/* =========================================================
   NEWTON'S GARAGE — visual system
   Editorial lesson notes × cinematic 3D test track
   ========================================================= */

:root {
  --paper: #f2ede3;
  --paper-light: #fbf7ef;
  --paper-deep: #e7dece;
  --ink: #171511;
  --ink-soft: #423d34;
  --muted: #675f52;
  --faint: #847a6b;
  --line: rgba(23, 21, 17, 0.14);
  --line-strong: rgba(23, 21, 17, 0.28);
  --accent: #e65a2b;
  --accent-deep: #bf3f17;
  --teal: #16786f;
  --blue: #2b6bb0;
  --gold: #b9841d;
  --coral: #cf5137;
  --violet: #7657b8;
  --stage: #071018;
  --stage-2: #0b1c29;
  --cream: #f3ecdf;
  --font-display: "Songti SC", "STSong", "Noto Serif SC", "Source Han Serif SC", Georgia, "Times New Roman", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "SF Pro Text", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", sans-serif;
  --font-mono: "SFMono-Regular", Menlo, Consolas, "Liberation Mono", monospace;
  --panel-width: clamp(430px, 41.5vw, 602px);
  --radius: 16px;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

html {
  background: var(--stage);
}

body {
  margin: 0;
  overflow: hidden;
  background: var(--stage);
  color: var(--ink);
  font-family: var(--font-sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

button,
input {
  font: inherit;
}

button {
  color: inherit;
}

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

button:focus-visible,
a:focus-visible,
input:focus-visible,
summary:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

::selection {
  background: var(--accent);
  color: #fff8ee;
}

.app {
  display: flex;
  width: 100%;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

/* ---------------------------------------------------------
   Lesson panel
   --------------------------------------------------------- */

.lesson {
  position: relative;
  z-index: 4;
  display: flex;
  flex: 0 0 var(--panel-width);
  flex-direction: column;
  width: var(--panel-width);
  height: 100%;
  overflow: hidden;
  background:
    radial-gradient(110% 60% at 96% -5%, rgba(230, 90, 43, 0.13), transparent 52%),
    linear-gradient(115deg, rgba(255, 255, 255, 0.28), transparent 34%),
    var(--paper);
  box-shadow: 22px 0 70px rgba(1, 7, 11, 0.42);
  isolation: isolate;
}

.lesson::after {
  position: absolute;
  z-index: 10;
  inset: 0;
  opacity: 0.32;
  pointer-events: none;
  content: "";
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 220 220' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.92' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='.16'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}

.lesson-header {
  position: relative;
  z-index: 2;
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  min-height: 88px;
  padding: 22px 32px 17px 34px;
  border-bottom: 1px solid var(--line);
}

.brand {
  display: flex;
  align-items: center;
  min-width: 0;
  gap: 12px;
}

.brand-mark {
  display: grid;
  flex: 0 0 43px;
  width: 43px;
  height: 43px;
  color: var(--cream);
  background: var(--ink);
  border-radius: 13px;
  box-shadow: 0 5px 14px rgba(23, 21, 17, 0.2);
  place-items: center;
}

.brand-mark svg {
  width: 36px;
  height: 36px;
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
  gap: 3px;
}

.brand-kicker {
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 8.5px;
  font-weight: 600;
  letter-spacing: 0.17em;
  line-height: 1;
  white-space: nowrap;
}

.brand-name {
  overflow: hidden;
  font-family: var(--font-display);
  font-size: 18px;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.1;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.header-tools {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 12px;
}

.edition {
  color: var(--faint);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  white-space: nowrap;
}

.lang-toggle {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  min-height: 32px;
  padding: 4px 9px;
  cursor: pointer;
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  transition: background 180ms ease, border-color 180ms ease;
}

.lang-toggle:hover {
  background: rgba(23, 21, 17, 0.05);
  border-color: var(--ink);
}

.lang-option {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.02em;
  transition: color 160ms ease;
}

.lang-option.is-active {
  color: var(--ink);
}

.lang-divider {
  color: rgba(23, 21, 17, 0.24);
  font-family: var(--font-mono);
  font-size: 9px;
}

.chapter-nav {
  position: relative;
  z-index: 2;
  display: grid;
  flex: 0 0 auto;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  padding: 0 27px;
  border-bottom: 1px solid var(--line);
}

.nav-step {
  position: relative;
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 0;
  padding: 12px 7px 11px;
  cursor: pointer;
  text-align: left;
  background: transparent;
  border: 0;
  border-bottom: 2px solid transparent;
  transition: color 180ms ease, border-color 180ms ease;
}

.nav-step::before {
  position: absolute;
  bottom: -1px;
  left: 7px;
  width: 0;
  height: 2px;
  content: "";
  background: var(--accent);
  transition: width 260ms var(--ease);
}

.nav-step:hover {
  color: var(--accent-deep);
}

.nav-step:hover::before {
  width: calc(100% - 14px);
}

.nav-step b {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.1em;
  line-height: 1;
  transition: color 160ms ease;
}

.nav-step span {
  overflow: hidden;
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 600;
  line-height: 1.2;
  text-overflow: ellipsis;
  white-space: nowrap;
  transition: color 160ms ease;
}

.nav-step.is-active {
  border-bottom-color: var(--accent);
}

.nav-step.is-active::before {
  width: calc(100% - 14px);
}

.nav-step.is-active b {
  color: var(--accent-deep);
}

.nav-step.is-active span {
  color: var(--ink);
}

.panel-scroll {
  position: relative;
  z-index: 1;
  display: flex;
  flex: 1 1 auto;
  flex-direction: column;
  min-height: 0;
  overflow-x: hidden;
  overflow-y: auto;
  scrollbar-color: rgba(23, 21, 17, 0.25) transparent;
  scrollbar-width: thin;
}

.panel-scroll::-webkit-scrollbar {
  width: 6px;
}

.panel-scroll::-webkit-scrollbar-thumb {
  background: rgba(23, 21, 17, 0.2);
  border-radius: 99px;
}

.chapter-root {
  flex: 1 0 auto;
  padding: 27px 34px 28px;
}

.chapter {
  animation: chapter-in 520ms var(--ease) both;
}

@keyframes chapter-in {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.chapter-kicker {
  display: flex;
  align-items: center;
  gap: 9px;
  margin-bottom: 16px;
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 8.5px;
  font-weight: 700;
  letter-spacing: 0.13em;
  line-height: 1.4;
  text-transform: uppercase;
}

.chapter-kicker::before {
  flex: 0 0 auto;
  width: 18px;
  height: 1px;
  content: "";
  background: var(--accent);
}

.chapter-kicker em {
  color: var(--faint);
  font-style: normal;
  font-weight: 500;
}

.chapter-title {
  max-width: 490px;
  margin: 0;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: clamp(37px, 3.5vw, 51px);
  font-weight: 600;
  letter-spacing: -0.035em;
  line-height: 1.05;
}

.chapter-title em {
  color: var(--accent-deep);
  font-style: normal;
}

.chapter-title .title-thin {
  display: block;
  color: var(--ink);
}

.chapter-title .title-accent {
  display: block;
  color: var(--accent-deep);
}

.chapter-english {
  margin: 13px 0 0;
  color: var(--muted);
  font-family: var(--font-display);
  font-size: 17px;
  font-style: italic;
  line-height: 1.3;
}

.chapter-intro {
  margin: 18px 0 0;
  color: var(--ink-soft);
  font-size: 13.5px;
  line-height: 1.82;
}

.chapter-intro strong {
  color: var(--ink);
  font-weight: 650;
}

.section-label {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 26px 0 11px;
  color: var(--ink);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.06em;
}

.section-label::after {
  flex: 1;
  height: 1px;
  content: "";
  background: var(--line);
}

.section-label em {
  order: 2;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 8px;
  font-style: normal;
  font-weight: 500;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.section-label::after {
  order: 1;
}

/* ---------------------------------------------------------
   Experiment panels & controls
   --------------------------------------------------------- */

.experiment-panel {
  position: relative;
  padding: 18px;
  background:
    linear-gradient(145deg, rgba(255, 255, 255, 0.7), rgba(255, 255, 255, 0.18)),
    var(--paper-light);
  border: 1px solid rgba(23, 21, 17, 0.12);
  border-radius: var(--radius);
  box-shadow: 0 10px 26px rgba(23, 21, 17, 0.055);
}

