:root {
  --green: #22c670;
  --green-deep: #119655;
  --green-dark: #0c7144;
  --night: #061914;
  --stage: #071d20;
  --ink: #122033;
  --cream: #f4fbf7;
  --paper: #ffffff;
  --mint: #e3f7ec;
  --line: #d4e9dd;
  --muted: #587065;
  --cyan: #48e5e0;
  --violet: #8587ff;
  --gold: #f5c542;
  --coral: #dc4c55;
  --shadow: 0 18px 45px rgba(16, 67, 49, 0.11);
  color-scheme: light;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

html {
  min-width: 0;
  background: var(--cream);
  color: var(--ink);
  scroll-behavior: smooth;
}

body {
  min-width: 0;
  margin: 0;
  background:
    radial-gradient(circle at 12% 5%, rgba(34, 198, 112, 0.13), transparent 24rem),
    radial-gradient(circle at 88% 14%, rgba(133, 135, 255, 0.08), transparent 26rem),
    linear-gradient(180deg, #fbfefc 0, var(--cream) 28rem, #eef8f2 100%);
}

button, input, select { font: inherit; }
button, select, input[type="range"] { cursor: pointer; }

button:focus-visible,
select:focus-visible,
input:focus-visible,
summary:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(34, 198, 112, 0.48);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 0.5rem;
  left: 0.5rem;
  z-index: 50;
  padding: 0.65rem 0.9rem;
  border-radius: 0.6rem;
  background: var(--night);
  color: white;
  transform: translateY(-160%);
}
.skip-link:focus { transform: translateY(0); }

.topbar {
  display: flex;
  min-height: 3.4rem;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.7rem clamp(1rem, 3vw, 2.5rem);
  border-bottom: 1px solid rgba(212, 233, 221, 0.85);
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(14px);
}

.brand { display: inline-flex; width: 8.7rem; align-items: center; }
.brand img { display: block; width: 100%; height: auto; }
.topbar-label {
  color: var(--green-dark);
  font-size: 0.74rem;
  font-weight: 850;
  letter-spacing: 0.11em;
  text-transform: uppercase;
}

.shell {
  width: min(100%, 1540px);
  margin: 0 auto;
  padding: clamp(1rem, 2.5vw, 2.1rem) clamp(0.75rem, 2.5vw, 2rem) 3rem;
}

.hero {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 2rem;
  margin-bottom: 1.15rem;
}

.hero-copy { max-width: 790px; }
.hero h1,
.lab-heading h2,
.panel-heading h2,
.stage-heading h2,
.measurement-panel h3,
.term-section h3 {
  margin: 0;
  letter-spacing: -0.035em;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 3.9rem);
  line-height: 0.99;
}

.hero-copy > p:last-child {
  margin: 0.8rem 0 0;
  color: var(--muted);
  font-size: clamp(0.96rem, 1.25vw, 1.08rem);
  line-height: 1.6;
}

.kicker,
.panel-kicker,
.section-id,
.notice-label {
  margin: 0 0 0.35rem;
  color: var(--green-dark);
  font-size: 0.7rem;
  font-weight: 850;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.duality-strip {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 0.6rem;
  padding: 0.65rem;
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: rgba(255, 255, 255, 0.86);
  box-shadow: 0 10px 26px rgba(16, 67, 49, 0.07);
}

.duality-strip > div {
  display: flex;
  align-items: center;
  gap: 0.55rem;
}

.duality-symbol {
  display: grid;
  width: 2.35rem;
  height: 2.35rem;
  place-items: center;
  border-radius: 50%;
  color: var(--night);
  font-size: 0.92rem;
  font-weight: 900;
}
.photon-symbol { background: var(--gold); }
.electron-symbol { background: var(--cyan); }
.duality-strip strong, .duality-strip small { display: block; }
.duality-strip strong { font-size: 0.74rem; }
.duality-strip small { margin-top: 0.12rem; color: var(--muted); font-size: 0.64rem; }
.duality-plus { color: var(--green-dark); font-weight: 900; }

.investigation-nav {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.55rem;
  margin-bottom: 1.25rem;
}

