:root { --fg: #1b1f24; --bg: #f7f5f0; --accent: #1f3a5f; --muted: #5b6370; --card: #ffffff; }
@media (prefers-color-scheme: dark) { :root { --fg: #e9e6df; --bg: #15181c; --accent: #8fb3e0; --muted: #a4abb5; --card: #1f2329; } }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--fg); font: 16px/1.7 system-ui, -apple-system, "Hiragino Sans", "Noto Sans JP", sans-serif; }
main { max-width: 560px; margin: 0 auto; padding: calc(16px + env(safe-area-inset-top)) 16px calc(24px + env(safe-area-inset-bottom)); }
h1 { font-size: 1.4rem; color: var(--accent); margin: 0 0 .25rem; }
h2 { font-size: 1rem; margin: 0 0 .5rem; }
section { background: var(--card); border-radius: 12px; padding: 16px; margin: 12px 0; }
.note, dt { color: var(--muted); font-size: .9rem; }
dl { margin: 0; } dd { margin: 0 0 .5rem; word-break: break-all; }
label { display: block; margin: .75rem 0 .25rem; }
input { width: 100%; padding: 12px; font-size: 16px; border: 1px solid var(--muted); border-radius: 8px; background: transparent; color: var(--fg); }
button { width: 100%; margin-top: .75rem; padding: 12px; font-size: 16px; border: 0; border-radius: 8px; background: var(--accent); color: var(--bg); }
#message { min-height: 1.5em; }