/* AMC 8 Practice - main stylesheet.
   Translated from amc8/lib/render.py's inline CSS (warm cream / serif / green-accent look).
   Phase A1 baseline; revisit in A3 against math.ahaanamg.com. */

:root {
  --paper:#fbf8f1; --ink:#222a2f; --soft:#5f6b72; --faint:#8a949a;
  --rule:#e6dfd0; --line:#efe9dc;
  --accent:#2f6f5e; --accent-d:#235244; --accent-bg:#e9f1ed;
  --step:#b5651d; --gold:#c8922b;
  --serif:"Iowan Old Style","Palatino Linotype",Palatino,Georgia,serif;
  --sans:ui-rounded,"Avenir Next",Avenir,"Segoe UI",system-ui,sans-serif;
}

* { box-sizing:border-box; -webkit-tap-highlight-color:transparent; }
body {
  margin:0; background:var(--paper); color:var(--ink);
  font-family:var(--serif); line-height:1.6; font-size:18px;
}
a { color:var(--accent-d); text-decoration:none; }
a:hover { text-decoration:underline; }
.muted { color:var(--soft); }

.wrap { max-width:720px; margin:0 auto; padding:0 20px; }
.wrap.wrap-wide { max-width:1280px; }
.wrap.wrap-lesson {
  max-width:1080px;
  padding:0 28px;
  font-size:15.5px;
  line-height:1.6;
}

.crumb {
  font-family:var(--sans); font-size:13px; color:var(--soft);
  padding:14px 20px; border-bottom:1px solid var(--line);
  position:sticky; top:0; z-index:10;
  background:rgba(251,248,241,.94); backdrop-filter:blur(6px);
}
.crumb a { color:var(--accent-d); }
.crumb .sep { color:var(--faint); margin:0 7px; }

header.hero { padding:40px 0 6px; text-align:center; }
.eyebrow {
  font-family:var(--sans); font-weight:700; font-size:12.5px;
  letter-spacing:2px; text-transform:uppercase; color:var(--accent);
}
h1 { font-size:34px; font-weight:600; margin:10px 0; letter-spacing:-.4px; line-height:1.15; }
.lede { color:var(--soft); font-style:italic; margin:0 auto; max-width:540px; }
.meta-row { display:flex; gap:10px; justify-content:center; flex-wrap:wrap; margin:18px 0 4px; font-family:var(--sans); font-size:13px; }
.pill {
  background:var(--accent-bg); border:1px solid #cfe3da; color:var(--accent-d);
  padding:6px 13px; border-radius:999px; font-weight:600;
}
.count-pill {
  font-family:var(--sans); font-size:12px; color:var(--faint);
  background:#fff; border:1px solid var(--rule); padding:2px 8px; border-radius:999px;
  margin-left:8px;
}

.set { margin:40px 0 0; padding-top:16px; border-top:2px solid var(--ink); }
.set-title { font-size:26px; font-weight:600; margin:2px 0 4px; }
.practice-head {
  font-family:var(--sans); font-weight:700; font-size:13px;
  letter-spacing:1px; text-transform:uppercase; color:var(--faint);
  margin:22px 0 0;
}

.link-list { list-style:none; padding:0; margin:18px 0 0; }
.link-list li { padding:10px 0; border-bottom:1px solid var(--line); display:flex; align-items:center; }
.link-list a { font-size:18px; flex:1; }

/* Problem card */
.q { padding:26px 0; border-bottom:1px solid var(--line); }
.q-tag {
  font-family:var(--sans); font-size:12.5px; font-weight:700;
  color:var(--accent); text-transform:uppercase;
  display:flex; gap:9px; align-items:center;
}
.q-tag .lvl {
  background:#fff; border:1px solid var(--rule); color:var(--soft);
  padding:2px 9px; border-radius:999px; font-size:11px;
}
.chips { display:flex; flex-wrap:wrap; gap:6px; margin:8px 0 2px; }
.chip {
  font-family:var(--sans); font-size:11px; font-weight:600;
  padding:3px 9px; border-radius:999px; border:1px solid var(--rule);
}
.chip.cat { background:var(--accent); color:#fff; border-color:var(--accent); }
.chip.cat2 { background:var(--accent-bg); color:var(--accent-d); }
.chip.tech { background:#fff; color:var(--soft); }
.q-body { font-size:18.5px; }
.q-body p { margin:.5em 0; }

/* ============================================================
   Inline math helpers — pure HTML/CSS (no KaTeX dependency).
   Used when a problem statement contains math notation that the
   AoPS source rendered as an image. We re-typeset using these
   classes so we don't ship a screenshot of LaTeX.
   ============================================================ */

/* Inline fraction (small):  <span class="frac"><span class="n">1</span><span class="d">2</span></span> */
.frac { display:inline-flex; flex-direction:column; vertical-align:middle; text-align:center; margin:0 .12em; font-size:.9em; line-height:1.1; }
.frac .n { border-bottom:1.4px solid var(--ink); padding:0 .35em; }
.frac .d { padding:0 .35em; }

/* Display fraction — bigger, for centered standalone expressions */
.frac-big { font-size:1.15em; margin:0 .15em; }
.frac-big .n, .frac-big .d { padding:0 .5em; }

/* Centered display math block — for set-piece expressions like '(a)(b)+(c)(d) / (e)(f)' */
.math-display {
  display:flex; justify-content:center; align-items:center;
  margin:14px 0; font-size:1.05em;
  font-family: 'Georgia', 'Times New Roman', serif;
  text-align:center;
}

/* Mixed number — e.g. 2 1/3 — keep whole and frac visually together */
.mixed { display:inline-flex; align-items:center; gap:.18em; vertical-align:middle; }

var { font-style:italic; }

/* Exponent / subscript — slightly smaller, baseline-shifted */
.sq { vertical-align:super; font-size:.72em; }
.sub { vertical-align:sub; font-size:.72em; }

/* Number array / grid — for problems that show a 5x5 number table or letter grid */
.math-grid {
  display:inline-grid;
  font-family:'Courier New', 'Lucida Console', monospace;
  font-size:1.05em;
  border-collapse:collapse;
  margin:12px auto;
  gap:0;
}
.math-grid > span {
  padding:6px 14px;
  text-align:center;
  min-width:24px;
}
/* When a kid is searching the array (1991 #6 style), highlight by row/col */
.math-grid.bordered > span { border:1px solid var(--rule); }

/* Card / boxed value — e.g. for a "card on the table" with a letter or number */
.math-card {
  display:inline-block;
  border:1.5px solid var(--ink);
  padding:6px 14px;
  margin:0 8px;
  font-family:'Georgia', serif;
  font-size:1.15em;
  min-width:18px;
  text-align:center;
  background:#fff;
  border-radius:3px;
}
.math-card-row { display:flex; justify-content:center; gap:8px; margin:14px 0; flex-wrap:wrap; }

/* Inline summation, product, etc. — rarely needed at AMC 8 level */
.sigma { font-size:1.3em; vertical-align:middle; }

.choices { display:flex; flex-wrap:wrap; gap:8px 14px; margin:14px 0 2px; }
.choices .c { white-space:nowrap; margin-right:12px; }
.choices .c b { color:var(--accent-d); margin-right:3px; }

figure { margin:18px 0; text-align:center; }
figure img, figure svg { max-width:100%; height:auto; }
figure img { border:1px solid #f1ece1; border-radius:12px; padding:8px; background:#fff; }
figcaption { font-family:var(--sans); font-size:12px; color:var(--faint); margin-top:6px; }

