/* Benchtop practice questions, in Benchtop's homepage style. Tokens, the top bar (.gn), sub-bar (.sn), tab bar and the shared
   blocks (.bt-sec, .bt-field, .bt-tag, .bt-list, .bt-btn) come from ../css/frame.css; colours and .steps from ../css/app.css. */
body.pr-page { display: flex; flex-direction: column; min-height: 100vh; background: var(--bg); }

.pr-main { flex: 1; width: 100%; max-width: 1320px; margin: 0 auto; padding: 28px max(20px, env(safe-area-inset-right, 0px)) 80px max(20px, env(safe-area-inset-left, 0px)); outline: none; } /* the same width and spacing as Benchtop's main */
.pr-loading { padding: 40px 0; color: var(--muted); }
.err { margin: 20px 0; padding: 14px 18px; border-radius: 14px; background: var(--bad-soft); color: var(--bad); }

/* neutral pill button */
.pr-btn { display: inline-flex; align-items: center; justify-content: center; min-height: 34px; padding: 6px 15px; border: 0; border-radius: 999px; background: var(--seg-bg); color: var(--ink); font: 500 14px/1.2 var(--font-body); text-decoration: none; cursor: pointer; -webkit-tap-highlight-color: transparent; }
.pr-btn:hover { background: color-mix(in oklab, var(--seg-bg), var(--ink) 8%); }
.pr-btn[hidden] { display: none; }
.pr-page .bt-btn > span[aria-hidden] { margin: 0 4px; }
.pr-page .bt-btn > span[aria-hidden]:first-child { margin: 0 6px 0 -2px; font-size: 1.2em; line-height: .8; }
.pr-page .bt-btn--fill { cursor: pointer; }

/* hero */
.pr-hero { margin-bottom: 32px; }
.pr-hero .eyebrow a { color: inherit; text-decoration: none; }
.pr-hero .eyebrow a:hover { text-decoration: underline; }
.pr-backrow { display: flex; flex-wrap: wrap; gap: 10px; margin: 20px 0 0; }
.pr-howto { margin: 16px 0 0; font-size: 15px; color: var(--muted); }
.pr-meta { display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 12px 18px; margin-top: 22px; }
.pr-meta[hidden] { display: none; }
.pr-prog { flex: 1 1 260px; max-width: 420px; }
.pr-prog[hidden] { display: none; }
.pr-bar { display: block; height: 4px; overflow: hidden; border-radius: 999px; background: var(--seg-bg); }
.pr-bar i { display: block; width: 0; height: 100%; border-radius: inherit; background: var(--good); transition: width .4s ease; }
.pr-progress { margin: 8px 0 0; font-size: 13px; font-weight: 600; color: var(--muted); }
.pr-warn { margin: 16px 0 0; padding: 12px 16px; border-radius: 14px; background: color-mix(in oklab, var(--warn) 14%, var(--surface-2)); font-size: 15px; }

/* sub-bar: question links on a topic page */
.pr-page .sn-links a.done { opacity: 1; }
.pr-tick { color: var(--good); font-weight: 700; }

/* five little dots per topic: done / started / not started */
.pr-dots { display: inline-flex; flex: none; gap: 4px; }
.pr-dots i { width: 8px; height: 8px; border-radius: 50%; background: var(--seg-bg); }
.pr-dots i.half { background: linear-gradient(90deg, var(--good) 50%, var(--seg-bg) 50%); }
.pr-dots i.on { background: var(--good); }

/* topic list */
.pr-area { margin-top: 44px; scroll-margin-top: calc(var(--snav) + 16px); }
.pr-area-head { display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px 14px; margin-bottom: 14px; }
.pr-area-head .bt-sec-h { margin: 0; font-size: 28px; }
.pr-trow { gap: 14px; -webkit-tap-highlight-color: transparent; }
.pr-tn { display: inline-grid; flex: none; place-items: center; width: 28px; height: 28px; border-radius: 50%; background: var(--surface); color: var(--muted); font: 600 13px/1 var(--font-body); }
.pr-trow.all-done .pr-tn { background: var(--good); color: var(--bg); }
.pr-tname { flex: 1; min-width: 0; font-size: 17px; font-weight: 500; }
.pr-tstat { display: inline-flex; flex: none; align-items: center; gap: 10px; font-size: 13px; color: var(--muted); }
.pr-count { white-space: nowrap; }
.pr-soon { color: var(--faint); white-space: nowrap; }
.pr-trow.soon .pr-tname { color: var(--muted); }
.pr-go { flex: none; font-size: 22px; line-height: 1; color: var(--faint); }

