:root { color-scheme: light dark; }
body { font-family: -apple-system, BlinkMacSystemFont, Segoe UI, Roboto, sans-serif; margin: 0; }
.container { max-width: 640px; margin: 40px auto; padding: 0 16px; }
header { margin-bottom: 24px; }
h1 { margin: 0 0 8px 0; font-size: 28px; }
main section { border: 1px solid #ddd; border-radius: 12px; padding: 16px; margin-bottom: 16px; }
label { display: block; margin-bottom: 8px; }
input { width: 100%; padding: 8px; margin-top: 4px; box-sizing: border-box; }
button { padding: 10px 14px; margin-top: 8px; }
.hint { color: #666; font-size: 13px; margin-top: 8px; }
.hidden { display: none; }