:root {
  --bg-a: #0d1116;
  --bg-b: #1c232e;
  --panel: rgba(10, 14, 20, 0.78);
  --panel-border: rgba(255, 255, 255, 0.14);
  --text: #ecf2ff;
  --accent: #ffaf45;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  color: var(--text);
  background:
    radial-gradient(100vmax 60vmax at 90% -10%, #2f3a47 0%, transparent 55%),
    radial-gradient(100vmax 70vmax at -10% 110%, #2d2a36 0%, transparent 60%),
    linear-gradient(140deg, var(--bg-a), var(--bg-b));
  font-family: "Trebuchet MS", "Verdana", "Segoe UI", sans-serif;
}

#simCanvas {
  display: block;
  width: 100%;
  height: 100%;
  image-rendering: auto;
  cursor: crosshair;
}

#lightIndicator {
  position: fixed;
  left: 0;
  top: 0;
  width: 24px;
  height: 24px;
  border: 1px solid rgba(255, 249, 193, 0.95);
  border-radius: 999px;
  background: radial-gradient(circle at 50% 50%, rgba(255, 252, 210, 0.95) 0%, rgba(255, 234, 153, 0.16) 70%, rgba(255, 219, 107, 0.0) 100%);
  box-shadow: 0 0 14px rgba(255, 232, 131, 0.6);
  pointer-events: none;
  z-index: 9;
  display: none;
  transform-origin: 50% 50%;
}

#lightIndicator::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 50%;
  width: 2px;
  height: 14px;
  transform: translate(-50%, -100%);
  border-radius: 99px;
  background: linear-gradient(to top, rgba(255, 253, 229, 0.2), rgba(255, 253, 229, 0.95));
}

#lightIndicator .head {
  position: absolute;
  left: 50%;
  top: 3px;
  width: 0;
  height: 0;
  transform: translateX(-50%);
  border-left: 5px solid transparent;
  border-right: 5px solid transparent;
  border-bottom: 7px solid rgba(255, 252, 210, 0.95);
}

.hud {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 10;
  width: min(520px, calc(100vw - 24px));
}

.title {
  font-weight: 700;
  letter-spacing: 0.4px;
  margin-bottom: 8px;
}

.panel {
  border: 1px solid rgba(255, 255, 255, 0.16);
  border-radius: 10px;
  background: rgba(0, 0, 0, 0.24);
  overflow: hidden;
  backdrop-filter: blur(8px);
}

.panel summary {
  cursor: pointer;
  padding: 8px 10px;
  font-weight: 700;
  font-size: 0.86rem;
  list-style: none;
}

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

.panel summary::after {
  content: "v";
  float: right;
  opacity: 0.75;
  transform: scale(0.9);
}

.panel:not([open]) summary::after {
  content: ">";
}

.panel .panel-body {
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  padding: 8px 10px 10px;
}

.controls-panel {
  border-color: var(--panel-border);
  background: var(--panel);
}

.elements-panel {
  position: fixed;
  left: 12px;
  right: auto;
  bottom: 12px;
  width: min(360px, calc(100vw - 24px));
  z-index: 12;
  border-color: var(--panel-border);
  background: var(--panel);
}

.elements-body {
  max-height: min(56vh, 520px);
  overflow: auto;
  display: grid;
  gap: 10px;
}

.tool-group h4 {
  margin: 0 0 6px;
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  opacity: 0.85;
}

.tools {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.elements-panel .tools {
  flex-wrap: wrap;
  overflow: visible;
  padding-bottom: 0;
}

.elements-panel .tool {
  flex: 0 0 auto;
  white-space: nowrap;
}

.chat-panel {
  position: fixed;
  right: 12px;
  top: 12px;
  z-index: 11;
  width: min(360px, calc(100vw - 24px));
  border-color: var(--panel-border);
  background: var(--panel);
}

.guide-panel {
  position: fixed;
  right: 12px;
  top: 242px;
  z-index: 11;
  width: min(400px, calc(100vw - 24px));
  border-color: var(--panel-border);
  background: var(--panel);
}

.tool,
#pauseBtn,
#clearBtn,
#hostRoomBtn,
#joinRoomBtn,
#leaveRoomBtn,
#chatSendBtn {
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.07);
  color: var(--text);
  border-radius: 10px;
  padding: 6px 10px;
  font-size: 0.92rem;
  cursor: pointer;
  transition: background 120ms ease, transform 120ms ease, border-color 120ms ease;
}

