:root {
  --bg: #000;
  --panel-bg: rgba(6, 6, 8, 0.82);
  --panel-border: rgba(255, 255, 255, 0.08);
  --text: #e8e6e3;
  --text-dim: rgba(255, 255, 255, 0.4);
  --r: 3px;
  --font-display: "Instrument Serif", serif;
  --font-mono: "DM Mono", monospace;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  font-family: var(--font-mono);
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ---- Canvas ---- */

#board {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  display: block;
  background: #000;
}

#grid-lines line {
  stroke: #fff;
  stroke-width: 0.5;
  stroke-opacity: 0;
}

#trail-layer line {
  pointer-events: none;
  stroke-linecap: round;
}

#hit-layer rect {
  fill: transparent;
  cursor: crosshair;
}

#hit-layer rect:hover {
  fill: rgba(255, 255, 255, 0.03);
}

.vector-mark {
  transform-box: fill-box;
  transform-origin: center center;
}

body.grid-hidden #grid-lines {
  display: none;
}

/* ---- Drop overlay ---- */

.drop-overlay {
  position: fixed;
  inset: 0;
  z-index: 50;
  display: none;
  place-items: center;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
}

body.drop-active .drop-overlay {
  display: grid;
}

.drop-overlay-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.2rem;
  padding: 3rem 5rem;
  border: 1px dashed rgba(255, 255, 255, 0.25);
  border-radius: 10px;
  animation: drop-pulse 1.8s ease-in-out infinite;
}

@keyframes drop-pulse {
  0%,
  100% {
    border-color: rgba(255, 255, 255, 0.15);
  }
  50% {
    border-color: rgba(255, 255, 255, 0.4);
  }
}

.drop-overlay-icon {
  font-family: var(--font-display);
  font-size: 3.2rem;
  color: var(--text);
  line-height: 1;
}

.drop-overlay-text {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.18em;
}

/* ---- UI toggle ---- */

.ui-toggle {
  position: fixed;
  top: 1rem;
  right: 1rem;
  z-index: 30;
  border: 1px solid var(--panel-border);
  background: var(--panel-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  color: var(--text-dim);
  padding: 0.4rem 0.65rem;
  border-radius: var(--r);
  font-family: var(--font-mono);
  font-size: 0.65rem;
  line-height: 1;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  transition: color 0.2s, border-color 0.2s;
}

.ui-toggle:hover {
  color: var(--text);
  border-color: rgba(255, 255, 255, 0.22);
}

/* ---- Panel ---- */

.ui-panel {
  position: fixed;
  top: 1rem;
  left: 1rem;
  z-index: 25;
  width: min(92vw, 320px);
  display: grid;
  gap: 0;
  background: var(--panel-bg);
  backdrop-filter: blur(24px) saturate(1.2);
  -webkit-backdrop-filter: blur(24px) saturate(1.2);
  border: 1px solid var(--panel-border);
  border-radius: 6px;
  padding: 0;
  overflow: hidden;
  transition: transform 200ms ease, opacity 160ms ease;
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.55),
    0 0 0 0.5px rgba(255, 255, 255, 0.04) inset;
}

body.ui-hidden .ui-panel {
  transform: translateX(calc(-100% - 2rem));
  opacity: 0;
  pointer-events: none;
}

body.ui-hidden .ui-toggle {
  opacity: 0;
  pointer-events: none;
  transition: opacity 160ms ease;
}

/* ---- Panel header ---- */

.panel-header {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  padding: 0.75rem 0.9rem 0.55rem;
}

.panel-header h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 400;
  letter-spacing: 0.02em;
  color: #fff;
  line-height: 1;
}

.panel-header h1 a,
.panel-header h1 a:visited,
.panel-header h1 a:hover,
.panel-header h1 a:active {
  color: inherit;
  text-decoration: none;
}

