/* ============================================================
   GRE Quant Pro — /learn/ reading surface
   Extends site.css (tokens, nav, footer, .btn, .wrap, .glow-*
   all come from there). This file only styles what's specific
   to the concept-notes section: the index/concept-map page and
   the individual note/practice-sheet reading pages.
   ============================================================ */

/* ---------- shared shell ---------- */

.lrn-main{position:relative;z-index:1;padding:48px 0 100px}
.lrn-wrap{max-width:760px;margin:0 auto;padding:0 24px}
.lrn-wrap.lrn-wide{max-width:980px}

.lrn-crumb{display:flex;align-items:center;gap:8px;font-size:13.5px;color:var(--ink3);margin-bottom:22px;flex-wrap:wrap}
.lrn-crumb a{color:var(--ink3);text-decoration:none;font-weight:600}
.lrn-crumb a:hover{color:var(--blue)}
.lrn-crumb span{color:var(--line2)}

/* ---------- concept-map / index page ---------- */

.lrn-hero{padding-bottom:36px;margin-bottom:36px;border-bottom:1px solid var(--line)}
.lrn-eyebrow{font-family:var(--fm);font-size:12.5px;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);font-weight:700;margin-bottom:14px}
.lrn-hero h1{font-family:var(--fd);font-weight:640;font-size:clamp(28px,4vw,40px);color:var(--navy);letter-spacing:-.4px;line-height:1.14;margin-bottom:16px}
.lrn-hero p{font-size:16.5px;color:var(--ink2);line-height:1.7;max-width:640px}
.lrn-hero-free{margin-top:10px}
.lrn-hero-free b{color:var(--navy)}
.lrn-hero-free a{color:var(--blue);font-weight:700;text-decoration:none}
.lrn-hero-free a:hover{text-decoration:underline}

.lrn-group{margin-bottom:38px}
.lrn-group h2{font-family:var(--fd);font-weight:640;font-size:20px;color:var(--navy);display:flex;align-items:baseline;justify-content:space-between;gap:12px;flex-wrap:wrap;padding-bottom:10px;border-bottom:1.5px solid var(--line);margin-bottom:6px;scroll-margin-top:90px}
.lrn-count{font-family:var(--fm);font-size:12px;font-weight:500;color:var(--ink3);white-space:nowrap}

.lrn-list{list-style:none;display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:2px 18px}
.lrn-item{display:flex;align-items:center;gap:9px;padding:11px 4px;border-bottom:1px solid var(--line)}
.lrn-item a{color:var(--ink);text-decoration:none;font-weight:600;font-size:15px;flex:1;min-width:0}
.lrn-item a:hover{color:var(--blue)}
.lrn-item code{font-family:var(--fm);font-size:11px;color:var(--ink3);background:var(--paper2);border-radius:5px;padding:2px 6px;white-space:nowrap}
.lrn-item.is-pro a{color:var(--ink2)}
.lrn-pro-tag{font-family:var(--fm);font-size:10.5px;font-weight:700;letter-spacing:.03em;color:var(--gold);background:var(--gold-soft);border-radius:20px;padding:2px 9px;white-space:nowrap}

/* ---------- note / practice-sheet page ---------- */

.lrn-doc{background:var(--card);border:1px solid var(--line);border-radius:var(--radius-lg);padding:44px 48px;box-shadow:var(--shadow)}

.lrn-head{margin-bottom:28px;padding-bottom:24px;border-bottom:1px solid var(--line)}
.lrn-head h1{font-family:var(--fd);font-weight:640;font-size:clamp(26px,3.4vw,34px);color:var(--navy);letter-spacing:-.3px;line-height:1.2;margin-bottom:14px}
.lrn-chips{display:flex;flex-wrap:wrap;gap:8px}
.lrn-chip{font-family:var(--fm);font-size:12px;color:var(--ink2);background:var(--paper2);border:1px solid var(--line);border-radius:20px;padding:5px 12px}
.lrn-chip b{color:var(--navy);font-weight:700}
.lrn-chip-pro{color:var(--gold);background:var(--gold-soft);border-color:#e8d29c;font-weight:700}

