/* ============================================================
   Plot Explorer — brand styling ported from kristianskorpen.com
   inverter-course (editorial paper aesthetic).
   ============================================================ */

@import url('https://fonts.googleapis.com/css2?family=IBM+Plex+Serif:ital,wght@0,400;0,500;0,600;0,700;1,400&family=Inter:wght@400;500;600;700&family=JetBrains+Mono:wght@400;500;700&display=swap');

* { box-sizing: border-box; }
/* HTML `hidden` attribute must always win over any class-level display rule. */
[hidden] { display: none !important; }

:root {
  /* brand greens */
  --green-50:  #ECF6EE;
  --green-100: #D5EBD9;
  --green-200: #A8D6B0;
  --green-300: #7BC086;
  --green-500: #1F8A4C;
  --green-600: #166E3D;
  --green-700: #0E5630;

  /* ink scale */
  --ink-900: #0E1413;
  --ink-700: #2E3633;
  --ink-500: #5A645F;
  --ink-400: #7B847F;
  --ink-300: #A8AEA9;
  --ink-200: #D6D9D4;
  --ink-150: #E6E5DE;
  --ink-100: #EFEDE5;
  --ink-50:  #F7F5EE;
  --ink-25:  #FAFAF6;
  --paper:   #FFFFFF;

  --warn-500: #B04A1B;
  --warn-100: #FAEADD;

  --fg:           var(--ink-900);
  --fg-soft:      var(--ink-500);
  --fg-muted:     var(--ink-400);
  --bg:           var(--ink-25);
  --bg-card:      var(--paper);
  --bg-paper:     var(--ink-50);
  --bg-inset:     var(--ink-100);
  --border:       var(--ink-150);
  --border-strong:var(--ink-200);
  --accent:       var(--green-500);
  --accent-hover: var(--green-600);
  --accent-soft:  var(--green-50);

  --font-serif: "IBM Plex Serif", "Source Serif 4", Charter, Georgia, serif;
  --font-sans:  "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono:  "JetBrains Mono", "SFMono-Regular", Menlo, Consolas, monospace;

  --radius-1: 4px;
  --radius-2: 6px;
  --radius-3: 8px;
  --radius-4: 12px;

  --shadow-1: 0 1px 2px rgba(10,15,13,0.04), 0 0 0 1px rgba(10,15,13,0.02);
  --shadow-2: 0 2px 6px rgba(10,15,13,0.06), 0 1px 2px rgba(10,15,13,0.04);
  --shadow-focus: 0 0 0 3px rgba(31,138,76,0.25);

  --dur-fast: 120ms;
  --dur-base: 180ms;
}

/* Scope to the explorer root only when standalone, so we don't override
   <body>, <header>, <footer> of the embedding page. The standalone HTML
   wraps everything in <div class="plot-explorer-root">. */
.plot-explorer-root {
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 15px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
.plot-explorer-root a { color: var(--accent); text-decoration: none; }
.plot-explorer-root a:hover { color: var(--accent-hover); text-decoration: underline; }

/* ─────────── header / footer (only inside the explorer root) ─────────── */
.plot-explorer-root > header {
  background: var(--bg-card);
  padding: 1.5rem 2rem 1.2rem;
  border-bottom: 1px solid var(--border);
}
.plot-explorer-root > header h1 {
  font-family: var(--font-serif); font-weight: 600;
  margin: 0 0 0.3rem; font-size: 1.7rem; color: var(--fg);
}
.plot-explorer-root .tagline { margin: 0; color: var(--fg-soft); font-size: 0.95rem; }

.plot-explorer-root > footer {
  padding: 1.5rem 2rem 2.5rem;
  color: var(--fg-muted);
  font-size: 0.8rem;
  text-align: center;
}

