:root {
  color-scheme:dark;
  --bg:#0b1019;
  --panel:#101722;
  --text:#eef3fa;
  --muted:#8896ab;
  --subtle:#b5c0d0;
  --line:#25303e;
  --cyan:#5ae0d3;
  --amber:#ffc779;
  --violet:#b79bfa;
  font-family:Inter,"Segoe UI",Arial,sans-serif;
  font-synthesis:none
}

* {
  box-sizing:border-box
}

body {
  margin:0;
  min-height:100svh;
  display:flex;
  flex-direction:column;
  background:var(--bg);
  color:var(--text)
}

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

button,input {
  font:inherit
}

button,a,input {
  outline-offset:5px
}

button:focus-visible,a:focus-visible,input:focus-visible {
  outline:2px solid var(--cyan)
}

button {
  cursor:pointer
}

button {
  color:inherit
}

button:disabled {
  cursor:default
}

a {
  color:inherit
}

button {
  border:0
}

button:active {
  transform:translateY(1px)
}

[hidden] {
  display:none!important
}

.topbar {
  height:56px;
  flex-shrink:0;
  padding:0 14px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  border-bottom:1px solid var(--line);
  gap:24px
}

.brand {
  display:flex;
  align-items:center;
  gap:12px;
  text-decoration:none;
  font-size:21px;
  font-weight:620;
  letter-spacing:-.7px
}

.brand svg {
  width:37px;
  height:34px;
  overflow:visible
}

.brand svg path {
  fill:none;
  stroke:var(--cyan);
  stroke-width:2.4
}

.brand svg circle {
  fill:var(--text)
}

.brand small {
  display:block;
  font-size:8px;
  font-weight:500;
  letter-spacing:2.3px;
  color:var(--muted);
  margin-top:5px
}

.modes {
  display:flex;
  align-self:stretch;
  gap:8px;
  min-width:0;
  overflow-x:auto;
  scrollbar-width:thin
}

.modes a {
  display:flex;
  align-items:center;
  justify-content:center;
  text-decoration:none
}

.modes :is(button,a) {
  position:relative;
  flex-shrink:0;
  background:transparent;
  color:var(--muted);
  padding:0 16px;
  font-size:13px;
  white-space:nowrap
}

.modes :is(button,a) span {
  font-size:10px;
  opacity:.65;
  margin-right:6px;
  font-variant-numeric:tabular-nums
}

.modes :is([aria-pressed=true],[aria-current=page]) {
  color:var(--cyan);
  background:linear-gradient(0deg,#5ae0d30b,transparent 70%)
}

.modes :is([aria-pressed=true],[aria-current=page]):after {
  content:"";
  position:absolute;
  bottom:-1px;
  left:15px;
  right:15px;
  height:2px;
  background:var(--cyan)
}

.modes :is(button,a):hover {
  color:var(--text)
}

.text-button {
  background:transparent;
  color:var(--subtle);
  font-size:12px;
  white-space:nowrap
}

.math-button span {
  font-family:Georgia,serif;
  font-size:24px;
  vertical-align:-2px;
  margin-right:9px;
  color:var(--cyan)
}

.laboratory {
  padding:0 12px;
  width:100%;
  flex:1;
  display:flex;
  flex-direction:column
}

.workspace {
  display:grid;
  grid-template-columns:minmax(0,1.18fr) 64px minmax(0,1fr);
  flex:1;
  min-height:360px;
  border:1px solid var(--line);
  border-radius:8px;
  overflow:hidden;
  background:var(--panel)
}

.world-pane,.integral-pane {
  min-width:0;
  display:flex;
  flex-direction:column;
  position:relative
}

.world-pane {
  border-right:1px solid var(--line);
  background:radial-gradient(ellipse at 40% 40%,#15212d70,transparent 75%)
}

.integral-pane {
  container-type:inline-size
}

.error-pane {
  position:relative;
  min-height:0;
  border-right:1px solid var(--line);
  background:#0b121a80
}