.experiment-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 14px;
}

.experiment-kicker {
  display: block;
  margin-bottom: 4px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.experiment-head h3 {
  margin: 0;
  color: var(--ink);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.experiment-status {
  display: flex;
  align-items: center;
  gap: 6px;
  padding-top: 2px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  white-space: nowrap;
}

.experiment-status i {
  width: 6px;
  height: 6px;
  background: var(--teal);
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(22, 120, 111, 0.1);
}

.segmented {
  display: grid;
  grid-auto-columns: minmax(0, 1fr);
  grid-auto-flow: column;
  gap: 3px;
  padding: 4px;
  margin-bottom: 16px;
  background: var(--paper-deep);
  border: 1px solid rgba(23, 21, 17, 0.06);
  border-radius: 11px;
}

.segmented button {
  min-width: 0;
  min-height: 35px;
  padding: 7px 5px;
  overflow: hidden;
  cursor: pointer;
  color: var(--muted);
  font-size: 10.5px;
  font-weight: 650;
  line-height: 1.2;
  text-overflow: ellipsis;
  white-space: nowrap;
  background: transparent;
  border: 0;
  border-radius: 8px;
  transition: color 180ms ease, background 180ms ease, box-shadow 180ms ease;
}

.segmented button:hover {
  color: var(--ink);
}

.segmented button.is-active {
  color: var(--cream);
  background: var(--ink);
  box-shadow: 0 3px 8px rgba(23, 21, 17, 0.16);
}

.segmented .seg-en {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 7px;
  font-weight: 500;
  letter-spacing: 0.02em;
  opacity: 0.6;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 14px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 7px;
  min-height: 42px;
  padding: 10px 17px;
  cursor: pointer;
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.2;
  background: transparent;
  border: 1px solid var(--line-strong);
  border-radius: 999px;
  transition: transform 180ms var(--ease), background 180ms ease, border-color 180ms ease, color 180ms ease, box-shadow 180ms ease;
}

.btn svg {
  width: 15px;
  height: 15px;
  flex: 0 0 auto;
}

.btn:hover {
  transform: translateY(-1px);
  border-color: var(--ink);
}

.btn:active {
  transform: translateY(0) scale(0.985);
}

.btn-primary {
  color: var(--cream);
  background: var(--ink);
  border-color: var(--ink);
  box-shadow: 0 4px 0 rgba(23, 21, 17, 0.12);
}

.btn-primary:hover {
  background: var(--accent-deep);
  border-color: var(--accent-deep);
  box-shadow: 0 6px 16px rgba(191, 63, 23, 0.2);
}

.btn-accent {
  color: #fff8ee;
  background: var(--accent);
  border-color: var(--accent);
}

.btn-accent:hover {
  background: var(--accent-deep);
  border-color: var(--accent-deep);
}

.btn-ghost {
  background: rgba(255, 255, 255, 0.22);
}

.btn-block {
  width: 100%;
}

.btn[disabled],
.btn[disabled]:hover {
  color: var(--muted);
  cursor: not-allowed;
  background: rgba(23, 21, 17, 0.09);
  border-color: transparent;
  box-shadow: none;
  opacity: 0.78;
  transform: none;
}

.btn .btn-en {
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 500;
  opacity: 0.55;
}

.demo-tabs {
  margin-bottom: 15px;
}

/* Sliders */

.field {
  margin-top: 14px;
}

.field:first-of-type {
  margin-top: 0;
}

.field-head {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 8px;
}

.field-label {
  color: var(--ink-soft);
  font-size: 11px;
  font-weight: 650;
}

.field-label span {
  margin-left: 4px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7.5px;
  font-weight: 500;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.field-value {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1;
  white-space: nowrap;
}

.field-value small {
  color: var(--muted);
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0;
}

input[type="range"] {
  display: block;
  width: 100%;
  height: 22px;
  margin: 0;
  cursor: pointer;
  background: transparent;
  appearance: none;
  -webkit-appearance: none;
}

input[type="range"]::-webkit-slider-runnable-track {
  width: 100%;
  height: 3px;
  background: linear-gradient(to right, var(--accent) 0 var(--range-fill, 50%), rgba(23, 21, 17, 0.14) var(--range-fill, 50%) 100%);
  border-radius: 99px;
}

input[type="range"]::-moz-range-track {
  width: 100%;
  height: 3px;
  background: rgba(23, 21, 17, 0.14);
  border-radius: 99px;
}

input[type="range"]::-moz-range-progress {
  height: 3px;
  background: var(--accent);
  border-radius: 99px;
}

input[type="range"]::-webkit-slider-thumb {
  width: 16px;
  height: 16px;
  margin-top: -6.5px;
  background: var(--paper-light);
  border: 2px solid var(--ink);
  border-radius: 50%;
  box-shadow: 0 2px 5px rgba(23, 21, 17, 0.18);
  transition: transform 120ms ease;
  appearance: none;
  -webkit-appearance: none;
}

input[type="range"]::-moz-range-thumb {
  width: 13px;
  height: 13px;
  background: var(--paper-light);
  border: 2px solid var(--ink);
  border-radius: 50%;
}

input[type="range"]:hover::-webkit-slider-thumb {
  transform: scale(1.12);
}

.field-scale {
  display: flex;
  justify-content: space-between;
  margin-top: 1px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7.5px;
  letter-spacing: 0.04em;
}

/* Data & results */

.result-board {
  margin-top: 16px;
  padding: 15px 16px 14px;
  color: var(--cream);
  background:
    radial-gradient(100% 160% at 100% 0, rgba(230, 90, 43, 0.22), transparent 50%),
    #191713;
  border-radius: 13px;
  box-shadow: 0 8px 18px rgba(23, 21, 17, 0.16);
}

.result-equation {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 4px 7px;
  color: rgba(243, 236, 223, 0.68);
  font-family: var(--font-mono);
  font-size: 10.5px;
  line-height: 1.4;
}

.result-equation strong {
  color: var(--cream);
  font-size: 14px;
  letter-spacing: -0.02em;
}

.result-equation .eq-accent {
  color: #ff9164;
}

.result-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-top: 14px;
  padding-top: 12px;
  border-top: 1px solid rgba(243, 236, 223, 0.14);
}

.result-stat span {
  display: block;
  color: rgba(243, 236, 223, 0.5);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.07em;
  text-transform: uppercase;
}

.result-stat b {
  display: block;
  margin-top: 3px;
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 19px;
  font-weight: 600;
  letter-spacing: -0.05em;
  line-height: 1.05;
}

.result-stat b small {
  margin-left: 2px;
  color: rgba(243, 236, 223, 0.48);
  font-size: 8px;
  font-weight: 400;
  letter-spacing: 0;
}

.result-stat.is-hot b {
  color: #ff9c72;
}

.chart-wrap {
  margin-top: 15px;
  padding: 11px 12px 9px;
  background: rgba(23, 21, 17, 0.035);
  border: 1px solid rgba(23, 21, 17, 0.09);
  border-radius: 11px;
}

.chart-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 4px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.chart-head b {
  color: var(--ink-soft);
  font-weight: 600;
}

.chart-wrap canvas {
  display: block;
  width: 100%;
  height: 105px;
}

.launch-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 10px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 8.5px;
  letter-spacing: 0.035em;
}

.launch-meta .run-time {
  color: var(--ink-soft);
  font-weight: 600;
}

/* Free-body diagram / force map */

.force-map {
  padding: 13px;
  background: rgba(23, 21, 17, 0.032);
  border: 1px solid rgba(23, 21, 17, 0.09);
  border-radius: 13px;
}

.fm-top,
.fm-bottom {
  display: flex;
  justify-content: center;
}

.fm-middle {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 94px minmax(0, 1fr);
  align-items: center;
  gap: 7px;
  margin: 8px 0;
}

.fm-car {
  position: relative;
  display: grid;
  width: 94px;
  height: 58px;
  place-items: center;
}