/* ─────────── steps ─────────── */
.step { padding: 1.5rem 2rem; }
.step + .step { border-top: 1px solid var(--border); }
.step-head { display: flex; align-items: center; gap: 0.8rem; margin-bottom: 1rem; flex-wrap: wrap; }
.step-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 1.8rem; height: 1.8rem; border-radius: 50%;
  background: var(--accent); color: white; font-weight: 600; font-size: 0.92rem;
  font-family: var(--font-mono);
}
.step-head h2 {
  margin: 0; font-size: 1.15rem; color: var(--fg);
  font-family: var(--font-serif); font-weight: 600;
}
.step-controls { margin-left: auto; display: flex; align-items: center; gap: 1rem; flex-wrap: wrap; }
.link-toggle {
  color: var(--fg-soft); font-size: 0.85rem; cursor: pointer; user-select: none;
  font-family: var(--font-mono);
}
.link-toggle input { vertical-align: middle; margin-right: 0.35rem; accent-color: var(--accent); }

/* ─────────── dropzone ─────────── */
.dropzone {
  border: 2px dashed var(--border-strong);
  border-radius: var(--radius-3);
  padding: 2.5rem 1.5rem;
  text-align: center;
  background: var(--bg-card);
  cursor: pointer;
  transition: border-color var(--dur-fast), background var(--dur-fast);
}
.dropzone:hover, .dropzone.drag {
  border-color: var(--accent);
  background: var(--accent-soft);
}
.dropzone .big { margin: 0; font-size: 1.02rem; color: var(--fg); font-family: var(--font-mono); }

.sample-row {
  display: flex; align-items: center; gap: 0.6rem 0.9rem;
  margin-top: 0.9rem; flex-wrap: wrap;
}
.sample-row .or {
  color: var(--fg-muted); font-size: 0.85rem; font-family: var(--font-mono);
  flex: 0 0 auto;
}
.sample-btn small {
  font-weight: 400; color: var(--fg-muted); margin-left: 0.4em;
  font-family: var(--font-mono); font-size: 0.78em;
}
.sample-btn:hover small { color: var(--ink-700); }

/* ─────────── clean banner ─────────── */
.clean-banner {
  margin-top: 1rem;
  padding: 0.7rem 1rem;
  background: var(--accent-soft);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius-2);
  font-size: 0.88rem;
  color: var(--green-700);
}
.clean-banner strong { color: var(--green-700); }
.clean-banner.err { background: var(--warn-100); border-left-color: var(--warn-500); color: var(--warn-500); }
.clean-banner ul { margin: 0.3rem 0 0 1.2rem; padding: 0; }
.clean-banner li { margin: 0.1rem 0; }
.clean-banner code { font-family: var(--font-mono); font-size: 0.85em; }

/* ─────────── data meta row ─────────── */
.data-meta {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 1rem;
  color: var(--fg-soft); font-size: 0.88rem;
}
.data-meta #data-summary { font-family: var(--font-mono); font-size: 0.82rem; }

/* ─────────── buttons ─────────── */
button {
  font-family: var(--font-sans);
  background: var(--accent); color: white; border: 1px solid var(--accent);
  border-radius: var(--radius-2);
  padding: 0.5rem 1rem; font-size: 0.88rem; cursor: pointer;
  transition: background var(--dur-fast), border-color var(--dur-fast);
  font-weight: 500;
}
button:hover { background: var(--accent-hover); border-color: var(--accent-hover); }
button:focus-visible { outline: none; box-shadow: var(--shadow-focus); }
button.ghost {
  background: transparent; color: var(--fg-soft); border-color: var(--border-strong);
}
button.ghost:hover { background: var(--bg-inset); color: var(--fg); border-color: var(--ink-300); }
button.sample-btn {
  background: var(--paper); color: var(--accent); border-color: var(--accent);
}
button.sample-btn:hover { background: var(--accent-soft); color: var(--accent-hover); }
button.mini {
  font-family: var(--font-mono); font-size: 11px;
  text-transform: uppercase; letter-spacing: 0.06em;
  padding: 0.35rem 0.7rem;
  background: var(--paper); color: var(--fg);
  border: 1px solid var(--border-strong);
}
button.mini:hover { background: var(--bg-inset); border-color: var(--ink-300); }
button.remove-plot, button.remove-slider {
  background: transparent; color: var(--fg-muted); border: 0;
  padding: 0.2rem 0.45rem; font-size: 1rem; line-height: 1;
}
button.remove-plot:hover, button.remove-slider:hover { color: var(--warn-500); background: transparent; }

