/* Gravity3D — cinematic dark-space HUD.
   System font stack only; no web fonts, no external assets. */

:root {
  --bg-0: #05060d;
  --bg-1: #090b16;
  --ink: #e8ecf8;
  --ink-mute: #8b93ad;
  --accent: #54e0ff;
  --accent-soft: rgba(84, 224, 255, 0.16);
  --hair: rgba(255, 255, 255, 0.08);
  --panel: rgba(12, 15, 26, 0.62);
  --panel-solid: rgba(14, 17, 30, 0.92);
  --good: #7cf5c6;
  --sans: ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --r: 14px;
  --shadow: 0 18px 50px -18px rgba(0, 0, 0, 0.85), 0 2px 0 rgba(255, 255, 255, 0.03) inset;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: radial-gradient(140% 120% at 50% 18%, #0a0d1c 0%, var(--bg-1) 42%, var(--bg-0) 100%);
  color: var(--ink);
  font-family: var(--sans);
  overflow: hidden;
  overscroll-behavior: none;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

#stage,
.aim {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
}

#stage { touch-action: none; cursor: grab; z-index: 0; }
#stage.is-dragging { cursor: grabbing; }
#stage.is-aiming { cursor: crosshair; }

.aim { pointer-events: none; z-index: 1; }

/* ---------- Fallback ---------- */
.fallback {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: grid;
  place-items: center;
  padding: 24px;
  background: radial-gradient(120% 120% at 50% 30%, #0b0e1d, var(--bg-0));
}
.fallback[hidden] { display: none; }
.fallback__card {
  max-width: 420px;
  padding: 28px 30px;
  border: 1px solid var(--hair);
  border-radius: var(--r);
  background: var(--panel-solid);
  box-shadow: var(--shadow);
}
.fallback__card h1 { margin: 0 0 10px; font-size: 18px; }
.fallback__card p { margin: 0; color: var(--ink-mute); line-height: 1.55; font-size: 14px; }

/* ---------- HUD ---------- */
.hud {
  position: fixed;
  top: 18px;
  left: 18px;
  z-index: 10;
  width: 304px;
  max-width: calc(100vw - 36px);
  border: 1px solid var(--hair);
  border-radius: var(--r);
  background: var(--panel);
  backdrop-filter: blur(18px) saturate(125%);
  -webkit-backdrop-filter: blur(18px) saturate(125%);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.hud__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 13px 14px 12px;
  border-bottom: 1px solid var(--hair);
}
.hud__brand { display: flex; align-items: center; gap: 9px; }
.hud__dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #fff, #ffce6b 38%, #ff9d3d 72%, #7a3d00);
  box-shadow: 0 0 12px 2px rgba(255, 183, 77, 0.65);
}
.hud__title { margin: 0; font-size: 15px; font-weight: 650; letter-spacing: 0.2px; }

.hud__body { padding: 13px 14px 15px; display: grid; gap: 13px; }
.hud.is-collapsed .hud__body { display: none; }
.hud.is-collapsed { width: auto; }

.hud__lede { margin: 0; font-size: 12.5px; line-height: 1.5; color: var(--ink-mute); }
.hud__lede strong { color: var(--ink); font-weight: 600; }

/* ---------- Buttons ---------- */
.btnrow { display: grid; grid-template-columns: repeat(4, 1fr); gap: 7px; }
.btn {
  appearance: none;
  display: flex; flex-direction: column; align-items: center; gap: 3px;
  padding: 9px 4px 7px;
  border: 1px solid var(--hair);
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.035);
  color: var(--ink);
  font-family: inherit;
  cursor: pointer;
  transition: background .16s ease, border-color .16s ease, transform .08s ease, box-shadow .16s ease;
}
.btn__ico { font-size: 15px; line-height: 1; }
.btn__lbl { font-size: 10.5px; color: var(--ink-mute); letter-spacing: .2px; }
.btn:hover { background: var(--accent-soft); border-color: rgba(84, 224, 255, 0.4); box-shadow: 0 0 0 1px rgba(84,224,255,.12), 0 6px 18px -10px rgba(84,224,255,.6); }
.btn:hover .btn__lbl { color: var(--ink); }
.btn:active { transform: translateY(1px); }
.btn[aria-pressed="true"] { background: var(--accent-soft); border-color: rgba(84, 224, 255, 0.5); }
.btn--ghost { opacity: .82; }
.btn:focus-visible,
.iconbtn:focus-visible,
.link:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.iconbtn {
  appearance: none; width: 28px; height: 28px;
  display: grid; place-items: center;
  border: 1px solid var(--hair); border-radius: 8px;
  background: rgba(255, 255, 255, 0.03); color: var(--ink-mute);
  cursor: pointer; transition: background .16s, color .16s;
}
.iconbtn:hover { background: var(--accent-soft); color: var(--ink); }
.iconbtn__glyph { font-size: 16px; line-height: 1; transform: translateY(-1px); }

