:root {
  --bg: #f5f6f8; --card: #ffffff; --text: #1b1f27; --muted: #667085; --line: #d9dde5;
  --accent: #2563eb; --accent-text: #ffffff; --danger: #c0392b; --field: #ffffff;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111418; --card: #1a1f26; --text: #e8eaef; --muted: #98a2b3; --line: #2b323c;
    --accent: #4c8dff; --accent-text: #0b1220; --danger: #ff6b5e; --field: #11151a;
  }
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body { background: var(--bg); color: var(--text); font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif; }
main { max-width: 640px; margin: 0 auto; padding: 24px 16px 48px; }
h1 { font-size: 24px; margin: 8px 0 4px; }
h2 { font-size: 17px; margin: 0 0 4px; }
.lead, .hint, .note { color: var(--muted); margin: 4px 0 14px; }
.hint { font-size: 14px; margin-bottom: 10px; }
.who { margin: 8px 0 0; font-size: 18px; }
form { display: grid; gap: 14px; margin-top: 12px; }
label { display: grid; gap: 6px; font-size: 14px; color: var(--muted); }
input, textarea { font: inherit; color: var(--text); background: var(--field); border: 1px solid var(--line); border-radius: 10px; padding: 12px; width: 100%; }
input:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
textarea.key { font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace; font-size: 13px; resize: vertical; word-break: break-all; }
button { font: inherit; font-weight: 600; background: var(--accent); color: var(--accent-text); border: 0; border-radius: 10px; padding: 12px 16px; cursor: pointer; }
button.secondary { background: transparent; color: var(--text); border: 1px solid var(--line); }
button:disabled { opacity: .6; cursor: default; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 16px; margin: 14px 0; }
summary.fold { cursor: pointer; font-weight: 600; margin-bottom: 8px; }
details.card:not([open]) summary.fold { margin-bottom: 0; }
.row { display: flex; gap: 10px; flex-wrap: wrap; margin-top: 10px; }
.row button { flex: 1 1 140px; }
.error { color: var(--danger); margin: 0; }
[hidden] { display: none !important; }