/* the reading surface itself — markdown output lives here */
.lrn-body{font-size:16.5px;line-height:1.75;color:var(--ink)}
.lrn-body > *:first-child{margin-top:0}
.lrn-body h2{font-family:var(--fd);font-weight:640;font-size:22px;color:var(--navy);letter-spacing:-.2px;margin:34px 0 14px}
.lrn-body h3{font-family:var(--fd);font-weight:600;font-size:17.5px;color:var(--navy);margin:24px 0 10px}
.lrn-body p{margin:0 0 14px}
.lrn-body strong{color:var(--navy);font-weight:700}
.lrn-body em{color:var(--ink2)}
.lrn-body ul,.lrn-body ol{margin:0 0 16px;padding-left:26px}
.lrn-body li{margin-bottom:9px}
.lrn-body li:last-child{margin-bottom:0}
.lrn-body code{font-family:var(--fm);font-size:.9em;background:var(--paper2);border-radius:5px;padding:2px 6px;color:var(--blue-dark)}
.lrn-body hr{border:none;border-top:1px solid var(--line);margin:28px 0}
.lrn-body blockquote{margin:0 0 16px;padding:14px 20px;background:var(--blue-soft);border-left:3px solid var(--blue);border-radius:0 var(--radius-sm) var(--radius-sm) 0;color:var(--blue-dark)}
.lrn-body blockquote p{margin:0;color:inherit}

.lrn-body table{width:100%;border-collapse:collapse;margin:0 0 20px;font-size:15px}
.lrn-body th,.lrn-body td{text-align:left;padding:10px 14px;border-bottom:1px solid var(--line)}
.lrn-body th{font-family:var(--fm);font-size:12px;text-transform:uppercase;letter-spacing:.04em;color:var(--ink3);font-weight:600}
.lrn-body td{font-family:var(--fm);font-size:14px}
.lrn-body tbody tr:last-child td{border-bottom:none}

.lrn-body details{margin:0 0 16px;background:var(--green-soft);border:1px solid #c4dfd0;border-radius:var(--radius-sm);padding:14px 18px}
.lrn-body details[open]{padding-bottom:16px}
.lrn-body details summary{cursor:pointer;font-weight:700;color:#2c5a41;list-style:none}
.lrn-body details summary::-webkit-details-marker{display:none}
.lrn-body details summary::before{content:"▸ ";display:inline-block;transition:transform .15s}
.lrn-body details[open] summary::before{content:"▾ "}
.lrn-body details p{margin-top:12px;margin-bottom:0}
.lrn-body details p+p{margin-top:8px}

/* ---------- Pro gate card ---------- */

.lrn-gate{text-align:center;padding:38px 34px;margin-top:6px;background:var(--paper2);border:1px solid var(--line);border-radius:var(--radius);transition:opacity .15s}
.lrn-gate.is-checking{opacity:.55;pointer-events:none}
.lrn-lock{width:52px;height:52px;margin:0 auto 16px;border-radius:50%;background:var(--blue-soft);color:var(--blue);display:flex;align-items:center;justify-content:center}
.lrn-gate h2{font-family:var(--fd);font-weight:640;font-size:20px;color:var(--navy);margin-bottom:10px}
.lrn-gate p{font-size:14.5px;color:var(--ink2);line-height:1.65;max-width:440px;margin:0 auto 22px}
.lrn-gate-btns{display:flex;flex-wrap:wrap;gap:12px;justify-content:center;margin-bottom:18px}
.lrn-gate-free{font-size:13.5px;color:var(--ink3);margin:0}
.lrn-gate-free a{color:var(--blue);font-weight:700;text-decoration:none}
.lrn-gate-free a:hover{text-decoration:underline}

/* ---------- related resources + prev/next ---------- */

.lrn-res-row{display:grid;grid-template-columns:repeat(auto-fit,minmax(220px,1fr));gap:14px;margin-top:28px}
.lrn-res{display:flex;flex-direction:column;gap:4px;background:var(--paper2);border:1px solid var(--line);border-radius:var(--radius-sm);padding:16px 18px;text-decoration:none;transition:border-color .15s,transform .15s}
.lrn-res:hover{border-color:var(--blue);transform:translateY(-2px)}
.lrn-res-k{font-family:var(--fm);font-size:11.5px;text-transform:uppercase;letter-spacing:.05em;color:var(--blue);font-weight:700}
.lrn-res-t{font-size:14px;color:var(--ink);font-weight:600}

.lrn-pn-row{display:flex;justify-content:space-between;gap:16px;margin-top:32px;padding-top:24px;border-top:1px solid var(--line)}
.lrn-pn{display:flex;flex-direction:column;gap:4px;text-decoration:none;max-width:48%}
.lrn-pn-next{text-align:right;margin-left:auto}
.lrn-pn span{font-family:var(--fm);font-size:11.5px;color:var(--ink3);text-transform:uppercase;letter-spacing:.04em}
.lrn-pn b{font-size:14.5px;color:var(--navy);font-weight:700}
.lrn-pn:hover b{color:var(--blue)}

/* ---------- responsive ---------- */

@media(max-width:640px){
  .lrn-doc{padding:30px 22px}
  .lrn-list{grid-template-columns:1fr}
  .lrn-pn-row{flex-direction:column}
  .lrn-pn,.lrn-pn-next{max-width:100%;text-align:left;margin-left:0}
  .lrn-gate{padding:30px 22px}
}