:root {
    --color-bg: #f8f9fa;
    --color-text: #212529;
    --color-primary: #2563eb;
    --font-mono: "SF Mono", "Fira Code", monospace;
    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: var(--font-sans);
    background: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
}

main {
    max-width: 960px;
    margin: 40px auto;
    padding: 0 20px;
}

h1 { font-size: 1.8rem; margin-bottom: 0.5rem; }
p  { margin-bottom: 0.5rem; }