:root {
  color-scheme: dark;
  --bg: #080a0d;
  --surface: #101419;
  --surface-hi: #171d24;
  --rule: #27313a;
  --text: #eef3f6;
  --muted: #8b9aa5;
  --ghost: #50606b;
  --accent: #75e1ca;
  --warm: #ffbd73;
  --mono: ui-monospace, "JetBrains Mono", "SF Mono", "Cascadia Code", Consolas, monospace;
  --ease: cubic-bezier(.2,.85,.2,1);
}

* { box-sizing: border-box; }

html,
body,
* {
  scrollbar-width: none;
}
html::-webkit-scrollbar,
body::-webkit-scrollbar,
*::-webkit-scrollbar {
  width: 0;
  height: 0;
  display: none;
}

html, body {
  min-width: 320px;
  min-height: 100%;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--mono);
  -webkit-font-smoothing: antialiased;
}

body {
  background-image:
    linear-gradient(rgba(255,255,255,.014) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255,255,255,.01) 1px, transparent 1px);
  background-size: 5px 5px;
}

button, input { font: inherit; }
button { color: inherit; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.skip-link {
  position: fixed;
  z-index: 10;
  top: 1rem;
  left: 1rem;
  transform: translateY(-150%);
  border: 1px solid var(--accent);
  border-radius: 999px;
  padding: .55rem .75rem;
  background: var(--surface);
  color: var(--text);
  text-decoration: none;
}
.skip-link:focus { transform: none; }

.gravity-shell {
  width: min(1320px, calc(100% - 2rem));
  min-height: 100dvh;
  margin: 0 auto;
  padding: clamp(1.25rem, 3vw, 2.75rem) 0 1.25rem;
}

.gravity-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 2rem;
  padding: 0 .25rem clamp(1.25rem, 3vw, 2rem);
  border-bottom: 1px solid var(--rule);
}

.eyebrow,
.stage-meta,
.stage-note,
.control-help,
.control-value,
.section-label,
.gravity-footer,
.sim-status,
.range-label,
.velocity-label {
  font-size: .68rem;
  letter-spacing: .1em;
  text-transform: uppercase;
}

.eyebrow { margin: 0 0 .8rem; color: var(--accent); }

h1, h2, p { margin: 0; }
h1 {
  max-width: 11ch;
  font-size: clamp(2.25rem, 6vw, 5.6rem);
  font-weight: 500;
  letter-spacing: -.08em;
  line-height: .86;
}

.intro {
  max-width: 42rem;
  margin-top: 1rem;
  color: var(--muted);
  font-size: clamp(.85rem, 1.5vw, 1rem);
  line-height: 1.55;
}

.sim-status {
  display: inline-flex;
  align-items: center;
  gap: .55rem;
  padding-top: .2rem;
  color: var(--muted);
  white-space: nowrap;
}

.status-dot {
  width: .5rem;
  height: .5rem;
  border-radius: 50%;
  background: var(--ghost);
}
.status-dot.is-running { background: var(--accent); box-shadow: 0 0 14px rgba(117,225,202,.55); }
.status-dot.is-paused { background: var(--warm); }

.gravity-workspace {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(18rem, 22rem);
  min-height: min(70dvh, 760px);
  border-bottom: 1px solid var(--rule);
}

.gravity-stage-wrap { min-width: 0; padding: 1rem 1rem 1rem 0; }
.stage-meta,
.stage-note {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  color: var(--muted);
}
.stage-meta { padding: 0 .2rem .7rem; }
.stage-meta span:last-child { color: var(--accent); text-align: right; }

.gravity-stage {
  position: relative;
  min-height: 540px;
  height: calc(100% - 2.8rem);
  overflow: hidden;
  border: 1px solid var(--rule);
  border-radius: 14px;
  background:
    radial-gradient(circle at 50% 48%, rgba(117,225,202,.08), transparent 23rem),
    radial-gradient(circle at 68% 22%, rgba(255,189,115,.06), transparent 18rem),
    #0b1015;
  box-shadow: 0 22px 70px rgba(0,0,0,.22), inset 0 1px 0 rgba(255,255,255,.035);
}

#gravity-canvas { display: block; width: 100%; height: 100%; min-height: 540px; cursor: crosshair; touch-action: none; }
.gravity-stage:has(#gravity-canvas:active) #gravity-canvas { cursor: grabbing; }

.stage-readout {
  position: absolute;
  right: 1rem;
  bottom: 1rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(5rem, auto));
  gap: .55rem 1rem;
  padding: .75rem .85rem;
  border: 1px solid rgba(151,182,196,.2);
  border-radius: 9px;
  background: rgba(8,10,13,.72);
  backdrop-filter: blur(10px);
  pointer-events: none;
}
.stage-readout div { display: grid; gap: .2rem; }
.stage-readout span { color: var(--muted); font-size: .62rem; letter-spacing: .08em; text-transform: uppercase; }
.stage-readout strong { font-size: .82rem; font-weight: 500; }
.stage-note { padding: .7rem .2rem 0; letter-spacing: .02em; text-transform: none; }

