:root {
  --ink: #18242f;
  --ink-soft: #334453;
  --muted: #637382;
  --paper: #fffefa;
  --paper-cool: #f7f9f8;
  --ground: #e9eeef;
  --line: #d2dadd;
  --line-strong: #9eabb3;
  --blue: #245f99;
  --blue-deep: #164873;
  --blue-soft: #dceaf5;
  --rust: #bd6035;
  --rust-deep: #854329;
  --rust-soft: #f5dfd3;
  --teal: #1f746c;
  --teal-soft: #dcece8;
  --danger: #a6433e;
  --shadow: 0 16px 44px rgba(24, 36, 47, .10);
  --sans: "Avenir Next", Avenir, "Helvetica Neue", ui-sans-serif, system-ui, sans-serif;
  --display: Charter, "Iowan Old Style", "Palatino Linotype", Georgia, serif;
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
}

* { box-sizing: border-box; }
html { color-scheme: light; scroll-behavior: smooth; }
body {
  min-width: 320px;
  margin: 0;
  color: var(--ink);
  background:
    radial-gradient(circle at 12% 4%, rgba(36, 95, 153, .08), transparent 28rem),
    linear-gradient(135deg, rgba(255,255,255,.48) 1px, transparent 1px),
    var(--ground);
  background-size: auto, 18px 18px, auto;
  font: 15px/1.48 var(--sans);
}
button, input, select { font: inherit; }
button, select, input[type="range"] { accent-color: var(--blue); }
button { color: inherit; }
a { color: var(--blue); }
[hidden] { display: none !important; }

.skip-link {
  position: fixed;
  z-index: 10;
  left: 14px;
  top: 10px;
  padding: 9px 13px;
  color: #fff;
  background: var(--blue-deep);
  transform: translateY(-160%);
  transition: transform .18s ease;
}
.skip-link:focus { transform: translateY(0); }

.topbar {
  min-height: 82px;
  display: grid;
  grid-template-columns: minmax(150px, 1fr) auto minmax(190px, 1fr);
  align-items: center;
  gap: 24px;
  padding: 13px clamp(18px, 3vw, 46px);
  color: #f7f4ee;
  background: var(--ink);
  border-bottom: 4px solid var(--rust);
}
.brand-lockup { text-align: center; }
.brand-lockup p { margin: 0 0 2px; color: #bfcad1; font-size: .64rem; font-weight: 700; letter-spacing: .13em; text-transform: uppercase; }
.brand-lockup h1 { margin: 0; font: 600 1.46rem/1.05 var(--display); letter-spacing: -.018em; }
.back, .companion-link { color: #dce4e7; text-decoration: none; }
.back { font-size: .78rem; font-weight: 650; }
.back::before { content: "← "; }
.companion-link { justify-self: end; display: grid; text-align: right; }
.companion-link span { color: #aebcc4; font-size: .58rem; font-weight: 700; letter-spacing: .1em; text-transform: uppercase; }
.companion-link strong { font-size: .75rem; }
.back:hover, .companion-link:hover { color: #fff; }

.app { max-width: 1580px; margin: 0 auto; padding: 23px clamp(12px, 2.1vw, 32px) 36px; }
.lab-intro {
  max-width: 1100px;
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(280px, .8fr);
  align-items: end;
  gap: clamp(30px, 7vw, 90px);
  margin: 0 auto 23px;
  padding: 0 4px;
}
.kicker, .eyebrow { margin: 0 0 4px; color: var(--blue); font: 800 .62rem/1.2 var(--mono); letter-spacing: .12em; text-transform: uppercase; }
.lab-intro h2 { margin: 0; max-width: 700px; font: 600 clamp(1.7rem, 3.4vw, 2.75rem)/1.02 var(--display); letter-spacing: -.035em; text-wrap: balance; }
.lab-intro > p { max-width: 56ch; margin: 0 0 2px; color: var(--ink-soft); font-size: .85rem; line-height: 1.58; text-wrap: pretty; }

