styles.css

/*
  The syntax within the styles.css file is also referred to as CSS - Cascading Style Sheets.
  CSS describes how HTML elements are to be displayed on the screen.
*/

* {
  box-sizing: border-box;
}

body {
  margin-top: 0;
  font-family: sans-serif;
  margin-left: 30px;
  margin-right: 30px;
  background-color: #e0e0e0;
}

nav {
  position: relative;
  top: 0;
  left: -30px;
  width: calc(100% + 60px);
  margin-bottom: 30px;
}

nav ul {
  list-style-type: none;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background-color: #333;
}

nav ul li {
  float: left;
  border-right: 1px solid #bbb;
}

nav ul li.project {
  float: right;
}

nav ul li.project:last-child {
  border-left: 1px solid #bbb;
}

nav ul li a {
  display: block;
  color: white;
  text-align: center;
  padding: 14px 16px;
  text-decoration: none;
}

#header {
  text-align: center;
}

.container {
  background-color: #ffffff;
  margin: 40px auto;
  max-width: 800px;
  padding: 38px 31px;
  border-radius: 8px;
  box-shadow: rgba(0, 0, 0, 0.1) 0px 4px 12px;
}

input {
  font-size: 21px;
  line-height: 33px;
  margin: 0 0 23px 0;
  padding: 0 9px;
  width: 100%;
}

button {
  font-size: 21px;
  line-height: 33px;
  margin: 0 0 23px 0;
  padding: 0 6px;
}

.output-div {
  background-color: lightgrey;
  margin: 20px auto;
  padding: 20px;
  width: 100%;
}

hr {
  margin-top: 2em;
  margin-bottom: 2em;
}

.instructions-text {
  font-size: 0.85em;
  font-style: italic;
}

.text-center {
  text-align: center;
}

.ice-double {
  display: flex;
}

.ice-double a {
  text-align: center;
  text-decoration: none;
  font-weight: bold;
  color: rgba(71, 71, 71, 1);
  display: block;
  flex-basis: 47.5%;
  margin: 0 1.25%;
  padding: 2em;
  border: 2px solid rgba(71, 71, 71, 1);
  border-radius: 8px;
}

.ice-double a:hover {
  color: rgba(71, 71, 71, 0.75);
  border: 2px solid rgba(71, 71, 71, 0.75);
}

.button-group {
  position: relative;
  display: inline-flex;
  vertical-align: middle;
  justify-self: center;
}

.button-group .button-group-button {
  position: relative;
  flex: 1 1 auto;
  background: transparent;
  color: #0d6efd;
  border-color: #0d6efd;
  display: inline-block;
  text-align: center;
  vertical-align: middle;
  background-color: transparent;
  padding: 0.5rem 1rem;
  border-radius: 0;
  text-decoration: none;
  border: 2px solid #333;
  color: #333;
  font-weight: bold;
}

.button-group .button-group-button.active {
  border: 2px solid #333;
  color: #fff;
  background-color: #333;
  font-weight: bold;
}

.button-group .button-group-button:not(.active):hover {
  background-color: rgba(51, 51, 51, 0.67);
  color: white;
}

.button-group .button-group-button:not(:first-child) {
  border-left: 0;
}

.button-group .button-group-button:first-child {
  border-top-left-radius: 0.375rem;
  border-bottom-left-radius: 0.375rem;
}

.button-group .button-group-button:last-child {
  border-top-right-radius: 0.375rem;
  border-bottom-right-radius: 0.375rem;
}

.flex {
  display: flex;
}

.justify-content-center {
  justify-content: center;
}