.error-pane canvas {
  position:absolute;
  inset:0;
  width:100%;
  height:100%
}

.pane-heading {
  height:44px;
  min-height:44px;
  padding:0 20px;
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:12px
}

.pane-heading h2 {
  font-size:12px;
  font-weight:500;
  margin:0;
  letter-spacing:.1px
}

.section-number {
  color:var(--muted);
  font-size:10px;
  margin-right:8px
}

.pane-heading>span {
  font-size:10px;
  color:var(--muted)
}

.live-label {
  display:flex;
  gap:6px;
  align-items:center;
  font-size:9px!important;
  letter-spacing:1px
}

.live-label i {
  width:5px;
  height:5px;
  border-radius:50%;
  background:var(--cyan);
  box-shadow:0 0 8px #5ae0d335
}

.world-stage {
  flex:1;
  min-height:0;
  position:relative;
  overflow:hidden
}

.world-stage canvas {
  position:absolute;
  inset:0;
  width:100%;
  height:100%;
  touch-action:none;
  cursor:default
}

.world-stage canvas:focus-visible {
  outline:1px dashed var(--cyan);
  outline-offset:-7px
}

.world-stage canvas.grabbable {
  cursor:grab
}

.world-stage canvas.dragging {
  cursor:grabbing
}

.world-stage canvas.smoothing {
  cursor:crosshair
}

.smoothing-hint {
  color:var(--muted);
  font-size:10px;
  white-space:nowrap
}

@media(max-width:1200px) {
  .smoothing-hint { display:none }
}

.scene-caption {
  pointer-events:none;
  position:absolute;
  bottom:82px;
  left:50%;
  transform:translateX(-50%);
  display:flex;
  align-items:center;
  gap:8px;
  color:var(--subtle);
  font-size:11px;
  white-space:nowrap;
  background:#101722d9;
  padding:8px 12px;
  border:1px solid #30415570;
  border-radius:30px;
  transition:opacity .3s
}

.cursor-mark {
  color:var(--cyan);
  font-size:17px
}

.solution-badge {
  position:absolute;
  right:18px;
  top:0;
  color:var(--violet);
  font-size:10px;
  border:1px solid #b79bfa40;
  background:#17192b;
  padding:7px 10px;
  border-radius:5px
}

.world-controls {
  height:auto;
  min-height:44px;
  border-top:1px solid #25303e90;
  display:flex;
  flex-wrap:wrap;
  align-items:center;
  justify-content:space-between;
  gap:6px 14px;
  padding:8px 20px;
  color:var(--subtle);
  font-size:11px
}

.dynamics-controls {
  display:flex;
  align-items:center;
  gap:8px;
  padding:0 12px;
  min-height:40px;
  border-top:1px solid var(--line);
  font-size:10px;
  color:var(--subtle)
}

.duration-control {
  display:flex;
  align-items:center;
  gap:6px
}

.dynamics-controls input {
  accent-color:var(--violet);
  min-width:0;
  height:4px;
  cursor:pointer
}

.duration-control input { width:70px }
.dynamics-controls #scrub { flex:1; width:55px }
.dynamics-controls output { white-space:nowrap; font-variant-numeric:tabular-nums }
.dynamics-controls button { padding:5px 7px; background:#b79bfa16; color:var(--violet); border-radius:4px; white-space:nowrap }

@media(max-width:1050px) {
  .dynamics-controls { gap:5px; padding:0 8px; font-size:9px }
  .duration-control input { width:48px }
  .modes :is(button,a) { padding-left:12px; padding-right:12px }
}

.brush-control {
  display:flex;
  flex:1;
  min-width:140px;
  align-items:center;
  gap:10px
}

.brush-control input {
  width:150px;
  max-width:150px;
  min-width:40px;
  flex:1;
  accent-color:var(--cyan);
  height:4px;
  cursor:pointer
}

.brush-size {
  color:var(--muted);
  width:41px;
  font-size:10px
}

.control-options {
  display:flex;
  align-items:center;
  gap:14px;
  margin-left:auto
}

