:root {
  --bg: #f4f5f7;
  --panel: #ffffff;
  --panel-2: #f7f8fa;
  --border: #e1e4e9;
  --text: #1b1f24;
  --muted: #5d6673;
  --accent: #c8733a;
  --accent-2: #3d7be0;
  --accent-soft: rgba(200, 115, 58, 0.12);
  --info: #2f6fd0;
  --warn: #b7791f;
  --bad: #c0392b;
  --radius: 10px;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.05);
  --mono: ui-monospace, "SF Mono", "JetBrains Mono", Menlo, Consolas, monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1216;
    --panel: #171b21;
    --panel-2: #1d2229;
    --border: #2a3039;
    --text: #e6e9ee;
    --muted: #96a0ad;
    --accent: #e08a4f;
    --accent-2: #6b9cf0;
    --accent-soft: rgba(224, 138, 79, 0.14);
    --info: #6b9cf0;
    --warn: #e0b04f;
    --bad: #f0715f;
    --shadow: none;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 14px/1.45 var(--sans);
  -webkit-font-smoothing: antialiased;
}
h1, h2 { margin: 0; font-weight: 600; }
h2 { font-size: 13px; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); margin-bottom: 10px; }
small { color: var(--muted); font-weight: 400; }
button { font: inherit; color: inherit; }

/* ---------- top bar ---------- */
.topbar {
  display: flex; align-items: center; justify-content: space-between; gap: 16px;
  padding: 14px 20px; border-bottom: 1px solid var(--border); background: var(--panel);
  position: sticky; top: 0; z-index: 10;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand svg { width: 34px; height: 34px; color: var(--accent); flex: none; }
.brand h1 { font-size: 17px; }
.brand p { margin: 0; color: var(--muted); font-size: 12.5px; }
.topbar-actions { display: flex; gap: 8px; }
.btn {
  border: 1px solid var(--border); background: var(--panel-2); padding: 7px 12px;
  border-radius: 8px; cursor: pointer;
}
.btn:hover { border-color: var(--accent); }

/* ---------- layout ---------- */
.layout {
  display: grid; grid-template-columns: 360px minmax(0, 1fr); gap: 16px;
  padding: 16px 20px 40px; max-width: 1600px; margin: 0 auto;
}
.panel {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 16px; box-shadow: var(--shadow);
}

/* ---------- controls ---------- */
.controls {
  align-self: start; position: sticky; top: 76px; max-height: calc(100vh - 92px);
  overflow-y: auto; padding: 4px 16px 12px;
}
fieldset {
  border: 0; border-bottom: 1px solid var(--border); margin: 0; padding: 14px 0 16px;
  display: grid; grid-template-columns: repeat(6, minmax(0, 1fr)); gap: 10px 10px;
}
fieldset:last-child { border-bottom: 0; }
legend {
  font-size: 12px; font-weight: 600; text-transform: uppercase; letter-spacing: 0.07em;
  color: var(--accent); padding: 0; margin-bottom: 4px; float: left; width: 100%;
  grid-column: 1 / -1;
}
.field { display: flex; flex-direction: column; gap: 4px; grid-column: span 3; min-width: 0; }
.field.wide, .check.wide, .presets { grid-column: 1 / -1; }
.field.third { grid-column: span 2; }
.field > span:first-child { font-size: 12px; color: var(--muted); }
.field i { font-family: Georgia, serif; }
.inp { position: relative; display: flex; }
.inp em {
  position: absolute; right: 9px; top: 50%; transform: translateY(-50%);
  font-style: normal; font-size: 12px; color: var(--muted); pointer-events: none;
}
input[type="number"], select {
  width: 100%; min-width: 0; padding: 7px 9px; font: 14px var(--mono);
  color: var(--text); background: var(--panel-2); border: 1px solid var(--border); border-radius: 7px;
}
.inp input { padding-right: 46px; }
select { font-family: var(--sans); font-size: 13px; }
input:focus, select:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
#freq { font-size: 18px; font-weight: 600; }
.check { display: flex; gap: 8px; align-items: center; font-size: 13px; color: var(--muted); }
.check input { accent-color: var(--accent); }
.presets { display: flex; flex-wrap: wrap; gap: 6px; }
.presets button {
  border: 1px solid var(--border); background: var(--panel-2); border-radius: 999px;
  padding: 3px 10px; font-size: 12px; cursor: pointer;
}
.presets button:hover { border-color: var(--accent); color: var(--accent); }

/* ---------- output ---------- */
.output { display: flex; flex-direction: column; gap: 16px; min-width: 0; }
.headline { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 12px; }
.kpi {
  background: var(--panel); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 12px 14px; display: flex; flex-direction: column; gap: 2px; box-shadow: var(--shadow);
}
.kpi > span { font-size: 12px; color: var(--muted); }
.kpi b { font: 600 24px/1.2 var(--mono); }
.kpi b small { font-size: 13px; }
.kpi > small { font-size: 12px; }