.grid-fig { border-collapse:separate; border-spacing:4px; margin:12px auto; font-family:var(--sans); font-weight:700; }
.grid-fig td { width:32px; height:32px; text-align:center; border-radius:7px; font-size:15px; }
.v1 { background:#eef3ef; color:#5b6f66; }
.v2 { background:#cfe2d9; color:#2f6f5e; }
.v3 { background:#2f6f5e; color:#fff; }

/* Reveals */
details { margin-top:12px; border:1px solid var(--rule); border-radius:12px; background:#fff; overflow:hidden; }
summary {
  cursor:pointer; list-style:none;
  font-family:var(--sans); font-weight:700; font-size:14px;
  padding:11px 15px; color:var(--accent-d);
}
summary::-webkit-details-marker { display:none; }
details.hint summary { color:var(--gold); }
details.hint { border-color:#ecdcbb; background:#fffdf6; }
.reveal { padding:2px 15px 15px; font-size:17px; }
.hint .reveal { color:#6b5320; }

.steps { counter-reset:s; margin:6px 0 0; padding:0; list-style:none; }
.steps li { position:relative; padding:7px 0 7px 42px; border-top:1px dashed var(--line); }
.steps li:first-child { border-top:none; }
.steps li::before {
  counter-increment:s; content:counter(s, decimal-leading-zero);
  position:absolute; left:0; top:8px;
  font-family:var(--sans); font-weight:700; font-size:12px; color:#fff;
  background:var(--step); width:27px; height:23px; border-radius:7px;
  display:grid; place-items:center;
}

.ans {
  margin-top:12px; display:inline-flex; align-items:center; gap:10px;
  font-weight:700; background:var(--accent-bg);
  border:1px solid #cfe3da; color:var(--accent-d);
  padding:9px 15px; border-radius:11px;
  font-family:var(--sans); font-size:15px;
}
.ans .ltr {
  background:var(--accent); color:#fff;
  width:25px; height:25px; border-radius:7px;
  display:grid; place-items:center;
}

/* MAA "Another way" alternate solutions */
.alternate { margin-top:18px; padding-top:14px; border-top:1px dashed var(--rule); }
.alt-title { font-family:var(--sans); font-weight:700; font-size:12.5px; letter-spacing:.4px;
  text-transform:uppercase; color:var(--accent); margin-bottom:6px; }
.alt-name { text-transform:none; letter-spacing:0; color:var(--soft); font-weight:600; }

/* Nav layout: handle pushed to the right */
.crumb { display:flex; align-items:center; flex-wrap:wrap; gap:0; }
.crumb .auth-nav { margin-left:auto; font-family:var(--sans); font-size:13px; }

/* Auth forms */
.auth-form { max-width:380px; margin:18px 0; display:flex; flex-direction:column; gap:14px; }
.auth-form label { display:flex; flex-direction:column; gap:6px; font-family:var(--sans); font-size:14px; font-weight:600; color:var(--ink); }
.auth-form input { font-family:var(--sans); font-size:17px; padding:10px 12px; border:1px solid var(--rule); border-radius:10px; background:#fff; }
.auth-form input:focus { outline:2px solid var(--accent); }
.auth-form .small { font-size:12.5px; margin:-4px 0 0; }
button.primary, .auth-form button {
  font-family:var(--sans); font-weight:700; font-size:15px;
  background:var(--accent); color:#fff; border:none;
  padding:11px 18px; border-radius:10px; cursor:pointer;
}
button.primary:hover, .auth-form button:hover { background:var(--accent-d); }
button.secondary {
  font-family:var(--sans); font-weight:600; font-size:13px;
  background:#fff; color:var(--soft); border:1px solid var(--rule);
  padding:7px 14px; border-radius:8px; cursor:pointer;
}
.flash { padding:10px 14px; margin:10px 0; background:#fff3cd; border:1px solid #ecdcbb; border-radius:8px; font-size:14px; color:#6b5320; }
.logout-form { margin-top:30px; }
.small { font-size:12.5px; }

/* Status chips */
.status-chip { font-family:var(--sans); font-size:11px; font-weight:700; padding:2px 8px; border-radius:999px; margin-left:6px; text-transform:none; letter-spacing:0; }
.status-correct { background:#e1f5e7; color:#1f6f3a; border:1px solid #b6dbc1; }
.status-wrong   { background:#fbe7e3; color:#8a3826; border:1px solid #e8c6bd; }
.status-tough   { background:#fff1d6; color:#8a5a16; border:1px solid #eed8a6; }
.status-easy    { background:#e9f1ed; color:var(--accent-d); border:1px solid #cfe3da; }
.status-got-it  { background:#e9f1ed; color:var(--accent-d); border:1px solid #cfe3da; }
.status-follow-up { background:#f0e5fa; color:#5e3b8c; border:1px solid #d9c2ef; }

/* Choice buttons (clickable) */
.choices-buttons { display:flex; flex-wrap:wrap; gap:8px; margin:14px 0 2px; }
.choice-btn {
  font-family:var(--serif); font-size:17px;
  background:#fff; border:1.5px solid var(--rule); color:var(--ink);
  padding:8px 14px; border-radius:10px; cursor:pointer;
  display:inline-flex; align-items:center; gap:6px;
  transition: background 0.1s, border-color 0.1s;
}
.choice-btn:hover { border-color:var(--accent); background:var(--accent-bg); }
.choice-btn b { color:var(--accent-d); }
.choice-btn.chosen { border-color:var(--accent); }
.choice-btn.correct { border-color:#2e9e5b; background:#e1f5e7; }
.choice-btn.correct b { color:#1f6f3a; }
.choice-btn.wrong { border-color:#c14d34; background:#fbe7e3; color:#8a3826; }
.choice-btn.wrong b { color:#8a3826; }

/* Compact variant for lesson cards — slightly smaller, no border-radius extras.
   Same click behavior; attempts still POST to /attempt/<pid> and write to progress. */
.choices-compact { gap:6px; margin:10px 0 4px; }
.choices-compact .choice-btn {
  font-size:14.5px;
  padding:6px 11px;
  border-radius:6px;
  border-width:1px;
}

.answer-feedback { margin-top:10px; font-family:var(--sans); font-size:14px; padding:8px 12px; border-radius:8px; }
.answer-feedback.ok  { background:#e1f5e7; color:#1f6f3a; border:1px solid #b6dbc1; }
.answer-feedback.no  { background:#fbe7e3; color:#8a3826; border:1px solid #e8c6bd; }
.answer-feedback.err { background:#fff3cd; color:#6b5320; border:1px solid #ecdcbb; }
.answer-feedback.pending { color:var(--faint); }

/* Mark row (subtle, tucked at the bottom of each card) */
.mark-row {
  margin-top:14px; padding-top:10px; border-top:1px dashed var(--line);
  font-family:var(--sans); font-size:12px; color:var(--faint);
  display:flex; flex-wrap:wrap; align-items:center; gap:6px;
}
.mark-btn {
  font-family:var(--sans); font-size:12px;
  background:transparent; border:1px solid var(--rule); color:var(--soft);
  padding:3px 9px; border-radius:999px; cursor:pointer;
}
.mark-btn:hover { background:#fff; border-color:var(--accent); color:var(--accent-d); }
.mark-btn.active { background:var(--accent); color:#fff; border-color:var(--accent); }
.mark-btn.mark-clear { color:var(--faint); }
.mark-note { font-size:11.5px; }
.mark-note a { color:var(--soft); }

