/* Problem page — split workspace, NeetCode-style. */

.prob-shell { padding: 0; max-width: none; min-height: calc(100vh - var(--nav-h)); }
.prob-loading { display: flex; align-items: center; justify-content: center; gap: 10px; padding: 80px 20px; }
.prob-loading[hidden] { display: none; }

.prob-app {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  min-height: calc(100vh - var(--nav-h));
}
@media (max-width: 980px) {
  .prob-app { grid-template-columns: 1fr; }
}

/* ── LEFT ────────────────────────────────────────────────── */

.prob-left {
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  background: var(--bg);
  min-width: 0;
  max-height: calc(100vh - var(--nav-h));
}
@media (max-width: 980px) { .prob-left { max-height: none; } }

.prob-header {
  padding: 14px 18px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.prob-meta { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.prob-back {
  color: var(--muted);
  font-size: 18px;
  text-decoration: none;
  padding: 4px 8px;
  border-radius: 4px;
  background: var(--bg-card);
  border: 1px solid var(--border);
}
.prob-back:hover { color: var(--text); text-decoration: none; }
.prob-pm {
  font-family: var(--font-mono);
  color: var(--accent);
  font-weight: 700;
  font-size: 13px;
}
.prob-title {
  font-size: 18px;
  font-weight: 800;
  margin: 0;
  color: var(--text);
  line-height: 1.3;
}
.prob-badges { display: flex; gap: 6px; margin-top: 8px; flex-wrap: wrap; }
.prob-nav { display: flex; gap: 6px; margin-top: 10px; }
.prob-nav .pm-btn { font-size: 12px; }

.prob-tabs {
  display: flex;
  gap: 0;
  padding: 0 12px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
  overflow-x: auto;
}
.prob-tabs button {
  background: transparent;
  border: 0;
  color: var(--muted);
  padding: 11px 14px;
  font-weight: 600;
  font-size: 13px;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  white-space: nowrap;
  display: inline-flex;
  align-items: center;
  gap: 6px;
}
.prob-tabs button:hover { color: var(--text); }
.prob-tabs button[aria-selected="true"] {
  color: var(--accent);
  border-bottom-color: var(--accent);
}
.badge-quota {
  display: inline-block;
  padding: 1px 6px;
  border-radius: 999px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 10px;
  font-weight: 700;
}
.badge-quota.is-low { color: var(--warn); border-color: var(--warn); }
.badge-quota.is-out { color: var(--danger); border-color: var(--danger); }

.prob-tab-body {
  flex: 1;
  overflow: auto;
  padding: 18px 20px 80px;
  min-height: 0;
}
.prob-prose h3 { margin: 18px 0 6px; font-size: 13px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--accent); font-weight: 700; }
.prob-prose p { margin: 6px 0; line-height: 1.65; }

.prob-actions-inline { margin-top: 18px; display: flex; gap: 8px; flex-wrap: wrap; }

/* Solution tab */
.sol-tabs { display: inline-flex; gap: 4px; margin-bottom: 12px; }
.sol-tabs button {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 6px 12px;
  font-size: 12px;
  font-weight: 700;
  border-radius: var(--r-sm);
  cursor: pointer;
}
.sol-tabs button[aria-pressed="true"] { color: var(--accent); border-color: var(--accent); }
.sol-tabs button:disabled { opacity: 0.4; cursor: default; }

.sol-code {
  background: #0a0c10;
  border: 1px solid var(--border);
  border-radius: var(--r-sm);
  padding: 14px;
  overflow: auto;
  font-family: var(--font-mono);
  font-size: 12.5px;
  line-height: 1.55;
  color: #d8e0e8;
  margin: 0 0 14px;
  white-space: pre;
}

/* AI tab */
.ai-shell {
  display: flex;
  flex-direction: column;
  height: 100%;
  min-height: 480px;
  gap: 12px;
}
.ai-header h3 { margin: 0; font-size: 16px; }
.ai-transcript {
  flex: 1;
  overflow: auto;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-height: 280px;
}
.ai-bubble {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--r-md);
  padding: 10px 12px;
  max-width: 90%;
  font-size: 13.5px;
  line-height: 1.55;
  white-space: pre-wrap;
}
.ai-bubble.is-user { align-self: flex-end; background: rgba(255, 213, 74, 0.10); border-color: rgba(255, 213, 74, 0.3); }
.ai-bubble.is-tutor { align-self: flex-start; }
.ai-bubble.is-system { align-self: center; max-width: 100%; background: transparent; border: 0; color: var(--muted); font-style: italic; padding: 4px 0; }
.ai-empty { color: var(--muted); margin: auto; text-align: center; }
.ai-composer { display: flex; flex-direction: column; gap: 8px; }
.ai-actions { display: flex; align-items: center; gap: 8px; }

.ai-cap-card {
  background: rgba(239, 90, 90, 0.08);
  border: 1px solid rgba(239, 90, 90, 0.25);
  border-radius: var(--r-md);
  padding: 14px;
  margin-top: 8px;
  font-size: 13px;
}
.ai-cap-card a { color: var(--accent); font-weight: 700; }