/* ─────────── form controls ─────────── */
.axis-row label {
  display: flex; flex-direction: column; gap: 0.25rem;
  font-family: var(--font-mono); font-size: 0.7rem;
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--fg-soft);
}
.opt { color: var(--fg-muted); text-transform: none; letter-spacing: 0; font-size: 0.65rem; }
select {
  background: var(--paper); color: var(--fg);
  font-family: var(--font-sans); font-size: 0.9rem;
  border: 1px solid var(--border-strong); border-radius: var(--radius-2);
  padding: 0.45rem 0.55rem;
}
select:focus { outline: none; border-color: var(--accent); box-shadow: var(--shadow-focus); }

/* ─────────── global sliders panel (sticky) ─────────── */
.shared-panel {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-3);
  padding: 0.85rem 1rem;
  margin-bottom: 1.25rem;
  box-shadow: var(--shadow-2);
}
.shared-panel-head {
  display: flex; align-items: center; gap: 0.8rem;
  margin-bottom: 0.6rem; flex-wrap: wrap;
}
.shared-title {
  font-family: var(--font-mono); font-size: 0.72rem;
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--fg-soft); font-weight: 600;
}
.shared-hint {
  font-size: 0.78rem; color: var(--fg-muted); font-style: italic;
  flex: 1;
}
.shared-add { display: flex; gap: 0.35rem; align-items: center; }
.shared-add #global-add-select {
  font-size: 0.78rem; padding: 0.3rem 0.5rem; max-width: 12rem;
}

/* ─────────── plot cards ─────────── */
.plots {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(520px, 1fr));
  gap: 1.25rem;
}
.plot-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-3);
  padding: 1rem 1rem 0.9rem;
  box-shadow: var(--shadow-1);
  display: flex; flex-direction: column;
}
.plot-card-head {
  display: flex; align-items: center; justify-content: space-between;
  margin-bottom: 0.8rem;
}
.plot-id {
  font-family: var(--font-mono); font-size: 0.72rem;
  color: var(--fg-soft); font-weight: 600;
  text-transform: uppercase; letter-spacing: 0.08em;
}

.axis-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.7rem; margin-bottom: 0.7rem; }
@media (max-width: 720px) { .axis-row { grid-template-columns: 1fr; } }

.curves-section { margin-bottom: 0.7rem; }
.curves-head {
  display: flex; align-items: center; justify-content: space-between;
  gap: 0.5rem; margin-bottom: 0.4rem; flex-wrap: wrap;
}
.curves-title {
  font-family: var(--font-mono); font-size: 0.7rem;
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--fg-soft);
}
.curves-add { display: flex; gap: 0.35rem; align-items: center; }
.curves-add .add-curve-select { font-size: 0.78rem; padding: 0.3rem 0.45rem; max-width: 12rem; }
.curves-list { display: flex; flex-direction: column; gap: 0.3rem; }
.curve-row {
  display: flex; align-items: center; gap: 0.45rem;
  padding: 0.3rem 0.5rem;
  background: var(--bg-paper);
  border: 1px solid var(--border);
  border-radius: var(--radius-2);
  min-width: 0;
}
.curve-row .swatch {
  width: 14px; height: 14px; border-radius: 50%;
  border: 1.5px solid var(--ink-200); flex: 0 0 auto;
}
.curve-row select { flex: 0 1 auto; min-width: 6em; font-size: 0.84rem; padding: 0.25rem 0.4rem; }
.curve-row .curve-expr {
  flex: 1 1 auto; min-width: 0;
  font-family: var(--font-mono); font-size: 0.78rem;
  padding: 0.25rem 0.45rem;
  border: 1px solid var(--border-strong); border-radius: var(--radius-2);
  background: var(--paper); color: var(--ink-900);
}
.curve-row .curve-expr:focus { outline: none; border-color: var(--accent); box-shadow: var(--shadow-focus); }
.curve-row .curve-expr.error { border-color: var(--warn-500); background: var(--warn-100); }
.curve-row .remove-curve {
  background: transparent; color: var(--fg-soft); border: 0;
  padding: 0.15rem 0.35rem; cursor: pointer; font-size: 1rem;
}
.curve-row .remove-curve:hover { color: var(--warn-500); }

