/* ==========================================================================
   Lab exercise engine — presentation
   Tokens fall back to literals so this works standalone (drafts/) or on top
   of site/assets/styles.css, which defines the same names.
   ========================================================================== */

.lx { background: var(--bg, #F5F6F8); min-height: 100%;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  color: var(--text, #0B0B0F); -webkit-font-smoothing: antialiased; }
.lx *, .lx *::before, .lx *::after { box-sizing: border-box; }

/* ---- header ---- */
.lx-head { background: var(--card, #fff); border-bottom: 1px solid var(--border-strong, #E2E4E9); }
.lx-head-in { max-width: 1320px; margin: 0 auto; padding: 14px 40px 18px; }
.lx-crumb { display: flex; align-items: center; gap: 7px; font-size: 12px;
  color: var(--text-muted, #9AA0AC); margin-bottom: 12px; }
.lx-crumb b { color: var(--text-body, #5B616E); font-weight: 600; }
.lx-head-row { display: flex; align-items: flex-start; justify-content: space-between; gap: 32px; }
.lx-title { font-family: 'Fraunces', Georgia, serif; font-size: 27px; font-weight: 600;
  letter-spacing: -.01em; margin: 0 0 6px; }
.lx-goal { margin: 0; font-size: 14px; color: var(--text-body, #5B616E); max-width: 640px; }

/* ---- embedded heading (chrome:false) ---- */
.lx-embed-head { margin-bottom: 20px; }
.lx-ex-title { font-size: 20px; font-weight: 800; margin: 0 0 10px; }
.lx-ex-goal { background: var(--info-bg, #EEF2FF); border-left: 4px solid var(--info, #1D4ED8);
  border-radius: 8px; padding: 12px 15px; font-size: 14px; line-height: 1.5; }

/* ---- layout ---- */
.lx-body { max-width: 1320px; margin: 0 auto; padding: 28px 40px 56px;
  display: grid; grid-template-columns: minmax(0,1fr) 372px; gap: 24px; align-items: start; }
.lx-col { display: flex; flex-direction: column; gap: 20px; min-width: 0; }

/* ---- containers ---- */
.lx-card { background: var(--card, #fff); border: 1px solid var(--border-strong, #E2E4E9);
  border-radius: 12px; box-shadow: var(--card-shadow, 0 2px 4px rgba(11,11,15,.04), 0 18px 40px rgba(11,11,15,.06)); }
.lx-card--q { border: 1.5px solid var(--blue-deep, #1D4ED8); overflow: hidden; }
.lx-card-head { padding: 15px 22px; border-bottom: 1px solid var(--border, #ECEDF1);
  display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.lx-card-title { font-size: 15px; font-weight: 700; }
.lx-card-sub { font-size: 12.5px; color: var(--text-body, #5B616E); margin-top: 3px; }
.lx-card-meta { font-size: 12px; color: var(--text-muted, #9AA0AC); font-variant-numeric: tabular-nums; }

/* ---- question ---- */
.lx-q-in { padding: 20px 22px 18px; }
.lx-kicker { font-size: 11px; font-weight: 700; letter-spacing: .06em; text-transform: uppercase;
  color: var(--blue-deep, #1D4ED8); margin-bottom: 9px; }
.lx-q-lead { margin: 0; font-size: 15px; line-height: 1.55; }
.lx-q-ask { margin: 14px 0 0; font-size: 21px; font-weight: 700; letter-spacing: -.01em; }
.lx-params { display: grid; gap: 22px; padding: 15px 22px; background: #FAFBFC;
  border-top: 1px solid var(--border, #ECEDF1); }
.lx-param-l { font-size: 10.5px; font-weight: 700; letter-spacing: .05em; text-transform: uppercase;
  color: var(--text-muted, #9AA0AC); margin-bottom: 4px; }
.lx-param-v { font-size: 17px; font-weight: 700; font-variant-numeric: tabular-nums; }
.lx-param-u { font-size: 12.5px; font-weight: 500; color: var(--text-body, #5B616E); }