.panel-header h1 a:hover {
  opacity: 0.7;
  transition: opacity 0.15s ease;
}

/* ---- Divider ---- */

.panel-divider {
  height: 1px;
  background: var(--panel-border);
}

/* ---- Controls ---- */

.control-row {
  display: grid;
  gap: 0.45rem;
  padding: 0.55rem 0.9rem;
}

.section-label {
  font-family: var(--font-mono);
  font-size: 0.55rem;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.22em;
  font-weight: 500;
}

/* ---- Buttons ---- */

.button-group {
  display: flex;
  flex-wrap: wrap;
  gap: 0.28rem;
}

button {
  appearance: none;
  border: 1px solid rgba(255, 255, 255, 0.1);
  background: rgba(255, 255, 255, 0.035);
  color: var(--text-dim);
  border-radius: var(--r);
  padding: 0.32rem 0.55rem;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  line-height: 1;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  transition: all 0.12s ease;
}

button:hover {
  background: rgba(255, 255, 255, 0.07);
  color: var(--text);
  border-color: rgba(255, 255, 255, 0.18);
}

button:active {
  transform: scale(0.97);
}

button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

button:disabled:hover {
  background: rgba(255, 255, 255, 0.035);
  color: var(--text-dim);
  border-color: rgba(255, 255, 255, 0.1);
}

button.is-active,
.toggle-btn.is-active,
.driver-btn.is-active {
  background: #fff;
  color: #000;
  border-color: #fff;
  font-weight: 500;
}

button.is-active:hover,
.toggle-btn.is-active:hover,
.driver-btn.is-active:hover {
  background: rgba(255, 255, 255, 0.88);
  border-color: rgba(255, 255, 255, 0.88);
  color: #000;
}

/* ---- Range sliders ---- */

.range-control {
  display: grid;
  gap: 0.25rem;
  color: var(--text-dim);
  font-size: 0.6rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.range-control.is-hidden {
  display: none;
}

.range-control.is-disabled {
  opacity: 0.45;
}

.range-control input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 2px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 1px;
  outline: none;
  cursor: pointer;
}

.range-control input[type="range"]:disabled {
  cursor: not-allowed;
}

.range-control input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #fff;
  border: none;
  cursor: pointer;
  box-shadow: 0 0 6px rgba(255, 255, 255, 0.2);
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.range-control input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.35);
  box-shadow: 0 0 10px rgba(255, 255, 255, 0.35);
}

.range-control input[type="range"]::-moz-range-thumb {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: #fff;
  border: none;
  cursor: pointer;
  box-shadow: 0 0 6px rgba(255, 255, 255, 0.2);
}

.range-control input[type="range"]::-moz-range-track {
  height: 2px;
  background: rgba(255, 255, 255, 0.1);
  border: none;
  border-radius: 1px;
}

/* ---- Driver ---- */

.driver-buttons {
  gap: 0.28rem;
}

.driver-status {
  margin: 0;
  font-size: 0.55rem;
  font-family: var(--font-mono);
  color: var(--text-dim);
  letter-spacing: 0.05em;
  line-height: 1.5;
}

.panel-note {
  margin: 0;
  padding: 0.55rem 0.9rem 0.7rem;
  font-size: 0.52rem;
  font-family: var(--font-mono);
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 0.14em;
}

/* ---- Camera preview ---- */

#camera-preview {
  width: min(260px, 100%);
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--panel-border);
  border-radius: var(--r);
  display: none;
  transform: none;
  filter: brightness(1.12) contrast(1.26);
  margin-top: 0.3rem;
}

body.camera-on #camera-preview {
  display: block;
}

body.camera-mirrored #camera-preview {
  transform: scaleX(-1);
}

/* ---- Image preview ---- */

#image-preview {
  width: min(260px, 100%);
  aspect-ratio: 16 / 9;
  object-fit: cover;
  border: 1px solid var(--panel-border);
  border-radius: var(--r);
  display: none;
  margin-top: 0.3rem;
}

body.image-on #image-preview {
  display: block;
}

/* ---- Mobile ---- */

@media (max-width: 760px) {
  .ui-panel {
    width: min(96vw, 300px);
  }

  .driver-buttons {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
  }

  .drop-overlay-inner {
    padding: 2rem 3rem;
  }
}