.ptype-row {
  display: flex; align-items: center; gap: 1rem;
  margin-bottom: 0.7rem; padding: 0.45rem 0.7rem;
  background: var(--bg-paper); border: 1px solid var(--border);
  border-radius: var(--radius-2);
  font-size: 0.85rem;
}
.ptype-row .ptype-label {
  font-family: var(--font-mono); font-size: 0.7rem;
  text-transform: uppercase; letter-spacing: 0.08em;
  color: var(--fg-soft);
}
.ptype-row label { color: var(--fg); cursor: pointer; }
.ptype-row input { vertical-align: middle; margin-right: 0.3rem; accent-color: var(--accent); }

.plot-area { position: relative; min-height: 340px; min-width: 0; }
.plot-canvas {
  width: 100%; min-height: 340px;
  background: var(--paper);
  border-radius: var(--radius-2);
}
.plot-empty {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  text-align: center; padding: 1.5rem;
  background: rgba(255,255,255,0.92);
  border-radius: var(--radius-2);
  font-family: var(--font-mono); font-size: 0.82rem;
  color: var(--fg-soft); line-height: 1.5;
  pointer-events: none;
}

/* ─────────── plot body — canvas on top, sliders below ─────────── */
.plot-body {
  display: flex; flex-direction: column;
  gap: 1rem;
  min-width: 0;
}

/* ─────────── sliders ─────────── */
.sliders-wrap {
  padding-top: 0.55rem;
  border-top: 1px solid var(--border);
  min-width: 0;
}
.sliders {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(190px, 1fr));
  gap: 0.35rem;
}
.sliders-head { display: none; }   /* sliders are self-evident; drop the section title */
.add-slider-row {
  display: flex; gap: 0.35rem; align-items: center;
  margin-top: 0.4rem;
}
.add-slider-row .add-slider-select {
  font-size: 0.74rem; padding: 0.2rem 0.4rem;
  flex: 1; min-width: 0;
}
.add-slider-row .add-slider { font-size: 10.5px; padding: 0.2rem 0.5rem; }