.tool:hover,
#pauseBtn:hover,
#clearBtn:hover,
#hostRoomBtn:hover,
#joinRoomBtn:hover,
#leaveRoomBtn:hover,
#chatSendBtn:hover {
  background: rgba(255, 255, 255, 0.16);
}

.tool:active,
#pauseBtn:active,
#clearBtn:active,
#hostRoomBtn:active,
#joinRoomBtn:active,
#leaveRoomBtn:active,
#chatSendBtn:active {
  transform: translateY(1px);
}

.tool.active {
  background: color-mix(in oklab, var(--accent) 35%, rgba(255, 255, 255, 0.1));
  border-color: color-mix(in oklab, var(--accent) 65%, white);
}

.controls {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

.controls label {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.net-controls {
  display: flex;
  gap: 8px;
  align-items: center;
  flex-wrap: wrap;
}

.net-controls label {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

#roomIdInput,
#playerNameInput {
  width: 92px;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.07);
  color: var(--text);
  border-radius: 8px;
  padding: 4px 6px;
  font-size: 0.82rem;
}

#netStatus {
  padding: 4px 8px;
  border-radius: 999px;
  font-size: 0.78rem;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.06);
}

#netPlayers {
  padding: 4px 8px;
  border-radius: 999px;
  font-size: 0.78rem;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.06);
}

.chat-messages {
  height: 132px;
  overflow: auto;
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: 8px;
  background: rgba(0, 0, 0, 0.2);
  padding: 6px;
  font-size: 0.76rem;
  line-height: 1.3;
}

.chat-line {
  margin: 0 0 4px;
  white-space: pre-wrap;
  word-break: break-word;
}

.chat-line:last-child {
  margin-bottom: 0;
}

.chat-line .name {
  opacity: 0.95;
  font-weight: 700;
}

.chat-line.system {
  opacity: 0.8;
  font-style: italic;
}

.chat-input-row {
  display: flex;
  gap: 6px;
}

#chatInput {
  flex: 1;
  min-width: 0;
  border: 1px solid rgba(255, 255, 255, 0.2);
  background: rgba(255, 255, 255, 0.07);
  color: var(--text);
  border-radius: 8px;
  padding: 6px 8px;
  font-size: 0.8rem;
}

#roomWatermark {
  position: fixed;
  left: 50%;
  top: 52%;
  transform: translate(-50%, -50%) rotate(-15deg);
  z-index: 1;
  pointer-events: none;
  user-select: none;
  font-size: min(16vw, 140px);
  font-weight: 700;
  letter-spacing: 0.12em;
  opacity: 0;
  color: rgba(255, 255, 255, 0.08);
  text-transform: uppercase;
  text-shadow: 0 1px 0 rgba(255, 255, 255, 0.04), 0 0 28px rgba(255, 255, 255, 0.05);
  transition: opacity 150ms ease;
}

#roomWatermark.visible {
  opacity: 1;
}

#brushSize {
  width: 120px;
}

#lightIntensity {
  width: 120px;
}

#lightIntensityValue {
  display: inline-block;
  min-width: 3.4em;
  text-align: right;
  font-variant-numeric: tabular-nums;
  opacity: 0.9;
}

.help {
  font-size: 0.82rem;
  opacity: 0.85;
}

.guide-content {
  font-size: 0.8rem;
  line-height: 1.35;
  max-height: min(40vh, 340px);
  overflow: auto;
}

.guide-content p {
  margin: 0 0 6px;
}

.guide-content ul {
  margin: 0 0 8px 16px;
  padding: 0;
}

.guide-content li {
  margin: 0 0 4px;
}

@media (max-width: 640px) {
  .hud {
    width: calc(100vw - 16px);
    top: 8px;
    left: 8px;
  }

  .elements-panel {
    left: 8px;
    right: 8px;
    bottom: 8px;
  }

  .elements-body {
    max-height: min(45vh, 300px);
  }

  .chat-panel {
    left: 8px;
    right: 8px;
    top: auto;
    bottom: 172px;
    width: auto;
  }

  .guide-panel {
    left: 8px;
    right: 8px;
    top: auto;
    bottom: 332px;
    width: auto;
  }

  .panel summary {
    font-size: 0.8rem;
  }

  .panel .panel-body {
    padding: 7px 8px 8px;
  }

  .tool,
  #pauseBtn,
  #clearBtn,
  #hostRoomBtn,
  #joinRoomBtn,
  #leaveRoomBtn,
  #chatSendBtn {
    font-size: 0.85rem;
    padding: 5px 8px;
  }

  #roomIdInput,
  #playerNameInput {
    width: 84px;
  }

  .chat-messages {
    height: 96px;
  }
}