:root {
  color-scheme: dark;
  --bg: #07111f;
  --bg-deep: #040a13;
  --panel: rgba(16, 30, 51, 0.92);
  --panel-soft: rgba(25, 43, 70, 0.72);
  --panel-line: rgba(157, 177, 217, 0.18);
  --text: #f4f7ff;
  --muted: #aebbd3;
  --quiet: #7f90ad;
  --blue: #6ea8ff;
  --cyan: #48d7e8;
  --purple: #a98bff;
  --orange: #ffb05f;
  --pink: #ff7ca8;
  --green: #62dfb3;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.3);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* {
  box-sizing: border-box;
}

html {
  min-width: 320px;
  background: var(--bg-deep);
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background:
    radial-gradient(circle at 12% 2%, rgba(86, 123, 255, 0.18), transparent 36rem),
    radial-gradient(circle at 92% 18%, rgba(104, 70, 210, 0.16), transparent 32rem),
    linear-gradient(145deg, #09182a 0%, var(--bg) 50%, #07101c 100%);
}

button,
input,
select {
  font: inherit;
}

button,
select,
a {
  -webkit-tap-highlight-color: transparent;
}

button:focus-visible,
select:focus-visible,
input:focus-visible,
a:focus-visible {
  outline: 3px solid rgba(110, 168, 255, 0.72);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  top: 0.75rem;
  left: 0.75rem;
  z-index: 20;
  transform: translateY(-180%);
  padding: 0.7rem 1rem;
  border-radius: 0.65rem;
  color: #07111f;
  background: #f4f7ff;
  font-weight: 700;
}

.skip-link:focus {
  transform: translateY(0);
}

.lab-shell {
  width: min(1440px, 100%);
  margin: 0 auto;
  padding: 1.6rem clamp(1rem, 3vw, 2.4rem) 1.2rem;
}

.site-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 1.5rem;
  padding: 0.45rem 0 1.35rem;
}

.eyebrow,
.section-kicker {
  margin: 0 0 0.3rem;
  color: var(--cyan);
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}

h1,
h2,
h3,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0.35rem;
  font-size: clamp(2rem, 4vw, 3.5rem);
  line-height: 1;
  letter-spacing: -0.045em;
}

h2 {
  margin-bottom: 0;
  font-size: 1.08rem;
  letter-spacing: -0.01em;
}

h3 {
  margin-bottom: 0.75rem;
  font-size: 0.9rem;
}

.subtitle {
  max-width: 60rem;
  margin-bottom: 0;
  color: var(--muted);
  font-size: clamp(0.92rem, 1.7vw, 1.05rem);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  flex: 0 0 auto;
}

.status-pill,
.ghost-link {
  display: inline-flex;
  align-items: center;
  min-height: 2.4rem;
  padding: 0.55rem 0.82rem;
  border: 1px solid var(--panel-line);
  border-radius: 999px;
  color: var(--muted);
  background: rgba(13, 27, 46, 0.75);
  font-size: 0.78rem;
  font-weight: 700;
  text-decoration: none;
}

.ghost-link:hover {
  color: var(--text);
  border-color: rgba(110, 168, 255, 0.45);
}

.status-dot {
  width: 0.5rem;
  height: 0.5rem;
  margin-right: 0.45rem;
  border-radius: 50%;
  background: var(--green);
  box-shadow: 0 0 0.9rem rgba(98, 223, 179, 0.65);
}

.workspace {
  display: grid;
  grid-template-columns: minmax(0, 1.9fr) minmax(310px, 0.85fr);
  gap: 1rem;
  align-items: start;
}

.visual-column {
  display: grid;
  gap: 1rem;
  min-width: 0;
}

.panel {
  border: 1px solid var(--panel-line);
  border-radius: 1.2rem;
  background: linear-gradient(150deg, rgba(22, 39, 65, 0.96), rgba(10, 22, 38, 0.94));
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
}

.apparatus-panel,
.graph-panel,
.control-panel {
  padding: 1rem;
}

.panel-heading,
.subheading-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.panel-heading {
  margin-bottom: 0.9rem;
}

.run-status {
  margin: 0;
  padding: 0.38rem 0.65rem;
  border-radius: 999px;
  color: var(--green);
  background: rgba(98, 223, 179, 0.1);
  font-size: 0.75rem;
  font-weight: 800;
}

.run-status.is-paused {
  color: var(--orange);
  background: rgba(255, 176, 95, 0.1);
}

.measurement-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.55rem;
  margin-bottom: 0.75rem;
}

.measurement {
  min-width: 0;
  padding: 0.65rem 0.72rem;
  border: 1px solid rgba(157, 177, 217, 0.12);
  border-radius: 0.78rem;
  background: rgba(35, 54, 84, 0.48);
}

.measurement span {
  display: block;
  margin-bottom: 0.25rem;
  overflow: hidden;
  color: var(--quiet);
  font-size: 0.68rem;
  font-weight: 700;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.measurement strong {
  display: block;
  overflow: hidden;
  font-size: clamp(0.82rem, 1.5vw, 1rem);
  font-variant-numeric: tabular-nums;
  text-overflow: ellipsis;
  white-space: nowrap;
}

canvas {
  display: block;
  width: 100%;
  border: 1px solid rgba(157, 177, 217, 0.12);
  border-radius: 0.9rem;
  background: rgba(4, 12, 23, 0.62);
}

#apparatus-canvas {
  height: clamp(250px, 29vw, 355px);
}

#graph-canvas {
  height: clamp(210px, 23vw, 278px);
}

.transport {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.55rem;
  padding-top: 0.78rem;
}