.investigation-tab {
  display: grid;
  min-height: 4.7rem;
  grid-template-columns: auto 1fr;
  align-items: center;
  gap: 0.7rem;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 0.85rem;
  background: rgba(255, 255, 255, 0.84);
  color: var(--ink);
  text-align: left;
  transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.investigation-tab:hover { border-color: #98d8b7; transform: translateY(-1px); }
.investigation-tab.is-active {
  border-color: var(--green);
  background: var(--night);
  color: white;
  box-shadow: 0 10px 24px rgba(6, 25, 20, 0.15);
}
.investigation-tab strong, .investigation-tab small { display: block; }
.investigation-tab strong { font-size: 0.86rem; }
.investigation-tab small { margin-top: 0.18rem; color: var(--muted); font-size: 0.7rem; }
.investigation-tab.is-active small { color: #aad1c1; }
.tab-number {
  display: grid;
  width: 1.8rem;
  height: 1.8rem;
  place-items: center;
  border-radius: 50%;
  background: var(--mint);
  color: var(--green-dark);
  font-size: 0.65rem;
  font-weight: 900;
}
.investigation-tab.is-active .tab-number { background: var(--green); color: var(--night); }

.lab-heading {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.8rem;
}
.lab-heading h2 { font-size: clamp(1.25rem, 2vw, 1.7rem); }
.lab-heading > div > p:last-child { margin: 0.35rem 0 0; color: var(--muted); font-size: 0.88rem; }

.reset-button,
.secondary-button,
.action-button,
.preset-row button,
.compare-actions button,
.nudge-group button {
  min-height: 2.75rem;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--line);
  border-radius: 0.65rem;
  background: white;
  color: var(--ink);
  font-weight: 760;
}
.reset-button:hover,
.secondary-button:hover,
.preset-row button:hover,
.compare-actions button:hover,
.nudge-group button:hover { border-color: var(--green); background: var(--mint); }

.lab-grid {
  display: grid;
  grid-template-columns: minmax(220px, 0.76fr) minmax(560px, 2.45fr) minmax(250px, 0.92fr);
  grid-template-areas: "controls stage analysis";
  align-items: start;
  gap: 0.85rem;
}

.control-panel,
.analysis-panel,
.stage-panel,
.measurement-panel {
  border: 1px solid var(--line);
  border-radius: 1rem;
  background: rgba(255, 255, 255, 0.95);
}
.control-panel, .analysis-panel {
  position: sticky;
  top: 0.75rem;
  padding: 1rem;
  box-shadow: 0 10px 28px rgba(18, 66, 50, 0.06);
}
.control-panel { grid-area: controls; }
.analysis-panel { grid-area: analysis; }
.stage-panel {
  grid-area: stage;
  min-width: 0;
  padding: 0.85rem;
  box-shadow: var(--shadow);
}

.panel-heading, .stage-heading { margin-bottom: 0.9rem; }
.panel-heading h2, .stage-heading h2 { font-size: 1.05rem; }
.stage-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}
.stage-status {
  display: inline-flex;
  min-height: 2rem;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0.65rem;
  border-radius: 999px;
  background: var(--cream);
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 800;
  white-space: nowrap;
}
.stage-status > span:first-child { width: 0.52rem; height: 0.52rem; border-radius: 50%; background: #8ca49a; }
.stage-status.is-running > span:first-child { background: var(--green); box-shadow: 0 0 0 5px rgba(34, 198, 112, 0.12); }

.transport {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.38rem;
  margin-bottom: 1rem;
}
.primary-button {
  display: inline-flex;
  min-height: 2.75rem;
  align-items: center;
  justify-content: center;
  gap: 0.45rem;
  padding: 0.55rem 0.75rem;
  border: 1px solid var(--green);
  border-radius: 0.65rem;
  background: var(--green);
  color: var(--night);
  font-weight: 850;
}
.primary-button:hover { background: #32d881; }

.control-set { padding-top: 0.15rem; }
.range-control, .select-control { display: block; margin: 0 0 0.95rem; }
.range-control > span, .select-control > span {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.42rem;
  color: var(--ink);
  font-size: 0.78rem;
  font-weight: 750;
}
output { color: var(--green-dark); font-variant-numeric: tabular-nums; font-weight: 850; }
input[type="range"] {
  width: 100%;
  height: 2.75rem;
  margin-block: -0.72rem;
  accent-color: var(--green-deep);
}
select {
  width: 100%;
  min-height: 2.75rem;
  padding: 0.5rem 2rem 0.5rem 0.65rem;
  border: 1px solid var(--line);
  border-radius: 0.65rem;
  background: white;
  color: var(--ink);
}