/* two-row grid: row 1 = name | val | buttons; row 2 = range bar full-width */
.slider-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto auto auto;
  grid-template-rows: auto auto;
  align-items: center;
  column-gap: 0.35rem;
  row-gap: 0.2rem;
  padding: 0.3rem 0.55rem;
  background: var(--bg-paper);
  border: 1px solid var(--border);
  border-radius: var(--radius-2);
  min-width: 0;
}
.slider-row .name {
  grid-row: 1; grid-column: 1 / 2;
  font-family: var(--font-mono);
  color: var(--ink-700);
  font-size: 0.76rem;
  overflow: hidden; text-overflow: ellipsis; white-space: nowrap;
  min-width: 0;
}
.slider-row .name.output-name { color: var(--ink-500); font-style: italic; }
.slider-row .val {
  grid-row: 1; grid-column: 2 / 3;
  font-family: var(--font-mono);
  color: var(--green-600);
  font-variant-numeric: tabular-nums;
  font-size: 0.78rem;
  font-weight: 500;
  padding: 0.05rem 0.25rem;
  border-radius: 3px;
  cursor: text;
  min-width: 2.6em;
  text-align: right;
  outline: none;
}
.slider-row .val:hover  { background: var(--bg-inset); }
.slider-row .val:focus  { background: var(--accent-soft); outline: 1px solid var(--accent); }
.slider-row .promote-slider { grid-row: 1; grid-column: 3 / 4; }
.slider-row .lock-toggle    { grid-row: 1; grid-column: 4 / 5; }
.slider-row .remove-slider  { grid-row: 1; grid-column: 5 / 6; }
.slider-row .range-input {
  grid-row: 2; grid-column: 1 / -1;
  width: 100%; min-width: 0; margin: 0;
}
.slider-row .ticks { display: none; }
/* in the floating global panel there's no ⬆ promote, so 4 cols suffice */
.shared-panel .slider-row { grid-template-columns: minmax(0, 1fr) auto auto auto; }
.shared-panel .slider-row .lock-toggle    { grid-row: 1; grid-column: 3 / 4; }
.shared-panel .slider-row .remove-slider  { grid-row: 1; grid-column: 4 / 5; }
.slider-row .lock-toggle {
  background: transparent; border: 0; padding: 0.2rem 0.3rem;
  color: var(--fg-soft); font-size: 0.95rem; cursor: pointer; line-height: 1;
  transition: color var(--dur-fast);
}
.slider-row .lock-toggle:hover { color: var(--ink-900); }
.slider-row.floating { background: var(--ink-25); border-style: dashed; }
.slider-row.floating .val { color: var(--ink-400); font-style: italic; }
.slider-row.floating .range-input { opacity: 0.45; }

/* legacy stacked-layout rules — overridden by the flex layout above */

/* feasibility shading on the track */
.slider-row .range-input.has-mask {
  /* JS sets background to a linear-gradient with stops where infeasible */
  background-image: var(--mask-gradient, none);
  background-repeat: no-repeat;
  background-size: 100% 6px;
  background-position: center;
}
@media (max-width: 720px) {
  .sliders { grid-template-columns: 1fr; }
}

/* range input — match inverter-course slider chrome */
input[type="range"] {
  -webkit-appearance: none; appearance: none;
  width: 100%; height: 18px;
  background: transparent;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-runnable-track {
  height: 2px; background: var(--border-strong); border-radius: 100px;
}
input[type="range"]::-moz-range-track {
  height: 2px; background: var(--border-strong); border-radius: 100px;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 14px; height: 14px;
  background: var(--paper); border: 2px solid var(--green-500);
  border-radius: 50%; margin-top: -6px;
  box-shadow: 0 1px 2px rgba(0,0,0,0.15);
  transition: transform 80ms;
}
input[type="range"]::-moz-range-thumb {
  width: 14px; height: 14px;
  background: var(--paper); border: 2px solid var(--green-500);
  border-radius: 50%;
  box-shadow: 0 1px 2px rgba(0,0,0,0.15);
}
input[type="range"]:hover::-webkit-slider-thumb { transform: scale(1.15); }
input[type="range"]:active::-webkit-slider-thumb { transform: scale(1.3); }

.plot-footnote {
  font-size: 0.7rem; color: var(--fg-muted);
  margin-top: 0.5rem;
  font-family: var(--font-mono);
}