.fm-car svg {
  width: 88px;
  height: auto;
  color: var(--ink);
}

.fm-car::before,
.fm-car::after {
  position: absolute;
  top: 50%;
  width: 14px;
  height: 1px;
  content: "";
  background: rgba(23, 21, 17, 0.18);
}

.fm-car::before {
  right: 100%;
}

.fm-car::after {
  left: 100%;
}

.force-chip {
  display: inline-flex;
  flex-direction: column;
  gap: 2px;
  min-width: 0;
  padding: 7px 8px;
  color: var(--ink-soft);
  background: rgba(255, 255, 255, 0.48);
  border: 1px solid rgba(23, 21, 17, 0.09);
  border-left: 3px solid var(--force-color, var(--line-strong));
  border-radius: 7px;
  line-height: 1.2;
}

.force-chip.is-right {
  align-items: flex-end;
  text-align: right;
  border-right: 3px solid var(--force-color, var(--line-strong));
  border-left: 1px solid rgba(23, 21, 17, 0.09);
}

.force-chip .fc-label {
  display: flex;
  align-items: center;
  gap: 4px;
  color: var(--muted);
  font-size: 9px;
  font-weight: 600;
  white-space: nowrap;
}

.force-chip.is-right .fc-label {
  flex-direction: row-reverse;
}

.force-chip .fc-arrow {
  color: var(--force-color, var(--ink));
  font-family: var(--font-mono);
  font-size: 11px;
  font-weight: 700;
}

.force-chip .fc-value {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: -0.04em;
  white-space: nowrap;
}

.force-chip .fc-value small {
  margin-left: 1px;
  color: var(--faint);
  font-size: 7px;
  font-weight: 500;
  letter-spacing: 0;
}

.force-chip.is-zero {
  opacity: 0.42;
}

.force-chip.is-normal {
  --force-color: var(--blue);
}

.force-chip.is-weight {
  --force-color: var(--gold);
}

.force-chip.is-drive {
  --force-color: var(--teal);
}

.force-chip.is-resist {
  --force-color: var(--coral);
}

.force-chip.is-action {
  --force-color: var(--violet);
}

.force-chip.is-reaction {
  --force-color: #1a9898;
}

.force-chip.is-belt {
  --force-color: #d88022;
}

.fm-net {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-top: 11px;
  padding-top: 10px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 9px;
  border-top: 1px dashed rgba(23, 21, 17, 0.14);
}

.fm-net strong {
  color: var(--accent-deep);
  font-size: 17px;
  letter-spacing: -0.04em;
}

.fm-net .fm-net-state {
  color: var(--ink-soft);
  font-family: var(--font-sans);
  font-size: 9.5px;
  font-weight: 650;
  text-align: right;
}

.fm-net.is-balanced .fm-net-state {
  color: var(--teal);
}

/* Two-car lanes */

.lane-pair {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 9px;
  margin-top: 14px;
}

.lane-card {
  position: relative;
  padding: 11px 12px 11px 14px;
  overflow: hidden;
  background: rgba(23, 21, 17, 0.035);
  border: 1px solid rgba(23, 21, 17, 0.1);
  border-radius: 10px;
}

.lane-card::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 3px;
  content: "";
  background: var(--lane-color, var(--accent));
}

.lane-card.is-ideal {
  --lane-color: var(--teal);
}

.lane-card.is-friction {
  --lane-color: var(--coral);
}

.lane-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 5px;
}

.lane-name {
  color: var(--ink-soft);
  font-size: 9.5px;
  font-weight: 700;
}

.lane-mode {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.lane-speed {
  margin-top: 6px;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 23px;
  font-weight: 600;
  letter-spacing: -0.06em;
  line-height: 1;
}

.lane-speed small {
  margin-left: 2px;
  color: var(--muted);
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0;
}

.lane-note {
  margin-top: 5px;
  color: var(--muted);
  font-size: 8.5px;
  line-height: 1.4;
}

/* Law quote / principle card */

.law-card {
  position: relative;
  padding: 17px 18px 17px 21px;
  margin-top: 24px;
  background: var(--paper-deep);
  border-radius: 4px 14px 14px 4px;
}

.law-card::before {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 4px;
  content: "";
  background: var(--accent);
  border-radius: 4px 0 0 4px;
}

.law-label {
  display: block;
  margin-bottom: 7px;
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.law-text {
  margin: 0;
  color: var(--ink);
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.58;
}

.law-text-en {
  margin: 8px 0 0;
  color: var(--muted);
  font-family: var(--font-display);
  font-size: 12.5px;
  font-style: italic;
  line-height: 1.55;
}

.formula-plate {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 18px;
  min-height: 66px;
  padding: 12px 18px;
  margin-top: 14px;
  background: var(--ink);
  border-radius: 13px;
  color: var(--cream);
}

.formula-main {
  font-family: var(--font-mono);
  font-size: clamp(21px, 2.4vw, 28px);
  font-weight: 500;
  letter-spacing: -0.04em;
  line-height: 1;
  white-space: nowrap;
}

.formula-main .f-accent {
  color: #ff8b5e;
}

.formula-main sub {
  position: relative;
  bottom: -0.1em;
  font-size: 0.5em;
}

.formula-caption {
  padding-left: 16px;
  color: rgba(243, 236, 223, 0.5);
  font-size: 8.5px;
  line-height: 1.55;
  border-left: 1px solid rgba(243, 236, 223, 0.18);
}

.formula-caption b {
  display: block;
  margin-bottom: 2px;
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0.05em;
}

/* Steps */

.mini-steps {
  display: grid;
  gap: 1px;
  margin-top: 17px;
  overflow: hidden;
  border: 1px solid rgba(23, 21, 17, 0.1);
  border-radius: 11px;
}

.mini-step {
  display: grid;
  grid-template-columns: 25px 1fr auto;
  align-items: center;
  gap: 9px;
  padding: 10px 12px;
  background: rgba(255, 255, 255, 0.24);
}

.mini-step:nth-child(even) {
  background: rgba(23, 21, 17, 0.026);
}

.step-num {
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.step-copy {
  color: var(--ink-soft);
  font-size: 10.5px;
  line-height: 1.45;
}

.step-copy b {
  color: var(--ink);
  font-weight: 700;
}

.step-tag {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.04em;
  text-align: right;
  text-transform: uppercase;
}

/* Notes, callouts, checklists */

.note-card {
  position: relative;
  padding: 14px 15px 14px 43px;
  margin-top: 16px;
  color: var(--ink-soft);
  background: rgba(255, 255, 255, 0.28);
  border: 1px dashed rgba(23, 21, 17, 0.2);
  border-radius: 11px;
}

.note-card::before {
  position: absolute;
  top: 15px;
  left: 15px;
  display: grid;
  width: 19px;
  height: 19px;
  color: var(--accent-deep);
  font-family: var(--font-display);
  font-size: 14px;
  font-style: italic;
  font-weight: 700;
  content: "!";
  border: 1px solid rgba(191, 63, 23, 0.35);
  border-radius: 50%;
  place-items: center;
}

.note-title {
  display: block;
  margin-bottom: 4px;
  color: var(--ink);
  font-size: 10px;
  font-weight: 700;
}

.note-card p {
  margin: 0;
  font-size: 11px;
  line-height: 1.65;
}

.inertia-banner {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 12px 13px;
  margin-top: 14px;
  color: var(--ink-soft);
  background: rgba(230, 90, 43, 0.08);
  border: 1px solid rgba(230, 90, 43, 0.2);
  border-radius: 10px;
}

.inertia-banner svg {
  flex: 0 0 auto;
  width: 22px;
  height: 22px;
  color: var(--accent-deep);
}

.inertia-banner p {
  margin: 0;
  font-size: 10.5px;
  line-height: 1.55;
}

.inertia-banner strong {
  color: var(--ink);
}

.pair-rules {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 7px;
  margin-top: 14px;
}

.rule-chip {
  display: flex;
  align-items: flex-start;
  gap: 7px;
  padding: 9px 10px;
  color: var(--ink-soft);
  font-size: 9.5px;
  line-height: 1.45;
  background: rgba(23, 21, 17, 0.033);
  border: 1px solid rgba(23, 21, 17, 0.08);
  border-radius: 8px;
}