.spectrum-track {
  position: relative;
  height: 0.62rem;
  margin: -0.6rem 0 0.9rem;
  border: 1px solid rgba(18, 32, 51, 0.12);
  border-radius: 999px;
  background: linear-gradient(90deg, #6b35c9 0, #355fd8 19%, #29aee4 32%, #2fd17d 46%, #e7dc3d 62%, #f49b38 76%, #dc4c55 89%, #65716b 100%);
}
.spectrum-track span {
  position: absolute;
  top: 50%;
  left: 30%;
  width: 0.9rem;
  height: 0.9rem;
  border: 2px solid white;
  border-radius: 50%;
  background: var(--night);
  box-shadow: 0 1px 5px rgba(6, 25, 20, 0.35);
  transform: translate(-50%, -50%);
}
.preset-row { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 0.32rem; margin: -0.15rem 0 1rem; }
.preset-row button { min-width: 0; padding-inline: 0.3rem; font-size: 0.68rem; }
.planck-presets { grid-template-columns: repeat(3, minmax(0, 1fr)); margin-top: 0.45rem; }
.action-button { width: 100%; margin-bottom: 0.75rem; border-color: var(--green); background: var(--mint); color: var(--green-dark); }
.action-button:hover { background: #d1f1df; }
.full-button { width: 100%; }
.polarity-key { display: flex; justify-content: space-between; margin: -0.55rem 0 0.8rem; color: var(--muted); font-size: 0.64rem; }

.display-controls {
  display: grid;
  gap: 0.55rem;
  margin: 0.2rem 0 0.7rem;
  padding: 0.8rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: var(--cream);
}
.display-controls legend { padding: 0 0.25rem; color: var(--muted); font-size: 0.68rem; font-weight: 850; letter-spacing: 0.08em; text-transform: uppercase; }
.display-controls label { display: flex; min-height: 2.75rem; align-items: center; gap: 0.5rem; font-size: 0.74rem; font-weight: 700; cursor: pointer; }
.display-controls input { width: 1.05rem; height: 1.05rem; accent-color: var(--green-deep); }
.fine-print { margin: 0.6rem 0 0; color: var(--muted); font-size: 0.67rem; line-height: 1.46; }

.canvas-wrap {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 0.85rem;
  background: #fdfffe;
  box-shadow: inset 0 0 0 1px rgba(227, 247, 236, 0.7);
}
#experiment-canvas { display: block; width: 100%; height: auto; aspect-ratio: 50 / 31; }
.canvas-legend {
  position: absolute;
  top: 0.65rem;
  left: 0.65rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
  padding: 0.38rem 0.5rem;
  border: 1px solid var(--line);
  border-radius: 0.5rem;
  background: rgba(255, 255, 255, 0.92);
  color: var(--muted);
  box-shadow: 0 4px 12px rgba(16, 67, 49, 0.07);
  font-size: 0.58rem;
  font-weight: 700;
  pointer-events: none;
}
.canvas-legend i { display: inline-block; width: 0.55rem; height: 0.55rem; margin-right: 0.2rem; border-radius: 50%; vertical-align: -0.04rem; }
.photon-key { background: var(--gold); }
.electron-key { background: var(--cyan); }
.wave-key { background: var(--violet); }
.canvas-hint {
  position: absolute;
  right: 0.65rem;
  bottom: 0.55rem;
  left: 0.65rem;
  margin: 0;
  overflow: hidden;
  padding: 0.28rem 0.45rem;
  border-radius: 0.4rem;
  background: rgba(255, 255, 255, 0.9);
  color: var(--muted);
  font-size: 0.61rem;
  text-align: center;
  text-overflow: ellipsis;
  white-space: nowrap;
  pointer-events: none;
}

.measurement-panel { margin-top: 0.7rem; padding: 0.8rem; background: var(--cream); }
.measurement-heading { display: flex; align-items: center; justify-content: space-between; gap: 0.8rem; }
.measurement-panel h3, .term-section h3 { font-size: 0.9rem; }
.result-badge, .count-badge, .level-badge {
  display: inline-flex;
  min-height: 1.75rem;
  align-items: center;
  padding: 0.28rem 0.65rem;
  border: 1px solid #bfe7d1;
  border-radius: 999px;
  background: var(--mint);
  color: var(--green-dark);
  font-size: 0.7rem;
  font-weight: 850;
  white-space: nowrap;
}
.result-badge.is-blocked { border-color: #efc4c7; background: #fff0f1; color: #a12d36; }
.large-output { font-size: 1.1rem; }