/* Range filter bar */
.range-bar {
  display:flex; flex-wrap:wrap; gap:6px; align-items:center;
  margin:18px 0 4px; padding:10px 14px;
  background:#fff; border:1px solid var(--rule); border-radius:12px;
  font-family:var(--sans); font-size:13px;
  position:sticky; top:48px; z-index:5;
}
.range-label { color:var(--soft); font-weight:700; margin-right:4px; }
.range-btn {
  font-family:var(--sans); font-size:13px; font-weight:600;
  background:#fff; border:1px solid var(--rule); color:var(--soft);
  padding:5px 11px; border-radius:999px; cursor:pointer;
}
.range-btn:hover { border-color:var(--accent); color:var(--accent-d); }
.range-btn.active { background:var(--accent); color:#fff; border-color:var(--accent); }

/* Dashboard */
.mark-bucket { margin:10px 0; }

/* Band / topic / order checkboxes (focused practice form) */
.band-form {
  background:#fff; border:1px solid var(--rule); border-radius:12px;
  padding:14px 18px; margin:18px 0; display:flex; flex-direction:column; gap:10px;
}
.band-row { display:flex; flex-wrap:wrap; gap:8px; align-items:center; }
.band-check, .topic-check {
  display:inline-flex; align-items:center; gap:5px;
  font-family:var(--sans); font-size:13px; font-weight:600;
  border:1px solid var(--rule); border-radius:999px;
  padding:5px 11px; cursor:pointer; background:#fff; color:var(--soft);
  user-select:none;
}
.band-check input, .topic-check input { margin:0; cursor:pointer; }
.band-check:hover, .topic-check:hover { border-color:var(--accent); color:var(--accent-d); }
.band-check.checked, .topic-check.checked {
  background:var(--accent-bg); border-color:var(--accent); color:var(--accent-d);
}
.band-count {
  display:inline-flex; align-items:center; gap:6px;
  font-family:var(--sans); font-size:13px; color:var(--soft); margin-left:auto;
}
.band-count input { width:64px; padding:5px 8px; font-size:14px; border:1px solid var(--rule); border-radius:6px; }

select.year-select {
  font-family:var(--sans); font-size:14px; font-weight:600; color:var(--ink);
  background:#fff; border:1.5px solid var(--rule); border-radius:8px;
  padding:6px 10px; cursor:pointer;
}
select.year-select:focus { outline:2px solid var(--accent); border-color:var(--accent); }

/* Letter-only choice buttons (for image-figure problems) */
.choice-btn.letter-only {
  min-width:54px; justify-content:center; font-size:18px;
}

/* Test mode: hide hints + solutions; suppress feedback; hide prior-attempt clues */
.test-mode details.hint,
.test-mode details:not(.hint),
.test-mode .answer-feedback,
.test-mode .q-tag .status-chip,
.test-mode .mark-row { display:none !important; }
.test-mode .choice-btn.chosen { border-color:var(--accent); background:var(--accent-bg); }
.test-mode .choice-btn { background:#fff !important; border-color:var(--rule) !important; color:var(--ink) !important; }
.test-mode .choice-btn.chosen { background:var(--accent-bg) !important; border-color:var(--accent) !important; }
.test-submit-bar {
  position:sticky; bottom:0; padding:14px 16px; margin-top:30px;
  background:rgba(251,248,241,0.95); backdrop-filter:blur(6px);
  border-top:2px solid var(--ink); text-align:center; z-index:6;
}
#test-results { margin-top:10px; font-family:var(--sans); font-size:15px; color:var(--accent-d); }
.test-link { background:var(--accent) !important; color:#fff !important; border-color:var(--accent) !important; }
.test-link:hover { background:var(--accent-d) !important; }

/* Test history table */
table.key th { font-family:var(--sans); font-size:12px; text-transform:uppercase; color:var(--faint); padding:6px 10px; text-align:left; }
table.key td:first-child { font-weight:600; color:var(--ink); }

/* Per-topic mastery table on /me */
table.mastery { width:100%; border-collapse:collapse; margin-top:8px; }
table.mastery th {
  font-family:var(--sans); font-size:11px; text-transform:uppercase;
  letter-spacing:1.5px; color:var(--faint);
  padding:6px 10px; text-align:left; border-bottom:1px solid var(--line);
}
table.mastery th.num { text-align:right; }
table.mastery td { padding:8px 10px; border-bottom:1px solid var(--line); vertical-align:middle; }
table.mastery td.num { text-align:right; font-family:'Courier New',monospace; font-size:14px; }
table.mastery td a { color:var(--ink); font-weight:600; }
table.mastery td a:hover { color:var(--lp-rust, var(--accent-d)); }

/* ============================================================
   .data-table — used in lesson concept_html for visual tables.
   Should look like a real reference table: bordered, alternating
   rows, colored header, friendly for grade 4-7 kids.
   ============================================================ */
table.data-table {
  border-collapse: collapse;
  width: 100%;
  margin: 12px 0;
  font-family: Georgia, "Times New Roman", serif;
  font-size: 14px;
  background: #fff;
  border: 2px solid #1a1a1a;
  box-shadow: 0 1px 3px rgba(0,0,0,0.08);
  border-radius: 4px;
  overflow: hidden;
}
table.data-table thead {
  background: linear-gradient(180deg, #b8493a, #9a3d31);
}
table.data-table thead th {
  color: #fff;
  font-family: Georgia, serif;
  font-weight: 700;
  padding: 10px 12px;
  text-align: left;
  border-right: 1px solid rgba(255,255,255,0.25);
  font-size: 13px;
  text-transform: none;
  letter-spacing: 0.2px;
}
table.data-table thead th:last-child { border-right: none; }
table.data-table tbody td {
  padding: 9px 12px;
  border-bottom: 1px solid #e8dfc8;
  border-right: 1px solid #f0e8d0;
  vertical-align: top;
  color: #1a1a1a;
  line-height: 1.45;
}
table.data-table tbody td:last-child { border-right: none; }
table.data-table tbody tr:nth-child(odd)  { background: #fdf9ef; }
table.data-table tbody tr:nth-child(even) { background: #faf4e3; }
table.data-table tbody tr:hover { background: #f4ecd9; }
table.data-table tbody tr:last-child td { border-bottom: none; }
/* Color-coded inline marks rendered inside cells via inline styles. The
   global rules above already make any text with explicit color (red/green)
   pop against the cream stripes. */
table.data-table code {
  background: #fff8e8;
  padding: 1px 5px;
  border-radius: 3px;
  font-size: 12.5px;
  border: 1px solid #e8dfc8;
}
table.data-table b, table.data-table strong { color: #1a1a1a; }
@media (max-width: 640px) {
  table.data-table { font-size: 12.5px; }
  table.data-table thead th { padding: 7px 8px; }
  table.data-table tbody td { padding: 6px 8px; }
}

.bar {
  display:inline-block; vertical-align:middle;
  width:60%; height:10px; max-width:240px;
  background:#eee; border-radius:5px; overflow:hidden;
}
.bar-fill {
  display:block; height:100%;
  background:linear-gradient(90deg, var(--lp-moss, #4a6b3a), var(--lp-teal, #2d6e7e));
}
.bar-pct {
  display:inline-block; margin-left:8px; vertical-align:middle;
  font-family:'Courier New',monospace; font-size:13px; color:var(--lp-muted, #6b6b6b);
}

/* "Revise N →" call-to-action pill on /me */
.pill-action {
  background:var(--lp-rust, var(--accent-d)) !important;
  color:#fff !important;
  font-weight:700;
}
.pill-action:hover { filter:brightness(1.1); text-decoration:none; }