.lab-grid { display: grid; grid-template-columns: 302px minmax(0, 1fr); align-items: start; gap: 18px; }
.controls, .workspace { background: rgba(255, 254, 250, .97); box-shadow: var(--shadow); }
.controls { position: sticky; top: 12px; border: 1px solid var(--line); }
.control-section { padding: 17px 18px 19px; border-bottom: 1px solid var(--line); }
.control-section:last-child { border-bottom: 0; }
.section-heading { display: flex; align-items: center; gap: 9px; margin-bottom: 13px; }
.section-heading > span { width: 26px; color: var(--rust); font: 700 .62rem var(--mono); }
.section-heading h2 { margin: 0; font-size: .76rem; font-weight: 750; letter-spacing: .08em; text-transform: uppercase; }
.field { display: grid; gap: 6px; margin: 0 0 13px; }
.field > span:first-child, .field-label { color: var(--muted); font-size: .69rem; font-weight: 700; letter-spacing: .025em; }
.field > span:has(output) { display: flex; justify-content: space-between; gap: 12px; }
.field output, .custom-tools output { color: var(--blue); font: 700 .72rem var(--mono); }
select, input[type="number"] { width: 100%; min-height: 44px; border: 1px solid var(--line-strong); border-radius: 3px; background: var(--paper); color: var(--ink); padding: 7px 9px; }
input[type="range"] { width: 100%; height: 44px; margin: -7px 0; }
.seed-row { display: grid !important; grid-template-columns: 1fr 42px; gap: 7px; }
.control-note { margin: -3px 0 12px; color: var(--muted); font-size: .68rem; line-height: 1.45; text-wrap: pretty; }
.width-note { margin: -5px 0 13px; padding: 8px 9px; border-left: 3px solid var(--blue); color: var(--ink-soft); background: var(--blue-soft); font-size: .64rem; line-height: 1.45; text-wrap: pretty; }
.width-note strong { color: var(--blue-deep); }
.custom-tools { margin-top: 13px; padding-top: 12px; border-top: 1px dashed var(--line-strong); }
.custom-tools-head { display: flex; justify-content: space-between; gap: 10px; align-items: baseline; }
.segmented { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-top: 7px; }
.segment, .icon-button, .preset-button, .primary-button, .secondary-button, .view-button, .mini-button {
  border: 1px solid var(--line-strong);
  border-radius: 3px;
  background: var(--paper);
  cursor: pointer;
  font-weight: 700;
  transition: border-color .18s ease, background .18s ease, color .18s ease, transform .12s ease;
}
.segment:active, .icon-button:active, .preset-button:active, .primary-button:active, .secondary-button:active, .view-button:active, .mini-button:active { transform: translateY(1px); }
.segment { min-width: 44px; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; gap: 7px; padding: 6px 7px; font-size: .68rem; border-radius: 3px 0 0 3px; }
.segment + .segment { border-left: 0; border-radius: 0 3px 3px 0; }
.segment.is-active, .view-button.is-active, .mini-button.is-active { border-color: var(--blue); color: var(--blue-deep); background: var(--blue-soft); }
.dot { width: 9px; height: 9px; display: inline-block; background: var(--rust); border: 1.5px solid #fff; outline: 1px solid var(--rust-deep); border-radius: 50%; }
.diamond { border-radius: 0; background: var(--blue); outline-color: var(--blue-deep); transform: rotate(45deg); }
.inline-actions { display: flex; justify-content: space-between; gap: 12px; margin-top: 7px; }
.text-button { min-width: 44px; min-height: 44px; padding: 4px 0; border: 0; color: var(--blue); background: transparent; cursor: pointer; font-size: .67rem; font-weight: 700; text-decoration: underline; text-underline-offset: 2px; }
.text-button.danger { color: var(--danger); }
.microcopy { margin: 3px 0 0; color: var(--muted); font-size: .61rem; }
.icon-button { min-width: 44px; min-height: 44px; }
.preset-row { display: grid; gap: 6px; }
.preset-button { min-height: 45px; display: grid; gap: 1px; padding: 7px 9px; text-align: left; }
.preset-button span { color: var(--blue-deep); font-size: .7rem; }
.preset-button small { color: var(--muted); font-size: .6rem; font-weight: 600; }
.preset-note { margin: 9px 0 0; color: var(--muted); font-size: .62rem; line-height: 1.42; text-wrap: pretty; }
.preset-note strong { color: var(--ink-soft); }
.preset-button:hover, .secondary-button:hover, .icon-button:hover { border-color: var(--blue); background: #f0f5f7; }
.recommended-button { border-color: var(--teal); background: #f1f8f6; box-shadow: inset 3px 0 0 var(--teal); }
.recommended-button span { color: #15564f; }
.recommended-button:hover { border-color: #15564f; background: var(--teal-soft); }
.train-section { background: #f1f5f4; }
.train-buttons { display: grid; grid-template-columns: 1.15fr 1fr 1fr; gap: 6px; }
.primary-button, .secondary-button { min-width: 44px; min-height: 44px; padding: 7px 8px; font-size: .69rem; }
.primary-button { border-color: var(--teal); color: #fff; background: var(--teal); }
.primary-button:hover { background: #185f58; }
.primary-button.is-running { border-color: var(--danger); background: var(--danger); }
.status { min-height: 2.8em; margin: 10px 0 0; color: var(--muted); font-size: .66rem; line-height: 1.4; }
.objective-note { margin: 9px 0 0; padding: 8px 9px; border-left: 3px solid var(--line-strong); color: var(--muted); background: rgba(255,255,255,.56); font-size: .62rem; line-height: 1.42; }
.objective-note strong { color: var(--ink-soft); }
button:disabled { cursor: not-allowed; opacity: .48; filter: saturate(.55); transform: none !important; }
button:disabled:hover { box-shadow: none; }
.primary-button:disabled { border-color: #6f8884; background: #6f8884; }