.rule-chip i {
  display: grid;
  flex: 0 0 auto;
  width: 13px;
  height: 13px;
  color: var(--teal);
  font-family: var(--font-mono);
  font-size: 8px;
  font-style: normal;
  font-weight: 700;
  border: 1px solid rgba(22, 120, 111, 0.35);
  border-radius: 50%;
  place-items: center;
}

.rule-chip b {
  color: var(--ink);
  font-weight: 700;
}

.compare-table {
  width: 100%;
  margin-top: 15px;
  overflow: hidden;
  font-size: 9.5px;
  line-height: 1.45;
  border: 1px solid rgba(23, 21, 17, 0.12);
  border-radius: 10px;
  border-collapse: separate;
  border-spacing: 0;
}

.compare-table th,
.compare-table td {
  padding: 8px 9px;
  vertical-align: top;
  text-align: left;
  border-bottom: 1px solid rgba(23, 21, 17, 0.08);
}

.compare-table tr:last-child td {
  border-bottom: 0;
}

.compare-table th {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7px;
  font-weight: 500;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: rgba(23, 21, 17, 0.035);
}

.compare-table td:first-child {
  color: var(--ink);
  font-weight: 650;
}

.compare-table td {
  color: var(--muted);
  background: rgba(255, 255, 255, 0.18);
}

.compare-table .is-good {
  color: var(--teal);
  font-weight: 650;
}

/* Summary */

.summary-stack {
  display: grid;
  gap: 8px;
  margin-top: 20px;
}

.summary-card {
  display: grid;
  grid-template-columns: 30px minmax(0, 1fr) auto;
  align-items: center;
  gap: 10px;
  padding: 11px 12px;
  background: rgba(255, 255, 255, 0.26);
  border: 1px solid rgba(23, 21, 17, 0.1);
  border-radius: 11px;
}

.summary-num {
  display: grid;
  width: 26px;
  height: 26px;
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 700;
  border: 1px solid rgba(191, 63, 23, 0.3);
  border-radius: 50%;
  place-items: center;
}

.summary-card h3 {
  margin: 0;
  color: var(--ink);
  font-size: 10.5px;
  font-weight: 700;
  line-height: 1.3;
}

.summary-card p {
  margin: 2px 0 0;
  color: var(--muted);
  font-size: 8.5px;
  line-height: 1.4;
}

.summary-formula {
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 10px;
  font-weight: 600;
  white-space: nowrap;
}

/* Quiz */

.quiz-wrap {
  margin-top: 17px;
}

.quiz-score {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 10px 12px;
  margin-bottom: 9px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: rgba(23, 21, 17, 0.04);
  border-radius: 8px;
}

.quiz-score strong {
  color: var(--accent-deep);
  font-size: 12px;
  letter-spacing: 0;
}

.quiz-card {
  padding: 14px;
  margin-bottom: 9px;
  background: var(--paper-light);
  border: 1px solid rgba(23, 21, 17, 0.12);
  border-radius: 12px;
}

.quiz-index {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 7px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.quiz-index i {
  font-style: normal;
  color: var(--teal);
}

.quiz-question {
  margin: 0 0 10px;
  color: var(--ink);
  font-size: 12px;
  font-weight: 650;
  line-height: 1.55;
}

.quiz-options {
  display: grid;
  gap: 5px;
}

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  width: 100%;
  padding: 9px 10px;
  cursor: pointer;
  color: var(--ink-soft);
  font-size: 10px;
  line-height: 1.45;
  text-align: left;
  background: rgba(23, 21, 17, 0.028);
  border: 1px solid rgba(23, 21, 17, 0.085);
  border-radius: 7px;
  transition: background 150ms ease, border-color 150ms ease;
}

.quiz-option:hover:not([disabled]) {
  background: rgba(23, 21, 17, 0.06);
  border-color: rgba(23, 21, 17, 0.2);
}

.quiz-option .option-letter {
  display: grid;
  flex: 0 0 auto;
  width: 16px;
  height: 16px;
  color: var(--muted);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  border: 1px solid rgba(23, 21, 17, 0.18);
  border-radius: 50%;
  place-items: center;
}

.quiz-option.is-correct {
  color: #0b5c54;
  background: rgba(22, 120, 111, 0.1);
  border-color: rgba(22, 120, 111, 0.4);
}

.quiz-option.is-correct .option-letter {
  color: #fff;
  background: var(--teal);
  border-color: var(--teal);
}

.quiz-option.is-wrong {
  color: #9a341c;
  background: rgba(207, 81, 55, 0.09);
  border-color: rgba(207, 81, 55, 0.4);
}

.quiz-option.is-wrong .option-letter {
  color: #fff;
  background: var(--coral);
  border-color: var(--coral);
}

.quiz-option[disabled] {
  cursor: default;
}

.quiz-feedback {
  padding: 8px 9px;
  margin-top: 8px;
  color: var(--ink-soft);
  font-size: 9px;
  line-height: 1.55;
  background: rgba(23, 21, 17, 0.04);
  border-left: 2px solid var(--accent);
  border-radius: 0 6px 6px 0;
}

.quiz-reset {
  margin-top: 3px;
}

.teacher-notes {
  margin-top: 20px;
  border-top: 1px solid var(--line);
}

.teacher-notes summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 14px 2px;
  cursor: pointer;
  color: var(--ink-soft);
  font-size: 10.5px;
  font-weight: 650;
  list-style: none;
}

.teacher-notes summary::-webkit-details-marker {
  display: none;
}

.teacher-notes summary::after {
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 14px;
  content: "+";
}

.teacher-notes[open] summary::after {
  content: "−";
}

.teacher-notes .notes-body {
  padding: 0 2px 12px;
  color: var(--muted);
  font-size: 10px;
  line-height: 1.7;
}

.teacher-notes ol {
  padding-left: 17px;
  margin: 0;
}

.teacher-notes li {
  margin-bottom: 6px;
}

.teacher-notes li:last-child {
  margin-bottom: 0;
}

.teacher-notes b {
  color: var(--ink-soft);
}

/* Footer */

.lesson-footer {
  position: relative;
  z-index: 2;
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  min-height: 57px;
  padding: 10px 31px;
  background: rgba(242, 237, 227, 0.92);
  border-top: 1px solid var(--line);
  backdrop-filter: blur(12px);
}

.footer-arrow {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  min-height: 32px;
  padding: 4px 2px;
  cursor: pointer;
  color: var(--muted);
  font-size: 9.5px;
  font-weight: 600;
  background: transparent;
  border: 0;
  transition: color 160ms ease;
}

.footer-arrow:hover {
  color: var(--accent-deep);
}

.footer-arrow:disabled {
  cursor: default;
  opacity: 0.28;
}

.footer-arrow svg {
  width: 15px;
  height: 15px;
}

.footer-count {
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.12em;
}

/* ---------------------------------------------------------
   Stage
   --------------------------------------------------------- */

.stage {
  position: relative;
  flex: 1 1 auto;
  min-width: 0;
  height: 100%;
  overflow: hidden;
  background: #071018;
  isolation: isolate;
}

#stageCanvas {
  position: absolute;
  z-index: 0;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
  cursor: grab;
}

#stageCanvas.is-dragging {
  cursor: grabbing;
}

.stage-scrim {
  position: absolute;
  z-index: 1;
  inset: 0;
  pointer-events: none;
  background:
    linear-gradient(180deg, rgba(2, 7, 11, 0.88) 0%, rgba(2, 7, 11, 0.62) 14%, rgba(2, 7, 11, 0.16) 30%, transparent 42%, transparent 58%, rgba(3, 8, 12, 0.82) 100%),
    radial-gradient(95% 72% at 56% 45%, transparent 42%, rgba(2, 7, 11, 0.38) 100%);
}

.stage-grain {
  position: absolute;
  z-index: 7;
  inset: 0;
  opacity: 0.18;
  pointer-events: none;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 180 180' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='s'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='.82' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23s)' opacity='.2'/%3E%3C/svg%3E");
  mix-blend-mode: soft-light;
}

.stage-watermark {
  position: absolute;
  z-index: 1;
  top: 50px;
  right: 34px;
  color: rgba(243, 236, 223, 0.03);
  font-family: var(--font-display);
  font-size: clamp(130px, 16vw, 230px);
  font-weight: 700;
  line-height: 0.8;
  pointer-events: none;
  user-select: none;
}