.guide-control {
  display:flex;
  align-items:center;
  gap:5px;
  white-space:nowrap;
  cursor:pointer
}

.guide-control input {
  accent-color:var(--cyan);
  width:13px;
  height:13px
}

.scoreboard {
  display:grid;
  grid-template-columns:auto minmax(0,1fr) auto;
  align-items:center;
  padding:2px 23px 4px;
  gap:10px
}

.current-score {
  display:flex;
  align-items:baseline;
  gap:9px;
  white-space:nowrap
}

.score-symbol {
  font-family:Georgia,serif;
  font-style:italic;
  font-size:20px;
  color:var(--subtle)
}

.current-score output {
  font-size:21px;
  font-weight:460;
  letter-spacing:-.9px;
  font-variant-numeric:tabular-nums;
  line-height:1.2
}

.score-unit {
  color:var(--muted);
  font-size:16px
}

.target-score {
  display:flex;
  flex-direction:column;
  text-align:right;
  gap:5px;
  font-size:10px;
  color:var(--muted)
}

.target-score strong {
  font-size:18px;
  color:var(--cyan);
  font-weight:450;
  letter-spacing:.1px;
  font-variant-numeric:tabular-nums;
  white-space:nowrap
}

.progress-area {
  padding:0 23px 6px
}

.progress-copy {
  display:flex;
  justify-content:space-between;
  gap:8px;
  font-size:11px;
  color:var(--muted);
  margin-bottom:0
}

.progress-copy #gap-value {
  color:var(--amber);
  white-space:nowrap;
  font-variant-numeric:tabular-nums
}

.integral-pane.solved .progress-copy {
  color:var(--cyan)
}

.integral-pane.solved #gap-value {
  color:var(--cyan)
}

.graph-stage {
  position:relative;
  flex:1;
  min-height:145px;
  margin:0 10px 0 4px
}

.graph-stage canvas {
  position:absolute;
  inset:0;
  width:100%;
  height:100%
}

.graph-legend {
  height:36px;
  min-height:36px;
  padding:0 23px;
  display:flex;
  gap:15px;
  align-items:center;
  font-size:9px;
  color:var(--muted)
}

.graph-legend>span {
  display:flex;
  align-items:center;
  gap:5px;
  white-space:nowrap
}

.graph-legend #local-value {
  margin-left:auto;
  color:var(--variation, var(--amber));
  font-variant-numeric:tabular-nums
}

.swatch {
  display:inline-block;
  width:8px;
  height:8px;
  border-radius:2px
}

.swatch.fill {
  background:#5ae0d336;
  border:1px solid #5ae0d370
}

.swatch.selected {
  background:var(--variation-fill, #ffc77955);
  border:1px solid var(--variation-border, #ffc779aa)
}

.formula-block {
  display:flex;
  align-items:center;
  justify-content:center;
  min-width:0
}

.formula-block>div {
  display:flex;
  align-items:center;
  justify-content:center;
  font-size:clamp(11.5px,2.8cqw,14px)
}

@container(max-width:520px) {
  .scoreboard {
    grid-template-columns:auto minmax(0,1fr);
    column-gap:8px;
    row-gap:2px
  }
  .current-score {
    grid-column:1;
    grid-row:1 / 3
  }
  .score-symbol { display:none }
  .score-unit { font-size:12px }
  .formula-block {
    grid-column:2;
    grid-row:1
  }
  .target-score {
    grid-column:2;
    grid-row:2;
    gap:2px
  }
}

math {
  font-family:"Cambria Math","STIX Two Math","Latin Modern Math",math;
  math-style:normal
}

math mfrac {
  math-style:compact
}

.actions {
  position:absolute;
  right:14px;
  bottom:30px;
  z-index:2;
  display:flex;
  gap:8px;
  white-space:nowrap
}

.secondary-button,.primary-button {
  padding:9px 12px;
  border-radius:6px;
  font-size:12px;
  font-weight:550;
  min-height:38px
}