.workspace { min-width: 0; padding: clamp(18px, 2.2vw, 30px); border-top: 4px solid var(--ink); }
.workspace-head, .panel-head { display: flex; align-items: flex-start; justify-content: space-between; gap: 18px; }
.workspace-head { margin-bottom: 13px; }
.title-meta { display: flex; flex-wrap: wrap; align-items: center; gap: 9px; margin-bottom: 3px; }
.title-meta .eyebrow { margin: 0; }
.workspace h2 { margin: 0; font: 600 clamp(1.35rem, 2.3vw, 2rem)/1.08 var(--display); letter-spacing: -.025em; text-wrap: balance; }
.workspace h3 { margin: 0; font-size: .87rem; line-height: 1.25; text-wrap: balance; }
.provenance-badge { padding: 2px 6px; border: 1px solid var(--line-strong); color: var(--muted); font: 700 .57rem var(--mono); letter-spacing: .04em; text-transform: uppercase; }
.provenance-badge.is-constructed { border-color: #b98748; color: #76501e; background: #f7ead0; }
.provenance-badge.is-carried { border-color: #8b7a69; color: #5e4c3d; background: #eee8e1; }
.provenance-badge.is-random { border-color: var(--blue); color: var(--blue-deep); background: var(--blue-soft); }
.provenance-badge.is-trained { border-color: var(--teal); color: #15564f; background: var(--teal-soft); }
.view-switch { flex: 0 0 auto; display: flex; }
.view-button, .mini-button { min-width: 44px; min-height: 44px; padding: 5px 10px; border-radius: 0; font-size: .65rem; }
.view-button:first-child, .mini-button:first-child { border-radius: 3px 0 0 3px; }
.view-button:last-child, .surface-toolbar .mini-button:last-child { border-radius: 0 3px 3px 0; }
.view-button + .view-button, .mini-button + .mini-button { border-left: 0; }