/* Video tab */
.vid-langs { display: flex; gap: 6px; margin-bottom: 8px; }
.vid-langs button {
  background: var(--bg-card);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 4px 10px;
  font-size: 12px;
  font-weight: 700;
  border-radius: var(--r-sm);
  cursor: pointer;
}
.vid-langs button[aria-pressed="true"] { color: var(--accent); border-color: var(--accent); }
#vid-player { width: 100%; max-height: 70vh; border-radius: var(--r-md); background: #000; }

/* Notes tab */
.notes-actions { display: flex; align-items: center; gap: 8px; margin-top: 8px; }

/* ── RIGHT (editor) ──────────────────────────────────────── */

.prob-right {
  display: flex;
  flex-direction: column;
  background: #0a0c10;
  max-height: calc(100vh - var(--nav-h));
  min-width: 0;
}
@media (max-width: 980px) { .prob-right { max-height: 90vh; } }

.ed-toolbar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.pm-select.sm { padding: 5px 8px; font-size: 13px; width: auto; }

.ed-wrap { flex: 1; min-height: 0; overflow: hidden; }
.ed-wrap .CodeMirror {
  height: 100%;
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.5;
}
.cm-s-material-darker.CodeMirror { background: #0a0c10; }

.ed-console {
  border-top: 1px solid var(--border);
  background: #06080b;
  max-height: 28vh;
  overflow: auto;
  font-family: var(--font-mono);
  font-size: 12px;
  flex-shrink: 0;
}
.ed-console-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 12px;
  background: var(--bg-elev);
  color: var(--muted);
  font-weight: 700;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
}
#ed-console-out {
  padding: 10px 12px;
  margin: 0;
  white-space: pre-wrap;
  color: #d8e0e8;
}
#ed-console-out.is-error { color: #ff8585; }
#ed-console-out.is-ok    { color: #7ddc9a; }

.ed-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 14px;
  border-top: 1px solid var(--border);
  background: var(--bg-elev);
}

/* Solution meta chips (rendered above #sol-code when meta.label/time/space present) */
.sol-meta-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin: 0 0 10px;
}
.sol-meta-chips .chip {
  display: inline-flex;
  align-items: center;
  padding: 3px 9px;
  border: 1px solid var(--border);
  border-radius: 999px;
  background: var(--bg-elev);
  color: var(--text);
  font-size: 11px;
  line-height: 1.4;
  letter-spacing: 0.01em;
}


/* ============================================================
   v2 enhanced layout (taxonomy banner, BASIC cards, solutions)
   Dark-theme palette so prose/diagram text stays readable on --bg.
   ============================================================ */
.tax-banner{display:flex;flex-wrap:wrap;gap:8px;margin:12px 0 6px}
.tax-chip{display:inline-flex;align-items:center;gap:8px;padding:6px 12px;border:1px solid var(--border);border-radius:999px;background:var(--bg-elev);font-size:.78rem;font-weight:600;color:var(--text)}
.tax-chip em{font-style:normal;font-weight:800;font-size:.66rem;letter-spacing:.06em;color:var(--good);text-transform:uppercase;padding:2px 6px;border-radius:4px;background:rgba(95,207,131,.14)}
.prob-subtitle{margin:6px 0 0;color:var(--muted);font-size:.85rem;font-weight:500}

.q-hook .hook{font-size:1.05rem;font-weight:600;color:var(--text);margin:0 0 14px;padding:12px 14px;background:rgba(95,207,131,.08);border-left:3px solid var(--good);border-radius:6px}

.basic-wrap{margin:24px 0 16px;padding:18px;border:1px solid var(--border);border-radius:12px;background:var(--bg-elev)}
.basic-h{margin:0 0 4px;font-size:.78rem;font-weight:900;letter-spacing:.18em;color:var(--good)}
.basic-summary{margin:0 0 14px;font-size:.92rem;color:var(--text);line-height:1.55}
.basic-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:12px}
.basic-card{background:var(--bg-card);border:1px solid var(--border);border-radius:10px;padding:14px}
.basic-card-title{margin:0 0 8px;font-size:.78rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;color:var(--accent)}
.basic-card p{margin:0 0 8px;color:var(--text);font-size:.88rem;line-height:1.55}
.basic-focus{margin:6px 0 0 18px;padding:0;color:var(--muted);font-size:.85rem;line-height:1.6}
.basic-focus li{margin:0 0 4px}
.basic-real{font-size:.82rem;color:var(--muted);margin-top:8px;padding:8px 10px;background:rgba(255,255,255,.04);border:1px solid var(--border);border-radius:6px}
.basic-real em{font-weight:700;color:var(--good);font-style:normal}