.revise-filters { margin-top:14px; gap:8px; }

/* Small "Retake" link in /me test history table */
.pill-mini {
  display:inline-block;
  padding:2px 10px;
  border:1px solid var(--lp-teal, var(--accent));
  border-radius:2px;
  background:#fff;
  color:var(--lp-teal, var(--accent-d));
  font-family:var(--sans); font-size:11.5px;
  letter-spacing:0.5px; font-weight:600;
  text-decoration:none;
}
.pill-mini:hover { background:var(--lp-teal, var(--accent)); color:#fff; text-decoration:none; }

/* About page — single article column. Heading + body share the same width so
   nothing looks orphaned. Uses default .wrap (720px) for the outer container. */
.about-body {
  font-size:15.5px;
  line-height:1.7;
  padding:24px 0 8px;
}
.about-eyebrow {
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:2.5px;
  color:var(--lp-rust, var(--accent-d));
  font-weight:700; text-transform:uppercase;
  margin-bottom:6px;
}
.about-h1 {
  font-size:26px; font-weight:600;
  line-height:1.3; letter-spacing:-0.3px;
  margin:0 0 24px;
  padding-bottom:14px;
  border-bottom:1px solid var(--lp-ink, var(--ink));
}
.about-body p { margin:0 0 14px; }
.about-body h2 {
  font-size:17px; font-weight:600;
  margin:26px 0 10px;
  padding-bottom:4px;
  border-bottom:1px solid var(--lp-ink, var(--ink));
  letter-spacing:-0.2px;
}
.about-body ul { margin:0 0 14px; padding-left:22px; }
.about-body li { margin-bottom:6px; }
.about-body a { color:var(--lp-rust, var(--accent-d)); font-weight:600; }
.about-body .pledge {
  background:#fffdf6;
  border-left:3px solid var(--lp-rust, var(--accent-d));
  padding:12px 16px;
  margin:16px 0;
  font-size:15px;
  border-radius:0 3px 3px 0;
}

@media (max-width:520px) {
  .about-h1 { font-size:22px; }
}

/* Leaderboard */
table.lb { width:100%; }
table.lb .lb-rank { font-family:var(--sans); font-weight:700; color:var(--faint); width:2.5em; text-align:right; }
table.lb tr.lb-me { background:var(--accent-bg, #f3f8f3); }
table.lb tr.lb-me td:first-child { color:var(--accent-d); }

/* Test mode: hide hints + solutions; suppress feedback; hide prior-attempt clues */
.test-mode details.hint,
.test-mode details:not(.hint),
.test-mode .answer-feedback,
.test-mode .q-tag .status-chip,
.test-mode .mark-row { display:none !important; }
.test-mode .choice-btn.chosen { border-color:var(--accent); background:var(--accent-bg); }
.test-mode .choice-btn { background:#fff !important; border-color:var(--rule) !important; color:var(--ink) !important; }
.test-mode .choice-btn.chosen { background:var(--accent-bg) !important; border-color:var(--accent) !important; }
.test-submit-bar {
  position:sticky; bottom:0; padding:14px 16px; margin-top:30px;
  background:rgba(251,248,241,0.95); backdrop-filter:blur(6px);
  border-top:2px solid var(--ink); text-align:center; z-index:6;
}
#test-results { margin-top:10px; font-family:var(--sans); font-size:15px; color:var(--accent-d); }
.test-link { background:var(--accent) !important; color:#fff !important; border-color:var(--accent) !important; }
.test-link:hover { background:var(--accent-d) !important; }

footer {
  margin:46px 20px 24px; padding:20px 0 0;
  border-top:1px solid var(--rule);
  font-family:var(--sans); font-size:12px; color:var(--faint); text-align:center;
}

/* ==========================================================
   LESSON PAGES (/learn/<cat>) — D:\Math-style teaching layout
   ========================================================== */
:root {
  --lp-paper: #faf7f0;
  --lp-ink:   #1a1a1a;
  --lp-rust:  #b8493a;
  --lp-teal:  #2d6e7e;
  --lp-gold:  #d4a83c;
  --lp-plum:  #6b3e5a;
  --lp-moss:  #4a6b3a;
  --lp-muted: #6b6b6b;
  --lp-soft:  #f1ebd9;
}

.lp-hero {
  padding:14px 0 14px;
  border-bottom:1px solid var(--lp-ink);
  margin:0 0 20px;
}
.lp-eyebrow {
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:1.5px;
  color:var(--lp-muted); text-transform:uppercase;
  margin-bottom:4px;
}
.lp-eyebrow a { color:var(--lp-rust); text-decoration:none; }
.lp-eyebrow a:hover { text-decoration:underline; }
.lp-eyebrow .sep { color:var(--lp-muted); margin:0 6px; }
.lp-eyebrow-here { color:var(--lp-ink); font-weight:bold; }
.lp-title {
  font-size:26px; font-weight:600; letter-spacing:-0.3px;
  margin:0 0 4px; color:var(--lp-ink); line-height:1.2;
}
.lp-title-sub {
  font-weight:400; color:var(--lp-muted); font-size:18px; font-style:italic;
}
.lp-hero-actions {
  display:flex; gap:14px; align-items:center;
  font-size:13px; font-family:var(--sans);
  margin-top:6px;
}
.lp-hero-meta { color:var(--lp-muted); }
.lp-hero-link { color:var(--lp-rust); font-weight:600; }

.lp-intro-details {
  margin:0 0 28px;
  border:1px solid var(--rule);
  background:#fffdf6;
}
.lp-intro-details > summary {
  cursor:pointer; padding:10px 16px;
  font-family:var(--sans); font-size:13px;
  color:var(--lp-rust); font-weight:600;
  list-style:none; user-select:none;
}
.lp-intro-details > summary::-webkit-details-marker { display:none; }
.lp-intro-details > summary::before { content:"▸ "; color:var(--lp-rust); display:inline-block; transition:transform .15s; }
.lp-intro-details[open] > summary::before { content:"▾ "; }
.lp-intro-details > summary:hover { background:var(--lp-soft); }
.lp-intro { padding:0 18px 16px; border-top:1px dashed var(--rule); }
.lp-intro p { margin:14px 0 12px; font-size:15px; max-width:780px; }

.lp-layout {
  display:grid;
  grid-template-columns:260px minmax(0, 1fr);
  gap:40px;
  max-width:none; margin:0 auto;
}

.lp-sidebar {
  position:sticky; top:56px; align-self:start;
  background:#fffdf6;
  border:1px solid #e4e1d8; border-left:3px solid var(--lp-gold);
  padding:14px 12px;
  max-height:calc(100vh - 76px);
  overflow-y:auto;
  font-size:13.5px;
}
.lp-toc-title {
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:2px;
  color:var(--lp-rust); font-weight:bold;
  margin-bottom:8px; text-transform:uppercase;
}
.lp-toc { list-style:none; padding:0; margin:0; }
.lp-toc li { margin:0 0 1px; }
.lp-toc a {
  display:block; padding:6px 8px 6px 12px;
  color:var(--lp-ink); text-decoration:none; line-height:1.35;
  border-left:2px solid transparent;
}
.lp-toc a:hover { background:var(--lp-soft); border-left-color:var(--lp-gold); text-decoration:none; }
.lp-toc-num {
  display:inline-block; width:28px; color:var(--lp-muted);
  font-family:'Courier New',monospace; font-size:12px;
}
.lp-toc-quiz a {
  font-family:'Courier New',monospace; font-size:11.5px;
  letter-spacing:1.2px; color:var(--lp-plum); text-transform:uppercase;
}
.lp-toc-test a, .lp-toc-appendix a {
  background:var(--lp-ink); color:var(--lp-gold) !important;
  font-family:'Courier New',monospace; font-size:11.5px;
  letter-spacing:1.5px; text-align:center;
  padding:8px 6px; margin-top:10px; border-left:3px solid var(--lp-gold);
}
.lp-toc-test a:hover, .lp-toc-appendix a:hover { background:var(--lp-rust); color:#fff !important; }

