:root {
  --slider-length: 60px;    /* vertical length in screen px */
  --slider-thickness: 12px; /* visual thickness (smaller = less wide) */
  --track-color: #444;
  --thumb-color: #fff;
  --thumb-size: 12px;
  --accent-gradient: linear-gradient(90deg, #c8c5fb, #d4c3fc, #f5bdd9);
  --font-family: 'Inter', 'Segoe UI', sans-serif;
}

body {
  background: #111 !important;
  color: #eee;
  font-family: var(--font-family);
  margin: 0;
}

canvas {
  display: block;
  background: #000;
}
#timeline { height: 40px; }
#status { margin-top: 0.5em; font-size: 13px; }

/* ----------------- CONTROLS ----------------- */


.left-panel input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: var(--thumb-size);
  border-radius: 50%;
  background: var(--thumb-color);
  box-shadow: 0 2px 6px rgba(0,0,0,0.6);
  transition: all 0.2s ease, box-shadow 0.2s ease;
}
.left-panel input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.4);
  box-shadow: 0 0 8px #fff, 0 0 16px #9333ea, 0 0 24px #ec4899;
}

/* Firefox track & thumb */
.left-panel input[type="range"]::-moz-range-track {
  height: 4px;
  background: var(--track-color);
  border-radius: 999px;
}
.left-panel input[type="range"]::-moz-range-thumb {
  width: var(--thumb-size);
  border-radius: 50%;
  background: var(--thumb-color);
  border: none;
  box-shadow: 0 2px 6px rgba(0,0,0,0.6);
  transition: all 0.2s ease, box-shadow 0.2s ease;
}
.left-panel input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.4);
  box-shadow: 0 0 8px #fff, 0 0 16px #9333ea, 0 0 24px #ec4899;
}

/* compact number inputs */
.left-panel input[type="number"] {
  width: 10ch;
  min-width: 10ch;
  max-width: 10ch;
  box-sizing: border-box;
  padding: 0.15rem 0.35rem;
  font-size: 0.95rem;
  background-color: #333;
  border-radius: 10px;
  border: 1px solid #aaa;
  color: #fff;
  margin-top: 2px;
}

/* ----------------- BUTTONS ----------------- */
.tool-btn,
#downloadWav, #downloadButton, #resetButton, #playPause, #stop,
#trueScale, #fileB, #rec, #yAxisMode, #undoBtn, #redoBtn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  padding: 6px;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  font-family: var(--font-family);
  font-weight: 700;
  background: var(--accent-gradient);
  color: #fff;
  box-shadow: 0 4px 12px rgba(0,0,0,0.6);
  transition: all 0.3s ease, box-shadow 0.3s ease;
  position: relative;
  z-index: 6000;
}

.tool-btn svg {
  width: 20px;
  height: 20px;
  display: block;
  transform: translateX(-0.5px);
}

/* neon glow hover */
.tool-btn:hover,
#downloadWav:hover, #downloadButton:hover, #resetButton:hover,
#playPause:hover, #stop:hover, #trueScale:hover,
#fileB:hover, #rec:hover, #yAxisMode:hover, #undoBtn:hover, #redoBtn:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 8px #fff, 0 0 16px #9333ea,
              0 0 32px #ec4899, 0 0 48px #4f46e5;
}

/* pulsing glow */
.tool-btn::after {
  content: '';
  position: absolute;
  border-radius: 6px;
  opacity: 0;
  transition: opacity 0.3s ease;
  box-shadow: 0 0 8px #fff, 0 0 16px #9333ea,
              0 0 32px #ec4899, 0 0 48px #4f46e5;
}
.tool-btn:hover::after { opacity: 0.6; }

/* ----------------- LAYOUT ----------------- */
.app {
  display: grid;
  grid-template-rows: 64px 1fr;
  grid-template-columns: 260px 1fr;
  height: 100vh;
  gap: 12px;
  box-sizing: border-box;
  padding: 0;
  margin: 0;
  overflow: hidden;
  font-family: var(--font-family);
}

.top-bar {
  grid-column: 1 / -1;
  grid-row: 1;
  display: flex;
  align-items: center;
  gap: 8px;
  /* padding: 8px 12px; */
  background: transparent;
  z-index: 7000;
  overflow-x: auto;
}

.left-panel {
  grid-column: 1;
  grid-row: 2;
  /* padding: 12px; */
  overflow-y: auto;
  background: transparent;
  box-sizing: border-box;
}
.left-panel .controls {
  flex-direction: column;
  gap: 0px;
  align-items: stretch;
  position: static;
}



.main-area {
  grid-column: 2;
  grid-row: 2;
  position: relative;
  overflow: hidden;
  /* padding: 12px; */
  display: flex;
  flex-direction: column;
  gap: 8px;
  align-items: stretch;
}

.top-bar .tool-btn,
.top-bar button,
.top-bar input[type="file"] {
  z-index: 8000;
}

/* responsive collapse */
@media (max-width: 900px) {
  .app {
    grid-template-columns: 1fr;
    grid-template-rows: 64px auto 1fr;
  }
  .top-bar { grid-column: 1; }
  .left-panel {
    grid-column: 1;
    grid-row: 2;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
  }
  .main-area { grid-column: 1; grid-row: 3; }
}