body {
    margin: 0;
    font-family: Arial, sans-serif;
}

.top-menu {
    background: #222;
    padding: 0;
    display: flex;
    gap: 0;
}

.top-menu button {
    background: #333;
    color: #fff;
    border: none;
    padding: 16px 32px;
    cursor: pointer;
    font-size: 1rem;
    transition: background 0.2s;
    border-right: 1px solid #444;
}

.top-menu button:last-child {
    border-right: none;
}

.top-menu button:hover,
.top-menu button:focus {
    background: #444;
}

.callout {
    border-left: 5px solid #0078d7;
    background: #f3f8fd;
    padding: 16px 24px;
    margin: 20px 0;
    border-radius: 6px;
    box-shadow: 0 2px 6px rgba(0,0,0,0.03);
    font-size: 1.05em;
}