end | center | baseline | first baseline | last baseline | start | end | self-start | self-end + ... safe | unsafe*/
  /*align-content: flex-start;*/ /*flex-start | flex-end | center | space-between | space-around | space-evenly | stretch | start | end | baseline | first baseline | last baseline + ... safe | unsafe*/

  max-width: 1200px;

  font-family: 'Open Sans', sans-serif;
}

  .parallax-background {
    background-image: url("https://images.unsplash.com/photo-1541240290619-3f2fad86473d?ixlib=rb-1.2.1&ixid=eyJhcHBfaWQiOjEyMDd9&auto=format&fit=crop&w=634&q=80");
    min-height: 100vh;
    background-attachment: fixed;
    background-position: center;
    background-repeat: no-repeat;
    background-size: cover;
  }


/********************************************/
/**Semantic HTML CSS Legacy Considerations***/
/********************************************/

section, article, aside, footer, header, nav {
  display: block;
}