.stage-header {
  position: absolute;
  z-index: 5;
  top: 25px;
  right: 28px;
  left: 30px;
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 20px;
  pointer-events: none;
}

.stage-identity {
  max-width: min(640px, 72%);
  color: var(--cream);
}

.live-badge {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 5px 8px;
  margin-bottom: 13px;
  color: rgba(243, 236, 223, 0.65);
  font-family: var(--font-mono);
  font-size: 7.5px;
  font-weight: 500;
  letter-spacing: 0.12em;
  line-height: 1;
  text-transform: uppercase;
  background: rgba(7, 16, 24, 0.5);
  border: 1px solid rgba(243, 236, 223, 0.13);
  border-radius: 99px;
  backdrop-filter: blur(8px);
}

.live-badge i {
  width: 5px;
  height: 5px;
  background: #e9834f;
  border-radius: 50%;
  box-shadow: 0 0 0 3px rgba(233, 131, 79, 0.14);
  animation: live-pulse 2.6s ease-in-out infinite;
}

@keyframes live-pulse {
  0%,
  100% {
    opacity: 1;
    box-shadow: 0 0 0 3px rgba(233, 131, 79, 0.14);
  }
  50% {
    opacity: 0.55;
    box-shadow: 0 0 0 5px rgba(233, 131, 79, 0.02);
  }
}

.scene-code {
  margin-bottom: 6px;
  color: rgba(243, 236, 223, 0.42);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0.14em;
  line-height: 1.3;
  text-transform: uppercase;
}

.scene-title {
  margin: 0;
  color: var(--cream);
  font-family: var(--font-display);
  font-size: clamp(23px, 2.2vw, 33px);
  font-weight: 600;
  letter-spacing: -0.025em;
  line-height: 1.08;
  text-shadow: 0 2px 20px rgba(0, 0, 0, 0.28);
}

.scene-subtitle {
  max-width: 470px;
  margin: 7px 0 0;
  color: rgba(243, 236, 223, 0.56);
  font-size: 10.5px;
  line-height: 1.5;
}

.stage-actions {
  display: flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 7px;
  pointer-events: none;
}

.stage-lang {
  display: none;
  min-width: 35px;
  min-height: 35px;
  padding: 0 9px;
  cursor: pointer;
  color: rgba(243, 236, 223, 0.78);
  font-family: var(--font-mono);
  font-size: 9px;
  font-weight: 600;
  letter-spacing: 0.03em;
  background: rgba(7, 16, 24, 0.42);
  border: 1px solid rgba(243, 236, 223, 0.17);
  border-radius: 999px;
  pointer-events: auto;
  backdrop-filter: blur(9px);
  transition: color 170ms ease, background 170ms ease, border-color 170ms ease;
}

.stage-lang:hover {
  color: var(--cream);
  background: rgba(7, 16, 24, 0.7);
  border-color: rgba(243, 236, 223, 0.4);
}

.present-button {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  gap: 7px;
  min-height: 35px;
  padding: 7px 11px;
  cursor: pointer;
  color: rgba(243, 236, 223, 0.68);
  font-family: var(--font-mono);
  font-size: 8px;
  letter-spacing: 0.04em;
  background: rgba(7, 16, 24, 0.42);
  border: 1px solid rgba(243, 236, 223, 0.17);
  border-radius: 999px;
  pointer-events: auto;
  backdrop-filter: blur(9px);
  transition: color 170ms ease, background 170ms ease, border-color 170ms ease;
}

.present-button:hover {
  color: var(--cream);
  background: rgba(7, 16, 24, 0.7);
  border-color: rgba(243, 236, 223, 0.4);
}

.present-button svg {
  width: 13px;
  height: 13px;
}

/* 3D-anchored labels */

.stage-labels {
  position: absolute;
  z-index: 3;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
}

.scene-label {
  position: absolute;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  gap: 7px;
  max-width: 240px;
  padding: 6px 9px 6px 7px;
  color: var(--cream);
  background: rgba(6, 14, 21, 0.72);
  border: 1px solid rgba(243, 236, 223, 0.15);
  border-radius: 7px;
  box-shadow: 0 5px 18px rgba(0, 0, 0, 0.18);
  opacity: 0;
  transform: translate(-50%, -50%) translateY(4px);
  transition: opacity 200ms ease;
  backdrop-filter: blur(10px);
  will-change: transform, left, top;
}

.scene-label.is-visible {
  opacity: 1;
}

.scene-label .label-dot {
  flex: 0 0 auto;
  width: 5px;
  height: 5px;
  background: var(--label-color, var(--accent));
  border-radius: 50%;
  box-shadow: 0 0 8px var(--label-color, var(--accent));
}

.scene-label .label-copy {
  min-width: 0;
  line-height: 1.15;
}

.scene-label .label-name {
  display: block;
  overflow: hidden;
  color: rgba(243, 236, 223, 0.72);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 500;
  letter-spacing: 0.04em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.scene-label .label-value {
  display: block;
  margin-top: 2px;
  overflow: hidden;
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: -0.02em;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.scene-label .label-value small {
  margin-left: 2px;
  color: rgba(243, 236, 223, 0.5);
  font-size: 7px;
  font-weight: 400;
  letter-spacing: 0;
}

.scene-label.is-vehicle {
  padding: 7px 10px;
  background: rgba(8, 17, 25, 0.78);
  border-color: rgba(243, 236, 223, 0.22);
}

.scene-label.is-vehicle .label-name {
  color: rgba(243, 236, 223, 0.92);
  font-size: 8.5px;
  font-weight: 600;
}

.scene-label.is-vehicle .label-value {
  font-size: 13px;
}

.scene-label.is-passenger {
  border-color: rgba(255, 157, 102, 0.32);
}

.scene-label.is-note {
  padding: 5px 8px;
  border-radius: 5px;
  background: rgba(8, 17, 25, 0.58);
}

.scene-label.is-note .label-value {
  color: rgba(243, 236, 223, 0.8);
  font-family: var(--font-sans);
  font-size: 9px;
  font-weight: 500;
}

.scene-label.is-active {
  border-color: color-mix(in srgb, var(--label-color) 52%, transparent);
}

/* Bottom HUD */

.stage-bottom {
  position: absolute;
  z-index: 5;
  right: 28px;
  bottom: 24px;
  left: 30px;
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  gap: 18px;
  pointer-events: none;
}

.telemetry {
  display: flex;
  align-items: stretch;
  min-height: 58px;
  overflow: hidden;
  color: var(--cream);
  background: rgba(5, 13, 20, 0.62);
  border: 1px solid rgba(243, 236, 223, 0.14);
  border-radius: 11px;
  box-shadow: 0 12px 28px rgba(0, 0, 0, 0.2);
  opacity: 0;
  transform: translateY(5px);
  transition: opacity 300ms ease, transform 300ms ease;
  backdrop-filter: blur(12px);
}

.telemetry.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.hud-item {
  position: relative;
  display: flex;
  min-width: 98px;
  flex-direction: column;
  justify-content: center;
  gap: 3px;
  padding: 10px 15px 9px;
}

.hud-item + .hud-item {
  border-left: 1px solid rgba(243, 236, 223, 0.1);
}

.hud-item .hud-label {
  color: rgba(243, 236, 223, 0.48);
  font-family: var(--font-mono);
  font-size: 7.2px;
  font-weight: 500;
  letter-spacing: 0.06em;
  line-height: 1.2;
  white-space: nowrap;
}

.hud-item .hud-number {
  display: flex;
  align-items: baseline;
  gap: 3px;
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 21px;
  font-weight: 500;
  letter-spacing: -0.055em;
  line-height: 1;
  white-space: nowrap;
}

.hud-item .hud-number small {
  color: rgba(243, 236, 223, 0.42);
  font-size: 7px;
  font-weight: 400;
  letter-spacing: 0;
}

