body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: #f0f2f5;
    color: #1c1e21;
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    margin: 0;
}

#tutor-container {
    background-color: #ffffff;
    border-radius: 8px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1), 0 8px 16px rgba(0, 0, 0, 0.1);
    width: 90%;
    max-width: 700px;
    padding: 20px;
    box-sizing: border-box;
}

#main-title {
    text-align: center;
    color: #003366;
    border-bottom: 2px solid #f0f2f5;
    padding-bottom: 15px;
    margin-bottom: 20px;
}

#content-area h2 {
    color: #0055a4;
}

#content-area h3 {
    color: #0077cc;
    border-left: 4px solid #0077cc;
    padding-left: 10px;
}

#content-area p, #content-area li {
    line-height: 1.6;
}

.example {
    background-color: #e7f3ff;
    border: 1px solid #cce0ff;
    padding: 15px;
    border-radius: 5px;
    margin: 15px 0;
}

.example-step {
    margin-bottom: 10px;
}

.practice-problem {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px dashed #ccc;
}

#input-area {
    margin-top: 20px;
    display: flex;
    gap: 10px;
}

#user-answer {
    flex-grow: 1;
    padding: 10px;
    border: 1px solid #ccc;
    border-radius: 5px;
}

#navigation-area {
    text-align: center;
    margin-top: 20px;
}

button {
    background-color: #0077cc;
    color: white;
    border: none;
    padding: 12px 25px;
    border-radius: 5px;
    cursor: pointer;
    font-size: 16px;
    transition: background-color 0.3s;
}

button:hover {
    background-color: #0055a4;
}

#progress-bar-container {
    width: 100%;
    background-color: #e0e0e0;
    border-radius: 5px;
    margin-bottom: 20px;
}

#progress-bar {
    width: 0%;
    height: 10px;
    background-color: #4caf50;
    border-radius: 5px;
    transition: width 0.5s ease-in-out;
}

.feedback {
    padding: 10px;
    border-radius: 5px;
    margin-top: 10px;
}

.correct {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.incorrect {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}