* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    background-color: #f0f2f5;
    color: #333;
}

.container {
    max-width: 800px;
    margin: 2rem auto;
    padding: 2rem;
    background-color: white;
    border-radius: 10px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

h1 {
    text-align: center;
    color: #1a73e8;
    margin-bottom: 2rem;
}

.settings {
    margin-bottom: 2rem;
}

.setting-group {
    margin-bottom: 1.5rem;
}

.setting-group label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: #444;
}

.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 1rem;
}

.checkbox-group label {
    font-weight: normal;
    margin-left: 0.5rem;
}

input[type="number"] {
    width: 100px;
    padding: 0.5rem;
    border: 1px solid #ddd;
    border-radius: 4px;
}

button {
    background-color: #1a73e8;
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.2s;
}

button:hover {
    background-color: #1557b0;
}

.practice-area {
    text-align: center;
    margin-top: 2rem;
}

.problem {
    font-size: 2rem;
    margin-bottom: 1.5rem;
}

.problem input {
    width: 100px;
    font-size: 2rem;
    text-align: center;
    margin-left: 0.5rem;
}

.progress {
    margin: 1rem 0;
    color: #666;
}

#feedback {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 4px;
}

#feedback.correct {
    background-color: #e6f4ea;
    color: #137333;
}

#feedback.incorrect {
    background-color: #fce8e6;
    color: #c5221f;
}

.results {
    text-align: center;
}

.results h2 {
    color: #1a73e8;
    margin-bottom: 1rem;
}

.results p {
    font-size: 1.2rem;
    margin-bottom: 1.5rem;
}

.sqrt-symbol {
    display: inline-block;
    font-size: 1.5em;
    font-weight: bold;
    margin-right: 2px;
    position: relative;
    top: 2px;
}

.sqrt-number {
    display: inline-block;
    font-size: 1.2em;
    padding: 0 2px;
}

@media (max-width: 600px) {
    .container {
        margin: 1rem;
        padding: 1rem;
    }

    .problem {
        font-size: 1.5rem;
    }

    .problem input {
        font-size: 1.5rem;
        width: 80px;
    }
}