.hud-item.is-accent .hud-number {
  color: #ff9a6e;
}

.hud-item.is-teal .hud-number {
  color: #71d5c5;
}

.hud-pair {
  display: flex;
  align-items: center;
  gap: 9px;
}

.hud-pair .pair-side {
  display: flex;
  flex-direction: column;
  gap: 3px;
}

.hud-pair .pair-side span {
  color: rgba(243, 236, 223, 0.42);
  font-family: var(--font-mono);
  font-size: 6.8px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.hud-pair .pair-side b {
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 500;
  letter-spacing: -0.04em;
  line-height: 1;
}

.hud-pair .pair-side small {
  color: rgba(243, 236, 223, 0.42);
  font-size: 7px;
}

.hud-pair .pair-equals {
  color: var(--accent);
  font-family: var(--font-display);
  font-size: 21px;
  font-style: italic;
}

.force-legend {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 5px;
  max-width: 270px;
  opacity: 0;
  transition: opacity 300ms ease 100ms;
}

.force-legend.is-visible {
  opacity: 1;
}

.legend-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 7px;
  color: rgba(243, 236, 223, 0.58);
  font-family: var(--font-mono);
  font-size: 6.8px;
  letter-spacing: 0.04em;
  line-height: 1;
  background: rgba(5, 13, 20, 0.48);
  border: 1px solid rgba(243, 236, 223, 0.1);
  border-radius: 4px;
  backdrop-filter: blur(8px);
}

.legend-chip i {
  width: 4px;
  height: 4px;
  background: var(--legend-color, var(--accent));
  border-radius: 50%;
}

.orbit-hint {
  position: absolute;
  z-index: 5;
  bottom: 92px;
  left: 50%;
  display: flex;
  align-items: center;
  gap: 6px;
  color: rgba(243, 236, 223, 0.34);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.05em;
  pointer-events: none;
  transform: translateX(-50%);
  white-space: nowrap;
}

.orbit-icon {
  display: inline-flex;
  width: 20px;
  height: 20px;
  align-items: center;
  justify-content: center;
  border: 1px solid rgba(243, 236, 223, 0.18);
  border-radius: 50%;
}

.orbit-icon svg {
  width: 14px;
  height: 14px;
}

.stage-toast {
  position: absolute;
  z-index: 8;
  top: 50%;
  left: 50%;
  max-width: 340px;
  padding: 10px 14px;
  color: var(--cream);
  font-size: 10px;
  line-height: 1.5;
  text-align: center;
  background: rgba(6, 14, 21, 0.84);
  border: 1px solid rgba(243, 236, 223, 0.18);
  border-radius: 9px;
  opacity: 0;
  pointer-events: none;
  transform: translate(-50%, -40%);
  transition: opacity 240ms ease, transform 240ms ease;
  backdrop-filter: blur(12px);
}

.stage-toast.is-visible {
  opacity: 1;
  transform: translate(-50%, -50%);
}

.impact-flash {
  position: absolute;
  z-index: 6;
  inset: 0;
  pointer-events: none;
  opacity: 0;
  background: radial-gradient(circle at 54% 50%, rgba(255, 211, 153, 0.78), rgba(255, 127, 73, 0.16) 16%, transparent 52%);
}

.impact-flash.is-active {
  animation: impact-flash 650ms ease-out both;
}

@keyframes impact-flash {
  0% {
    opacity: 0;
  }
  12% {
    opacity: 1;
  }
  100% {
    opacity: 0;
  }
}

.noscript {
  position: absolute;
  z-index: 20;
  top: 50%;
  left: 50%;
  padding: 18px 22px;
  color: var(--ink);
  font-size: 12px;
  line-height: 1.6;
  background: var(--paper);
  border-radius: 10px;
  transform: translate(-50%, -50%);
}

/* Stage state classes */

.stage.is-impact .stage-scrim {
  background:
    linear-gradient(180deg, rgba(3, 9, 14, 0.72) 0%, transparent 24%, transparent 56%, rgba(3, 8, 12, 0.82) 100%),
    radial-gradient(90% 65% at 54% 48%, rgba(255, 154, 92, 0.08), transparent 58%);
}

/* ---------------------------------------------------------
   Responsive
   --------------------------------------------------------- */

@media (max-width: 1240px) {
  :root {
    --panel-width: clamp(410px, 42vw, 535px);
  }

  .chapter-root {
    padding-right: 28px;
    padding-left: 29px;
  }

  .lesson-header {
    padding-right: 27px;
    padding-left: 29px;
  }

  .chapter-nav {
    padding-right: 22px;
    padding-left: 22px;
  }

  .edition {
    display: none;
  }

  .stage-header {
    left: 25px;
  }

  .stage-bottom {
    left: 25px;
    right: 24px;
  }

  .telemetry {
    max-width: calc(100% - 160px);
    overflow-x: auto;
    scrollbar-width: none;
  }

  .telemetry::-webkit-scrollbar {
    display: none;
  }

  .hud-item {
    min-width: 84px;
    padding-right: 11px;
    padding-left: 11px;
  }

  .force-legend {
    max-width: 150px;
  }
}

@media (max-width: 980px) {
  .stage-lang {
    display: inline-flex;
  }

  .app {
    flex-direction: column-reverse;
    overflow-y: auto;
    height: auto;
    min-height: 100dvh;
  }

  .lesson {
    flex: 0 0 auto;
    width: 100%;
    height: auto;
    overflow: visible;
    box-shadow: 0 -18px 50px rgba(1, 7, 11, 0.24);
  }

  .panel-scroll {
    overflow: visible;
  }

  .chapter-root {
    padding-right: max(30px, calc((100vw - 780px) / 2));
    padding-left: max(30px, calc((100vw - 780px) / 2));
  }

  .lesson-header {
    padding-right: max(30px, calc((100vw - 780px) / 2));
    padding-left: max(30px, calc((100vw - 780px) / 2));
  }

  .chapter-nav {
    padding-right: max(26px, calc((100vw - 780px) / 2));
    padding-left: max(26px, calc((100vw - 780px) / 2));
  }

  .lesson-footer {
    padding-right: max(30px, calc((100vw - 780px) / 2));
    padding-left: max(30px, calc((100vw - 780px) / 2));
  }

  .chapter-title {
    font-size: clamp(39px, 6vw, 56px);
  }

  .chapter-intro {
    max-width: 690px;
    font-size: 13.5px;
  }

  .stage {
    flex: 0 0 auto;
    width: 100%;
    height: min(64vh, 650px);
    min-height: 440px;
  }

  .stage-watermark {
    top: 30px;
    font-size: 150px;
  }

  .stage-header {
    top: 20px;
  }

  .stage-bottom {
    bottom: 18px;
  }

  .orbit-hint {
    bottom: 84px;
  }

  .force-legend {
    max-width: 200px;
  }
}

@media (max-width: 640px) {
  .app {
    display: flex;
  }

  .lesson-header {
    min-height: 72px;
    padding: 15px 20px 13px;
  }

  .brand-mark {
    flex-basis: 38px;
    width: 38px;
    height: 38px;
    border-radius: 11px;
  }

  .brand-mark svg {
    width: 32px;
    height: 32px;
  }

  .brand-name {
    font-size: 16px;
  }

  .brand-kicker {
    font-size: 7.5px;
  }

  .chapter-nav {
    padding: 0 13px;
  }

  .nav-step {
    padding: 10px 5px 9px;
  }

  .nav-step b {
    font-size: 7px;
  }

  .nav-step span {
    font-size: 9px;
  }

  .chapter-root {
    padding: 23px 20px 25px;
  }

  .chapter-title {
    font-size: clamp(34px, 10vw, 44px);
  }

  .chapter-english {
    font-size: 15px;
  }

  .chapter-intro {
    font-size: 12.5px;
  }

  .experiment-panel {
    padding: 15px;
  }

  .stage {
    height: 58vh;
    min-height: 410px;
  }

  .stage-header {
    top: 15px;
    right: 15px;
    left: 16px;
    gap: 8px;
  }

  .live-badge {
    padding: 4px 7px;
    margin-bottom: 9px;
    font-size: 6.5px;
  }

  .scene-code {
    font-size: 6.5px;
    letter-spacing: 0.08em;
  }

  .scene-title {
    font-size: 22px;
  }

  .scene-subtitle {
    max-width: 260px;
    font-size: 9px;
  }

  .present-button {
    min-height: 31px;
    padding: 6px 8px;
  }

  .present-button span {
    display: none;
  }

  .stage-lang {
    min-width: 31px;
    min-height: 31px;
    padding: 0 7px;
    font-size: 8px;
  }

