:root {
  --bg: #f6f6f4;
  --surface: #ffffff;
  --ink: #1c1d1f;
  --ink-2: #4a4d52;
  --ink-3: #6c7076;
  --line: #dcdcd8;
  --line-strong: #b9bab5;
  --accent: #2f5bd3;
  --accent-ink: #ffffff;
  --accent-soft: #eaf0fd;
  --error: #b42318;
  --error-soft: #fdecea;
  --focus: #2f5bd3;
  --radius: 10px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #141517;
    --surface: #1d1f22;
    --ink: #ececea;
    --ink-2: #c3c5c8;
    --ink-3: #9a9da2;
    --line: #33363a;
    --line-strong: #4a4e53;
    --accent: #7c9cf5;
    --accent-ink: #0d1430;
    --accent-soft: #232c45;
    --error: #ff8a80;
    --error-soft: #3a1f1d;
    --focus: #9db4ff;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #141517; --surface: #1d1f22; --ink: #ececea; --ink-2: #c3c5c8; --ink-3: #9a9da2;
  --line: #33363a; --line-strong: #4a4e53; --accent: #7c9cf5; --accent-ink: #0d1430;
  --accent-soft: #232c45; --error: #ff8a80; --error-soft: #3a1f1d; --focus: #9db4ff; color-scheme: dark;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}
.wrap { max-width: 680px; margin: 0 auto; padding: 24px 16px 48px; }
.brand { display: flex; align-items: center; gap: 9px; font-size: 13px; color: var(--ink-3); letter-spacing: .02em; margin-bottom: 16px; }
.brand img { width: 44px; height: 44px; object-fit: contain; border-radius: 10px; flex: none; }
.brand a { color: inherit; }
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 28px 24px;
}
@media (max-width: 480px) { .card { padding: 22px 16px; } }
h1 { font-size: 24px; line-height: 1.25; margin: 0 0 16px; }
h2 { font-size: 13px; text-transform: uppercase; letter-spacing: .06em; color: var(--ink-3); margin: 0 0 10px; font-weight: 600; }
p { margin: 0 0 12px; color: var(--ink-2); }
.muted { color: var(--ink-3); font-size: 14px; }
a { color: var(--accent); }

.progress { margin-bottom: 20px; }
.progress-meta span:last-child { white-space: nowrap; }
.progress-meta { display: flex; justify-content: space-between; font-size: 13px; color: var(--ink-3); margin-bottom: 6px; gap: 12px; }
.progress-track { height: 6px; background: var(--line); border-radius: 3px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--accent); border-radius: 3px; transition: width .2s ease; }

fieldset { border: 0; padding: 0; margin: 0; min-width: 0; }
legend { font-size: 19px; font-weight: 600; line-height: 1.35; padding: 0; margin-bottom: 6px; color: var(--ink); }
.qhint { font-size: 14px; color: var(--ink-3); margin: 0 0 14px; }
.qnum { color: var(--ink-3); font-weight: 500; }

.concept {
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  padding: 12px 14px;
  border-radius: 6px;
  margin: 0 0 20px;
  color: var(--ink);
  font-size: 15px;
}

.options { display: grid; gap: 8px; margin-top: 14px; }
.opt {
  display: flex; align-items: flex-start; gap: 12px;
  padding: 12px 14px;
  border: 1px solid var(--line-strong);
  border-radius: 8px;
  cursor: pointer;
  background: var(--surface);
  min-height: 48px;
}
.opt:hover { border-color: var(--accent); }
.opt input { margin: 3px 0 0; width: 18px; height: 18px; flex: none; accent-color: var(--accent); }
.opt:has(input:checked) { border-color: var(--accent); background: var(--accent-soft); }
.opt:has(input:focus-visible) { outline: 2px solid var(--focus); outline-offset: 2px; }

.field { margin-top: 14px; }
.field label { display: block; font-size: 14px; font-weight: 600; margin-bottom: 6px; color: var(--ink); }
input[type="text"], input[type="email"], textarea {
  width: 100%; font: inherit; color: var(--ink); background: var(--surface);
  border: 1px solid var(--line-strong); border-radius: 8px; padding: 10px 12px;
}
textarea { min-height: 140px; resize: vertical; }
input:focus-visible, textarea:focus-visible, button:focus-visible, a:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
[aria-invalid="true"] { border-color: var(--error) !important; }
.counter { font-size: 12px; color: var(--ink-3); text-align: right; margin-top: 4px; }

.error {
  color: var(--error); background: var(--error-soft);
  border-radius: 6px; padding: 8px 12px; font-size: 14px; margin-top: 12px;
}
.error:empty { display: none; }

.notice { font-size: 14px; color: var(--ink-2); border: 1px dashed var(--line-strong); border-radius: 8px; padding: 10px 12px; margin-top: 14px; }

.nav { display: flex; justify-content: space-between; gap: 12px; margin-top: 28px; }
button {
  font: inherit; font-weight: 600; border-radius: 8px; padding: 11px 20px; min-height: 46px;
  cursor: pointer; border: 1px solid transparent;
}
.btn-primary { background: var(--accent); color: var(--accent-ink); margin-left: auto; }
.btn-primary[disabled] { opacity: .6; cursor: progress; }
.btn-secondary { background: transparent; color: var(--ink); border-color: var(--line-strong); }

.hp { position: absolute; left: -10000px; width: 1px; height: 1px; overflow: hidden; }
.test-banner { background: #fff4d6; color: #5c4400; border: 1px solid #e9c46a; padding: 8px 12px; border-radius: 8px; font-size: 14px; margin-bottom: 12px; }
footer { margin-top: 18px; font-size: 13px; color: var(--ink-3); text-align: center; }
footer a { color: var(--ink-3); }
.ref { font-family: ui-monospace, SFMono-Regular, Menlo, monospace; font-size: 14px; background: var(--bg); padding: 2px 6px; border-radius: 4px; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }
noscript p { color: var(--error); }
.card h2:not(:first-child) { margin-top: 24px; }