body {
    margin: 0;
    font-family: Arial, sans-serif;
    line-height: 1.6;
    color: #1f2937;
    background: #f3f4f6;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 32px 20px 60px;
}

.card {
    background: #ffffff;
    border-radius: 16px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.08);
    padding: 32px;
}

h1, h2, h3 {
    color: #0f172a;
    margin-top: 0;
}

h1 {
    font-size: 2rem;
    margin-bottom: 8px;
}

h2 {
    margin-top: 28px;
    font-size: 1.25rem;
}

p, li {
    font-size: 1rem;
}

.muted {
    color: #6b7280;
}

.nav {
    display: flex;
    gap: 16px;
    flex-wrap: wrap;
    margin: 16px 0 24px;
}

.nav a,
.button {
    display: inline-block;
    text-decoration: none;
    background: #2563eb;
    color: #ffffff;
    padding: 12px 18px;
    border-radius: 10px;
    font-weight: 600;
}

.nav a.secondary,
.button.secondary {
    background: #e5e7eb;
    color: #111827;
}

.note {
    background: #eff6ff;
    border-left: 4px solid #2563eb;
    padding: 14px 16px;
    border-radius: 8px;
    margin: 20px 0;
}

ul {
    padding-left: 22px;
}

code {
    background: #f3f4f6;
    padding: 2px 6px;
    border-radius: 6px;
}

@media (max-width: 640px) {
    .card {
        padding: 22px;
    }

    h1 {
        font-size: 1.6rem;
    }
}