/* a question: a grey tile with white part cards */
.pr-qs { display: flex; flex-direction: column; gap: 20px; }
.pr-q { padding: 28px 28px 24px; scroll-margin-top: calc(var(--snav) + 16px); }
.pr-qhead { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 10px; }
.pr-qh { margin: 0 4px 0 0; font: 600 24px/1.2 var(--font-display); letter-spacing: -.01em; }
.pr-stars { gap: 1px; letter-spacing: 1px; }
.pr-stars .on { color: var(--ink); }
.pr-stars .off { color: var(--line-strong); }
.pr-page .lvl-tag { padding: 2px 8px; border-radius: 999px; font-size: 12px; line-height: 1.4; vertical-align: middle; }
.pr-stretch { background: none; box-shadow: inset 0 0 0 1px var(--line-strong); }
.pr-qstat { margin-left: auto; font-size: 13px; font-weight: 600; color: var(--muted); }
.pr-qstat.done { color: var(--good); }
.pr-style { margin: 10px 0 0; font-size: 14px; font-style: italic; color: var(--muted); }
.pr-uses { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; margin: 12px 0 0; }
.pr-uses-k { font-size: 13px; font-weight: 600; color: var(--muted); }
a.pr-use { color: var(--ink); text-decoration: none; }
a.pr-use:hover { background: color-mix(in oklab, var(--seg-bg), var(--ink) 8%); }
.pr-use.chem { background: none; box-shadow: inset 0 0 0 1px var(--line-strong); }
.pr-stem { max-width: 72ch; margin: 16px 0 0; font-size: 17px; line-height: 1.6; }

.pr-fig { max-width: 540px; margin: 16px 0 0; padding: 14px; border-radius: 16px; background: var(--surface); color: var(--ink); --mo-hi: #d97706; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .pr-fig { --mo-hi: #fbbf24; } }
:root[data-theme="dark"] .pr-fig { --mo-hi: #fbbf24; }
.pr-fig svg { display: block; width: 100%; height: auto; overflow: visible; font-family: var(--font-body); }

.pr-table-wrap { max-width: 100%; margin: 16px 0 0; overflow-x: auto; -webkit-overflow-scrolling: touch; }
.pr-table { overflow: hidden; border-collapse: collapse; border-radius: 14px; background: var(--surface); font-size: 15px; font-variant-numeric: tabular-nums; }
.pr-table th, .pr-table td { padding: 8px 14px; border: 0; border-top: 1px solid var(--line); text-align: center; white-space: nowrap; }
.pr-table thead th { border-top: 0; color: var(--muted); font-size: 13px; font-weight: 600; }
.pr-table tr > * + * { border-left: 1px solid var(--line); }