.lp-main {
  min-width:0;
  font-size: 15.5px;
  line-height: 1.6;
}
/* No max-width here — the wrap-lesson container (1080px) caps the layout, and the
   grid 260px sidebar + 40px gap + main means main is naturally ~720px on common viewports.
   Width is constrained at the container, not per-element. */
.lp-main p { margin: 0 0 10px; }
.lp-main ul, .lp-main ol { margin: 6px 0 12px; padding-left: 22px; }
.lp-main li { margin-bottom: 4px; }
.lp-intro {
  margin-bottom:28px; padding:0 0 16px;
  border-bottom:1px dashed var(--lp-muted);
}
.lp-intro p { margin-bottom:14px; font-size:16px; }

.lp-chapter { margin:36px 0 56px; }
.lp-chapter:first-of-type { margin-top:8px; }
.lp-chapter-num {
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:2.5px;
  color:var(--lp-rust); font-weight:bold;
  margin-bottom:4px;
}
.lp-quiz-num { color:var(--lp-plum); }
.lp-final-num { color:var(--lp-gold); letter-spacing:4px; }
.lp-app-num { color:var(--lp-teal); }
.lp-chapter-title {
  font-size:21px; color:var(--lp-ink); font-weight:600;
  margin:0 0 14px; padding-bottom:6px;
  border-bottom:1px solid var(--lp-ink);
  letter-spacing:-0.2px;
}

.lp-section-head {
  font-family:'Courier New',monospace;
  font-size:10.5px; letter-spacing:2px;
  color:var(--lp-rust); font-weight:bold;
  margin:18px 0 8px; text-transform:uppercase;
}
.lp-concept, .lp-trick, .lp-trap, .lp-worked, .lp-rot, .lp-mlt {
  margin:18px 0;
}
.lp-concept p, .lp-trick p, .lp-trap p, .lp-rot p { margin-bottom:12px; }

.lp-trick { background:#fffdf6; border-left:3px solid var(--lp-gold); padding:14px 18px; }
.lp-trap  { background:#fff; border:1px dashed var(--lp-rust); padding:12px 18px; }
.lp-trap::before { content:"⚠ "; color:var(--lp-rust); }

.lp-problem {
  background:#fff; border:1px solid #ddd;
  border-left:5px solid var(--lp-gold);
  padding:16px 22px; margin:14px 0;
  font-size:16px; line-height:1.65;
}
.lp-label {
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:2px;
  color:var(--lp-rust); font-weight:bold;
  margin-bottom:6px;
}
.lp-stmt { margin-bottom:8px; }
.lp-figure { display:flex; justify-content:center; margin:10px 0; }
.lp-figure img { max-width:100%; height:auto; }
.lp-diagram { display:flex; justify-content:center; margin:18px 0 4px; }
.lp-diagram svg { max-width:100%; height:auto; }
.lp-caption { text-align:center; font-size:13px; color:var(--lp-muted); font-style:italic; margin:0 0 16px; }
.lp-choices { margin-top:8px; font-size:15px; }
.lp-choice { display:inline-block; margin:2px 14px 2px 0; color:var(--lp-ink); }

.lp-worked-soln {
  background:#fff; border-left:3px solid var(--lp-moss);
  padding:12px 18px; margin:12px 0;
}
.lp-worked-soln p { margin-bottom:10px; }
.lp-think {
  background:var(--lp-soft); border-left:3px solid var(--lp-teal);
  padding:12px 18px; margin:12px 0;
  font-style:italic; color:var(--lp-ink); font-size:15.5px;
}
.lp-think::before { content:"Think: "; font-style:normal; font-weight:bold; color:var(--lp-teal); }
.lp-answer {
  background:var(--lp-ink); color:var(--lp-paper);
  padding:10px 18px; margin:12px 0; border-radius:2px;
  font-size:15.5px;
}
.lp-answer b { color:var(--lp-gold); }

.lp-rot {
  background:#fff; border:2px solid var(--lp-moss);
  padding:14px 20px; margin:18px 0;
  font-size:15.5px;
}
.lp-rot p { margin-bottom:8px; }
.lp-rot .lp-section-head { color:var(--lp-moss); margin-top:0; }

.lp-mlt { margin-top:24px; }
.lp-mlt-grid {
  display:grid; grid-template-columns:repeat(auto-fill, minmax(280px, 1fr)); gap:10px;
  margin-top:8px;
}

/* "More like this" cards are now <details> — click to expand the full problem inline,
   no navigation away from the lesson. Open card spans full grid row.
   Explicit resets neutralize the legacy global `details { border, border-radius, margin-top, background }`. */
details.lp-mini {
  display:block;
  margin-top:0;
  border:none;
  border-left:3px solid var(--lp-gold);
  border-radius:0;
  overflow:visible;
  background:var(--lp-soft);
  color:var(--lp-ink);
  font-size:14px; line-height:1.45;
  padding:0;
}
details.lp-mini > summary {
  list-style:none; cursor:pointer;
  padding:9px 14px;
  user-select:none;
  position:relative;
}
details.lp-mini > summary::-webkit-details-marker { display:none; }
details.lp-mini > summary::after {
  content:"▸";
  position:absolute; right:12px; top:9px;
  color:var(--lp-rust); font-size:11px;
}
details.lp-mini[open] > summary::after { content:"▾"; }
details.lp-mini:hover > summary,
details.lp-mini[open] > summary { background:#ede4cb; }
details.lp-mini > summary > .lp-mini-body {
  padding-right:18px;  /* leave room for caret */
}
.lp-mini-label {
  display:block;
  font-family:'Courier New',monospace; font-size:10.5px;
  letter-spacing:1.5px; color:var(--lp-rust); font-weight:bold;
  margin-bottom:4px;
}
.lp-mini-body { color:var(--lp-ink); }

/* Expanded card body */
.lp-mlt-grid > details.lp-mini[open] { grid-column: 1 / -1; }
.lp-mini-open {
  padding:6px 16px 14px;
  background:#fff;
  border-top:1px dashed var(--rule);
}
.lp-mini-open .lp-problem {
  margin:10px 0; padding:12px 16px;
  background:#fffdf6;
  border:1px solid var(--rule);
  border-left:4px solid var(--lp-gold);
  font-size:14.5px;
}
.lp-mini-reveals {
  display:flex; flex-wrap:wrap; gap:8px;
  margin-top:10px;
}
.lp-mini-reveals > details.lp-mini-r {
  flex:1 1 100%;
  margin-top:0;
  border:none;
  border-radius:0;
  background:transparent;
  overflow:visible;
  padding:0;
}
details.lp-mini-r > summary {
  list-style:none; cursor:pointer; user-select:none;
  display:inline-block;
  padding:5px 12px;
  font-family:var(--sans); font-size:11px;
  letter-spacing:1px; font-weight:700;
  text-transform:uppercase;
  border-radius:3px;
  border:1px solid;
}
details.lp-mini-r > summary::-webkit-details-marker { display:none; }
details.lp-mini-r > summary::before { content:"▸ "; }
details.lp-mini-r[open] > summary::before { content:"▾ "; }
details.lp-mini-r-ans > summary  { background:#e6f1e6; color:#2a5e2a; border-color:#7aaa7a; }
details.lp-mini-r-hint > summary { background:#fff3e0; color:#8a5a1a; border-color:var(--lp-gold); }
details.lp-mini-r-soln > summary { background:var(--lp-soft); color:var(--lp-teal); border-color:var(--lp-teal); }
details.lp-mini-r-ans:hover  > summary { background:#d9ead9; }
details.lp-mini-r-hint:hover > summary { background:#fde8c8; }
details.lp-mini-r-soln:hover > summary { background:#eee9d2; }
.lp-mini-r-body {
  margin:8px 0 0; padding:10px 14px;
  background:#fff;
  border-left:2px solid var(--rule);
  font-size:14px; line-height:1.55;
  color:var(--lp-ink);
}
.lp-mini-r-body.lp-hint-list { padding-left:32px; padding-right:14px; }

