index.css

html, body {
    margin: 0;
    height: 100vh;
    box-sizing: border-box;
    display: flex;
    justify-content: flex-start;
    align-items: center;
    padding: 1rem 1rem;
    flex-direction: column;
    gap: 1rem;
    background-color: whitesmoke;
}

input,
button {
    cursor: pointer;
    width: 40%;
    height: 5vh;
    font-size: large;
    border-radius: 0.5rem;
    -webkit-border-radius: 0.5rem;
    -moz-border-radius: 0.5rem;
    -ms-border-radius: 0.5rem;
    -o-border-radius: 0.5rem;
    border: none;
}

input {
    text-align: center;
    background-color: rgb(151, 212, 212);
}

button {
    padding: auto auto;
    background-color: green;
    color: gold;
}

img {
    width: 50%;
}

ul {
    display: grid;
    grid-template-columns: 13rem 13rem 13rem;
    grid-gap: 1rem;
    list-style-type: none;
}

ul li {
    border-radius: 0.5rem;
    width: 10rem;
    height: 2rem;
    background-color: rgb(151, 212, 212);
    text-align: center;
    align-content: center;
    font-size: 1.5rem;
}