:root {
  color-scheme: light dark;
  --bg: #f6f5f1; --card: #ffffff; --ink: #1a1a18; --muted: #6b6a64; --line: #dcdad2;
  --accent: #1f5d4f; --on-accent: #ffffff; --danger: #a4262c;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111210; --card: #1c1d1a; --ink: #eeede8; --muted: #9c9b93; --line: #33342f;
    --accent: #7fd1bb; --on-accent: #0c1f1a; --danger: #ff8a84;
  }
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { margin: 0; min-height: 100%; background: var(--bg); color: var(--ink);
  font: 17px/1.45 -apple-system, system-ui, "Hiragino Sans", Roboto, "Noto Sans CJK JP", sans-serif; }
main { display: flex; flex-direction: column; gap: 14px; min-height: 100dvh; max-width: 560px; margin: 0 auto;
  padding: calc(env(safe-area-inset-top) + 24px) 20px calc(env(safe-area-inset-bottom) + 24px); }
main.center { justify-content: center; text-align: center; }
h1 { font-size: 28px; line-height: 1.2; margin: 0; }
h2 { font-size: 13px; font-weight: 600; color: var(--muted); margin: 0 0 6px; }
p { margin: 0; }
.mark { font-size: 44px; font-weight: 700; letter-spacing: -0.02em; color: var(--accent); }
.lead { color: var(--muted); margin-bottom: 18px; }
.muted { color: var(--muted); }
.problem { color: var(--danger); }
button { font: inherit; min-height: 50px; padding: 12px 16px; border-radius: 12px; border: 1px solid transparent; }
.primary { background: var(--accent); color: var(--on-accent); font-weight: 600; }
.primary:disabled { opacity: 0.45; }
.secondary { background: transparent; color: var(--accent); }
.danger { background: var(--danger); color: var(--bg); font-weight: 600; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 14px 16px; color: var(--ink); text-align: left; }
.row { display: flex; justify-content: space-between; align-items: center; gap: 12px; width: 100%; }
.row small { display: block; color: var(--muted); font-size: 13px; }
.did { font: 13px/1.4 ui-monospace, Menlo, monospace; overflow-wrap: anywhere; margin: 0; }
.words { display: grid; grid-template-columns: 1fr 1fr; gap: 8px 20px; padding: 14px 16px 14px 44px; margin: 0;
  background: var(--card); border: 1px solid var(--line); border-radius: 14px; font-weight: 600; user-select: none; -webkit-user-select: none; }
.field { display: flex; flex-direction: column; gap: 6px; margin-top: 6px; }
.field span { font-size: 13px; color: var(--muted); }
input:not([type]), textarea { font: inherit; width: 100%; padding: 12px; color: var(--ink); background: var(--card);
  border: 1px solid var(--line); border-radius: 10px; }
dl { margin: 0; display: grid; gap: 4px; }
dt { font-size: 13px; color: var(--muted); margin-top: 8px; }
dd { margin: 0; }
.code { font: 700 32px/1.2 ui-monospace, Menlo, monospace; letter-spacing: 0.04em; }
.confirm { display: flex; gap: 10px; align-items: center; padding: 10px 0; }
.confirm input { width: 22px; height: 22px; flex: none; }
.devices, .proofs { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.proofs li { padding: 10px 0; border-bottom: 1px solid var(--line); }
.score { font-size: 64px; font-weight: 700; line-height: 1; color: var(--accent); }