body {
    font-family: Arial, sans-serif;
    background-color: #f4f4f4;
    color: #333;
    display: flex;
    justify-content: center;
    align-items: flex-start; /* Align to start to make space for nav */
    min-height: 100vh;
    margin: 0;
    padding-top: 60px; /* Space for the fixed nav bar */
}

.container {
    background-color: #fff;
    padding: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 700px;
    text-align: center;
    position: relative; /* For potential positioning of elements inside */
}

h1, h2 {
    color: #0056b3;
}

/* Navigation Bar Styles (added) */
#main-nav {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    background-color: #0056b3;
    padding: 10px 20px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    z-index: 1000;
    text-align: left;
}

.nav-button {
    background-color: #f0f0f0;
    color: #0056b3;
    border: none;
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1em;
    transition: background-color 0.3s ease;
}

.nav-button:hover {
    background-color: #e0e0e0;
}


.intro-screen, .question-container, .results-container {
    margin-top: 20px;
}

.dataset-selection {
    margin-bottom: 20px;
}

select, button {
    padding: 10px 15px;
    margin: 5px;
    border-radius: 5px;
    border: 1px solid #ddd;
    font-size: 1em;
    cursor: pointer;
}

select {
    width: calc(100% - 20px);
    max-width: 300px;
}

button {
    background-color: #007bff;
    color: white;
    border: none;
    transition: background-color 0.3s ease;
}

button:hover {
    background-color: #0056b3;
}

button:disabled {
    background-color: #cccccc;
    cursor: not-allowed;
}

.options-container {
    text-align: left;
    margin-top: 20px;
}

.option {
    display: block;
    margin-bottom: 10px;
    padding: 10px;
    border: 1px solid #e0e0e0;
    border-radius: 5px;
    cursor: pointer;
    background-color: #f9f9f9;
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.option:hover {
    background-color: #f0f0f0;
    border-color: #c0c0c0;
}

.option input[type="checkbox"] {
    margin-right: 10px;
}

.option.disabled {
    pointer-events: none; /* Disable clicks */
    opacity: 0.7;
}

.instant-feedback {
    margin-top: 15px;
    padding: 10px;
    border-radius: 5px;
    font-weight: bold;
    color: white;
}

.instant-feedback.correct {
    background-color: #28a745; /* Green */
}

.instant-feedback.incorrect {
    background-color: #dc3545; /* Red */
}

.code-block {
    background-color: #eee;
    padding: 15px;
    border-radius: 5px;
    text-align: left;
    white-space: pre-wrap; /* Preserve whitespace and wrap long lines */
    word-break: break-word; /* Break long words */
    font-family: 'Courier New', Courier, monospace;
    margin-top: 15px;
    margin-bottom: 20px;
    overflow-x: auto; /* Enable horizontal scrolling if code is too long */
}

.correct-highlight {
    background-color: #d4edda; /* Light green for correct answers */
    border-color: #28a745;
}

.incorrect-highlight {
    background-color: #f8d7da; /* Light red for incorrect selected answers */
    border-color: #dc3545;
}

.hidden {
    display: none;
}

/* Styles for buttons in results container (added) */
.results-button {
    margin-top: 15px;
    padding: 12px 20px;
    font-size: 1.1em;
}

.results-button:last-of-type {
    margin-left: 10px; /* Space between "New Test" and "Home" */
}