/* Progressive hints — each hint is nested under the previous "still stuck?" link */
.lp-hint-progressive { padding:0; }
.lp-hint-stage {
  margin:0 0 4px;
  padding:10px 14px;
  background:#fff;
  border-left:2px solid var(--lp-gold);
}
.lp-hint-num {
  font-family:var(--sans); font-size:10.5px;
  letter-spacing:1.5px; color:var(--lp-rust);
  font-weight:700; text-transform:uppercase;
  margin-bottom:4px;
}
.lp-hint-text { font-size:14px; line-height:1.55; color:var(--lp-ink); }
.lp-hint-text > p:first-child { margin-top:0; }
.lp-hint-text > p:last-child  { margin-bottom:0; }

details.lp-hint-next {
  margin-top:10px;
  border:none;
  border-top:1px dashed var(--rule);
  border-radius:0;
  background:transparent;
  overflow:visible;
  padding-top:8px;
}
details.lp-hint-next > summary {
  list-style:none; cursor:pointer; user-select:none;
  font-family:var(--sans); font-size:12.5px;
  color:var(--lp-teal); font-style:italic;
  padding:4px 0;
}
details.lp-hint-next > summary::-webkit-details-marker { display:none; }
details.lp-hint-next > summary:hover { color:var(--lp-rust); text-decoration:underline; }
details.lp-hint-next[open] > summary { color:var(--lp-muted); font-size:11.5px; }
.lp-soln-list { margin:4px 0; padding-left:22px; }
.lp-soln-list li { margin-bottom:6px; }
.lp-soln-approach { color:var(--lp-muted); font-size:13px; margin-bottom:8px; font-style:italic; }
.lp-soln-alt {
  margin-top:12px; padding-top:10px;
  border-top:1px dashed var(--rule);
}
.lp-soln-alt > b { color:var(--lp-rust); }

.lp-quiz { margin:56px 0; padding:22px 26px; background:#fffdf6; border:1px solid #e4e1d8; }
.lp-quiz .lp-chapter-title { border-bottom-color:var(--lp-plum); }
.lp-blurb { font-style:italic; color:var(--lp-muted); margin-bottom:14px; }

.lp-final { margin:56px 0; padding:24px 26px; background:var(--lp-ink); color:var(--lp-paper); border-radius:3px; }
.lp-final .lp-chapter-title { color:var(--lp-paper); border-bottom-color:var(--lp-gold); }
.lp-final .lp-blurb { color:var(--lp-soft); }
/* Final-test (dark) variant for the inline-expand mini cards */
.lp-final details.lp-mini { background:#2a2a28; border-left-color:var(--lp-gold); color:var(--lp-paper); }
.lp-final details.lp-mini > summary { color:var(--lp-paper); }
.lp-final details.lp-mini:hover > summary,
.lp-final details.lp-mini[open] > summary { background:#3a3a36; }
.lp-final .lp-mini-body { color:var(--lp-paper); }
.lp-final .lp-mini-open { background:#1a1a1a; border-top-color:#3a3a36; }
.lp-final .lp-mini-open .lp-problem { background:#2a2a28; color:var(--lp-paper); border-color:#3a3a36; }
.lp-final .lp-mini-r-body { background:#2a2a28; color:var(--lp-paper); border-left-color:#3a3a36; }
.lp-final .lp-soln-approach { color:#aaa; }

.lp-appendix { margin:56px 0; padding:24px 26px; background:#fffdf6; border:1px solid #e4e1d8; border-top:3px solid var(--lp-teal); }
.lp-app-block { margin:14px 0; }
.lp-app-block .lp-section-head { color:var(--lp-teal); }

.lp-foot {
  margin:60px 0 30px; padding-top:18px;
  border-top:1px solid var(--lp-muted);
  font-family:var(--sans); font-size:14px;
}
.lp-foot a { color:var(--lp-rust); }

/* ==========================================================
   LANDING PAGE — restructured hero + action cards + topic grid
   ========================================================== */
.home-hero {
  padding: 18px 0 14px;
  border-bottom: 1px solid var(--lp-ink);
  margin: 0 0 28px;
}
.home-hero-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.home-hero-titleblock { flex: 1 1 auto; min-width: 280px; }
.home-hero-title {
  font-size: 26px; font-weight: 600; letter-spacing: -0.3px;
  margin: 0 0 4px; color: var(--lp-ink); line-height: 1.2;
}
.home-hero-lede {
  font-size: 14px; color: var(--lp-muted);
  margin: 0; line-height: 1.7;
}
.home-contest-chip {
  display: inline-block;
  padding: 2px 9px;
  margin: 0 2px;
  border: 1px solid var(--lp-ink);
  background: var(--lp-ink);
  color: var(--lp-paper);
  font-family: 'Courier New', monospace;
  font-size: 11px;
  letter-spacing: 0.5px;
  font-weight: bold;
  border-radius: 2px;
  vertical-align: 1px;
}
.home-contest-chip.home-contest-soon {
  background: transparent;
  color: var(--lp-muted);
  border-color: var(--rule);
  font-weight: normal;
}
.home-hero-stats {
  display: flex; gap: 0; align-items: center;
  font-family: var(--sans); font-size: 12px; color: var(--lp-muted);
  flex-shrink: 0;
}
.home-stat {
  display: flex; flex-direction: column; align-items: center;
  padding: 0 18px; border-right: 1px solid var(--rule);
  line-height: 1.2;
}
.home-stat:last-child { border-right: none; padding-right: 0; }
.home-stat:first-child { padding-left: 0; }
.home-stat b {
  color: var(--lp-rust); font-size: 20px; font-weight: 600;
  font-family: 'Georgia', serif;
}
.home-stat span {
  font-size: 11px; text-transform: uppercase;
  letter-spacing: 1px; color: var(--lp-muted);
  margin-top: 2px;
}

/* Primary action grid (4 big cards) */
.home-actions {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 16px;
  margin: 0 0 56px;
}
.home-action-card {
  display: block;
  padding: 24px 22px;
  background: #fff;
  border: 1px solid var(--rule);
  border-top: 4px solid var(--lp-gold);
  text-decoration: none; color: var(--lp-ink);
  transition: transform .12s, box-shadow .12s, border-top-color .12s;
}
.home-action-card:hover {
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: 0 6px 18px rgba(0,0,0,0.08);
}
.home-action-learn:hover    { border-top-color: var(--lp-teal); }
.home-action-practice:hover { border-top-color: var(--lp-moss); }
.home-action-mock:hover     { border-top-color: var(--lp-rust); }
.home-action-board:hover    { border-top-color: var(--lp-gold); }
.home-action-icon { font-size: 28px; margin-bottom: 12px; }
.home-action-title {
  font-size: 22px; font-weight: 600; margin: 0 0 8px;
  letter-spacing: -0.2px;
}
.home-action-sub {
  color: var(--lp-muted); font-size: 14.5px; line-height: 1.55;
  margin-bottom: 16px; min-height: 60px;
}
.home-action-cta {
  font-family: 'Courier New', monospace; font-size: 11.5px;
  letter-spacing: 1.5px; color: var(--lp-rust); font-weight: bold;
  text-transform: uppercase;
}