  .stage-watermark {
    top: 18px;
    right: 15px;
    font-size: 95px;
  }

  .stage-bottom {
    right: 14px;
    bottom: 14px;
    left: 15px;
    display: block;
  }

  .telemetry {
    max-width: 100%;
    width: fit-content;
  }

  .hud-item {
    min-width: 76px;
    padding: 9px 10px 8px;
  }

  .hud-item .hud-number {
    font-size: 18px;
  }

  .hud-item .hud-label {
    font-size: 6px;
  }

  .force-legend {
    position: absolute;
    right: 0;
    bottom: calc(100% + 7px);
    display: flex;
    flex-wrap: nowrap;
    gap: 4px;
    max-width: 100%;
    overflow: hidden;
  }

  .legend-chip {
    flex: 0 0 auto;
    padding: 4px 6px;
    font-size: 6px;
  }

  .orbit-hint {
    display: none;
  }

  .scene-label {
    max-width: 180px;
    padding: 5px 7px;
  }

  .scene-label .label-name {
    font-size: 6px;
  }

  .scene-label .label-value {
    font-size: 9px;
  }

  .scene-label.is-vehicle .label-value {
    font-size: 11px;
  }

  .lesson-footer {
    padding: 9px 20px;
  }

  .fm-middle {
    grid-template-columns: minmax(0, 1fr) 76px minmax(0, 1fr);
    gap: 4px;
  }

  .fm-car {
    width: 76px;
  }

  .fm-car svg {
    width: 72px;
  }

  .force-chip {
    padding: 6px;
  }

  .force-chip .fc-value {
    font-size: 11.5px;
  }

  .force-chip .fc-label {
    font-size: 8px;
  }

  .formula-plate {
    gap: 12px;
    padding: 11px 13px;
  }

  .formula-caption {
    display: none;
  }

  .pair-rules {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 380px) {
  .chapter-root {
    padding-right: 16px;
    padding-left: 16px;
  }

  .chapter-nav {
    padding-right: 9px;
    padding-left: 9px;
  }

  .stage {
    min-height: 370px;
  }

  .nav-step span {
    font-size: 8px;
  }

  .segmented button {
    font-size: 9.5px;
  }
}

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

/* ---------------------------------------------------------
   Additional chapter components
   --------------------------------------------------------- */

.stage {
  background:
    radial-gradient(115% 84% at 66% 40%, #0d242f 0%, #07141e 40%, #030a10 78%, #02060a 100%);
}

.law-note {
  margin: 9px 0 0;
  color: var(--ink-soft);
  font-size: 9.5px;
  line-height: 1.6;
}

.experiment-note {
  margin: 11px 0 0;
  color: var(--muted);
  font-size: 10px;
  line-height: 1.62;
}

.pair-board {
  overflow: hidden;
  background: rgba(23, 21, 17, 0.032);
  border: 1px solid rgba(23, 21, 17, 0.1);
  border-radius: 12px;
}

.pair-row {
  display: grid;
  grid-template-columns: 28px minmax(0, 1fr) auto;
  align-items: center;
  gap: 9px;
  padding: 11px 12px;
}

.pair-arrow {
  display: grid;
  width: 25px;
  height: 25px;
  color: var(--pair-color, var(--violet));
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  line-height: 1;
  background: color-mix(in srgb, var(--pair-color, var(--violet)) 11%, transparent);
  border: 1px solid color-mix(in srgb, var(--pair-color, var(--violet)) 35%, transparent);
  border-radius: 50%;
  place-items: center;
}

.pair-arrow.is-action {
  --pair-color: var(--violet);
  background: rgba(118, 87, 184, 0.08);
  border-color: rgba(118, 87, 184, 0.32);
}

.pair-arrow.is-reaction {
  --pair-color: #1a9898;
  background: rgba(26, 152, 152, 0.08);
  border-color: rgba(26, 152, 152, 0.32);
}

.pair-copy {
  min-width: 0;
}

.pair-copy b {
  display: block;
  color: var(--ink);
  font-size: 10px;
  font-weight: 700;
  line-height: 1.35;
}

.pair-copy small {
  display: block;
  margin-top: 2px;
  overflow: hidden;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 6.5px;
  letter-spacing: 0.035em;
  line-height: 1.3;
  text-overflow: ellipsis;
  text-transform: uppercase;
  white-space: nowrap;
}

.pair-value {
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: -0.05em;
  white-space: nowrap;
}

.pair-value small {
  margin-left: 2px;
  color: var(--faint);
  font-size: 7px;
  font-weight: 500;
  letter-spacing: 0;
}

.pair-equal-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 4px 10px;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 6.5px;
  letter-spacing: 0.07em;
  background: rgba(23, 21, 17, 0.03);
  border-top: 1px dashed rgba(23, 21, 17, 0.12);
  border-bottom: 1px dashed rgba(23, 21, 17, 0.12);
}

.pair-equal-row span {
  color: var(--accent-deep);
  font-family: var(--font-display);
  font-size: 13px;
  font-style: italic;
}

.closing-line {
  margin: 22px 0 0;
  padding-top: 15px;
  color: var(--faint);
  font-family: var(--font-display);
  font-size: 11px;
  font-style: italic;
  line-height: 1.6;
  border-top: 1px solid var(--line);
}

.telemetry.is-formulas .hud-number {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 500;
  letter-spacing: -0.035em;
}

.stage.is-fallback .orbit-hint {
  display: none;
}

.sr-only {
  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: 640px) {
  .pair-row {
    padding: 9px 10px;
  }

  .pair-value {
    font-size: 14px;
  }

  .experiment-note {
    font-size: 9px;
  }
}

/* ---------------------------------------------------------
   Chapter 01 · What is a force?
   --------------------------------------------------------- */

.concept-row {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 7px;
  margin-top: 20px;
}

.concept-cell {
  display: flex;
  min-width: 0;
  flex-direction: column;
  gap: 4px;
  padding: 10px 10px 11px;
  background: rgba(255, 255, 255, 0.25);
  border: 1px solid rgba(23, 21, 17, 0.1);
  border-radius: 10px;
}

.concept-cell b {
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.08em;
}

.concept-cell span {
  color: var(--ink);
  font-size: 10px;
  font-weight: 700;
  line-height: 1.3;
}

.concept-cell small {
  color: var(--muted);
  font-size: 8px;
  line-height: 1.45;
}

.view-tabs {
  margin-bottom: 10px;
}

.view-tabs button {
  min-height: 39px;
  font-size: 10px;
}

.view-caption {
  min-height: 30px;
  margin: 0 0 12px;
  color: var(--muted);
  font-size: 9.5px;
  line-height: 1.55;
}

.knowledge-panel {
  border-top: 3px solid var(--mode-color, var(--accent));
}

.knowledge-panel .segmented button.is-active {
  box-shadow: inset 0 -2px 0 var(--mode-color, var(--accent)), 0 3px 8px rgba(23, 21, 17, 0.16);
}

.knowledge-tabs {
  margin-top: 1px;
}

.knowledge-tabs button {
  min-height: 37px;
  padding-right: 4px;
  padding-left: 4px;
  font-size: 9.5px;
}

.knowledge-summary {
  display: flex;
  align-items: stretch;
  gap: 10px;
  margin: 1px 0 17px;
}

.knowledge-rule {
  flex: 0 0 3px;
  width: 3px;
  min-height: 38px;
  border-radius: 99px;
}

.knowledge-summary p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 10.5px;
  line-height: 1.7;
}

.knowledge-formula {
  align-items: flex-start;
  flex-direction: column;
  gap: 8px;
  padding: 16px 18px 14px;
  border-radius: 12px;
}

.knowledge-formula .formula-main {
  max-width: 100%;
  font-size: clamp(19px, 2.2vw, 25px);
  line-height: 1.32;
  white-space: normal;
}

.knowledge-formula .formula-main.is-compact {
  font-size: clamp(17px, 1.85vw, 21px);
}

.knowledge-formula .formula-caption {
  padding-left: 0;
  border-left: 0;
  line-height: 1.55;
}