/* ─────────── onboarding overlay ─────────── */
.onboard {
  position: fixed; inset: 0;
  background: rgba(14, 20, 19, 0.55);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  backdrop-filter: blur(2px);
}
.onboard-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-3);
  padding: 1.6rem 1.8rem;
  max-width: 440px;
  text-align: center;
  box-shadow: var(--shadow-2);
}
.onboard-card h3 {
  font-family: var(--font-serif); font-weight: 600;
  margin: 0 0 0.6rem; font-size: 1.25rem;
}
.onboard-card p { color: var(--fg-soft); margin: 0 0 1.2rem; }
.onboard-card.help-card {
  max-width: 720px; max-height: 80vh; overflow: auto;
  text-align: left;
}
.help-body { font-size: 0.88rem; line-height: 1.5; color: var(--ink-700); }
.help-body h4 {
  font-family: var(--font-serif); font-weight: 600;
  margin: 1.1rem 0 0.35rem; font-size: 1rem;
  color: var(--fg);
}
.help-body code, .help-body .mono { font-family: var(--font-mono); font-size: 0.85em;
  background: var(--bg-inset); padding: 0.06rem 0.3rem; border-radius: 3px; color: var(--ink-900); }
.help-body table { border-collapse: collapse; width: 100%; font-size: 0.85rem; margin: 0.3rem 0 0.6rem; }
.help-body td, .help-body th { text-align: left; padding: 0.25rem 0.5rem; border-bottom: 1px solid var(--border); vertical-align: top; }
.help-body th { color: var(--fg-soft); font-weight: 500; font-size: 0.78rem; }
.help-body td:first-child { font-family: var(--font-mono); font-size: 0.85em; white-space: nowrap; color: var(--green-700); }
.curve-help { background: var(--paper); color: var(--fg-soft); border: 1px solid var(--border-strong); width: 1.6rem; padding: 0.2rem 0; font-weight: 600; }
.curve-help:hover { color: var(--accent); border-color: var(--accent); background: var(--accent-soft); }

/* ─────────── responsive ─────────── */
@media (max-width: 720px) {
  header { padding: 1rem 0.9rem 0.8rem; }
  header h1 { font-size: 1.3rem; }
  .tagline { font-size: 0.85rem; }
  .step { padding: 1rem 0.9rem; }
  footer { padding: 1rem 0.9rem 1.5rem; }

  .step-head h2 { font-size: 1rem; }
  .step-controls { width: 100%; justify-content: flex-end; }

  .dropzone { padding: 1.5rem 1rem; }
  .dropzone .big { font-size: 0.92rem; }
  .sample-row { flex-direction: column; align-items: stretch; gap: 0.5rem; }
  .sample-btn { width: 100%; }

  .data-meta { flex-direction: column; align-items: flex-start; gap: 0.4rem; }
  .data-meta #data-summary { font-size: 0.78rem; word-break: break-word; }

  .shared-panel { padding: 0.7rem 0.7rem; margin-bottom: 0.9rem; border-radius: var(--radius-2); }
  .shared-panel-head { flex-direction: column; align-items: stretch; gap: 0.45rem; }
  .shared-add { width: 100%; }
  .shared-add #global-add-select { flex: 1; max-width: none; min-width: 0; }

  .plots { gap: 0.9rem; grid-template-columns: 1fr; }
  .plot-card { padding: 0.7rem; min-height: 0; }
  .plot-card-head { margin-bottom: 0.5rem; }

  .axis-row { grid-template-columns: 1fr; gap: 0.45rem; }
  .ptype-row { flex-wrap: wrap; gap: 0.5rem; padding: 0.35rem 0.5rem; }

  .plot-area { min-height: 280px; }
  .plot-canvas { min-height: 280px; }

  .sliders { grid-template-columns: 1fr; gap: 0.4rem; }
  .slider-row .name { font-size: 0.8rem; }
  .slider-row .val  { font-size: 0.82rem; }
  .lock-toggle, .remove-slider, .promote-slider { padding: 0.18rem 0.35rem; min-width: 1.5rem; }
  .add-slider-row { flex-wrap: wrap; }
  .add-slider-row .add-slider-select { flex: 1 1 100%; }

  /* avoid sticky covering too much on phones — keep panel relative on small screens */
  .shared-panel { position: relative; top: auto; box-shadow: var(--shadow-1); }

  .onboard-card { padding: 1.1rem 1.2rem; max-width: 90vw; }
}

/* slightly larger touch targets */
@media (max-width: 720px) and (pointer: coarse) {
  input[type="range"] { height: 28px; }
  input[type="range"]::-webkit-slider-thumb { width: 20px; height: 20px; margin-top: -9px; }
  input[type="range"]::-moz-range-thumb { width: 20px; height: 20px; }
  button { min-height: 38px; }
}
