section {
  background: greenyellow;
  padding: 30px 0;
}

div {
  background: pink;
  padding: 3px;
  margin: 20px;
  border: 1px solid green;
}

.container {
  max-width: 720px;
  margin-inline: auto;
  border: 2px solid blue;
}

.container--fixed-size {
  width: 600px;
  height: 400px;
}

.container--hidden {
  overflow: hidden;
}

.container--scroll {
  overflow: scroll;
}

.header {
  padding: 50px 0;
  display: flex;
}

.header--fixed {
  width: 100%;
  position: fixed;
  z-index: 1;
}

.header--lesson {
  padding: 0;
  display: flex;
  justify-content: center;
}

.nav__list {
  display: flex;
  flex-direction: column;
  gap: 15px;
  padding: 0;
}

.nav__list--row {
  flex-direction: row;
  list-style: none;
  gap: 10px;
}

.nav__item::marker {
  color: orangered;
}

.nav__link {
  text-decoration: transparent;
  font-family: arial;
  background: lightblue;
  padding: 6px;
  border-radius: 6px;
}

.div-block {
  background: orange;
  margin-bottom: 2px;
  padding-bottom: 2px;
}

.div-block--inline {
  display: inline;
}

.span-inline {
  background: lightcoral;
  margin-top: 10px;
  padding-top: 10px;
}

.span-inline--block {
  display: block;
}

.separator {
  margin: 20px 0;
}

.oh-my-span {
  background: cadetblue;
  color: white;
  padding: 6px;
  margin: 15px;
}

.oh-my-spoon {
  background: olivedrab;
  color: wheat;
  margin: 20px;
}

.div-flex {
  display: flex;
}

.border {
  border: 5px solid;
  width: 30px;
}

.border-box {
  box-sizing: border-box;
}

.image {
  width: 100px;
  height: 100px;
  background: violet;
  display: flex;
  justify-content: center;
  align-items: center;
  text-align: center;
}

.image--wide {
  width: 700px;
}

.image--tall {
  height: 700px;
}

.float-left {
  float: left;
}

.float-right {
  float: right;
}

.clearfix {
  clear: both;
  text-align: center;
}

.relative {
  position: relative;
}

.absolute {
  position: absolute;
}

.image.absolute:nth-child(1) {
  bottom: 5px;
  right: 5px;
}

.image.absolute:nth-child(2) {
  top: 5px;
  right: 5px;
}

.image.absolute:nth-child(3) {
  bottom: 5px;
  left: 5px;
}

.image.absolute:nth-child(4) {
  top: 5px;
  left: 5px;
}

.image--sticky {
  position: sticky;
}

h2 {
  text-align: center;
}