.secondary-button {
  background:#101722f2;
  border:1px solid #344152;
  color:var(--subtle)
}

.secondary-button:hover {
  background:#ffffff07;
  border-color:var(--muted)
}

.secondary-button span {
  font-size:17px;
  vertical-align:-1px;
  margin-right:5px
}

.primary-button {
  background:var(--cyan);
  color:#0b272b;
  border:1px solid var(--cyan)
}

.primary-button:hover {
  background:#7bf0e4
}

.primary-button span {
  font-size:16px;
  margin-left:10px
}

.sr-only {
  position:absolute;
  left:-10000px;
  width:1px;
  height:1px;
  overflow:hidden
}

dialog {
  background:#111b28;
  color:var(--text);
  border:1px solid #39495d;
  border-radius:13px;
  width:min(640px,calc(100% - 28px));
  padding:27px 30px;
  max-height:88svh;
  box-shadow:0 25px 100px #0008
}

dialog::backdrop {
  background:#040910c9;
  backdrop-filter:blur(5px)
}

.dialog-heading {
  display:flex;
  justify-content:space-between;
  align-items:center
}

.eyebrow {
  font-size:10px;
  letter-spacing:2px;
  color:var(--cyan)
}

.dialog-heading button {
  font-size:28px;
  background:transparent;
  color:var(--muted);
  width:36px;
  height:36px
}

dialog h2 {
  font-size:28px;
  font-weight:500;
  margin:15px 0 18px;
  letter-spacing:-.7px
}

dialog h3 {
  font-size:14px;
  font-weight:550;
  margin-top:24px
}

dialog p {
  font-size:13px;
  color:var(--subtle);
  line-height:1.75
}

dialog .equation {
  font-family:Cambria,Georgia,serif;
  color:var(--text);
  font-size:19px;
  line-height:1.6;
  padding:10px 14px;
  background:#080f1980;
  border-left:2px solid var(--cyan);
  overflow-wrap:anywhere
}

dialog .equation math {
  font-size:23px
}

dialog .fine-print {
  font-size:11px;
  color:var(--muted)
}

.lecture-links {
  display:flex;
  flex-direction:column;
  gap:12px;
  border-top:1px solid var(--line);
  margin-top:25px;
  padding-top:20px
}

.lecture-links span {
  font-size:9px;
  color:var(--muted);
  letter-spacing:1px
}

.lecture-links a {
  font-size:12px;
  color:var(--cyan);
  text-decoration:none
}

.lecture-links a:hover {
  text-decoration:underline
}

@media(min-width:1600px) {
  .workspace {
    grid-template-columns:minmax(0,1.25fr) 64px minmax(0,1fr)
  }
  .current-score output {
    font-size:25px
  }
}

@media(max-width:1050px) {
  .topbar {
    padding:0 12px;
    gap:14px
  }
  .brand {
    font-size:19px
  }
  .modes {
    gap:0
  }
  .modes :is(button,a) {
    padding:0 16px
  }
  .laboratory {
    padding:0 10px
  }
  .scoreboard {
    padding:2px 17px 4px;
    gap:8px
  }
  .current-score {
    gap:6px
  }
  .current-score output {
    font-size:17px
  }
  .score-symbol {
    font-size:17px
  }
  .target-score {
    font-size:9px
  }
  .target-score strong {
    font-size:16px
  }
  .progress-area {
    padding-left:17px;
    padding-right:17px
  }
  .pane-heading {
    padding:0 17px
  }
  .graph-legend {
    padding:0 16px;
    gap:12px
  }
  .graph-legend #local-value {
    display:none
  }
  .world-controls {
    padding:8px 14px
  }
  .brush-control {
    gap:7px
  }
  .brush-control input {
    width:110px
  }
  .math-button {
    font-size:11px
  }
  .math-button span {
    margin-right:5px
  }
  .secondary-button,.primary-button {
    padding:9px 10px;
    font-size:11px
  }
}

