* {
    text-align: center;
}

/* Setup container for operator selection */
#setupContainer {
    background-color: lightblue;
    border: 3px solid darkblue;
    width: 300px;
    padding: 20px;
    margin: 30px auto;
    border-radius: 10px;
}

#operatorSelect {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

#operatorSelect label {
    font-size: 18px;
    font-weight: bold;
    color: darkblue;
}

#operatorSelect select {
    padding: 10px;
    font-size: 16px;
    border: 2px solid darkblue;
    border-radius: 5px;
    background-color: white;
    cursor: pointer;
}

#operatorSelect button {
    padding: 10px 20px;
    font-size: 16px;
    background-color: darkblue;
    color: white;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: bold;
    transition: background-color 0.3s;
}

#operatorSelect button:hover {
    background-color: navy;
}

/* Flashcard container */
#fc {
    background-color: lightcyan;
    border: 2px solid black;
    width: 180px;
    height: 300px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    color: black;
    font-size: 18px;
    padding: 10px;
    box-sizing: border-box;
    margin: 20px auto;
}

/* Answer input */
input[type="text"] {
    padding: 10px;
    font-size: 16px;
    border: 2px solid black;
    border-radius: 5px;
    margin-top: 10px;
}

input[type="text"]:focus {
    outline: none;
    border-color: blue;
    box-shadow: 0 0 5px blue;
}
body {
    background-color: lightskyblue;
    animation: backgroundColor linear 20s infinite;
}
@keyframes backgroundColor {
    0% { background-color: lightskyblue;}
    25% { background-color: lightcoral;}
    50% { background-color: lightgreen;}
    75% { background-color: lightyellow;}
    100% { background-color: lightskyblue;}
}