index.css

body * {
  box-sizing: border-box;
}

html {
  height: 100%;
}

body {
  font-family: 'Bitter', serif;
  color: white;
  background: url(https://static.pexels.com/photos/9186/food-beans-coffee-drink.jpg) no-repeat;
  background-size: cover;
  height: 100%;
  text-align: center;
}

.hidden {
  display: none;
}

.blackbox {
  width: 90%;
  height: 75%;
  background-color: rgba(0, 0, 0, 0.8);
  padding: 25px;
  margin-left: auto;
  margin-right: auto;
  margin-top: 30px;
}

.espresso {
  height: auto;
  width: 50%;
}

legend {
  font-size: 24px;
}

fieldset {
  border: none;
}

.button {
  height: 35px;
  width: 120px;
  text-align: center;
  border-radius: 5px;
  background-color: white;
  font-size: 16px;
  font-family: 'Bitter', serif;
}

.coffee-question {
  padding-left: 50px;
  font-size: 18px;
  text-align: left;
}

.coffee-answers {
  text-align: left;
  padding-left: 50px;
  font-size: 18px;
  line-height: 140%;
  margin-bottom: 30px;
}

.button.disabled {
  opacity: 0.50; 
  cursor: not-allowed;
}

.results-counter {
  font-size: 20px;
  text-align: center;
}

.all-feedback {
  font-size: 18px;
  margin-top: 10px;
  position: relative;
  line-height: 150%;
}

.happy-coffee {
  height: auto;
  width: 35%;
  margin-top: -15px;
}

.sad-coffee {
  height: auto;
  width: 30%;
  margin-top: -25px;
}

#final-correct {
  margin-top: -30px;
}

.many-cups {
  height: auto;
  width: 40%;
}

.craving {
  font-size: 18px;
}

#retake {
  height: 35px;
  width: 200px;
  text-align: center;
  border-radius: 5px;
  background-color: white;
  font-size: 16px;
  font-family: 'Bitter', serif;
}