@media(max-width:740px) {
  .topbar {
    height:113px;
    flex-wrap:wrap;
    align-content:space-between;
    padding:14px 16px 0;
    gap:0
  }
  .brand {
    font-size:18px
  }
  .brand svg {
    width:30px;
    height:25px
  }
  .brand small {
    font-size:7px
  }
  .math-button {
    margin-left:auto
  }
  .modes {
    order:3;
    width:100%;
    height:46px;
    justify-content:flex-start;
    gap:0;
    overflow-x:auto
  }
  .modes :is(button,a) {
    flex:1;
    padding:0 12px
  }
  .modes :is([aria-pressed=true],[aria-current=page]):after {
    left:12px;
    right:12px
  }
  .laboratory {
    padding:0 12px
  }
  .workspace {
    grid-template-columns:minmax(0,1fr) 64px;
    grid-template-rows:395px 350px;
    height:auto;
    max-height:none;
    min-height:0;
    flex:none;
    border-radius:9px
  }
  .world-pane {
    height:395px;
    grid-column:1;
    grid-row:1;
    border-bottom:1px solid var(--line)
  }
  .error-pane {
    grid-column:2;
    grid-row:1;
    border-right:0;
    border-bottom:1px solid var(--line)
  }
  .integral-pane {
    height:350px;
    grid-column:1 / -1;
    grid-row:2
  }
  .pane-heading {
    height:44px;
    min-height:44px;
    padding:0 15px
  }
  .world-controls {
    height:auto;
    min-height:47px
  }
  .brush-control input {
    width:92px
  }
  .scoreboard {
    padding:2px 17px 4px
  }
  .current-score output {
    font-size:18px
  }
  .target-score strong {
    font-size:17px
  }
  .target-score {
    font-size:10px
  }
  .graph-legend {
    height:34px;
    min-height:34px
  }
  .graph-legend #local-value {
    display:flex;
    font-size:9px
  }
  .graph-stage {
    min-height:130px
  }
  .progress-area {
    padding-bottom:10px
  }
  .actions {
    right:10px;
    gap:6px
  }
  .scene-caption {
    font-size:10px
  }
  .solution-badge {
    right:12px;
    font-size:9px
  }
  .world-controls {
    font-size:10px
  }
  .brush-size {
    font-size:9px
  }
  .graph-legend {
    font-size:9px
  }
  dialog {
    padding:20px
  }
}

@media(max-width:380px) {
  .workspace {
    grid-template-rows:375px 350px
  }
  .graph-legend #local-value {
    display:none
  }
  .math-button {
    font-size:10px
  }
  .world-controls {
    padding:0 10px
  }
  .brush-control input {
    width:66px
  }
  .target-score {
    font-size:9px
  }
  .current-score output {
    font-size:16px
  }
  .score-symbol {
    font-size:16px
  }
  .brand {
    gap:8px
  }
  .world-pane {
    height:375px
  }
}

@media(max-width:740px) and (min-height:700px) {
  .workspace {
    grid-template-rows:320px 320px
  }
  .topbar {
    height:105px
  }
  .world-pane {
    height:320px
  }
  .integral-pane {
    height:320px
  }
  .scoreboard {
    padding-top:2px;
    padding-bottom:4px
  }
  .progress-area {
    padding-bottom:8px
  }
  .graph-stage {
    min-height:100px
  }
}

@media(max-width:920px) and (min-width:741px) {
  .modes :is(button,a) {
    padding:0 10px;
    font-size:11px
  }
  .modes :is(button,a) span {
    display:none
  }
  .brand small {
    font-size:7px
  }
  .math-button {
    font-size:10px
  }
  .topbar {
    gap:10px
  }
}

@media(max-width:450px) {
  .modes {
    gap:0
  }
  .modes :is(button,a) {
    font-size:11px;
    padding:0 7px
  }
  .modes :is(button,a) span {
    display:none
  }
}

@media(prefers-reduced-motion:reduce) {
  *,*:before,*:after {
    scroll-behavior:auto!important;
    transition:none!important
  }
}