.gravity-controls {
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
  padding: 1.15rem 0 1.15rem 1.25rem;
  border-left: 1px solid var(--rule);
}

.control-heading,
.inspector-heading,
.range-label,
.velocity-label { display: flex; align-items: baseline; justify-content: space-between; gap: 1rem; }
.control-heading { align-items: flex-start; }
.control-heading h2 { font-size: 1rem; font-weight: 500; }
.transport-controls { display: flex; align-items: center; gap: .45rem; }
.icon-button,
.text-button,
.remove-button {
  border: 1px solid var(--rule);
  border-radius: 6px;
  background: var(--surface);
  cursor: pointer;
}
.icon-button { width: 2.25rem; height: 2.25rem; color: var(--accent); }
.text-button, .remove-button { padding: .48rem .6rem; color: var(--muted); font-size: .67rem; letter-spacing: .08em; text-transform: uppercase; }
.icon-button:hover, .text-button:hover, .remove-button:hover { border-color: var(--accent); color: var(--text); }

.control-group {
  display: grid;
  gap: .62rem;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
}
.range-label { color: var(--muted); }
.range-label output { color: var(--text); font-size: .72rem; }
.control-help { margin-top: -.15rem; color: var(--ghost); letter-spacing: .02em; text-transform: none; }
.control-value { color: var(--ghost); letter-spacing: .02em; text-transform: none; }

input[type="range"] {
  width: 100%;
  height: 1.1rem;
  margin: 0;
  accent-color: var(--accent);
  cursor: ew-resize;
}

.body-presets { display: grid; grid-template-columns: repeat(2, 1fr); gap: .45rem; }
.preset-button {
  display: inline-flex;
  align-items: center;
  gap: .5rem;
  min-height: 2.5rem;
  border: 1px solid var(--rule);
  border-radius: 7px;
  padding: .5rem .6rem;
  background: transparent;
  color: var(--muted);
  font-size: .7rem;
  cursor: pointer;
  text-align: left;
}
.preset-button:hover, .preset-button.is-active { border-color: var(--accent); background: rgba(117,225,202,.08); color: var(--text); }
.preset-dot { width: .55rem; height: .55rem; border-radius: 50%; }
.planet-dot { background: #4db8ff; }
.moon-dot { background: #b6c4d0; }
.star-dot { background: #ffbd73; }
.asteroid-dot { background: #d7795f; }

.inspector { gap: .65rem; }
.inspector-heading { align-items: center; }
.inspector-heading > div { display: grid; gap: .25rem; }
.section-label { color: var(--muted); }
.inspector-heading strong { font-size: .9rem; font-weight: 500; }
.velocity-label { margin-top: .1rem; color: var(--muted); }
.velocity-grid { display: grid; grid-template-columns: 1fr 1fr; gap: .7rem; }
.velocity-grid label { display: flex; align-items: center; gap: .5rem; color: var(--ghost); font-size: .68rem; }

.control-footnote {
  display: flex;
  align-items: flex-start;
  gap: .65rem;
  margin-top: auto;
  padding-top: 1rem;
  border-top: 1px solid var(--rule);
  color: var(--ghost);
  font-size: .68rem;
  line-height: 1.5;
}
.footnote-mark {
  display: grid;
  flex: none;
  width: 1rem;
  height: 1rem;
  place-items: center;
  border: 1px solid var(--ghost);
  border-radius: 50%;
  color: var(--muted);
  font-size: .62rem;
}

.gravity-footer {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem .25rem 0;
  color: var(--ghost);
}
.gravity-footer a { color: var(--muted); text-decoration: none; }
.gravity-footer a:hover { color: var(--accent); }

@media (max-width: 820px) {
  .gravity-header { flex-direction: column; gap: 1.2rem; }
  .sim-status { padding-top: 0; }
  .gravity-workspace { display: block; }
  .gravity-stage-wrap { padding-right: 0; }
  .gravity-stage { min-height: 460px; }
  #gravity-canvas { min-height: 460px; }
  .gravity-controls { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem; padding: 1.25rem 0 0; border-top: 1px solid var(--rule); border-left: 0; }
  .control-heading, .control-footnote { grid-column: 1 / -1; }
  .control-footnote { margin-top: 0; }
}

@media (max-width: 560px) {
  .gravity-shell { width: min(100% - 1rem, 1320px); padding-top: 1rem; }
  .gravity-header { padding-inline: .1rem; }
  h1 { font-size: clamp(2.25rem, 15vw, 4rem); }
  .gravity-stage { min-height: 390px; }
  #gravity-canvas { min-height: 390px; }
  .stage-readout { right: .6rem; bottom: .6rem; gap: .45rem .7rem; padding: .6rem .7rem; }
  .gravity-controls { display: flex; }
  .gravity-footer { flex-direction: column; gap: .6rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: .001ms !important; }
}