.transport button,
.preset-grid button {
  min-height: 2.45rem;
  border: 1px solid transparent;
  border-radius: 0.72rem;
  cursor: pointer;
  font-size: 0.78rem;
  font-weight: 800;
  transition: transform 150ms ease, border-color 150ms ease, background 150ms ease;
}

.transport button:active,
.preset-grid button:active {
  transform: translateY(1px);
}

.primary-button {
  padding: 0.58rem 0.95rem;
  color: #07111f;
  background: linear-gradient(135deg, var(--cyan), var(--blue));
  box-shadow: 0 8px 24px rgba(72, 215, 232, 0.18);
}

.button-icon {
  display: inline-block;
  width: 1.05rem;
  margin-right: 0.2rem;
}

.secondary-button,
.preset-grid button {
  padding: 0.58rem 0.82rem;
  color: var(--muted);
  border-color: var(--panel-line) !important;
  background: rgba(38, 58, 89, 0.55);
}

.secondary-button:hover,
.preset-grid button:hover {
  color: var(--text);
  border-color: rgba(110, 168, 255, 0.45) !important;
  background: rgba(52, 77, 116, 0.68);
}

.speed-control {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
  color: var(--quiet);
  font-size: 0.72rem;
  font-weight: 700;
}

.speed-control select {
  min-height: 2.35rem;
  padding: 0 1.85rem 0 0.65rem;
  border: 1px solid var(--panel-line);
  border-radius: 0.65rem;
  color: var(--text);
  background: #152844;
}

.graph-heading {
  align-items: flex-end;
}

.trace-toggles {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 0.75rem;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
}

.trace-toggles label {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  cursor: pointer;
}

.trace-toggles input {
  accent-color: var(--blue);
}

.control-panel {
  position: sticky;
  top: 1rem;
}

.control-stack {
  display: grid;
  gap: 0.92rem;
}

.range-field {
  display: grid;
  gap: 0.48rem;
}

.range-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.75rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
}

.range-header output {
  color: var(--text);
  font-variant-numeric: tabular-nums;
}

input[type="range"] {
  width: 100%;
  height: 0.35rem;
  margin: 0.2rem 0;
  border-radius: 999px;
  accent-color: var(--blue);
  cursor: pointer;
}

.presets,
.derived-panel,
.energy-panel,
.equation-panel {
  margin-top: 1rem;
  padding-top: 1rem;
  border-top: 1px solid var(--panel-line);
}

.preset-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.45rem;
}

.preset-grid button {
  min-height: 2.85rem;
  padding: 0.5rem;
  line-height: 1.2;
}

.subheading-row {
  margin-bottom: 0.75rem;
}

.subheading-row h3 {
  margin-bottom: 0;
}

.subheading-row > span {
  color: var(--quiet);
  font-size: 0.67rem;
  font-weight: 700;
}

.derived-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.5rem;
  margin: 0;
}

.derived-grid div {
  padding: 0.62rem;
  border-radius: 0.7rem;
  background: rgba(35, 54, 84, 0.44);
}

.derived-grid dt {
  margin-bottom: 0.22rem;
  color: var(--quiet);
  font-size: 0.65rem;
  font-weight: 700;
}

.derived-grid dd {
  margin: 0;
  color: var(--text);
  font-size: 0.82rem;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.energy-row {
  display: grid;
  grid-template-columns: 4.4rem minmax(0, 1fr) 4.3rem;
  align-items: center;
  gap: 0.55rem;
  margin-top: 0.55rem;
  color: var(--muted);
  font-size: 0.7rem;
  font-weight: 700;
}

.energy-row output {
  color: var(--text);
  text-align: right;
  font-variant-numeric: tabular-nums;
}

.energy-track {
  height: 0.55rem;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(118, 139, 177, 0.17);
}

.energy-track span {
  display: block;
  height: 100%;
  width: 0;
  border-radius: inherit;
  transition: width 80ms linear;
}

.potential-bar {
  background: linear-gradient(90deg, var(--purple), var(--pink));
}

.kinetic-bar {
  background: linear-gradient(90deg, var(--cyan), var(--blue));
}

.equation-panel {
  color: var(--muted);
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.77rem;
  line-height: 1.7;
}

.equation-panel p {
  margin-bottom: 0.2rem;
}

.site-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.15rem 0 0;
  color: var(--quiet);
  font-size: 0.76rem;
}

.site-footer p {
  margin-bottom: 0;
}

.site-footer a {
  color: var(--blue);
  font-weight: 700;
  text-decoration: none;
}

.site-footer a:hover {
  text-decoration: underline;
}

@media (max-width: 1020px) {
  .workspace {
    grid-template-columns: 1fr;
  }

  .control-panel {
    position: static;
  }

  .control-stack {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }
}

@media (max-width: 700px) {
  .lab-shell {
    padding: 1rem 0.75rem;
  }

  .site-header,
  .site-footer {
    align-items: flex-start;
    flex-direction: column;
  }

  .header-actions {
    width: 100%;
    justify-content: space-between;
  }

  .measurement-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .graph-heading {
    align-items: flex-start;
    flex-direction: column;
  }

  .trace-toggles {
    justify-content: flex-start;
  }

  .control-stack {
    grid-template-columns: 1fr;
  }

  .speed-control {
    width: 100%;
    margin-left: 0;
    justify-content: space-between;
  }
}

@media (max-width: 430px) {
  h1 {
    font-size: 2rem;
  }

  .status-pill {
    display: none;
  }

  .preset-grid,
  .derived-grid {
    grid-template-columns: 1fr;
  }

  .transport button {
    flex: 1 1 auto;
  }
}

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