:root {
  --bg: #f4f2ed;
  --surface: #ffffff;
  --surface-2: #faf9f6;
  --hover: #f1eee8;
  --line: #e5e1d8;
  --line-strong: #d3cec3;

  --ink: #1f2328;
  --soft: #545b64;
  --dim: #8a9099;

  /* Ember - the one primary action and the current selection */
  --accent: #c2410c;
  --accent-hover: #9a3412;
  --accent-soft: #fdf1ea;
  --accent-line: #f3c5ad;

  --ok: #1a7f37;     --ok-bg: #e9f6ec;    --ok-line: #b7e0c1;
  --warn: #9a6700;   --warn-bg: #fff5d6;  --warn-line: #f0d98c;
  --bad: #c9252d;    --bad-bg: #ffecec;   --bad-line: #f5bcbf;
  --info: #0a5bc4;   --info-bg: #ebf3ff;  --info-line: #b7d2f7;

  --k-lp: #1d4ed8;   --k-lp-bg: #ecf2ff;
  --k-milp: #7c3aed; --k-milp-bg: #f3edff;
  --k-qp: #0f766e;   --k-qp-bg: #e6f7f4;
  --k-miqp: #be185d; --k-miqp-bg: #fdeef5;

  --code-bg: #fbfaf7;
  --shadow: 0 1px 2px rgba(31, 35, 40, 0.05);
  --shadow-pop: 0 12px 32px -8px rgba(31, 35, 40, 0.2);
  --radius: 12px;
  --radius-sm: 8px;
  --sans: "Inter", system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--ink);
  font: 14px/1.5 var(--sans);
  -webkit-font-smoothing: antialiased;
}

body { display: flex; flex-direction: column; }
button, input, select, textarea { font: inherit; color: inherit; }
code, kbd, pre, textarea { font-family: var(--mono); font-variant-ligatures: none; }
p { margin: 0; }

svg {
  width: 16px; height: 16px; flex-shrink: 0;
  fill: none; stroke: currentColor; stroke-width: 1.8;
  stroke-linecap: round; stroke-linejoin: round;
}

/* ---------- Top bar ---------- */

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.55rem 1.25rem;
  background: var(--surface);
  border-bottom: 1px solid var(--line);
}

.brand { display: flex; align-items: center; gap: 0.65rem; color: inherit; text-decoration: none; min-width: 0; }
.brand img { display: block; }
.brand-name { font-size: 1.1rem; font-weight: 700; letter-spacing: 0.16em; }
.brand-sub {
  padding-left: 0.7rem;
  border-left: 1px solid var(--line-strong);
  color: var(--soft);
  font-size: 0.85rem;
  white-space: nowrap;
}

.topbar-right { display: flex; align-items: center; gap: 0.75rem; }

.alert {
  padding: 0.25rem 0.7rem;
  border: 1px solid var(--bad-line);
  border-radius: 999px;
  background: var(--bad-bg);
  color: var(--bad);
  font-size: 0.78rem;
  font-weight: 500;
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.45rem 0.85rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--ink);
  font-size: 0.84rem;
  font-weight: 500;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.12s, border-color 0.12s;
}

.btn:hover { background: var(--hover); }
.btn:disabled { opacity: 0.55; cursor: default; }
.btn-block { width: 100%; }
.btn-small { padding: 0.25rem 0.6rem; font-size: 0.78rem; }
.btn-strong { background: var(--ink); border-color: var(--ink); color: #fff; }
.btn-strong:hover { background: #000; }

.link {
  padding: 0;
  border: 0;
  background: none;
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 500;
  cursor: pointer;
}
.link:hover { text-decoration: underline; }

/* ---------- Layout ---------- */

.app {
  flex: 1;
  min-height: 0;
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
}

.sidebar {
  display: flex;
  flex-direction: column;
  min-height: 0;
  border-right: 1px solid var(--line);
  background: var(--surface-2);
}

.side-panel {
  flex: 1;
  min-height: 0;
  overflow-y: auto;
  padding: 0.25rem 0.75rem 1.5rem;
}

