styles.css

* {
 font-family:'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

footer {
 font-size: small;
 color: gray;
 padding: 1rem 0;
 margin: 1rem 0;
 text-align: center;
}

legend {
 background-color:#555555;
 color: white;
 padding: 3px 6px;
}

input {
 margin: 0.4rem;
}

#practiceApp input:checked + label {
 font-weight: bold;
}

input[type='text'] {
 border: #000000 1px solid;
 font-size: 2rem;
 width: 16ch
}

#answer.correct {
 border: #00AA00 1px solid;
}

#answer.incorrect {
 border: #FF0000 1px solid;
}

#result.correct {
 color: #00AA00;
}

#result.incorrect {
 color: #FF0000;
}

section {
 max-width: 75ch;
 margin: 3rem auto;
}

#quiz {
 text-align: center;
 padding-top: 2rem;
 font-size: 2rem;
}

label {
 font-size: larger;
}

input[type='submit'], input[type='reset'] {
 font-size: large;
}