body {
    font-family: Arial, sans-serif;
    margin: 0;
    background-color: #f4f4f4;
    text-align: center;
}

header {
    background-color: #2c3e50;
    color: white;
    padding: 30px;
}

h1 {
    margin: 0;
}

h2 {
    color: #2c3e50;
    margin-top: 40px;
}

.course {
    background-color: white;
    width: 60%;
    margin: 20px auto;
    padding: 30px;
    border-radius: 10px;
}

button {
    background-color: #3498db;
    color: white;
    border: none;
    padding: 12px 20px;
    margin: 10px;
    font-size: 16px;
    cursor: pointer;
    border-radius: 5px;
}

button:hover {
    background-color: #2980b9;
}

footer {
    background-color: #2c3e50;
    color: white;
    padding: 15px;
    margin-top: 40px;
}

/* Notes page styles */
.notes-wrapper {
    max-width: 900px;
    margin: 40px auto;
    background: linear-gradient(180deg, #ffffff 0%, #f7fbff 100%);
    padding: 36px 48px;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(44,62,80,0.08);
    text-align: left;
    color: #22303f;
}

.notes-wrapper h1 {
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    color: #0b2b4a;
    margin-bottom: 6px;
}

.notes-wrapper .subtitle {
    color: #537089;
    margin-top: 0;
    margin-bottom: 20px;
}

pre.code {
    background: #0b2b4a;
    color: #e6f2ff;
    padding: 14px;
    border-radius: 8px;
    overflow-x: auto;
    font-family: 'Courier New', Consolas, monospace;
    line-height: 1.5;
    margin: 12px 0;
}

pre.output {
    background: #f3f6f9;
    color: #0b2b4a;
    padding: 10px 12px;
    border-left: 4px solid #bcdffb;
    border-radius: 6px;
    margin: 8px 0 18px 0;
}

.note-box {
    background: linear-gradient(90deg,#fff8e6,#fff);
    border-left: 4px solid #ffcf66;
    padding: 12px 14px;
    border-radius: 6px;
    margin: 14px 0;
    color: #4a3b00;
}

table.ref {
    width: 100%;
    border-collapse: collapse;
    margin: 12px 0 18px 0;
}

table.ref th, table.ref td {
    border: 1px solid #e6eef6;
    padding: 8px 10px;
}

table.ref th {
    background: #f0f6fb;
    color: #14344a;
    text-align: left;
}

@media (max-width: 640px) {
    .notes-wrapper { padding: 20px; margin: 20px; }
    .course { width: auto; }
}