.main {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  min-width: 0;
  min-height: 0;
  padding: 1rem 1.25rem 1.25rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

/* ---------- Sidebar ---------- */

.seg {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 1fr;
  gap: 2px;
  margin: 0.85rem 0.75rem 0.75rem;
  padding: 3px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--hover);
}

.seg-btn {
  padding: 0.4rem 0.5rem;
  border: 0;
  border-radius: 7px;
  background: transparent;
  color: var(--soft);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
}

.seg-btn:hover { color: var(--ink); }
.seg-btn.active { background: var(--surface); color: var(--ink); box-shadow: 0 1px 2px rgba(31, 35, 40, 0.1); }

.side-intro { margin: 0.1rem 0.25rem 0.75rem; color: var(--soft); font-size: 0.82rem; }
.side-intro code { font-size: 0.9em; }

.search { position: relative; display: flex; align-items: center; margin-bottom: 0.6rem; }
.search svg { position: absolute; left: 0.65rem; color: var(--dim); }
.search input[type="search"] {
  width: 100%;
  height: 36px;
  padding: 0 0.7rem 0 2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  font-size: 0.85rem;
}

.empty { color: var(--dim); font-size: 0.85rem; margin: 0.5rem 0.25rem; }

.group { margin-bottom: 0.25rem; }

.group > summary {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.45rem 0.35rem;
  border-radius: 6px;
  color: var(--ink);
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.group > summary::-webkit-details-marker { display: none; }
.group > summary:hover { background: var(--hover); }

.group > summary::before {
  content: "";
  width: 5px;
  height: 5px;
  margin: 0 0.2rem 0 0.15rem;
  border-right: 1.5px solid var(--dim);
  border-bottom: 1.5px solid var(--dim);
  transform: rotate(-45deg);
  transition: transform 0.12s;
}

.group[open] > summary::before { transform: rotate(45deg); }

.count {
  margin-left: auto;
  min-width: 1.4rem;
  padding: 0 0.4rem;
  border-radius: 999px;
  background: var(--hover);
  color: var(--soft);
  font-size: 0.7rem;
  font-weight: 500;
  text-align: center;
}

.group-about { margin: -0.1rem 0.35rem 0.35rem 1.35rem; color: var(--dim); font-size: 0.75rem; line-height: 1.4; }

.item {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.05rem 0.5rem;
  width: 100%;
  padding: 0.45rem 0.6rem 0.45rem 1.35rem;
  border: 0;
  border-radius: var(--radius-sm);
  background: transparent;
  text-align: left;
  cursor: pointer;
  position: relative;
}

.item:hover { background: var(--hover); }
.item.active { background: var(--accent-soft); }
.item.active::before {
  content: "";
  position: absolute;
  left: 0.55rem;
  top: 0.55rem;
  bottom: 0.55rem;
  width: 3px;
  border-radius: 2px;
  background: var(--accent);
}

.item-title { overflow: hidden; text-overflow: ellipsis; white-space: nowrap; font-size: 0.86rem; font-weight: 500; }
.item-sub { grid-column: 1 / -1; color: var(--dim); font-size: 0.74rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

/* Card lists (Write / Generate) */

.cards { display: grid; gap: 0.5rem; }

.pick {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto;
  gap: 0.2rem 0.5rem;
  width: 100%;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  text-align: left;
  cursor: pointer;
  transition: border-color 0.12s, box-shadow 0.12s;
}

.pick:hover { border-color: var(--line-strong); box-shadow: var(--shadow); }
.pick.active { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.pick-title { font-weight: 600; font-size: 0.88rem; }
.pick-sub { grid-column: 1 / -1; color: var(--soft); font-size: 0.78rem; line-height: 1.4; }


/* ---------- Class badge ---------- */

.kind {
  align-self: center;
  padding: 0.05rem 0.45rem;
  border-radius: 999px;
  background: var(--k-bg, var(--hover));
  color: var(--k, var(--soft));
  font-family: var(--mono);
  font-size: 0.66rem;
  font-weight: 500;
  letter-spacing: 0.03em;
}