/* Generic content section */
.home-section { margin: 0 0 56px; }
.home-section-head { margin-bottom: 20px; }
.home-section-head h2 {
  font-size: 28px; font-weight: 400; letter-spacing: -0.3px;
  margin: 0 0 8px; padding-bottom: 8px;
  border-bottom: 1px solid var(--lp-ink);
  color: var(--lp-ink);
}
.home-section-head p {
  color: var(--lp-muted); font-size: 15.5px;
  margin: 0; max-width: 720px; line-height: 1.6;
}

/* Topic grid (mirrors /learn index) */
.home-topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}
.home-topic-card {
  display: block;
  padding: 18px 20px;
  background: #fffdf6;
  border: 1px solid var(--rule);
  border-left: 4px solid var(--lp-gold);
  color: var(--lp-ink); text-decoration: none;
  transition: transform .12s, border-left-color .12s, box-shadow .12s;
}
.home-topic-card:hover {
  text-decoration: none;
  transform: translateY(-2px);
  border-left-color: var(--lp-rust);
  box-shadow: 0 4px 12px rgba(0,0,0,0.06);
}
.home-topic-tag {
  font-family: 'Courier New', monospace;
  font-size: 10.5px; letter-spacing: 2px;
  color: var(--lp-rust); font-weight: bold; text-transform: uppercase;
  margin-bottom: 8px;
}
.home-topic-title {
  font-size: 18px; font-weight: 600; margin-bottom: 6px;
  letter-spacing: -0.15px;
}
.home-topic-count {
  font-size: 13px; color: var(--lp-muted); margin-bottom: 12px;
}
.home-topic-cta {
  font-family: 'Courier New', monospace; font-size: 10.5px;
  letter-spacing: 1.4px; color: var(--lp-teal); font-weight: bold;
  text-transform: uppercase;
  padding-top: 8px; border-top: 1px dashed var(--rule);
}

/* Difficulty bands strip */
.home-bands {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px;
}
.home-band {
  display: block; padding: 18px 16px;
  background: #fff; border: 1px solid var(--rule);
  color: var(--lp-ink); text-decoration: none; text-align: center;
  transition: background .12s, border-color .12s;
}
.home-band:hover {
  background: var(--lp-soft); border-color: var(--lp-gold); text-decoration: none;
}
.home-band-num {
  font-family: 'Georgia', serif; font-size: 26px; font-weight: 600;
  color: var(--lp-rust); margin-bottom: 4px;
}
.home-band-label {
  font-size: 12.5px; color: var(--lp-muted);
  font-family: var(--sans);
}

/* Decade grouping for contest browser */
.home-decades { display: flex; flex-direction: column; gap: 16px; }
.home-decade {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: 16px;
  align-items: baseline;
}
.home-decade-label {
  font-family: 'Courier New', monospace;
  font-size: 13px; letter-spacing: 2px;
  color: var(--lp-rust); font-weight: bold;
}
.home-decade-years { display: flex; gap: 8px; flex-wrap: wrap; }
.home-year {
  display: inline-block;
  padding: 6px 12px;
  background: #fff;
  border: 1px solid var(--rule);
  color: var(--lp-ink); text-decoration: none;
  font-family: 'Courier New', monospace; font-size: 13px;
  transition: background .12s, border-color .12s;
  min-width: 60px; text-align: center;
}
.home-year:hover {
  background: var(--lp-ink); color: var(--lp-paper);
  border-color: var(--lp-ink); text-decoration: none;
}
.home-archive-link {
  margin-top: 18px;
  font-size: 14px; color: var(--lp-muted);
}
.home-archive-link a { color: var(--lp-rust); font-weight: 600; }

@media (max-width: 640px) {
  /* Hero — title is smaller (not bigger!), stats become a tight horizontal strip below */
  .home-hero { padding: 14px 0 12px; margin: 0 0 22px; }
  .home-hero-row { gap: 12px; }
  .home-hero-titleblock { min-width: 0; flex: 1 1 100%; }
  .home-hero-title { font-size: 22px; line-height: 1.25; letter-spacing: -0.2px; }
  .home-hero-lede { font-size: 13px; line-height: 1.7; }
  .home-contest-chip { font-size: 10px; padding: 1px 7px; margin: 2px 1px; }
  .home-hero-stats {
    width: 100%; gap: 0; justify-content: space-around;
    border-top: 1px solid var(--rule); padding-top: 10px; margin-top: 4px;
  }
  .home-stat { padding: 0 10px; border-right: 1px solid var(--rule); }
  .home-stat:last-child { border-right: none; }
  .home-stat b { font-size: 18px; }
  .home-stat span { font-size: 10px; letter-spacing: 0.5px; }

  /* Action cards — tighter padding, drop the desktop min-height that wasted ~30px per card */
  .home-actions { gap: 12px; margin: 0 0 36px; grid-template-columns: 1fr; }
  .home-action-card { padding: 18px 16px; border-top-width: 3px; }
  .home-action-icon { font-size: 24px; margin-bottom: 8px; }
  .home-action-title { font-size: 19px; margin-bottom: 6px; }
  .home-action-sub { font-size: 13.5px; min-height: 0; margin-bottom: 12px; line-height: 1.5; }
  .home-action-cta { font-size: 11px; letter-spacing: 1.2px; }

  /* Section heads */
  .home-section { margin: 0 0 36px; }
  .home-section-head { margin-bottom: 14px; }
  .home-section-head h2 { font-size: 22px; padding-bottom: 6px; }
  .home-section-head p { font-size: 14px; line-height: 1.55; }

  /* Topic grid — force one column; 260px minimum was too wide for 320–375px phones */
  .home-topic-grid { grid-template-columns: 1fr; gap: 10px; }
  .home-topic-card { padding: 14px 16px; border-left-width: 3px; }
  .home-topic-title { font-size: 16px; }
  .home-topic-count { font-size: 12.5px; margin-bottom: 10px; }
  .home-topic-cta { font-size: 10px; padding-top: 6px; }

  /* Difficulty bands — 2 columns instead of squeezed 1 */
  .home-bands { grid-template-columns: repeat(2, 1fr); gap: 8px; }
  .home-band { padding: 12px 8px; }
  .home-band-num { font-size: 22px; }
  .home-band-label { font-size: 11.5px; }

  /* Decade browser — label above years, smaller year chips */
  .home-decade { grid-template-columns: 1fr; gap: 6px; }
  .home-decade-years { gap: 6px; }
  .home-year { padding: 5px 10px; font-size: 12px; min-width: 50px; }
  .home-archive-link { font-size: 13px; margin-top: 14px; }
}

@media (max-width: 380px) {
  /* Bands collapse to single column on very narrow screens */
  .home-bands { grid-template-columns: 1fr; }
}

/* Problem page back-link */
.problem-back {
  font-family:var(--sans); font-size:14px; padding:14px 0 0;
  margin:0 0 8px;
}
.problem-back a { color:var(--lp-rust); font-weight:600; }