/* ---------- Sliders ---------- */
.ctrl { display: grid; gap: 7px; }
.ctrl__label {
  display: flex; align-items: baseline; justify-content: space-between;
  font-size: 12px; color: var(--ink-mute); letter-spacing: .2px;
}
.ctrl__val { font-family: var(--mono); font-size: 12px; color: var(--accent); }

.slider {
  appearance: none; -webkit-appearance: none;
  width: 100%; height: 4px; margin: 4px 0;
  border-radius: 999px;
  background: linear-gradient(90deg, rgba(84,224,255,.7), rgba(84,224,255,.18));
  outline: none; cursor: pointer;
}
.slider::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 15px; height: 15px; border-radius: 50%;
  background: radial-gradient(circle at 35% 30%, #fff, var(--accent) 60%, #1f7fa0);
  border: none; box-shadow: 0 0 10px 1px rgba(84, 224, 255, 0.7);
  cursor: pointer; transition: transform .1s ease;
}
.slider::-webkit-slider-thumb:hover { transform: scale(1.12); }
.slider::-moz-range-thumb {
  width: 15px; height: 15px; border-radius: 50%; border: none;
  background: radial-gradient(circle at 35% 30%, #fff, var(--accent) 60%, #1f7fa0);
  box-shadow: 0 0 10px 1px rgba(84, 224, 255, 0.7); cursor: pointer;
}
.slider::-moz-range-track { height: 4px; border-radius: 999px; background: rgba(84,224,255,.22); }

/* ---------- Toggles ---------- */
.toggles { display: flex; gap: 16px; }
.chk { display: inline-flex; align-items: center; gap: 8px; cursor: pointer; font-size: 12.5px; color: var(--ink-mute); }
.chk input { position: absolute; opacity: 0; width: 0; height: 0; }
.chk__box {
  width: 34px; height: 18px; border-radius: 999px;
  background: rgba(255, 255, 255, 0.1); border: 1px solid var(--hair);
  position: relative; transition: background .16s ease, border-color .16s ease; flex: 0 0 auto;
}
.chk__box::after {
  content: ""; position: absolute; top: 1px; left: 1px;
  width: 14px; height: 14px; border-radius: 50%;
  background: #cfd6e8; transition: transform .16s ease, background .16s ease;
}
.chk input:checked + .chk__box { background: var(--accent-soft); border-color: rgba(84,224,255,.5); }
.chk input:checked + .chk__box::after { transform: translateX(16px); background: var(--accent); box-shadow: 0 0 8px rgba(84,224,255,.8); }
.chk input:focus-visible + .chk__box { outline: 2px solid var(--accent); outline-offset: 2px; }
.chk:hover .chk__lbl { color: var(--ink); }

/* ---------- Stats ---------- */
.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 7px; }
.stat {
  display: grid; gap: 2px; padding: 8px 9px;
  border: 1px solid var(--hair); border-radius: 9px;
  background: rgba(255, 255, 255, 0.025);
}
.stat__k { font-size: 10px; text-transform: uppercase; letter-spacing: .6px; color: var(--ink-mute); }
.stat__v { font-family: var(--mono); font-size: 15px; color: var(--ink); }

/* ---------- Help ---------- */
.link {
  appearance: none; background: none; border: none; padding: 0;
  color: var(--accent); font-family: inherit; font-size: 12px; cursor: pointer;
  text-align: left; justify-self: start; opacity: .9;
}
.link:hover { text-decoration: underline; }
.help { list-style: none; margin: 0; padding: 4px 0 0; display: grid; gap: 5px; }
.help li { font-size: 11.5px; color: var(--ink-mute); display: flex; align-items: center; gap: 8px; }
.help kbd {
  font-family: var(--mono); font-size: 10.5px; color: var(--ink);
  background: rgba(255, 255, 255, 0.06); border: 1px solid var(--hair);
  border-radius: 5px; padding: 1px 6px; min-width: 14px; text-align: center;
}

/* ---------- Footer ---------- */
.footer {
  position: fixed; right: 16px; bottom: 14px; z-index: 10;
  font-size: 11.5px; color: var(--ink-mute); text-decoration: none;
  padding: 6px 11px; border: 1px solid var(--hair); border-radius: 999px;
  background: var(--panel); backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  transition: color .16s ease, border-color .16s ease;
}
.footer:hover { color: var(--ink); border-color: rgba(84, 224, 255, 0.4); }

/* ---------- Responsive ---------- */
@media (max-width: 560px) {
  .hud { top: 12px; left: 12px; right: 12px; width: auto; }
  .footer { left: 12px; right: 12px; text-align: center; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition-duration: .001ms !important; }
}