.energy-equation {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  align-items: stretch;
  gap: 0.45rem;
  margin-top: 0.7rem;
}
.energy-equation > div {
  padding: 0.65rem;
  border: 1px solid var(--line);
  border-radius: 0.7rem;
  background: white;
}
.energy-equation span, .energy-equation strong { display: block; }
.energy-equation div span { color: var(--muted); font-size: 0.63rem; }
.energy-equation div strong { margin-top: 0.2rem; color: var(--ink); font-size: 0.95rem; }
.energy-equation .operator { align-self: center; color: var(--green-dark); font-weight: 900; }
.compare-actions { display: grid; grid-template-columns: auto auto 1fr; align-items: center; gap: 0.45rem; margin-top: 0.65rem; }
.compare-actions button { font-size: 0.68rem; }
.compare-actions p { margin: 0 0 0 0.3rem; color: var(--muted); font-size: 0.68rem; line-height: 1.42; }

.measurement-readouts { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 0.45rem; margin-top: 0.7rem; }
.measurement-readouts p, .fit-readouts p {
  margin: 0;
  padding: 0.62rem;
  border: 1px solid var(--line);
  border-radius: 0.65rem;
  background: white;
}
.measurement-readouts span, .measurement-readouts strong, .fit-readouts span, .fit-readouts strong { display: block; }
.measurement-readouts span, .fit-readouts span { color: var(--muted); font-size: 0.62rem; }
.measurement-readouts strong, .fit-readouts strong { margin-top: 0.18rem; color: var(--ink); font-size: 0.82rem; font-variant-numeric: tabular-nums; }

.planck-data-grid { display: grid; grid-template-columns: minmax(270px, 1.4fr) minmax(210px, 1fr); gap: 0.65rem; margin-top: 0.7rem; }
.table-wrap { overflow-x: auto; }
table { width: 100%; border-collapse: collapse; font-size: 0.7rem; }
th, td { padding: 0.48rem; border-bottom: 1px solid var(--line); text-align: right; font-variant-numeric: tabular-nums; }
th:first-child, td:first-child { text-align: left; }
th { color: var(--muted); font-size: 0.62rem; text-transform: uppercase; letter-spacing: 0.05em; }
.empty-row td { color: var(--muted); text-align: center; }
.fit-readouts { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.4rem; }

.ruler-controls { display: grid; grid-template-columns: 1fr 1.1fr auto; align-items: end; gap: 0.55rem; margin-top: 0.7rem; }
.ruler-controls label { color: var(--muted); font-size: 0.67rem; font-weight: 740; }
.ruler-controls label select, .ruler-controls label input { margin-top: 0.35rem; }
.nudge-group { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.3rem; }
.nudge-group button { padding-inline: 0.45rem; font-size: 0.68rem; }

.readout-list { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.45rem; margin: 0 0 0.85rem; }
.readout-list div { min-width: 0; padding: 0.62rem; border: 1px solid var(--line); border-radius: 0.65rem; background: var(--cream); }
.readout-list dt { color: var(--muted); font-size: 0.61rem; font-weight: 700; }
.readout-list dd { margin: 0.18rem 0 0; color: var(--ink); font-size: 0.87rem; font-variant-numeric: tabular-nums; font-weight: 850; overflow-wrap: anywhere; }

.equation-block { margin-bottom: 0.7rem; padding: 0.72rem; border-radius: 0.7rem; background: var(--night); color: white; }
.equation-block span, .equation-block strong { display: block; }
.equation-block span { color: #9cc8b5; font-size: 0.61rem; font-weight: 750; letter-spacing: 0.08em; text-transform: uppercase; }
.equation-block strong { margin-top: 0.25rem; color: var(--cyan); font-size: 1.05rem; letter-spacing: 0.01em; }

.evidence-board { margin-bottom: 0.65rem; padding: 0.75rem; border-radius: 0.72rem; background: var(--night); color: white; }
.evidence-board .notice-label { color: var(--gold); }
.evidence-board > div { padding: 0.48rem 0; border-top: 1px solid rgba(227, 247, 236, 0.15); }
.evidence-board > div span { color: #9cc8b5; font-size: 0.6rem; font-weight: 850; letter-spacing: 0.07em; text-transform: uppercase; }
.evidence-board p:not(.notice-label) { margin: 0.18rem 0 0; color: #edfdf5; font-size: 0.7rem; line-height: 1.45; }

