:root {
  --bg: #f7f7f8;
  --fg: #1b1c1f;
  --muted: #6b6e75;
  --accent: #1b5e9b;
  --accent-soft: #e5eef7;
  --pass: #2a7c2a;
  --pass-soft: #e5f3e2;
  --stop: #b8342d;
  --stop-soft: #fae8e6;
  --border: #d8d9de;
  --card: #ffffff;
  --mono: ui-monospace, "Cascadia Code", Consolas, monospace;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; background: var(--bg); color: var(--fg); }
body { font: 15px/1.55 -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }
code { font: 13.5px var(--mono); background: #eeeff2; padding: 1px 5px; border-radius: 3px; }

header {
  max-width: 980px; margin: 0 auto; padding: 30px 24px 8px;
}
header h1 { margin: 0 0 6px; font-weight: 600; font-size: 1.55rem; }
header .lede { margin: 0; color: var(--muted); max-width: 760px; line-height: 1.5; }

main { max-width: 980px; margin: 0 auto; padding: 8px 24px 32px; }
section { margin-top: 22px; background: var(--card); border: 1px solid var(--border); border-radius: 6px; padding: 16px 18px; }
section h2 { font-size: 1.12rem; margin: 0 0 10px; font-weight: 600; }
section h3 { font-size: 0.95rem; margin: 0 0 6px; font-weight: 600; }

.hidden { display: none !important; }

/* ------------------------- presets ------------------------- */
.preset-grid {
  display: grid; gap: 10px;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}
.preset {
  background: var(--card); border: 1px solid var(--border); border-radius: 6px;
  padding: 10px 12px; text-align: left; cursor: pointer;
  display: flex; flex-direction: column; gap: 4px;
  transition: border-color 0.12s ease, background 0.12s ease;
}
.preset strong { color: var(--fg); font-weight: 600; font-size: 0.95rem; }
.preset small { color: var(--muted); line-height: 1.35; }
.preset:hover { border-color: var(--accent); background: var(--accent-soft); }

/* ------------------------ spec editor ---------------------- */
.spec-header { display: flex; justify-content: space-between; align-items: flex-start; gap: 14px; flex-wrap: wrap; margin-bottom: 12px; }
.order-block { display: flex; gap: 12px; }
.order-block label { display: flex; flex-direction: column; align-items: center; gap: 2px; font-weight: 600; }
.order-block input { width: 68px; padding: 5px 8px; text-align: center; font: 14px var(--mono); border: 1px solid var(--border); border-radius: 4px; }
.order-block .hint { font-weight: 400; color: var(--muted); font-size: 0.78rem; }

.bands { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 680px) { .bands { grid-template-columns: 1fr; } }
.band-col header { display: flex; align-items: center; justify-content: space-between; margin-bottom: 6px; }
.badge { display: inline-block; font-size: 0.72rem; font-weight: 700; padding: 1px 6px; border-radius: 3px; vertical-align: middle; margin-left: 4px; }
.badge.pass { background: var(--pass-soft); color: var(--pass); }
.badge.stop { background: var(--stop-soft); color: var(--stop); }

.row-add {
  background: transparent; border: 1px dashed var(--border); color: var(--muted);
  padding: 3px 8px; border-radius: 4px; cursor: pointer; font-size: 0.82rem;
}
.row-add:hover { color: var(--accent); border-color: var(--accent); }

.band-tbl { width: 100%; border-collapse: collapse; font: 13.5px var(--mono); }
.band-tbl thead th {
  text-align: left; font: 12px -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-weight: 500; color: var(--muted); padding: 0 6px 4px;
}
.band-tbl tbody td { padding: 3px 0; }
.band-tbl input { width: 100%; padding: 5px 7px; border: 1px solid var(--border); border-radius: 4px; font: 13.5px var(--mono); }
.band-tbl input:focus { outline: 2px solid var(--accent); outline-offset: -1px; border-color: var(--accent); }
.band-tbl td:first-child input, .band-tbl td:nth-child(2) input { text-align: right; }
.band-tbl td:nth-child(3) { width: 80px; }
.band-tbl td:nth-child(3) input { text-align: right; width: 68px; }
.band-tbl td:last-child { width: 28px; text-align: center; }
.band-tbl .row-del {
  background: transparent; border: none; color: var(--muted);
  cursor: pointer; font-size: 1.1rem; line-height: 1; padding: 0;
}
.band-tbl .row-del:hover { color: var(--stop); }

.run-block { margin-top: 18px; display: flex; align-items: center; gap: 14px; flex-wrap: wrap; }
#run-btn {
  background: var(--accent); color: #fff; border: none; border-radius: 4px;
  padding: 9px 18px; font-size: 0.98rem; font-weight: 600; cursor: pointer;
}
#run-btn:disabled { opacity: 0.55; cursor: default; }
#status { color: var(--muted); font-size: 0.9rem; }
#status.warn { color: var(--stop); }
#status.busy::before {
  content: ""; display: inline-block; width: 10px; height: 10px;
  border: 2px solid var(--border); border-top-color: var(--accent);
  border-radius: 50%; animation: spin 0.8s linear infinite;
  margin-right: 7px; vertical-align: -1px;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ------------------------- results ------------------------- */
.result-head { display: flex; justify-content: space-between; align-items: baseline; margin-bottom: 10px; }
.m-badge {
  font: 14px/1.2 var(--mono);
  background: var(--accent-soft); color: var(--accent);
  padding: 6px 10px; border-radius: 4px;
}
.m-badge.fail { background: var(--stop-soft); color: var(--stop); }
.m-badge.ok   { background: var(--pass-soft); color: var(--pass); }

.plot { width: 100%; height: 460px; }

.summary { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; margin-top: 14px; }
@media (max-width: 680px) { .summary { grid-template-columns: 1fr; } }
.result-tbl { width: 100%; border-collapse: collapse; font: 13.5px var(--mono); }
.result-tbl th, .result-tbl td { text-align: left; padding: 4px 8px; border-bottom: 1px solid #eee; }
.result-tbl th { color: var(--muted); font: 11.5px -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif; font-weight: 500; }
.result-tbl td.ok   { color: var(--pass); font-weight: 600; }
.result-tbl td.fail { color: var(--stop); font-weight: 600; }
.result-tbl td.num  { text-align: right; }

.zeros summary { cursor: pointer; color: var(--muted); margin-top: 12px; font-size: 0.9rem; }
.zeros-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 8px; }
.zeros-grid h4 { margin: 0 0 4px; font-size: 0.85rem; color: var(--muted); }
.zeros-grid ul { margin: 0; padding-left: 18px; font: 12.5px var(--mono); color: var(--fg); }
#coeffs {
  font: 11.5px var(--mono); background: #f4f5f7; border: 1px solid var(--border); border-radius: 4px;
  padding: 10px; overflow-x: auto; white-space: pre-wrap; word-break: break-all;
}

footer {
  max-width: 980px; margin: 0 auto; padding: 24px 24px 44px;
  color: var(--muted); font-size: 0.85rem; border-top: 1px solid var(--border);
}