body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Arial, sans-serif;
    background-color: #fdfdfd;
    color: #333;
    line-height: 1.6;
    margin: 0;
    display: flex;
    justify-content: center;
}

.container {
    width: 90%;
    max-width: 1000px; /* Limits width on huge screens for readability */
    padding: 40px 20px;
}

header {
    border-bottom: 1px solid #eee;
    margin-bottom: 30px;
    padding-bottom: 10px;
}

h1 { font-size: 2.2rem; color: #222; margin-bottom: 5px; }
h2 { font-size: 1.8rem; border-bottom: 2px solid #f0f0f0; padding-bottom: 10px; }

.lecture-card {
    background: #ffffff;
    border: 1px solid #e1e4e8;
    border-radius: 8px;
    padding: 24px;
    margin-bottom: 30px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.03);
}

.lecture-title { font-size: 1.4rem; font-weight: bold; margin: 0; color: #111; }

.meta { color: #800000; font-weight: 500; margin: 8px 0 20px 0; font-size: 0.95rem; }

.section-label { font-weight: bold; margin-top: 15px; display: block; }

ul { list-style: disc; padding-left: 20px; margin: 10px 0; }

li { margin: 6px 0; font-size: 0.95rem; }

a { color: #0056b3; text-decoration: none; font-weight: 500; }
a:hover { text-decoration: underline; }

.code-link { font-family: monospace; background: #f4f4f4; padding: 2px 4px; border-radius: 3px; }
.lecture-description {
    margin: 10px 0;
    color: #444;
    line-height: 1.5;
}