/* parts */
.pr-parts { display: flex; flex-direction: column; gap: 12px; margin: 20px 0 0; padding: 0; list-style: none; }
.pr-part { padding: 18px 20px; border-radius: 18px; background: var(--surface); transition: box-shadow .2s ease; }
.pr-part.ok { box-shadow: inset 0 0 0 1.5px var(--good); }
.pr-ask { margin: 0 0 12px; font-size: 16px; font-weight: 500; line-height: 1.5; }
.pr-try { max-width: 480px; min-height: 52px; padding-right: 6px; }
.pr-try .pr-in { font: 500 18px/1.3 var(--font-mono); }
.pr-in::placeholder, .pr-ta::placeholder { color: var(--faint); font-family: var(--font-body); }
.pr-try .bt-btn { flex: none; }
.pr-keys { display: flex; gap: 6px; margin-top: 8px; }
.pr-key { min-width: 40px; height: 36px; padding: 0 12px; border: 0; border-radius: 999px; background: var(--seg-bg); color: var(--ink); font: 500 15px/1 var(--font-body); cursor: pointer; -webkit-tap-highlight-color: transparent; }
.pr-key:hover { background: color-mix(in oklab, var(--seg-bg), var(--ink) 8%); }
.pr-ta-lab { display: block; margin-bottom: 8px; font-size: 13px; font-weight: 600; color: var(--muted); }
.pr-tafield { align-items: stretch; padding: 4px 16px; }
.pr-tafield .pr-ta { display: block; min-height: 96px; resize: vertical; font: 400 16px/1.5 var(--font-body); }
.pr-fb { margin: 10px 0 0; font-size: 15px; }
.pr-fb:empty { display: none; }
.pr-fb.ok { color: var(--good); font-weight: 600; }
.pr-fb.bad { color: var(--bad); }
.pr-fb.info { color: var(--muted); }
.pr-fb-conv { margin-left: 4px; color: var(--ink); font-family: var(--font-mono); font-weight: 500; }
.pr-fb-note { display: block; margin-top: 3px; font-size: 13px; font-weight: 400; color: var(--muted); }
.pr-btns { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.pr-btns [hidden] { display: none; }
.pr-k { margin: 0 6px 0 0; font: 600 12px/1.3 var(--font-body); color: var(--muted); }
.pr-hint, .pr-work, .pr-ans, .pr-model { margin: 12px 0 0; padding: 14px 16px; border-radius: 14px; background: var(--surface-2); font-size: 15px; line-height: 1.55; }
.pr-hint .pr-k, .pr-ans .pr-k { display: block; margin-bottom: 4px; }
.pr-work .steps { font-size: 15px; }
.pr-work .steps li { grid-template-columns: 28px 1fr; }
.pr-work .steps .k { padding: 4px 0; border-radius: 999px; font-size: 12px; }
.pr-mistake { margin: 12px 0 0; padding: 10px 14px; border-radius: 12px; background: color-mix(in oklab, var(--warn) 14%, var(--surface)); font-size: 14px; }
.pr-work > .pr-mistake:first-child { margin-top: 0; }
.pr-ans { background: var(--accent-soft); }
.pr-ans b { font: 600 18px/1.3 var(--font-mono); }
.pr-model > p { margin: 0 0 8px; }
.pr-model > .pr-k { margin-bottom: 6px; }
.pr-note { margin: 10px 0 0 !important; font-size: 13px; color: var(--muted); }
.pr-empty p { margin: 0; color: var(--muted); }

/* pager */
.pr-pager { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; margin-top: 36px; }
.pr-pg { display: flex; flex-direction: column; gap: 4px; padding: 18px 22px; border-radius: 18px; background: var(--surface-2); color: var(--ink); text-decoration: none; -webkit-tap-highlight-color: transparent; transition: transform .25s ease, box-shadow .25s ease; }
.pr-pg:hover { transform: scale(1.01); box-shadow: 0 4px 24px rgba(0, 0, 0, .08); }
.pr-pg--next { grid-column: 2; align-items: flex-end; text-align: right; }
.pr-pg-k { font-size: 12px; font-weight: 600; color: var(--muted); }
.pr-pg b { font: 600 19px/1.25 var(--font-display); }
.pr-calc { margin: 20px 0 0; text-align: center; }

.pr-foot { max-width: 1320px; width: 100%; margin: 0 auto; padding: 0 20px 40px; font-size: 12.5px; color: var(--faint); } /* like Benchtop's .site-foot */
.pr-foot a { color: var(--muted); }

@media (max-width: 734px) {
  .pr-main { padding: 20px 16px 40px; }
  .pr-hero { margin-bottom: 24px; }
  .pr-area { margin-top: 36px; }
  .pr-area-head .bt-sec-h { font-size: 22px; }
  .pr-trow { gap: 12px; padding: 13px 14px; }
  .pr-tname { font-size: 16px; }
  .pr-tstat .pr-dots { display: none; }
  .pr-qs { gap: 14px; }
  .pr-q { padding: 20px 16px 18px; }
  .pr-qh { font-size: 21px; }
  .pr-stem { font-size: 16px; }
  .pr-fig { padding: 8px; }
  .pr-part { padding: 14px 14px 16px; }
  .pr-try { max-width: none; }
  .pr-try .pr-in { font-size: 17px; }
  .pr-btn, .pr-key { min-height: 40px; }
  .pr-pager { grid-template-columns: 1fr; gap: 10px; }
  .pr-pager > span:empty { display: none; }
  .pr-pg--next { grid-column: auto; }
  .pr-pg { padding: 14px 18px; }
  .pr-pg b { font-size: 17px; }
  .pr-foot { padding: 0 16px 32px; }
}
@media (prefers-reduced-motion: reduce) {
  .pr-bar i, .pr-part, .pr-pg { transition: none; }
  .pr-pg:hover { transform: none; }
}