/* ---- given table ---- */
.lx-grid { display: grid; grid-template-columns: 150px minmax(0,1fr) 92px 104px; }
.lx-th { padding: 9px 0; font-size: 10.5px; font-weight: 700; letter-spacing: .05em;
  text-transform: uppercase; color: var(--text-muted, #9AA0AC); }
.lx-given-h { padding: 0 22px; background: #FAFBFC; border-bottom: 1px solid var(--border, #ECEDF1); }
.lx-given-r { padding: 13px 22px; border-bottom: 1px solid var(--border, #ECEDF1); align-items: center; }
.lx-given-r:last-child { border-bottom: 0; }
.lx-g-name { font-size: 13.5px; font-weight: 600; }
.lx-g-content { font-size: 12.5px; color: var(--text-body, #5B616E); overflow: hidden;
  text-overflow: ellipsis; white-space: nowrap; padding-right: 18px; }
.lx-g-tok { font-size: 15px; font-weight: 700; text-align: right; font-variant-numeric: tabular-nums; }
.lx-g-dir { text-align: right; }
.lx-chip { display: inline-block; font-size: 10.5px; font-weight: 700; letter-spacing: .03em;
  padding: 3px 10px; border-radius: 20px; }
.lx-chip--in { background: var(--info-bg, #EEF2FF); color: var(--blue-deep, #1D4ED8); }
.lx-chip--out { background: #F3EEFF; color: var(--violet, #7C5CFF); }

/* ---- steps ---- */
.lx-step { padding: 18px 22px; border-bottom: 1px solid var(--border, #ECEDF1); }
.lx-step:last-child { border-bottom: 0; }
.lx-step[data-state="locked"] { opacity: .45; pointer-events: none; }
.lx-step[data-state="active"] { background: #FCFDFF; }
.lx-step-row { display: flex; align-items: flex-start; gap: 13px; }
.lx-dot { flex: none; width: 23px; height: 23px; border-radius: 50%; font-size: 11.5px;
  font-weight: 700; display: flex; align-items: center; justify-content: center; margin-top: 1px;
  background: var(--border, #ECEDF1); color: var(--text-muted, #9AA0AC); }
.lx-step[data-state="active"] .lx-dot { background: var(--blue-deep, #1D4ED8); color: #fff; }
.lx-step[data-state="done"] .lx-dot { background: var(--success, #16A34A); color: #fff; }
.lx-step-main { flex: 1; min-width: 0; }
.lx-step-top { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; }
.lx-q { font-size: 14px; font-weight: 600; }
.lx-step[data-state="locked"] .lx-q { color: var(--text-muted, #9AA0AC); }
.lx-answer { flex: none; font-size: 15px; font-weight: 700; color: var(--success, #16A34A);
  font-variant-numeric: tabular-nums; }

.lx-note { display: flex; gap: 9px; align-items: flex-start; padding: 10px 13px; border-radius: 8px;
  font-size: 12.5px; line-height: 1.5; }
.lx-note svg { flex: none; margin-top: 1px; }
.lx-note--hint { background: var(--info-bg, #EEF2FF); color: var(--blue-deep, #1D4ED8); margin: 11px 0 14px; }
.lx-note--err { background: var(--danger-bg, #FCE9EA); color: #B3373B; margin-top: 12px; }

.lx-opts { display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 9px; }
.lx-opt { padding: 14px 10px; border: 1.5px solid var(--border-strong, #E2E4E9); border-radius: 9px;
  background: var(--card, #fff); color: var(--text, #0B0B0F); font-family: inherit; font-size: 17px;
  font-weight: 700; cursor: pointer; font-variant-numeric: tabular-nums; min-height: 48px; }
.lx-opt:hover { border-color: var(--text-disabled, #C7CCE0); }
.lx-opt[data-wrong] { border-color: var(--danger, #E5484D); background: var(--danger-bg, #FCE9EA);
  color: var(--danger, #E5484D); }

/* ---- estimate rail ---- */
.lx-rail { background: var(--card, #fff); border: 1px solid var(--border-strong, #E2E4E9);
  border-radius: 12px; position: sticky; top: 24px; overflow: hidden;
  box-shadow: var(--card-shadow, 0 2px 4px rgba(11,11,15,.04), 0 18px 40px rgba(11,11,15,.06)); }
.lx-rail-sec { padding: 16px 20px 4px; }
.lx-rail-sec + .lx-rail-sec { margin-top: 6px; border-top: 1px solid var(--border, #ECEDF1); padding-top: 14px; }
.lx-rail-h { font-size: 10.5px; font-weight: 700; letter-spacing: .05em; text-transform: uppercase;
  color: var(--text-muted, #9AA0AC); margin-bottom: 9px; }
.lx-rail-row { display: flex; justify-content: space-between; align-items: baseline; padding: 6px 0; }
.lx-rail-row span:first-child { font-size: 13px; color: var(--text-body, #5B616E); }
.lx-rail-row span:last-child { font-size: 14px; font-weight: 700; font-variant-numeric: tabular-nums;
  color: var(--text-disabled, #C7CCE0); }
.lx-rail-row.is-set span:last-child { color: var(--text, #0B0B0F); }