/* Learn index — topic cards grid */
.learn-grid {
  display:grid;
  grid-template-columns:repeat(auto-fill, minmax(300px, 1fr));
  gap:18px;
  margin:30px 0;
}
.learn-card {
  display:block; padding:22px 24px;
  background:#fff; border:1px solid var(--rule);
  border-left:5px solid var(--lp-gold);
  color:var(--lp-ink); text-decoration:none;
  transition:transform .12s, box-shadow .12s, border-left-color .12s;
}
.learn-card:hover {
  text-decoration:none;
  transform:translateY(-2px);
  box-shadow:0 4px 14px rgba(0,0,0,0.08);
  border-left-color:var(--lp-rust);
}
.learn-card-head {
  display:flex; justify-content:space-between; align-items:center;
  font-family:'Courier New',monospace;
  font-size:11px; letter-spacing:2px;
  color:var(--lp-rust); font-weight:bold;
  margin-bottom:10px; text-transform:uppercase;
}
.learn-card-meta { color:var(--lp-muted); font-weight:normal; }
.learn-card-title {
  font-size:22px; font-weight:400; margin:0 0 6px;
  color:var(--lp-ink); letter-spacing:-0.2px;
}
.learn-card-sub { font-style:italic; color:var(--lp-muted); font-size:14px; margin:0 0 10px; }
.learn-card-tag-line { font-size:14px; color:var(--lp-ink); margin:0 0 14px; line-height:1.55; }
.learn-card-foot {
  font-family:'Courier New',monospace; font-size:11px; letter-spacing:1.5px;
  color:var(--lp-teal); text-transform:uppercase; font-weight:bold;
  padding-top:8px; border-top:1px dashed var(--rule);
}

/* lesson page mobile */
@media (max-width:900px) {
  .lp-layout { grid-template-columns:1fr; }
  .lp-sidebar { position:static; max-height:none; }
  .lp-mlt-grid { grid-template-columns:1fr; }
}
@media (max-width:520px) {
  .lp-title { font-size:28px; }
  .lp-chapter-title { font-size:22px; }
  .lp-final { padding:18px 14px; margin:36px -8px; border-radius:0; }
}

@media (max-width:520px) {
  h1 { font-size:28px; }
  body { font-size:17px; }
}

/* ==========================================================
   LESSON WIDGETS — collapsible reveal + try-it practice
   Ported from D:/Math (math.ahaanamg.com) bar-model lesson.
   Kid-friendly tone — interactive, not lecture.
   ========================================================== */

/* Collapsible "click to see why" blocks */
details.reveal {
  margin: 14px 0;
  border: none;
  border-left: 3px solid var(--lp-teal);
  background: #f6f3e8;
  padding: 0;
  border-radius: 2px;
  overflow: visible;
}
details.reveal > summary {
  cursor: pointer;
  padding: 10px 14px;
  font-family: var(--sans);
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: 0.3px;
  color: var(--lp-teal);
  list-style: none;
  user-select: none;
}
details.reveal > summary::-webkit-details-marker { display: none; }
details.reveal > summary::before { content: "▸ "; color: var(--lp-teal); font-size: 11px; }
details.reveal[open] > summary::before { content: "▾ "; color: var(--lp-rust); }
details.reveal[open] > summary { color: var(--lp-rust); }
details.reveal > .reveal-body {
  padding: 0 18px 14px;
  font-size: 15px;
  color: var(--lp-ink);
  line-height: 1.6;
}
details.reveal > .reveal-body > *:first-child { margin-top: 0; }

/* "Try it!" practice widget — input + check + show-solution */
.practice-block {
  background: #fffdf6;
  border: 2px solid var(--lp-gold);
  border-radius: 4px;
  padding: 16px 18px;
  margin: 18px 0;
}
.practice-block .qtag {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--lp-rust);
  font-weight: 700;
  text-transform: uppercase;
  margin-bottom: 6px;
}
.practice-block .qtext {
  font-size: 15.5px;
  line-height: 1.55;
  margin-bottom: 12px;
  color: var(--lp-ink);
}
.practice-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.practice-row .unit {
  font-family: var(--sans);
  font-size: 13px;
  color: var(--lp-muted);
}
.practice-row input[type="number"],
.practice-row input[type="text"] {
  padding: 8px 12px;
  border: 1.5px solid var(--rule);
  border-radius: 3px;
  font-family: 'Courier New', monospace;
  font-size: 16px;
  width: 110px;
  background: #fff;
  color: var(--lp-ink);
}
.practice-row input:focus { outline: none; border-color: var(--lp-teal); }
.practice-row button {
  padding: 8px 16px;
  border: 1.5px solid var(--lp-ink);
  background: var(--lp-ink);
  color: var(--lp-paper);
  font-family: var(--sans);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 1px;
  text-transform: uppercase;
  cursor: pointer;
  border-radius: 3px;
}
.practice-row button:hover { background: var(--lp-rust); border-color: var(--lp-rust); }
.practice-row button.secondary {
  background: transparent;
  color: var(--lp-ink);
}
.practice-row button.secondary:hover { background: var(--lp-soft); color: var(--lp-ink); }
.practice-feedback {
  margin-top: 10px;
  padding: 8px 12px;
  font-family: var(--sans);
  font-size: 14px;
  border-radius: 3px;
  min-height: 0;
  display: none;
}
.practice-feedback.ok {
  display: block; background: #e6f1e6; color: #2a5e2a;
  border-left: 3px solid #4a8a4a;
}
.practice-feedback.no {
  display: block; background: #fbe9e7; color: #8a2a1a;
  border-left: 3px solid var(--lp-rust);
}
.practice-walk {
  display: none;
  margin-top: 12px;
  padding: 12px 14px;
  background: var(--lp-soft);
  border-left: 3px solid var(--lp-teal);
  font-size: 14.5px;
  line-height: 1.6;
}
.practice-walk.show { display: block; }
.practice-walk strong { color: var(--lp-rust); }

/* Kid-aside — a warm, conversational callout (different from RULE-OF-THUMB) */
.kid-aside {
  background: #fff3e0;
  border-left: 3px solid var(--lp-gold);
  padding: 10px 14px;
  margin: 14px 0;
  border-radius: 0 3px 3px 0;
  font-family: var(--serif);
  font-size: 14.5px;
  line-height: 1.55;
}
.kid-aside-tag {
  font-family: var(--sans);
  font-size: 11px;
  letter-spacing: 1.5px;
  color: var(--lp-rust);
  font-weight: 700;
  text-transform: uppercase;
  margin-bottom: 4px;
}
.kid-aside > p:first-of-type { margin-top: 4px; }
.kid-aside > p:last-child { margin-bottom: 0; }

/* Big concept callout — pull-quote style */
.big-callout {
  text-align: center;
  font-family: var(--serif);
  font-size: 17px;
  color: var(--lp-rust);
  font-style: italic;
  padding: 12px 14px;
  margin: 16px 0;
  border-top: 1.5px solid var(--lp-rust);
  border-bottom: 1.5px solid var(--lp-rust);
  line-height: 1.4;
}

@media (max-width: 520px) {
  details.reveal > summary { font-size: 13px; padding: 9px 12px; }
  details.reveal > .reveal-body { padding: 0 14px 12px; font-size: 14.5px; }
  .practice-block { padding: 14px; }
  .practice-block .qtext { font-size: 14.5px; }
  .practice-row input { width: 90px; }
  .big-callout { font-size: 18px; padding: 12px; }
  .kid-aside { font-size: 14.5px; padding: 10px 14px; }
}