.kind-LP { --k: var(--k-lp); --k-bg: var(--k-lp-bg); }
.kind-MILP { --k: var(--k-milp); --k-bg: var(--k-milp-bg); }
.kind-QP { --k: var(--k-qp); --k-bg: var(--k-qp-bg); }
.kind-QCQP { --k: var(--k-qp); --k-bg: var(--k-qp-bg); }
.kind-MIQCQP, .kind-MIQP { --k: var(--k-miqp); --k-bg: var(--k-miqp-bg); }

.tag { padding: 0.1rem 0.5rem; border-radius: 999px; font-size: 0.7rem; font-weight: 600; }
.tag-warn { background: var(--warn-bg); color: var(--warn); }

/* ---------- Model card ---------- */

.model-card { padding: 1rem 1.15rem; }

.model-head { display: flex; justify-content: space-between; align-items: flex-start; gap: 1.5rem; flex-wrap: wrap; }
.model-id { min-width: 0; }
.model-title-row { display: flex; align-items: center; gap: 0.6rem; flex-wrap: wrap; }
.model-title-row h1 { margin: 0; font-size: 1.3rem; font-weight: 650; letter-spacing: -0.015em; }
.model-path { margin-top: 0.15rem; color: var(--dim); font-family: var(--mono); font-size: 0.76rem; overflow-wrap: anywhere; }

.stats {
  display: flex;
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  overflow: hidden;
}

.stats div { display: flex; flex-direction: column-reverse; padding: 0.35rem 0.85rem; border-left: 1px solid var(--line); }
.stats div:first-child { border-left: 0; }
.stats dt { color: var(--dim); font-size: 0.7rem; }
.stats dd { margin: 0; font-family: var(--mono); font-size: 0.95rem; font-weight: 500; }
.stats:empty { display: none; }

.callout {
  margin-top: 0.8rem;
  padding: 0.5rem 0.75rem;
  border-radius: var(--radius-sm);
  background: var(--surface-2);
  border: 1px solid var(--line);
  color: var(--soft);
  font-size: 0.8rem;
}

.run-bar {
  display: flex;
  align-items: flex-end;
  gap: 0.75rem;
  margin-top: 0.9rem;
  flex-wrap: wrap;
}

.field { display: flex; flex-direction: column; gap: 0.25rem; min-width: 140px; }
.field > span { color: var(--soft); font-size: 0.74rem; font-weight: 500; }
.field-engine { min-width: 220px; }
.field-narrow { min-width: 0; width: 110px; }

select,
input[type="number"] {
  height: 36px;
  padding: 0 0.65rem;
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm);
  background: var(--surface);
  font-size: 0.86rem;
}

select {
  appearance: none;
  padding-right: 2rem;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3E%3Cpath d='m6 8 4 4 4-4' fill='none' stroke='%238a9099' stroke-width='1.8' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0.5rem center;
  background-size: 16px;
  cursor: pointer;
}

select:hover, input:hover { border-color: var(--dim); }

.more { position: relative; }
.more > summary { list-style: none; height: 36px; }
.more > summary::-webkit-details-marker { display: none; }
.more[open] > summary { background: var(--hover); }

.more-panel {
  position: absolute;
  z-index: 10;
  top: calc(100% + 6px);
  left: 0;
  display: grid;
  gap: 0.75rem;
  width: 320px;
  padding: 0.9rem;
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow-pop);
}

.check { display: flex; align-items: flex-start; gap: 0.5rem; font-size: 0.84rem; cursor: pointer; }
input[type="checkbox"] { accent-color: var(--accent); width: 15px; height: 15px; margin: 0.15rem 0 0; }

.hw-note {
  padding-top: 0.75rem;
  border-top: 1px solid var(--line);
  color: var(--soft);
  font-size: 0.78rem;
}
.hw-note strong { color: var(--ink); font-weight: 600; }
.hw-note p + p { margin-top: 0.35rem; }
.hw-note code { font-size: 0.92em; }

