:root {
  --bg: #0f1419;
  --panel: #1a212b;
  --panel2: #222c38;
  --ink: #e6edf3;
  --muted: #8b98a5;
  --line: #2d3845;
  --accent: #4ea1ff;
  --good: #3fb950;
  --warn: #d29922;
  --bad: #f85149;
  --mono: ui-monospace, "Cascadia Code", "Consolas", monospace;
}
* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--ink);
  font-family: system-ui, "Segoe UI", Roboto, sans-serif;
  font-size: 14px;
  line-height: 1.45;
}
header {
  display: flex; justify-content: space-between; align-items: center;
  flex-wrap: wrap; gap: 12px;
  padding: 14px 22px; border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, #16202b, #0f1419);
}
.brand h1 { margin: 0; font-size: 22px; letter-spacing: .5px; }
.brand h1 .web { color: var(--accent); font-weight: 400; }
.tag { margin: 2px 0 0; color: var(--muted); font-size: 12.5px; }
.headio { display: flex; gap: 8px; flex-wrap: wrap; }

.btn {
  background: var(--panel2); color: var(--ink); border: 1px solid var(--line);
  padding: 7px 13px; border-radius: 7px; cursor: pointer; font-size: 13px;
  transition: background .12s, border-color .12s;
}
.btn:hover { background: #2c3a49; border-color: #3a4a5a; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #06243f; font-weight: 600; }
.btn.primary:hover { background: #6fb4ff; }
.btn.sm { padding: 3px 9px; font-size: 12px; }

main {
  display: grid;
  grid-template-columns: 320px 1fr;
  grid-template-areas: "params zones" "params results";
  gap: 16px; padding: 18px 22px; align-items: start;
}
@media (max-width: 920px) { main { grid-template-columns: 1fr; grid-template-areas: "params" "zones" "results"; } }
.params { grid-area: params; }
.zones { grid-area: zones; }
.results { grid-area: results; }

.panel {
  background: var(--panel); border: 1px solid var(--line);
  border-radius: 10px; padding: 16px;
}
.panel h2 { margin: 0 0 12px; font-size: 14px; text-transform: uppercase; letter-spacing: 1px; color: var(--muted); }

.grid { display: grid; grid-template-columns: 1fr; gap: 10px; }
label { display: flex; flex-direction: column; font-size: 12px; color: var(--muted); gap: 4px; }
input, select {
  background: #0d141b; border: 1px solid var(--line); color: var(--ink);
  padding: 7px 9px; border-radius: 6px; font-size: 14px; font-family: var(--mono);
}
input:focus, select:focus { outline: none; border-color: var(--accent); }
.derived { margin-top: 14px; padding-top: 12px; border-top: 1px solid var(--line); font-family: var(--mono); font-size: 12.5px; color: var(--muted); }
.derived b { color: var(--ink); }

.zones-head { display: flex; justify-content: space-between; align-items: center; }
.zbtns { display: flex; gap: 6px; }
table { width: 100%; border-collapse: collapse; font-family: var(--mono); font-size: 13px; }
th, td { text-align: right; padding: 5px 8px; border-bottom: 1px solid var(--line); }
th { color: var(--muted); font-weight: 500; font-size: 11px; text-transform: uppercase; }
th:first-child, td:first-child { text-align: center; color: var(--muted); }
td input { width: 92px; text-align: right; padding: 4px 6px; }
td.calc { color: var(--accent); }
.hint { color: var(--muted); font-size: 11.5px; margin: 10px 0 0; }
.hint em { color: var(--ink); font-style: normal; }

.metrics { display: grid; grid-template-columns: repeat(auto-fit, minmax(135px, 1fr)); gap: 10px; margin-bottom: 16px; }
.metric { background: var(--panel2); border: 1px solid var(--line); border-radius: 8px; padding: 10px 12px; }
.metric .k { color: var(--muted); font-size: 11px; text-transform: uppercase; letter-spacing: .5px; }
.metric .v { font-family: var(--mono); font-size: 19px; margin-top: 3px; }
.metric .v small { font-size: 12px; color: var(--muted); }
.metric.grade-good .v { color: var(--good); }
.metric.grade-warn .v { color: var(--warn); }
.metric.grade-bad  .v { color: var(--bad); }

.charts figure { margin: 0; }
canvas { width: 100%; height: auto; background: #0b1118; border: 1px solid var(--line); border-radius: 8px; }
figcaption { color: var(--muted); font-size: 11.5px; margin-top: 6px; text-align: center; }
.method { color: var(--muted); font-size: 11px; margin-top: 14px; border-top: 1px solid var(--line); padding-top: 10px; }

.drop-overlay {
  position: fixed; inset: 0; display: none; align-items: center; justify-content: center;
  background: rgba(15,20,25,.85); z-index: 50; font-size: 26px; color: var(--accent);
  border: 3px dashed var(--accent);
}
.drop-overlay.show { display: flex; }

dialog { background: var(--panel); color: var(--ink); border: 1px solid var(--line); border-radius: 10px; padding: 20px; min-width: 320px; }
dialog::backdrop { background: rgba(0,0,0,.5); }
dialog h3 { margin: 0 0 12px; }
#sampleList { list-style: none; padding: 0; margin: 0 0 14px; max-height: 50vh; overflow: auto; }
#sampleList li { padding: 8px 10px; border: 1px solid var(--line); border-radius: 6px; margin-bottom: 6px; cursor: pointer; font-family: var(--mono); font-size: 13px; }
#sampleList li:hover { background: var(--panel2); border-color: var(--accent); }

footer { padding: 16px 22px; color: var(--muted); font-size: 11.5px; border-top: 1px solid var(--line); }