:root {
  /* Borders */
  --border-radius: 7.5px;
  --border-thickness: 2px;

  /* Generic colors */
  --color-gray-100: #f9fafb;
  --color-gray-200: #f1f1f1;
  --color-gray-300: #ccc;
  --color-gray-400: #888;
  --color-gray-500: #666;
  --color-gray-600: #333;
  --color-blue-100: #EBF3FF;
  --color-blue-300: #1F78FF;
  --color-blue-400: #0066ff;
  --color-green-100: #F4FCEE;
  --color-green-400: #559C1C;
  --color-red-100: #FFEBEB;
  --color-red-400: #D00000;

  /* Specific colors */
  --color-body: #444;
  --color-headings: #111;

  /* Spacing */
  --spacing-l: 20px;
  --spacing-lxl: 40px;
  --spacing-s: 10px;
  --spacing-xs: 5px;
  --spacing-xxl: 60px;
  --spacing-xl: 40px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body {
  align-items: center;
  display: flex;
  justify-content: center;
  margin: 0;
  min-height: 100%;
  text-rendering: optimizeLegibility;
}

body {
  color: var(--color-body);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
  font-size: 16px;
}

.container {
  display: flex;
  flex-direction: column;
  flex-wrap: wrap;
  gap: var(--spacing-xxl);
  margin: 0 auto;
  max-width: 420px;
  padding: 20px;
}

main {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xxl);
}

.screen {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-s);
}

h1,
h2,
h3 {
  color: var(--color-headings);
}

h1 {
  font-size: 2.25rem;
  font-weight: 500;
  line-height: 3rem;
}

h2 {
  font-size: 1.5rem;
  line-height: 2rem;
}

.intro-screen .subtitle {
  font-size: 1.425rem;
	color: var(--color-gray-400);
  font-weight: 300;
}

.outro-screen .title {
	font-size: 1.725rem;
	line-height: 2.25rem;
}

h3 {
  font-size: 1.75rem;
  font-weight: 500;
  line-height: 2.25rem;
  margin-top: var(--spacing-l);
}

h4 {
	font-size: 1.5rem;
	font-weight: 500;
	line-height: 2rem;
}

p {
	line-height: 1.425rem;
}

.centered {
  text-align: center;
}

.progress-indicator {
  color: var(--color-gray-400);
  font-size: 12px;
  text-transform: uppercase;
}

.question {
  text-align: center;
}

.button {
	appearance: button;
  backface-visibility: hidden;
  border-radius: var(--border-radius);
  cursor: pointer;
  display: block;
  font-size: 16px;
  font-weight: 600;
  min-height: 50px;
  overflow: hidden;
  padding: 0 25px;
  text-align: center;
  touch-action: manipulation;
  user-select: none;
  width: 100%;
}

.primary-button {
  background-color: var(--color-blue-400);
  border: none;
  box-shadow: 
    rgba(0, 0, 0, 0.1) 0px 7.5px 15px -2.5px, 
    rgba(0, 0, 0, 0.25) 0px -2.5px 0px inset;
  color: #fff;
  margin-top: var(--spacing-l);
}

.primary-button:hover {
  background-color: var(--color-blue-300);
}

.secondary-button {
	background-color: transparent;
	border: var(--border-thickness) solid var(--color-blue-400);
	color: var(--color-blue-400);
	margin-top: var(--spacing-xs);
}

.secondary-button:hover {
  border-color: var(--color-blue-300);
  color: var(--color-blue-300);
}

button.inactive {
  background-color: var(--color-gray-400);
  cursor: default;
}

button.inactive:hover {
  background-color: var(--color-gray-400);
}

.privacy-notice {
  color: var(--color-gray-400);
  font-size: 12px;
  line-height: 1.125rem;
  margin-top: var(--spacing-s);
}

.answers {
  display: flex;
  flex-direction: column;
  gap: calc(var(--spacing-l)*0.75);
  margin-top: var(--spacing-l);
}

.answer {
  flex-grow: 1;
  position: relative;
}

.answer input[type="radio"],
.answer input[type="checkbox"] {
  height: 0;
  opacity: 0;
  position: absolute;
  width: 0;
}

.answer label {
  background-color: transparent;
  border: 1px solid var(--color-gray-300);
  border-radius: var(--border-radius);
  box-sizing: border-box;
  cursor: pointer;
  display: block;
  line-height: 1.4rem;
  padding: 20px;
  text-align: center;
  width: 100%;
}

.answer input[type="radio"]:checked + label,
.answer input[type="checkbox"]:checked + label {
  border-color: var(--color-blue-400);
  background-color: var(--color-blue-100);
  color: var(--color-blue-400);
}

.unanswered .answer input[type="radio"]:checked + label:hover,
.unanswered .answer input[type="checkbox"]:checked + label:hover {
	background-color: var(--color-blue-100);
}

.answers.unanswered .answer label:hover {
  background-color: var(--color-gray-200);
}

.answers.answered .answer label {
  cursor: default;
}

div.answers.answered .right-answer label {
  background-color: var(--color-green-100);
  border-color: var(--color-green-400);
  color: var(--color-green-400);
}

div.answers.answered.answered-incorrectly .wrong-answer label {
  background-color: var(--color-red-100);
  border-color: var(--color-red-400);
  color: var(--color-red-400);
}

.feedback {
  border-left: 3px solid var(--color-gray-200);
  color: var(--color-gray-500);
	display: flex;
	flex-direction: column;
  font-size: 15px;
	gap: 10px;
	margin-top: var(--spacing-l);
  padding-left: var(--spacing-l);
}

.feedback h4 {
  color: var(--color-gray-600);
}

.intro-screen {
  align-items: center;
}

.featured-image {
  border: 2.5px solid white;
  border-radius: 50%;
  height: 175px;
  margin-bottom: var(--spacing-l);
  max-width: 100%;
  outline: 5px solid var(--color-gray-200);
  width: 175px;
}

.icon-copy {
  height: 18px;
  width: 18px;
}

footer {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-l);
}

footer .copyright {
  color: var(--color-gray-300);
  font-size: 12px;
  text-align: center;
}