.knowledge-formula .formula-caption b {
  display: inline;
  margin-right: 7px;
}

.formula-detail {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 9px;
  line-height: 1.6;
}

.formula-constant {
  margin: 4px 0 0;
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 8.5px;
  line-height: 1.55;
}

.data-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 7px;
  margin-top: 12px;
}

.data-cell {
  min-width: 0;
  padding: 9px 9px 10px;
  background: rgba(23, 21, 17, 0.032);
  border: 1px solid rgba(23, 21, 17, 0.08);
  border-radius: 8px;
}

.data-cell > span {
  display: block;
  overflow: hidden;
  color: var(--faint);
  font-family: var(--font-mono);
  font-size: 6.8px;
  letter-spacing: 0.035em;
  line-height: 1.35;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.data-cell > b {
  display: block;
  margin-top: 5px;
  overflow-wrap: anywhere;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: -0.045em;
  line-height: 1.08;
}

.data-cell > b small {
  margin-left: 2px;
  color: var(--muted);
  font-size: 7px;
  font-weight: 500;
  letter-spacing: 0;
}

.data-cell.is-textual > b {
  font-family: var(--font-sans);
  font-size: 10px;
  font-weight: 650;
  letter-spacing: 0;
  line-height: 1.4;
}

.car-insight {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  margin-top: 13px;
  padding: 11px 12px;
  background: rgba(230, 90, 43, 0.055);
  border: 1px solid rgba(230, 90, 43, 0.16);
  border-radius: 10px;
}

.car-insight-mark {
  display: grid;
  flex: 0 0 38px;
  width: 38px;
  height: 30px;
  color: var(--accent-deep);
  place-items: center;
}

.car-insight-mark svg {
  width: 38px;
  height: auto;
}

.car-insight-label {
  display: block;
  margin-bottom: 2px;
  color: var(--accent-deep);
  font-family: var(--font-mono);
  font-size: 7px;
  font-weight: 600;
  letter-spacing: 0.07em;
}

.car-insight p {
  margin: 0;
  color: var(--ink-soft);
  font-size: 9.5px;
  line-height: 1.6;
}

.knowledge-table {
  margin-top: 4px;
}

.knowledge-table th {
  font-size: 6.5px;
}

.knowledge-table td {
  font-size: 8.5px;
  line-height: 1.45;
}

.knowledge-table tr.is-current td {
  background: rgba(230, 90, 43, 0.075);
  color: var(--ink-soft);
}

.table-force-name {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  color: var(--ink);
  font-weight: 650;
  white-space: nowrap;
}

.table-force-name i {
  width: 5px;
  height: 5px;
  flex: 0 0 auto;
  border-radius: 50%;
}

.strength-order {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 8.5px;
  line-height: 1.6;
}

.extension-details {
  margin-top: 15px;
  border-top: 1px dashed var(--line);
  border-bottom: 1px dashed var(--line);
}

.extension-details .notes-body p {
  margin: 0 0 10px;
}

.extension-details .notes-body p:last-child {
  margin-bottom: 0;
}

.extension-formula {
  display: inline-block;
  padding: 2px 5px;
  margin: 2px 2px;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.4;
  background: rgba(23, 21, 17, 0.06);
  border-radius: 4px;
  white-space: nowrap;
}

.analysis-intro {
  margin-top: 0;
  margin-bottom: 14px;
}

.formula-sheet {
  margin-top: 0;
  border-top: 0;
}

.formula-sheet .notes-body {
  padding-top: 2px;
}

.formula-sheet-row {
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  align-items: baseline;
  gap: 8px;
  padding: 7px 0;
  border-bottom: 1px solid var(--line);
}

.formula-sheet-row:last-of-type {
  border-bottom: 0;
}

.formula-sheet-row span {
  color: var(--ink-soft);
  font-size: 9px;
  font-weight: 650;
}

.formula-sheet-row code {
  overflow-wrap: anywhere;
  color: var(--ink);
  font-family: var(--font-mono);
  font-size: 9px;
  line-height: 1.5;
}

.formula-sheet-note {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 8.5px;
  line-height: 1.6;
}

@media (max-width: 640px) {
  .concept-row {
    gap: 5px;
    margin-top: 16px;
  }

  .concept-cell {
    padding: 8px 7px;
  }

  .concept-cell span {
    font-size: 9px;
  }

  .concept-cell small {
    font-size: 7.5px;
  }

  .knowledge-tabs button {
    font-size: 8.5px;
  }

  .knowledge-formula {
    padding: 14px;
  }

  .knowledge-formula .formula-main {
    font-size: 18px;
  }

  .knowledge-formula .formula-main.is-compact {
    font-size: 15.5px;
  }

  .data-cell {
    padding: 7px;
  }

  .data-cell > b {
    font-size: 14px;
  }

  .data-cell.is-textual > b {
    font-size: 9px;
  }

  .data-cell > span {
    font-size: 6.2px;
    white-space: normal;
  }

  .knowledge-table {
    display: block;
    overflow-x: auto;
    white-space: nowrap;
  }

  .knowledge-table th,
  .knowledge-table td {
    padding: 7px 7px;
  }

  .car-insight {
    gap: 8px;
    padding: 9px 10px;
  }

  .car-insight-mark {
    flex-basis: 30px;
    width: 30px;
  }

  .car-insight-mark svg {
    width: 30px;
  }

  .car-insight p {
    font-size: 9px;
  }

  .formula-sheet-row {
    grid-template-columns: 60px minmax(0, 1fr);
  }
}


.hud-item.is-text .hud-number {
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 650;
  letter-spacing: -0.01em;
  line-height: 1.2;
  white-space: normal;
}

.model-inline {
  margin: 11px 0 0;
  padding-top: 10px;
  color: var(--muted);
  font-size: 8.5px;
  line-height: 1.62;
  border-top: 1px dashed rgba(23, 21, 17, 0.14);
}

.model-inline b {
  margin-right: 5px;
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.06em;
}


.knowledge-formula .formula-caption > span {
  display: inline;
  margin-left: 7px;
  color: rgba(243, 236, 223, 0.4);
  font-family: var(--font-mono);
  font-size: 7px;
  letter-spacing: 0.04em;
}

.hud-item.is-text {
  min-width: 116px;
}


.webgl-fallback {
  position: absolute;
  z-index: 9;
  top: 50%;
  left: 50%;
  display: none;
  width: min(390px, calc(100% - 48px));
  padding: 20px 24px;
  color: rgba(243, 236, 223, 0.8);
  font-size: 11px;
  line-height: 1.65;
  text-align: center;
  background: rgba(7, 16, 24, 0.86);
  border: 1px solid rgba(243, 236, 223, 0.16);
  border-radius: 12px;
  transform: translate(-50%, -50%);
  backdrop-filter: blur(12px);
}

.webgl-fallback b {
  display: block;
  margin-bottom: 3px;
  color: var(--cream);
  font-family: var(--font-mono);
  font-size: 9px;
  letter-spacing: 0.04em;
}

.webgl-fallback p {
  margin: 0 0 9px;
}

.webgl-fallback p:last-child {
  margin-bottom: 0;
}

.stage.is-fallback .webgl-fallback {
  display: block;
}

@media (max-width: 380px) {
  .telemetry {
    width: 100%;
    max-width: 100%;
    overflow-x: auto;
  }

  .hud-item {
    min-width: 0;
    flex: 1 1 0;
    padding-right: 7px;
    padding-left: 7px;
  }

  .hud-item.is-text {
    min-width: 0;
  }

  .hud-item .hud-label {
    overflow: hidden;
    font-size: 5.8px;
    line-height: 1.2;
    text-overflow: ellipsis;
    white-space: normal;
  }

  .hud-item .hud-number {
    font-size: 16px;
  }

  .hud-item.is-text .hud-number {
    font-size: 10.5px;
    line-height: 1.2;
  }

  .hud-pair {
    gap: 5px;
  }

  .hud-pair .pair-side b {
    font-size: 15px;
  }
}

@media (max-width: 380px) {
  .scene-title {
    font-size: 19px;
    line-height: 1.12;
  }

  .scene-subtitle {
    font-size: 8.5px;
    line-height: 1.4;
  }

  .scene-label.is-icon {
    display: none;
  }
}