.solve {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  height: 38px;
  margin-left: auto;
  padding: 0 1.4rem;
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(154, 52, 18, 0.3);
  transition: background 0.12s;
}

.solve:hover:not(:disabled) { background: var(--accent-hover); }
.solve:disabled { opacity: 0.55; cursor: default; }
.solve kbd { padding: 0.05rem 0.35rem; border-radius: 4px; background: rgba(255, 255, 255, 0.18); font-family: var(--sans); font-size: 0.72rem; }
.solve.busy { opacity: 1; cursor: wait; }
.solve.busy kbd { display: none; }

.spinner {
  display: none;
  width: 14px;
  height: 14px;
  border: 2px solid rgba(255, 255, 255, 0.35);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}
.solve.busy .spinner { display: block; }

/* ---------- Work area ---------- */

.work {
  flex: 1;
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(360px, 5fr) minmax(0, 6fr);
  gap: 1rem;
}

/* ---------- Result ---------- */

.result {
  --tone: var(--soft);
  --tone-bg: var(--hover);
  --tone-line: var(--line);
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.result.ok { --tone: var(--ok); --tone-bg: var(--ok-bg); --tone-line: var(--ok-line); }
.result.warn { --tone: var(--warn); --tone-bg: var(--warn-bg); --tone-line: var(--warn-line); }
.result.bad { --tone: var(--bad); --tone-bg: var(--bad-bg); --tone-line: var(--bad-line); }
.result.info { --tone: var(--info); --tone-bg: var(--info-bg); --tone-line: var(--info-line); }
.result.run { --tone: var(--accent); --tone-bg: var(--accent-soft); --tone-line: var(--accent-line); }

.result-empty { padding: 1.4rem 1.3rem; }

.steps { margin: 0; padding: 0; list-style: none; display: grid; gap: 1.1rem; }
.steps li { display: flex; gap: 0.8rem; }
.steps li > span {
  display: grid;
  place-items: center;
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 0.8rem;
  font-weight: 700;
}
.steps strong { font-size: 0.92rem; }
.steps p { margin-top: 0.1rem; color: var(--soft); font-size: 0.82rem; }

.result-body { display: flex; flex-direction: column; min-height: 0; flex: 1; }

.summary {
  padding: 1.1rem 1.2rem 1rem;
  background: linear-gradient(180deg, var(--tone-bg), var(--surface) 70%);
  border-bottom: 1px solid var(--line);
}

.result-top { display: flex; align-items: center; gap: 0.5rem; flex-wrap: wrap; }

.status {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.25rem 0.75rem;
  border: 1px solid var(--tone-line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--tone);
  font-weight: 600;
}

.status::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: currentColor; }
.result.run .status::before { animation: pulse 1s ease-in-out infinite; }

.proof {
  padding: 0.2rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--soft);
  font-family: var(--mono);
  font-size: 0.74rem;
}

.proof:empty, .wall:empty { display: none; }
.wall { margin-left: auto; color: var(--soft); font-family: var(--mono); font-size: 0.8rem; }

.objective { margin-top: 0.9rem; }
.label { color: var(--dim); font-size: 0.7rem; font-weight: 600; letter-spacing: 0.06em; text-transform: uppercase; }
.objective-value {
  margin-top: 0.05rem;
  font-family: var(--mono);
  font-size: 2rem;
  font-weight: 500;
  letter-spacing: -0.03em;
  line-height: 1.15;
  overflow-wrap: anywhere;
}

.human { margin-top: 0.3rem; color: var(--soft); }
.human:empty { display: none; }

.notes { margin: 0.75rem 0 0; padding: 0; list-style: none; display: grid; gap: 0.35rem; }
.notes:empty { display: none; }
.notes li {
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--warn-line);
  border-radius: var(--radius-sm);
  background: var(--warn-bg);
  color: var(--warn);
  font-size: 0.8rem;
}

.tiles { display: grid; grid-template-columns: 1fr 1fr; gap: 0.5rem; margin: 0.9rem 0 0; }
.tiles:empty { display: none; }

