:root {
  --bg: #f5f6f8; --card: #ffffff; --text: #1b1f24; --muted: #667085; --line: #d9dde3;
  --accent: #0b6bcb; --accent-text: #ffffff; --ok: #1a7f37; --ok-bg: #e6f4ea; --bad: #b42318; --bad-bg: #fdecea;
}
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14171c; --card: #1d2229; --text: #e8eaed; --muted: #98a2b3; --line: #343b45;
    --accent: #4da3ff; --accent-text: #0b1520; --ok: #56d364; --ok-bg: #12301b; --bad: #ff8a80; --bad-bg: #3a1a18;
  }
}
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); color: var(--text); font: 16px/1.5 system-ui, -apple-system, "Segoe UI", sans-serif; }
header { display: flex; justify-content: space-between; align-items: center; padding: 10px 16px; background: var(--card); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 5; }
header nav { display: flex; gap: 6px; }
header button { background: none; border: 0; color: var(--accent); font: inherit; padding: 6px 10px; cursor: pointer; border-radius: 6px; }
main { max-width: 720px; margin: 0 auto; padding: 16px; }
h2 { font-size: 1.1rem; margin: 24px 0 8px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 16px; margin-bottom: 14px; }
.center { text-align: center; }
.muted { color: var(--muted); }
.small { font-size: .85rem; }
.row { display: flex; gap: 8px; flex-wrap: wrap; margin-top: 12px; }
.center .row { justify-content: center; }
.big { font-size: 2.6rem; font-weight: 700; line-height: 1.1; }
.txt { white-space: pre-wrap; margin: 0 0 8px; }
pre { background: var(--bg); border: 1px solid var(--line); border-radius: 6px; padding: 10px; overflow-x: auto; font-size: .85rem; }
figure { margin: 10px 0; }
figure img { max-width: 100%; height: auto; border: 1px solid var(--line); border-radius: 6px; background: #fff; }
figcaption { font-size: .85rem; color: var(--muted); }
.qhead { display: flex; justify-content: space-between; align-items: center; gap: 8px; margin-bottom: 10px; font-size: .9rem; }
.hint { color: var(--muted); font-size: .9rem; margin: 4px 0 8px; }

.btn { font: inherit; padding: 9px 16px; border-radius: 8px; border: 1px solid var(--line); background: var(--card); color: var(--text); cursor: pointer; }
.btn.primary { background: var(--accent); color: var(--accent-text); border-color: var(--accent); }
.btn.danger { color: var(--bad); }
.btn.sm { padding: 2px 10px; }
.btn:disabled { opacity: .4; cursor: not-allowed; }
.star { font: inherit; background: none; border: 0; color: var(--muted); cursor: pointer; padding: 2px 4px; }
.star.on { color: #d19a00; }
button:focus-visible, input:focus-visible, select:focus-visible, summary:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.opts { display: grid; gap: 8px; margin-top: 8px; }
label.opt { display: flex; gap: 10px; align-items: flex-start; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; cursor: pointer; white-space: pre-wrap; }
label.opt:has(input:checked) { border-color: var(--accent); background: color-mix(in srgb, var(--accent) 10%, transparent); }
label.opt input { margin-top: 5px; flex: none; }
label.opt input:disabled + span { opacity: .5; }

.order .orow { display: flex; align-items: center; gap: 8px; padding: 8px 10px; border: 1px solid var(--line); border-radius: 8px; margin-bottom: 6px; }
.onum { color: var(--muted); width: 1.4em; flex: none; }
.otext { flex: 1; }
.mrow { display: grid; gap: 6px; padding: 10px 0; border-bottom: 1px solid var(--line); }
.mrow:last-child { border-bottom: 0; }
select { font: inherit; padding: 8px; border-radius: 8px; border: 1px solid var(--line); background: var(--card); color: var(--text); max-width: 100%; }

.nav { display: flex; gap: 8px; justify-content: space-between; margin: 4px 0 12px; }
.nav .btn:last-child:not(:first-child) { margin-left: auto; }
.qmap { display: flex; flex-wrap: wrap; gap: 5px; }
.qdot { width: 32px; height: 32px; border-radius: 6px; border: 1px solid var(--line); background: var(--card); color: var(--muted); font: inherit; font-size: .8rem; cursor: pointer; padding: 0; }
.qdot.done { background: color-mix(in srgb, var(--accent) 18%, var(--card)); color: var(--text); }
.qdot.cur { border: 2px solid var(--accent); color: var(--text); }

details.case { border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px; margin-bottom: 12px; background: var(--bg); }
details.case summary { cursor: pointer; font-weight: 600; }

.review { margin: 12px 0; }
.rlabel { font-weight: 600; font-size: .9rem; margin-top: 8px; }
.rlabel.ok, .rrow.ok .small { color: var(--ok); }
.rlabel.bad, .rrow.bad .small { color: var(--bad); }
.review ul, .review ol { margin: 4px 0; padding-left: 22px; }
.rrow { padding: 8px 10px; border-radius: 8px; margin-bottom: 6px; }
.rrow.ok { background: var(--ok-bg); }
.rrow.bad { background: var(--bad-bg); }
.explain { border-top: 1px solid var(--line); padding-top: 10px; margin-top: 10px; }

.stats { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 10px; margin-bottom: 14px; }
.stat { background: var(--card); border: 1px solid var(--line); border-radius: 10px; padding: 12px; }
.stat b { display: block; font-size: 1.5rem; line-height: 1.2; }
table { width: 100%; border-collapse: collapse; font-size: .92rem; }
th, td { text-align: left; padding: 6px 4px; border-bottom: 1px solid var(--line); }
td.num, th.num { text-align: right; }
.bm { display: flex; justify-content: space-between; gap: 10px; align-items: center; padding: 8px 0; border-bottom: 1px solid var(--line); }
.form-row { display: grid; gap: 6px; margin: 12px 0; }

/* Drag-and-drop and visual answer-area controls */
.draggable-row { cursor: grab; touch-action: pan-y; }
.draggable-row:active { cursor: grabbing; }
.dragging { opacity: .45; }
.drop-target { outline: 2px dashed var(--accent, #2563eb); outline-offset: 2px; background: rgba(37,99,235,.08); }
.match-row { display: grid; gap: .55rem; padding: .85rem 0; border-bottom: 1px solid var(--line, #ddd); }
.match-drop { min-height: 2.8rem; display:flex; align-items:center; padding:.55rem .75rem; border:2px dashed var(--line, #aaa); border-radius: .55rem; color: var(--muted, #666); background: var(--surface, #fff); }
.match-drop.filled { border-style: solid; color: inherit; }
.match-choices { display:flex; flex-wrap:wrap; gap:.45rem; }
.choice-chip { border:1px solid var(--line, #bbb); border-radius:999px; padding:.45rem .7rem; background:var(--surface, #fff); cursor:grab; }
.choice-chip:active { cursor:grabbing; }
.match-row select { max-width:100%; }
.manual-card figure { margin:.7rem 0; }
.manual-card img { display:block; max-width:100%; height:auto; border-radius:.45rem; border:1px solid var(--line, #ddd); }
.manual-card .txt { white-space:pre-wrap; }

.source-warning {
  margin: 1rem 0;
  padding: .85rem 1rem;
  border-left: 4px solid #b7791f;
  background: #fff8e8;
  color: #5c4615;
  border-radius: .35rem;
}
.source-warning p { margin: .35rem 0 0; }