.viewer-panel { padding: 0; overflow: hidden; }
.viewer-bar {
  display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap;
  padding: 8px 10px; border-bottom: 1px solid var(--border);
}
.tabs { display: flex; gap: 4px; background: var(--panel-2); padding: 3px; border-radius: 8px; }
.tabs button {
  border: 0; background: transparent; padding: 5px 12px; border-radius: 6px; cursor: pointer; color: var(--muted);
}
.tabs button[aria-selected="true"] { background: var(--panel); color: var(--text); box-shadow: 0 0 0 1px var(--border); }
.viewer-info { font: 12px var(--mono); color: var(--muted); }
.viewer { position: relative; height: min(62vh, 600px); min-height: 320px; }
.viewer canvas { display: block; width: 100%; height: 100%; cursor: grab; }
.viewer canvas:active { cursor: grabbing; }
.viewer-msg {
  position: absolute; inset: 0; display: grid; place-items: center; color: var(--muted);
  padding: 20px; text-align: center;
}

.downloads { display: grid; grid-template-columns: repeat(auto-fill, minmax(210px, 1fr)); gap: 10px; }
.dl-group { display: contents; }
.dl {
  display: flex; flex-direction: column; align-items: flex-start; gap: 2px; text-align: left;
  border: 1px solid var(--border); background: var(--panel-2); border-radius: 8px;
  padding: 10px 12px; cursor: pointer;
}
.dl b { font-weight: 600; }
.dl span { font-size: 12px; color: var(--muted); }
.dl:hover:not(:disabled) { border-color: var(--accent); background: var(--accent-soft); }
.dl:disabled { opacity: 0.5; cursor: not-allowed; }

.warnings { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 6px; }
.warnings li { padding: 7px 10px 7px 12px; border-left: 3px solid var(--info); background: var(--panel-2); border-radius: 0 6px 6px 0; }
.warnings li.warn { border-color: var(--warn); }
.warnings li.bad { border-color: var(--bad); }

.results { display: grid; grid-template-columns: repeat(auto-fill, minmax(340px, 1fr)); gap: 16px; }
table { width: 100%; border-collapse: collapse; }
th, td { padding: 5px 0; vertical-align: baseline; border-bottom: 1px dashed var(--border); }
tr:last-child th, tr:last-child td { border-bottom: 0; }
th { text-align: left; font-weight: 400; color: var(--muted); width: 42%; padding-right: 8px; }
td { font-family: var(--mono); white-space: nowrap; }
td.hint { font: 12px var(--sans); color: var(--muted); white-space: normal; padding-left: 8px; }
.tag { font-size: 10px; letter-spacing: 0.04em; border: 1px solid var(--border); padding: 1px 6px; border-radius: 999px; margin-left: 6px; }

.howto summary { cursor: pointer; list-style: none; }
.howto summary::-webkit-details-marker { display: none; }
.howto summary h2 { display: inline; }
.howto ol { margin: 4px 0 8px; padding-left: 20px; display: flex; flex-direction: column; gap: 6px; }
.note { color: var(--muted); font-size: 12.5px; margin: 0; }

.busy {
  position: fixed; inset: 0; background: rgba(0, 0, 0, 0.35); display: flex; gap: 12px;
  align-items: center; justify-content: center; color: #fff; z-index: 50; font-weight: 600;
}
.busy[hidden] { display: none; }
.spinner {
  width: 22px; height: 22px; border: 3px solid rgba(255, 255, 255, 0.35); border-top-color: #fff;
  border-radius: 50%; animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---------- responsive ---------- */
@media (max-width: 1000px) {
  .layout { grid-template-columns: 1fr; padding: 12px 16px 32px; }
  .controls { position: static; max-height: none; }
  .headline { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
}
@media (max-width: 560px) {
  .topbar { flex-wrap: wrap; padding: 12px 16px; }
  .results { grid-template-columns: 1fr; }
  td { white-space: normal; }
  .kpi b { font-size: 20px; }
}

/* ---------- print: build sheet ---------- */
@media print {
  :root { --bg: #fff; --panel: #fff; --panel-2: #fff; --text: #000; --muted: #444; --border: #bbb; }
  .topbar-actions, .viewer-panel, .downloads, .presets, .busy { display: none !important; }
  .topbar { position: static; }
  .layout { display: block; padding: 0; }
  .controls { position: static; max-height: none; overflow: visible; margin-bottom: 12px; }
  .output { gap: 10px; }
  .panel, .kpi { box-shadow: none; break-inside: avoid; }
  .downloads, .viewer-panel { display: none; }
  .panel:has(.downloads) { display: none; }
  input, select { border: 0; background: none; padding: 2px 0; }
}