/* Minimal starting point. Jiaqi owns the visual polish. */
* { box-sizing: border-box; }
body { margin: 0 auto; max-width: 960px; padding: 20px; font-family: Arial, sans-serif; line-height: 1.5; color: #222; }
header, section { margin-bottom: 20px; }
section { padding: 16px; border: 1px solid #ccc; }
h1, h2, h3 { margin-top: 0; }
button { padding: 8px 12px; font: inherit; cursor: pointer; }
button:disabled { cursor: not-allowed; }
section > div { overflow-x: auto; }
table { width: 100%; margin-top: 12px; border-collapse: collapse; }
caption { text-align: left; }
th, td { padding: 8px; border-bottom: 1px solid #ddd; text-align: left; }
dt { font-weight: bold; }
dd { margin: 0 0 8px; }
:focus-visible { outline: 2px solid #2357b5; outline-offset: 3px; }