.metric-row { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); margin-bottom: 14px; border: 1px solid var(--line); background: var(--paper-cool); }
.metric { padding: 9px 12px; border-right: 1px solid var(--line); }
.metric:last-child { border-right: 0; }
.metric span, .metric strong { display: block; }
.metric span { color: var(--muted); font-size: .59rem; font-weight: 750; letter-spacing: .055em; text-transform: uppercase; }
.metric strong { margin-top: 1px; font: 700 1.08rem var(--mono); font-variant-numeric: tabular-nums; }
figure { margin: 0; }
canvas { display: block; width: 100%; background: var(--paper-cool); }
#mainCanvas { min-height: 440px; aspect-ratio: 16 / 8.4; border: 1px solid var(--line); touch-action: none; }
.plot-caption { display: flex; justify-content: space-between; gap: 16px; align-items: center; margin: 8px 0 0; color: var(--muted); font-size: .63rem; }
.plot-legend { display: flex; flex-wrap: wrap; gap: 13px; align-items: center; }
.plot-legend span { display: inline-flex; align-items: center; gap: 5px; }
.marker { width: 11px; height: 11px; display: inline-block; border: 2px solid #fff; outline: 1px solid var(--ink); }
.marker-zero { border-radius: 50%; background: var(--rust); }
.marker-one { background: var(--blue); transform: rotate(45deg); }
.boundary-swatch { width: 18px; display: inline-block; border-top: 2px solid var(--ink); }
.probe-swatch { width: 10px; height: 10px; display: inline-block; border: 2px solid var(--ink); border-radius: 50%; background: #f6c55a; box-shadow: 0 0 0 2px #fff; }

.model-row { display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(260px, .65fr); gap: 13px; margin-top: 17px; }
.network-panel, .history-panel, .analysis-panel { min-width: 0; border: 1px solid var(--line); background: #fbfcfa; }
.network-panel, .history-panel { padding: 13px; }
.parameter-count { color: var(--rust); font: 700 .66rem var(--mono); white-space: nowrap; }
.history-note { color: var(--muted); font: .6rem var(--mono); }
#networkCanvas, #historyCanvas { height: 145px; margin-top: 9px; background: transparent; }

.analysis-grid { display: grid; grid-template-columns: minmax(0, 1.06fr) minmax(390px, .94fr); gap: 13px; margin-top: 13px; }
.analysis-panel { padding: 14px; }
.panel-copy { max-width: 72ch; margin: 7px 0 0; color: var(--muted); font-size: .68rem; line-height: 1.48; }
.shared-scale { flex: 0 0 auto; color: var(--muted); font: .56rem var(--mono); white-space: nowrap; }
.shared-scale i { width: 50px; height: 6px; display: block; margin: 2px 0 3px auto; border: 1px solid var(--line-strong); background: linear-gradient(90deg, var(--rust), #fff 50%, var(--blue)); }
.feature-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(145px, 1fr)); gap: 8px; margin-top: 11px; }
.feature-card { min-width: 0; padding: 8px; border: 1px solid var(--line); background: var(--paper); }
.feature-card header { display: flex; justify-content: space-between; gap: 5px; align-items: baseline; margin-bottom: 5px; }
.feature-card strong { font-size: .65rem; }
.feature-card header span, .feature-card .feature-meta { color: var(--muted); font: .55rem var(--mono); }
.feature-card canvas { aspect-ratio: 1 / 1; min-height: 0; border: 1px solid var(--line); }
.feature-card p { margin: 6px 0 0; color: var(--ink-soft); font: .56rem/1.38 var(--mono); overflow-wrap: anywhere; }
.empty-feature { grid-column: 1 / -1; display: grid; place-items: center; min-height: 165px; padding: 24px; border: 1px dashed var(--line-strong); color: var(--muted); font-size: .72rem; text-align: center; }
.surface-head { align-items: center; }
.surface-toolbar { display: flex; }
.surface-toolbar .reset-camera { margin-left: 5px; border-left: 1px solid var(--line-strong); border-radius: 3px; color: var(--muted); }
.surface-instruction { margin: 7px 0 0; color: var(--muted); font-size: .61rem; }
#surfaceCanvas { height: 350px; margin-top: 8px; border: 1px solid var(--line); cursor: grab; touch-action: none; }
#surfaceCanvas:active { cursor: grabbing; }
.probe-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 12px; margin-top: 9px; }
.probe-row label { display: grid; grid-template-columns: auto 1fr auto; align-items: center; gap: 7px; color: var(--muted); font-size: .64rem; font-weight: 700; }
.probe-row output { width: 3.2em; color: var(--rust); font: 700 .62rem var(--mono); }
.probe-readout { margin: 7px 0 0; text-align: center; font: 700 .67rem var(--mono); font-variant-numeric: tabular-nums; }

