body {
  margin: 0;
  font-family: "Inter", "Noto Sans JP", sans-serif;
  background: #f9f9f9;
  color: #222;
}

/* Layout */
.layout {
  display: flex;
  height: 100vh;
}

/* Sidebar */
.sidebar {
  width: 200px;
  background: #ffffff;
  padding: 16px;
  border-right: 1px solid #e5e5e5;
}

.sidebar-title {
  font-size: 13px;
  font-weight: 600;
  color: #666;
  margin-bottom: 8px;
  padding-left: 4px;
  letter-spacing: 0.5px;
}

/* Subtle divider line */
.sidebar-title::after {
  content: "";
  display: block;
  margin-top: 8px;
  height: 1px;
  background: #e5e5e5;   /* soft grey */
}



.sidebar button {
  width: 100%;
  padding: 10px 12px;
  margin-bottom: 6px;
  background: none;
  border: none;
  text-align: left;
  font-size: 15px;
  color: #444;
  border-radius: 4px;
  cursor: pointer;
}

.sidebar button:hover {
  background: #f0f0f0;
}

.sidebar button.active {
  background: #e6f0ff;
  color: #1a73e8;
  font-weight: 600;
}

/* Content */
.content {
  flex: 1;
  padding: 24px;
  overflow-y: auto;
}

/* Audio block */
.audio-controls {
  padding: 12px 0;
  border-bottom: 1px solid #eaeaea;
  display: flex;
  align-items: center;
  gap: 10px;
}

.audio-controls.active {
  background: #f2f7ff;
}

.audio-controls div {
  font-weight: 600;
  width: 40px;
  color: #333;
}

/* Icon buttons */
.audio-controls button {
  font-size: 16px;
  padding: 4px 6px;
  border: none;
  background: none;
  cursor: pointer;
  color: #444;
  transition: color 0.15s ease, transform 0.15s ease;
}

.audio-controls button:hover {
  color: #1a73e8;
  transform: translateY(-1px);
}

.audio-controls button:active {
  transform: translateY(0);
}

/* Text box */
.text-box {
  display: none;
  background: #ffffff;
  padding: 16px;
  margin: 8px 0 24px 40px;
  border-left: 3px solid #1a73e8;
  border-radius: 4px;
  line-height: 1.6;
  font-size: 15px;
  color: #333;
}

/* Tooltip wrapper */
.tooltip {
  position: relative;
  display: inline-block;
}

/* Tooltip bubble */
.tooltip:hover::after {
  content: attr(data-tip);
  position: absolute;
  top: -32px;
  left: 50%;
  transform: translateX(-50%);
  background: #333;
  color: white;
  padding: 4px 8px;
  font-size: 12px;
  border-radius: 4px;
  white-space: nowrap;
  opacity: 1;
  pointer-events: none;
}

/* Tooltip arrow */
.tooltip:hover::before {
  content: "";
  position: absolute;
  top: -8px;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: #333;
}

/* Default hidden state */
.tooltip::after,
.tooltip::before {
  opacity: 0;
  transition: opacity 0.15s ease;
}

.tooltip:hover::after,
.tooltip:hover::before {
  opacity: 1;
}

/* Audio seek bar */
.audio-controls input[type="range"] {
  appearance: none;
  -webkit-appearance: none;
  width: 140px;
  height: 4px;
  background: #e0e0e0;        /* light grey track */
  border-radius: 2px;
  outline: none;
  cursor: pointer;
}

/* WebKit browsers (Chrome, Edge, Safari) */
.audio-controls input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 12px;
  height: 12px;
  background: #c8c8c8;        /* light grey circle */
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.15s ease;
}

.audio-controls input[type="range"]::-webkit-slider-thumb:hover {
  background: #a0a0a0;        /* slightly darker on hover */
}

/* Firefox */
.audio-controls input[type="range"]::-moz-range-thumb {
  width: 12px;
  height: 12px;
  background: #c8c8c8;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  transition: background 0.15s ease;
}

.audio-controls input[type="range"]::-moz-range-thumb:hover {
  background: #a0a0a0;
}

/* Firefox track */
.audio-controls input[type="range"]::-moz-range-track {
  background: #e0e0e0;
  height: 4px;
  border-radius: 2px;
}
.audio-controls button {
  font-size: 16px;
  padding: 4px 6px;
  border: none;
  background: none;
  cursor: pointer;
  color: #888;              /* soft gray */
  transition: color 0.15s ease, transform 0.15s ease;
}

.audio-controls button:hover {
  color: #1a73e8;           /* blue accent on hover */
  transform: translateY(-1px);
}