:root {
  --bg: #f5f7fa;
  --panel: #ffffff;
  --border: #e2e8f0;
  --muted: #64748b;
  --text: #0f172a;
  --accent: #1d4ed8;
  --accent-hover: #1e40af;
  --good: #15803d;
  --warn: #c2410c;
  --danger: #b91c1c;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
               "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  background: var(--bg);
  font-size: 14px;
  line-height: 1.4;
}

.topbar {
  background: var(--panel);
  border-bottom: 1px solid var(--border);
  padding: 14px 24px;
  display: flex; align-items: baseline; justify-content: space-between;
  position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: center; gap: 10px; }
.brand .logo { font-size: 22px; color: var(--accent); }
.brand h1 { margin: 0; font-size: 18px; font-weight: 600; }
.tagline { color: var(--muted); font-size: 12px; }

.layout {
  display: grid;
  grid-template-columns: minmax(420px, 1fr) minmax(360px, 1fr);
  gap: 16px;
  padding: 16px 24px;
}
@media (max-width: 900px) {
  .layout { grid-template-columns: 1fr; }
}

.panel {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px 18px;
}
.panel h2 {
  margin: 0 0 10px;
  font-size: 14px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--muted);
}

fieldset {
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 10px 12px;
  margin: 0 0 14px;
}
fieldset legend {
  font-size: 12px;
  font-weight: 600;
  color: var(--text);
  padding: 0 4px;
}

.grid.two {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px 14px;
}
label {
  display: flex;
  flex-direction: column;
  font-size: 12px;
  color: var(--muted);
  gap: 3px;
}
label.check {
  flex-direction: row;
  align-items: center;
  gap: 6px;
  color: var(--text);
  font-size: 13px;
}
label .req { color: var(--danger); margin-left: 2px; }

input[type="number"], input[type="text"], select {
  font: inherit;
  padding: 5px 8px;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: white;
  color: var(--text);
  width: 100%;
}
input:focus, select:focus {
  outline: 2px solid #93c5fd;
  border-color: var(--accent);
}
.inline-num { width: 70px; display: inline-block; margin-left: 4px; }

.profile-row {
  display: flex; flex-wrap: wrap; gap: 14px;
  margin-bottom: 6px;
}
.profile-row label {
  flex-direction: row; align-items: center; gap: 4px;
  color: var(--text); font-size: 13px;
}
.profile-desc {
  margin-top: 6px;
  padding: 8px 10px;
  background: #f1f5f9;
  border-left: 3px solid var(--accent);
  border-radius: 4px;
  font-size: 12px;
  line-height: 1.45;
  color: var(--text);
}
.profile-desc b { font-weight: 600; }
.profile-desc .ref {
  display: block; margin-top: 4px;
  color: var(--muted); font-size: 11px;
}

.constraints {
  width: 100%; border-collapse: collapse; font-size: 12px;
  margin: 6px 0;
}
.constraints th { color: var(--muted); font-weight: 500; text-align: left; padding: 4px; }
.constraints td { padding: 3px 4px; }
.constraints input, .constraints select {
  padding: 3px 5px; font-size: 12px;
}

button {
  font: inherit; font-size: 13px; cursor: pointer;
  padding: 7px 14px; border-radius: 5px; border: 1px solid var(--border);
  background: white; color: var(--text);
}
button.primary {
  background: var(--accent); color: white; border-color: var(--accent);
  font-weight: 600;
}
button.primary:hover { background: var(--accent-hover); }
button.ghost { background: transparent; }
button.small { padding: 3px 9px; font-size: 12px; }
button:disabled { opacity: 0.5; cursor: not-allowed; }

.actions {
  display: flex; align-items: center; gap: 10px; margin-top: 10px;
}
.status { color: var(--muted); font-size: 12px; }
.status.error { color: var(--danger); }
.status.ok { color: var(--good); }

.muted { color: var(--muted); }
.small { font-size: 12px; }

.spine-frame {
  background: #fafbfc;
  border: 1px dashed var(--border);
  border-radius: 6px;
  height: 520px;
  display: flex; align-items: stretch; justify-content: center;
  padding: 6px;
}
.spine-svg { width: 100%; height: 100%; display: block; }

/* Results panel */
.results { margin: 0 24px 24px; padding: 16px 18px; }
.results.hidden { display: none; }
.results-grid {
  display: grid;
  grid-auto-flow: column;
  grid-auto-columns: 340px;
  gap: 14px;
  overflow-x: auto;
  padding-bottom: 8px;
  scroll-snap-type: x proximity;
}
.plan-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #fbfcfe;
  padding: 12px;
  display: flex; flex-direction: column;
  scroll-snap-align: start;
}
.plan-card h3 {
  margin: 0 0 6px; font-size: 13px;
  display: flex; justify-content: space-between; align-items: baseline;
}
.plan-card .badge {
  font-size: 10px; padding: 2px 6px; border-radius: 10px;
  background: var(--accent); color: white;
}
.plan-card .badge.warn { background: var(--warn); }
.plan-card .badge.danger { background: var(--danger); }
.plan-card .plan-text {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 11px; line-height: 1.5; color: var(--text);
  background: white; border: 1px solid var(--border);
  border-radius: 4px; padding: 6px 8px; margin: 4px 0;
}
.plan-card .tp-row {
  display: grid; grid-template-columns: 1fr 1fr; gap: 8px;
}
.plan-card .tp { font-size: 11px; }
.plan-card .tp .label {
  font-weight: 600; text-transform: uppercase; letter-spacing: 0.04em;
  color: var(--muted); font-size: 10px; margin-bottom: 2px;
}
.plan-card .spine-mini {
  height: 240px; background: #fafbfc; border: 1px dashed var(--border);
  border-radius: 4px; padding: 4px; margin-top: 6px;
}
.plan-card .params-mini {
  font-family: ui-monospace, monospace; font-size: 10px;
  display: grid; grid-template-columns: auto 1fr; gap: 1px 6px;
  color: var(--text);
}
.plan-card .params-mini .k { font-weight: 700; }

.footer {
  margin: 0 24px 16px; padding: 8px 0;
  color: var(--muted); font-size: 11px;
  border-top: 1px solid var(--border);
}