body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: #f4f5f7;
    margin: 0;
    color: #333;
    line-height: 1.6;
}

header {
    background: #020741;
    color: white;
    padding: 10px 15px; /* Significantly reduced padding */
    text-align: center;
}

header h1 {
    font-size: 1.2rem; /* Adjusted to a readable but compact size */
    margin: 0;
}

header p {
    font-size: 0.85rem;
    margin: 5px 0 0 0;
}


#audio-container {
    max-width: 800px;
    margin: 20px auto;
    padding: 0 15px;
}

.grade-section {
    margin-top: 30px;
}

.grade-title {
    border-bottom: 2px solid #005a87;
    color: #005a87;
    padding-bottom: 5px;
}

.audio-card {
    background: white;
    border-radius: 8px;
    padding: 15px;
    margin-bottom: 15px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    display: flex;
    flex-direction: column;
}

.audio-card h3 {
    margin-top: 0;
    font-size: 1.1rem;
}

audio {
    width: 100%;
    margin-top: 10px;
}

footer {
    text-align: center;
    padding: 2rem;
    font-size: 0.9rem;
    color: #666;
}

#textbook-box {
    margin: 20px 0;
    padding: 10px;
    background: white;
    border-radius: 8px;
    border: 2px solid #005a87;
}

#textbook-select {
    width: 100%;
    font-size: 1rem;
    padding: 8px;
    margin-top: 8px;
    border-radius: 5px;
    border: 1px solid #333;
}

.collapsible {
    cursor: pointer;
    padding: 8px 0;
}

.collapsible:hover {
    color: #003d5c;
}

.content-box {
    margin-top: 10px;
    border-left: 2px solid #005a87;
    padding-left: 10px;
}