* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

#canvas-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
}

#controls {
  position: fixed;
  top: 0;
  left: 0;
  bottom: 0;
  z-index: 10000;
  display: flex;
  flex-direction: column;
  background: rgba(0, 0, 0, 0.45);
  color: #fff;
  font-size: 13px;
  width: 310px;
}

.controls-header {
  flex-shrink: 0;
  padding: 14px 18px 10px;
}

.controls-body {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 0 18px 18px;
}

/* ── MODE SWITCHER ─────────────────────────────────────────── */
.mode-switcher {
  display: flex;
  gap: 0;
  border: 1px solid rgba(255, 255, 255, 0.3);
  border-radius: 5px;
  overflow: hidden;
  margin-bottom: 2px;
}

.mode-btn {
  flex: 1;
  background: transparent;
  color: rgba(255, 255, 255, 0.55);
  border: none;
  border-radius: 0;
  padding: 7px 0;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 0.04em;
  transition: background 0.15s, color 0.15s;
}

.mode-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

.mode-btn.active {
  background: rgba(255, 255, 255, 0.18);
  color: #fff;
}

/* ── LINE / MESH CONTROL BLOCKS ────────────────────────────── */
#lineControls,
#meshControls {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

/* ── SECTION HEADERS ───────────────────────────────────────── */
.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.7em;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  opacity: 0.55;
  margin-top: 4px;
  padding: 6px 0 4px;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
  cursor: pointer;
  user-select: none;
  transition: opacity 0.15s;
}

.section-header:hover {
  opacity: 0.9;
}

.section-header .chevron {
  font-size: 0.85em;
  opacity: 0.7;
}

/* ── SECTION BODIES ────────────────────────────────────────── */
.section-body {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

/* ── LFO ROWS ──────────────────────────────────────────────── */
.lfo-row {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding-left: 8px;
}

.lfo-params {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
  font-size: 0.85em;
  opacity: 0.8;
}

/* ── LFO ACTIVE INDICATOR ──────────────────────────────────── */
@keyframes lfo-pulse {
  0%, 100% { opacity: 1; }
  50%       { opacity: 0.3; }
}

.lfo-active::after {
  content: '';
  display: inline-block;
  width: 5px;
  height: 5px;
  background: #7cf;
  border-radius: 50%;
  margin-left: 6px;
  vertical-align: middle;
  animation: lfo-pulse 1.2s ease-in-out infinite;
}

/* ── PRESETS ROW ───────────────────────────────────────────── */
.presets-row {
  flex-wrap: wrap;
  gap: 5px;
}

.preset-btn {
  background: rgba(255, 255, 255, 0.08);
  color: rgba(255, 255, 255, 0.75);
  border: 1px solid rgba(255, 255, 255, 0.2);
  padding: 3px 8px;
  border-radius: 3px;
  cursor: pointer;
  font-size: 12px;
}

.preset-btn:hover {
  background: rgba(255, 255, 255, 0.18);
  color: #fff;
}

#randomizeBtn {
  margin-left: auto;
}

/* ── SLIDERS ───────────────────────────────────────────────── */
input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  border-radius: 2px;
  background: rgba(255, 255, 255, 0.25);
  cursor: pointer;
}

#controls input[type="range"] {
  width: 100%;
}

#controls .lfo-params input[type="range"] {
  width: 90px;
  flex-shrink: 0;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: #fff;
  cursor: pointer;
}

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: #fff;
  border: none;
  cursor: pointer;
}

/* ── TYPOGRAPHY ────────────────────────────────────────────── */
.big-four-label {
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
}

/* ── BIG FOUR SLIDERS ──────────────────────────────────────── */
.big-four-slider {
  height: 7px !important;
  background: rgba(255, 255, 255, 0.35) !important;
  border-radius: 4px !important;
}

.big-four-slider::-webkit-slider-thumb {
  width: 18px !important;
  height: 18px !important;
}

.big-four-slider::-moz-range-thumb {
  width: 18px !important;
  height: 18px !important;
}

/* ── BIG FOUR BLOCK (visual grouping) ──────────────────────── */
.big-four-block {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(255, 255, 255, 0.15);
  margin-bottom: 2px;
}

/* ── BUTTONS ───────────────────────────────────────────────── */
.action-row {
  display: flex;
  align-items: center;
  gap: 8px;
}

button {
  background: rgba(255, 255, 255, 0.12);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.3);
  padding: 4px 10px;
  border-radius: 3px;
  cursor: pointer;
  font-size: 13px;
}

button:hover {
  background: rgba(255, 255, 255, 0.22);
}

/* ── SELECT ────────────────────────────────────────────────── */
select {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
  border: 1px solid rgba(255, 255, 255, 0.3);
  padding: 2px 4px;
  cursor: pointer;
  font-size: 0.85em;
}

/* ── IMAGE PREVIEW ─────────────────────────────────────────── */
#imageUpload {
  cursor: pointer;
}

#imgPreview {
  display: none;
  width: 80px;
  height: 80px;
  object-fit: cover;
  opacity: 0.8;
}

/* ── RESIZE HANDLE ─────────────────────────────────────────── */
#resize-handle {
  position: fixed;
  top: 0;
  bottom: 0;
  width: 8px;
  left: 310px;
  z-index: 10001;
  cursor: ew-resize;
  background: transparent;
  transition: background 0.15s;
}

#resize-handle::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 3px;
  transform: translateY(-50%);
  width: 2px;
  height: 36px;
  border-radius: 1px;
  background: rgba(255, 255, 255, 0.2);
  transition: background 0.15s, height 0.15s;
}

#resize-handle:hover,
#resize-handle.dragging {
  background: rgba(255, 255, 255, 0.07);
}

#resize-handle:hover::after,
#resize-handle.dragging::after {
  background: rgba(255, 255, 255, 0.55);
  height: 48px;
}

/* ── COLOR FILTER OVERLAY ──────────────────────────────────── */
#color-filter {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
}