.lecture-prompts { margin-top: 14px; padding: 14px 16px 16px; border-top: 4px solid var(--ink); background: #eaf0f1; }
.prompt-heading { display: flex; align-items: baseline; gap: 10px; }
.prompt-heading > span { color: var(--rust); font: 800 .57rem var(--mono); letter-spacing: .08em; text-transform: uppercase; }
.prompt-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 15px; margin-top: 10px; }
.prompt-grid p { margin: 0; padding-left: 9px; border-left: 2px solid var(--line-strong); color: var(--muted); font-size: .68rem; line-height: 1.48; }
.prompt-grid strong { display: block; color: var(--ink); }

.footer { max-width: 1580px; display: flex; justify-content: space-between; gap: 22px; margin: 0 auto; padding: 0 clamp(18px, 3vw, 46px) 34px; color: var(--muted); font-size: .65rem; }
.footer nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 18px; }
.footer a { font-weight: 700; text-underline-offset: 3px; }

button:focus-visible, a:focus-visible, select:focus-visible, input:focus-visible, canvas:focus-visible { outline: 3px solid rgba(36, 95, 153, .36); outline-offset: 2px; }

@media (max-width: 1120px) {
  .lab-grid { grid-template-columns: 270px minmax(0, 1fr); }
  .analysis-grid { grid-template-columns: 1fr; }
  #surfaceCanvas { height: 410px; }
}

@media (max-width: 800px) {
  .topbar { min-height: 74px; grid-template-columns: auto 1fr auto; gap: 10px; padding: 10px 13px; }
  .brand-lockup p { display: none; }
  .brand-lockup h1 { font-size: 1.12rem; }
  .back { font-size: .67rem; }
  .companion-link span { display: none; }
  .companion-link strong { font-size: .64rem; }
  .lab-intro { grid-template-columns: 1fr; gap: 12px; }
  .lab-grid { grid-template-columns: 1fr; }
  .controls { position: static; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .workspace > .controls { margin: 14px 0 17px; box-shadow: none; }
  .control-section { border-right: 1px solid var(--line); }
  .train-section { grid-column: 1 / -1; }
  .workspace { padding: 15px; }
  .workspace-head { align-items: flex-end; }
  .metric-row { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .metric:nth-child(2) { border-right: 0; }
  .metric:nth-child(-n + 2) { border-bottom: 1px solid var(--line); }
  #mainCanvas { min-height: 390px; aspect-ratio: 1 / 1; }
  .model-row { grid-template-columns: 1fr; }
  .prompt-grid { grid-template-columns: 1fr; gap: 8px; }
  .footer { flex-direction: column; gap: 7px; }
  .footer nav { justify-content: flex-start; }
}

@media (max-width: 520px) {
  .app { padding: 16px 8px 28px; }
  .topbar { grid-template-columns: 1fr auto; }
  .brand-lockup { grid-column: 1 / -1; grid-row: 1; }
  .back { grid-column: 1; grid-row: 2; }
  .companion-link { grid-column: 2; grid-row: 2; }
  .lab-intro { padding: 0 8px; }
  .lab-intro h2 { font-size: 1.7rem; }
  .controls { grid-template-columns: 1fr; }
  .control-section, .train-section { grid-column: auto; border-right: 0; }
  .workspace-head { display: grid; }
  .view-switch { justify-self: start; }
  .view-button { padding-inline: 9px; }
  .plot-caption { display: grid; }
  #mainCanvas { min-height: 340px; }
  .analysis-panel, .network-panel, .history-panel { padding: 10px; }
  .panel-head { display: grid; }
  .shared-scale { justify-self: start; }
  .shared-scale i { margin-left: 0; }
  .surface-toolbar { justify-self: start; }
  #surfaceCanvas { height: 300px; }
  .probe-row { grid-template-columns: 1fr; }
  .feature-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .01ms !important; }
}