.realworld{margin:18px 0;padding:14px 16px;background:rgba(154,215,255,.06);border-left:3px solid var(--accent-2);border-radius:6px}
.realworld h3{margin:0 0 6px;font-size:.85rem;font-weight:800;color:var(--accent-2);letter-spacing:.04em;text-transform:uppercase}
.realworld p{color:var(--text)}
.tech-signals{margin:18px 0}
.tech-signals h3{font-size:.95rem;margin:0 0 6px;color:var(--accent)}
.tech-signals ul{margin:0 0 0 20px;color:var(--text);line-height:1.6}

.q-outro{margin:18px 0;padding:14px 16px;border:1px dashed var(--border-strong);border-radius:8px;background:rgba(255,161,74,.06)}
.q-outro h3{margin:0 0 6px;font-size:.85rem;font-weight:800;color:var(--warn);letter-spacing:.04em;text-transform:uppercase}
.q-outro p{color:var(--text)}

.sol-intro{margin:0 0 16px;color:var(--muted);font-style:italic}
.sol-cards{display:flex;flex-direction:column;gap:18px}
.sol-approach{border:1px solid var(--border);border-radius:12px;padding:18px;background:var(--bg-elev);display:none}
.sol-approach.is-active{display:block}
.sol-approach-head{display:flex;flex-wrap:wrap;align-items:baseline;gap:10px;margin-bottom:12px}
.sol-approach-tag{display:inline-block;padding:3px 10px;border-radius:999px;background:var(--good);color:#0d0e10;font-size:.7rem;font-weight:800;letter-spacing:.06em;text-transform:uppercase}
.sol-approach-name{margin:0;font-size:1.15rem;font-weight:800;color:var(--text)}
.sol-position{margin:0;font-size:.82rem;color:var(--muted);width:100%}
.sol-approach section{margin:14px 0}
.sol-approach h4{margin:0 0 6px;font-size:.78rem;font-weight:800;letter-spacing:.04em;text-transform:uppercase;color:var(--accent)}
.sol-approach p{margin:0;color:var(--text);font-size:.92rem;line-height:1.55}
.sol-steps,.sol-watch{margin:0 0 0 20px;padding:0;color:var(--text);font-size:.9rem;line-height:1.6}
.sol-steps li,.sol-watch li{margin:0 0 4px}
.sol-coach{margin:14px 0;padding:10px 12px;background:rgba(255,161,74,.10);border-left:3px solid var(--warn);border-radius:6px;color:var(--text);font-size:.88rem}
.sol-coach em{font-style:normal;font-weight:800;color:var(--warn)}
.sol-codewrap pre.sol-code{background:#0a0c10;color:#e2e8f0;padding:14px;border-radius:8px;overflow-x:auto;font-family:'JetBrains Mono',ui-monospace,monospace;font-size:.84rem;line-height:1.5}
.sol-code-empty{font-size:.85rem;font-style:italic;padding:10px 0;color:var(--muted)}

.diagram-box{padding:14px;border:1px solid var(--border);border-radius:8px;background:var(--bg-elev);text-align:center}
.diagram-mermaid svg{max-width:100%;height:auto}
.diagram-caption{margin:6px 0 0;font-size:.8rem;color:var(--muted)}
.diagram-fallback{margin:0;padding:0;list-style:none;display:flex;flex-wrap:wrap;justify-content:center;gap:8px}
.diagram-fallback li{padding:6px 10px;border:1px solid var(--border-strong);border-radius:6px;background:var(--bg-card);color:var(--text);font-size:.85rem;font-family:'JetBrains Mono',ui-monospace,monospace}
.diagram-pre{margin:0;padding:10px;text-align:left;font-family:'JetBrains Mono',ui-monospace,monospace;font-size:.82rem;color:var(--text);background:var(--bg-card);border:1px solid var(--border);border-radius:6px}

.sol-comparison{margin:18px 0;padding:14px 16px;background:rgba(154,215,255,.06);border-radius:8px;border-left:3px solid var(--accent-2)}
.sol-comparison h3{margin:0 0 6px;font-size:.85rem;font-weight:800;color:var(--accent-2);letter-spacing:.04em;text-transform:uppercase}
.sol-comparison p{color:var(--text)}
.sol-tabs{margin-bottom:16px}
.sol-tabs button{padding:6px 12px;margin-right:6px;border:1px solid var(--border);border-radius:6px;background:var(--bg-card);color:var(--muted);font-size:.85rem;font-weight:600;cursor:pointer}
.sol-tabs button[aria-pressed=true]{background:var(--good);color:#0d0e10;border-color:var(--good)}

/* reusable pattern diagram block (Solution tab) */
.sol-pattern{margin:4px 0 22px;padding:14px 16px;border:1px solid var(--border);border-radius:14px;
  background:linear-gradient(180deg,rgba(255,213,74,.06),transparent)}
.sol-pattern-h{margin:0 0 4px;font-size:15px;font-weight:800}
.sol-pattern-sub,.sol-pattern .muted{margin:0 0 12px;font-size:13px;line-height:1.5}
.pattern-diagram-host{margin-top:6px}
.sol-diagram .diagram-host{margin-top:6px}