.tile {
  margin: 0;
  padding: 0.45rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  min-width: 0;
}

.tile dt { color: var(--dim); font-size: 0.72rem; }
.tile dd { margin: 0.05rem 0 0; font-family: var(--mono); font-size: 0.9rem; font-weight: 500; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.verify-line {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
  margin-top: 0.75rem;
  padding: 0.5rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--soft);
  font-size: 0.82rem;
  text-align: left;
  cursor: pointer;
}

.verify-line strong { font-family: var(--mono); font-size: 0.8rem; letter-spacing: 0.02em; }
.verify-line .go { margin-left: auto; opacity: 0.75; font-size: 0.78rem; white-space: nowrap; }
.verify-line.ok { border-color: var(--ok-line); background: var(--ok-bg); color: var(--ok); }
.verify-line.bad { border-color: var(--bad-line); background: var(--bad-bg); color: var(--bad); }
.verify-line.info { border-color: var(--info-line); background: var(--info-bg); color: var(--info); }

.rtabs { display: flex; gap: 0.15rem; padding: 0 0.9rem; border-bottom: 1px solid var(--line); }

.rtab, .tab {
  padding: 0.6rem 0.6rem 0.55rem;
  border: 0;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  background: none;
  color: var(--soft);
  font-size: 0.82rem;
  font-weight: 500;
  cursor: pointer;
}

.rtab:hover, .tab:hover { color: var(--ink); }
.rtab.active, .tab.active { color: var(--ink); border-bottom-color: var(--accent); }

.rpanel { flex: 1; min-height: 0; overflow: auto; padding: 0.9rem 1.2rem 1.1rem; }
.panel-intro { color: var(--soft); font-size: 0.8rem; margin-bottom: 0.6rem; }

.kv {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  margin: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  overflow: hidden;
}

.kv dt, .kv dd { margin: 0; padding: 0.35rem 0.65rem; border-top: 1px solid var(--line); font-size: 0.8rem; }
.kv dt:first-of-type, .kv dt:first-of-type + dd { border-top: 0; }
.kv dt { color: var(--soft); background: var(--surface-2); white-space: nowrap; }
.kv dd { font-family: var(--mono); font-size: 0.78rem; overflow-wrap: anywhere; }

.verdict {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  padding: 0.6rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  margin-bottom: 0.6rem;
  font-size: 0.84rem;
}

.verdict strong { font-family: var(--mono); letter-spacing: 0.02em; }
.verdict.ok { border-color: var(--ok-line); background: var(--ok-bg); color: var(--ok); }
.verdict.bad { border-color: var(--bad-line); background: var(--bad-bg); color: var(--bad); }
.verdict.info { border-color: var(--info-line); background: var(--info-bg); color: var(--info); }

.checks { margin: 0; padding: 0; list-style: none; border: 1px solid var(--line); border-radius: var(--radius-sm); }
.checks li {
  display: grid;
  grid-template-columns: 1.1rem minmax(0, 1fr) auto;
  gap: 0.5rem;
  align-items: baseline;
  padding: 0.4rem 0.65rem;
  border-top: 1px solid var(--line);
  font-size: 0.8rem;
}
.checks li:first-child { border-top: 0; }
.checks .mark { font-weight: 700; }
.checks .pass .mark { color: var(--ok); }
.checks .fail .mark { color: var(--bad); }
.checks .res { color: var(--soft); font-family: var(--mono); font-size: 0.74rem; }
.checks.muted { opacity: 0.75; }

.cmd {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.6rem 0.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--code-bg);
}
.cmd code { flex: 1; font-size: 0.78rem; overflow-wrap: anywhere; }

.log {
  margin: 0;
  padding: 0.7rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--code-bg);
  font-size: 0.72rem;
  line-height: 1.5;
  white-space: pre;
  overflow: auto;
}

/* ---------- Editor ---------- */

.editor { display: flex; flex-direction: column; min-height: 0; overflow: hidden; }