.notice-block, .challenge-block { margin-bottom: 0.65rem; padding: 0.75rem; border-left: 3px solid var(--green); border-radius: 0 0.6rem 0.6rem 0; background: var(--mint); }
.challenge-block { border-left-color: var(--gold); background: #fff9df; }
.notice-block p:last-child, .challenge-block p:last-child { margin: 0; color: #294239; font-size: 0.72rem; line-height: 1.5; }

.term-section { padding-top: 0.75rem; border-top: 1px solid var(--line); }
.subheading-row { display: flex; align-items: center; justify-content: space-between; gap: 0.65rem; }
.term-list { margin: 0.6rem 0 0; }
.term-list div { padding: 0.5rem 0; border-top: 1px solid #e7f0eb; }
.term-list div:first-child { border-top: 0; }
.term-list dt { color: var(--green-dark); font-size: 0.69rem; font-weight: 850; }
.term-list dd { margin: 0.15rem 0 0; color: var(--muted); font-size: 0.67rem; line-height: 1.42; }

.misconception-note, .model-note { margin-top: 0.65rem; border-top: 1px solid var(--line); }
.misconception-note summary, .model-note summary { display: flex; min-height: 2.75rem; align-items: center; padding: 0.7rem 0; color: var(--green-dark); cursor: pointer; font-size: 0.69rem; font-weight: 820; }
.misconception-note p, .model-note p { margin: 0.5rem 0 0; color: var(--muted); font-size: 0.67rem; line-height: 1.48; }

.sr-only, .visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

@media (max-width: 1240px) {
  .lab-grid {
    grid-template-columns: minmax(220px, 0.72fr) minmax(520px, 2fr);
    grid-template-areas: "controls stage" "analysis stage";
  }
  .control-panel, .analysis-panel { position: static; }
  .analysis-panel { align-self: start; }
  .energy-equation { grid-template-columns: 1fr auto 1fr; }
  .energy-equation > div:last-child { grid-column: 1 / 2; }
  .energy-equation > .operator:nth-of-type(2) { display: none; }
}

@media (max-width: 930px) {
  .hero { align-items: start; flex-direction: column; gap: 0.9rem; }
  .duality-strip { width: 100%; justify-content: center; }
  .investigation-nav { grid-template-columns: repeat(4, minmax(9.5rem, 1fr)); overflow-x: auto; padding-bottom: 0.35rem; scroll-snap-type: x proximity; scrollbar-width: thin; }
  .investigation-tab { scroll-snap-align: start; }
  .lab-grid { grid-template-columns: 1fr 1fr; grid-template-areas: "stage stage" "controls analysis"; }
}

@media (max-width: 680px) {
  .topbar { padding-inline: 0.8rem; }
  .brand { width: 7.1rem; }
  .topbar-label { max-width: 10rem; font-size: 0.6rem; text-align: right; }
  .shell { padding-inline: 0.55rem; }
  .hero h1 { font-size: 2.15rem; }
  .duality-strip { align-items: stretch; flex-direction: column; }
  .duality-plus { display: none; }
  .duality-strip > div { justify-content: center; }
  .investigation-nav {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    overflow-x: visible;
    padding-bottom: 0;
    scroll-snap-type: none;
  }
  .investigation-tab { min-width: 0; scroll-snap-align: none; }
  .lab-heading { align-items: start; flex-direction: column; }
  .lab-grid { grid-template-columns: 1fr; grid-template-areas: "stage" "controls" "analysis"; }
  .stage-panel, .control-panel, .analysis-panel { padding: 0.7rem; border-radius: 0.8rem; }
  .canvas-legend { gap: 0.35rem; font-size: 0.52rem; }
  .energy-equation { grid-template-columns: 1fr; }
  .energy-equation .operator { display: none; }
  .energy-equation > div:last-child { grid-column: auto; }
  .compare-actions { grid-template-columns: 1fr 1fr; }
  .compare-actions p { grid-column: 1 / -1; margin-left: 0; }
  .measurement-readouts { grid-template-columns: 1fr; }
  .planck-data-grid { grid-template-columns: 1fr; }
  .ruler-controls { grid-template-columns: 1fr; }
  .nudge-group { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 390px) {
  .hero h1 { font-size: 1.92rem; }
  .investigation-tab { min-height: 4.3rem; }
  .readout-list { gap: 0.32rem; }
  .fit-readouts { grid-template-columns: 1fr; }
  .preset-row { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .planck-presets { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.01ms !important;
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
  }
}