.lx-total { margin-top: 14px; padding: 18px 20px; background: #FAFBFC;
  border-top: 1px solid var(--border, #ECEDF1); }
.lx-total-l { font-size: 11px; font-weight: 700; letter-spacing: .05em; text-transform: uppercase;
  color: var(--text-muted, #9AA0AC); }
.lx-total-v { font-size: 32px; font-weight: 800; margin-top: 5px; letter-spacing: -.02em;
  font-variant-numeric: tabular-nums; color: var(--text-disabled, #C7CCE0); }
.lx-total-note { font-size: 12.5px; margin-top: 9px; line-height: 1.55; display: none; }
.lx-rail.is-done .lx-total { background: var(--success-bg, #EAFAF1); }
.lx-rail.is-done .lx-total-l, .lx-rail.is-done .lx-total-v { color: #15803D; }
.lx-rail.is-done .lx-total-note { display: block; color: #15803D; }

.lx-learned { padding: 16px 20px; border-top: 1px solid var(--border, #ECEDF1); display: none; }
.lx-rail.is-done .lx-learned { display: block; }
.lx-learned-list { margin: 0; padding: 0 0 0 17px; }
.lx-learned-list li { font-size: 12.5px; line-height: 1.5; color: var(--text-body, #5B616E);
  margin-bottom: 9px; }
.lx-learned-list li:last-child { margin-bottom: 0; }
.lx-learned-list li::marker { color: var(--success, #16A34A); }

.lx-ladder { padding: 16px 20px; border-top: 1px solid var(--border, #ECEDF1); display: none; }
.lx-rail.is-done .lx-ladder { display: block; }
.lx-ladder-row { display: flex; justify-content: space-between; padding: 5px 0; font-size: 12.5px;
  font-variant-numeric: tabular-nums; color: var(--text-body, #5B616E); }
.lx-ladder-row.is-here { font-weight: 800; color: var(--text, #0B0B0F); }

/* ---- buttons ---- */
.lx-btn { display: inline-flex; align-items: center; gap: 7px; padding: 8px 15px;
  border: 1px solid var(--border-strong, #E2E4E9); border-radius: 8px; background: var(--card, #fff);
  color: var(--text-body, #5B616E); font-family: inherit; font-size: 13px; font-weight: 600;
  cursor: pointer; flex: none; margin-top: 4px; }
.lx-btn:hover { background: var(--bg, #F5F6F8); }
.lx-btn--sm { margin-top: 0; padding: 6px 12px; font-size: 12px; }

/* ---- phone ---- */
@media (max-width: 900px) {
  .lx-head-in, .lx-body { padding-left: 18px; padding-right: 18px; }
  .lx-body { grid-template-columns: minmax(0,1fr); gap: 14px; padding-bottom: 104px; }
  .lx-title { font-size: 20px; }
  .lx-q-ask { font-size: 16px; }
  .lx-grid { grid-template-columns: minmax(0,1fr) auto; }
  .lx-g-content, .lx-given-h { display: none; }
  .lx-given-r { display: flex; justify-content: space-between; align-items: center; gap: 10px; }
  .lx-g-tok { margin-left: auto; padding-right: 9px; }
  .lx-opts { grid-template-columns: minmax(0,1fr); }
  .lx-rail { position: fixed; inset: auto 0 0 0; top: auto; border-radius: 0;
    border-left: 0; border-right: 0; border-bottom: 0; box-shadow: 0 -4px 16px rgba(11,11,15,.06); }
  .lx-rail-sec, .lx-ladder, .lx-learned { display: none !important; }
  .lx-total { margin-top: 0; padding: 13px 18px; border-top: 0; }
  .lx-total-v { font-size: 24px; }
  .lx-total-note { display: none !important; }
}