.editor-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0 0.9rem;
  border-bottom: 1px solid var(--line);
}

.tabs { display: flex; gap: 0.15rem; }
.editor-meta { color: var(--dim); font-size: 0.76rem; text-align: right; }

.code {
  flex: 1;
  width: 100%;
  min-height: 0;
  padding: 0.85rem 1rem;
  border: 0;
  background: var(--code-bg);
  color: var(--ink);
  font-size: 0.8rem;
  line-height: 1.6;
  resize: none;
  tab-size: 4;
  white-space: pre;
  outline: none;
}

.code[readonly] { color: var(--soft); }
.eq-pane { flex: 1; display: flex; flex-direction: column; min-height: 0; }
.eq-help { padding: 0.55rem 1rem; border-top: 1px solid var(--line); color: var(--dim); font-size: 0.76rem; }
.eq-help code { color: var(--accent); font-size: 0.95em; }

:focus-visible { outline: 2px solid var(--accent-line); outline-offset: 1px; }
select:focus-visible, input:focus-visible { outline: 0; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

@keyframes spin { to { transform: rotate(360deg); } }
@keyframes pulse { 50% { opacity: 0.3; } }

/* ---------- Responsive ---------- */

@media (max-width: 1100px) {
  html, body { height: auto; }
  .app { grid-template-columns: 260px minmax(0, 1fr); }
  .work { grid-template-columns: 1fr; }
  .editor { min-height: 420px; }
  .result { overflow: visible; }
}

@media (max-width: 760px) {
  .app { grid-template-columns: 1fr; }
  .sidebar { max-height: 50vh; border-right: 0; border-bottom: 1px solid var(--line); }
  .main { padding: 1rem; }
  .brand-sub { display: none; }
  .topbar { padding: 0.55rem 1rem; }
  .stats { flex-wrap: wrap; }
  .field, .field-engine { min-width: 0; flex: 1 1 140px; }
  .solve { margin-left: 0; width: 100%; justify-content: center; }
}

/* Solution (.sol) viewer */
.sol-scalars { display: flex; flex-wrap: wrap; gap: 0.5rem; margin-bottom: 0.75rem; }
.sol-bar { display: flex; flex-wrap: wrap; align-items: center; gap: 0.5rem; margin-bottom: 0.5rem; }
.sol-bar input[type="search"] { flex: 1 1 10rem; min-width: 8rem; padding: 0.35rem 0.6rem; border: 1px solid var(--line); border-radius: 6px; background: var(--surface); color: inherit; font: inherit; }
.sol-table { overflow: auto; border: 1px solid var(--line); border-radius: 6px; }
.sol-table table { width: 100%; border-collapse: collapse; font-family: "JetBrains Mono", monospace; font-size: 0.8rem; }
.sol-table th { position: sticky; top: 0; background: var(--surface-2); text-align: left; font-weight: 600; }
.sol-table th, .sol-table td { padding: 0.3rem 0.6rem; border-bottom: 1px solid var(--line); }
.sol-table .num { text-align: right; }
.sol-table .idx { color: var(--soft); width: 3.5rem; }
.sol-table tr.zero td { color: var(--soft); }
.sol-table .log { margin: 0; border: 0; max-height: max(15rem, calc(100vh - 20rem)); overflow: auto; }
.sol-pane { flex: 1; min-height: 0; overflow: auto; padding: 0.85rem 1rem; }
.sol-pane[hidden] { display: none; }
.tab-sol {
  align-self: center;
  margin-left: 0.5rem;
  padding: 0.3rem 0.9rem;
  border: 0;
  border-radius: var(--radius-sm);
  background: var(--accent);
  color: #fff;
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  box-shadow: 0 1px 2px rgba(154, 52, 18, 0.3);
  transition: background 0.12s, box-shadow 0.12s;
}
.tab-sol:hover { background: var(--accent-hover); }
.tab-sol.active { background: var(--accent-hover); box-shadow: 0 0 0 3px var(--accent-soft); }
.tab-sol[hidden] { display: none; }
.sol-bar .seg { margin: 0; }