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

:root {
  --bg: #1a1a1a;
  --bg-panel: #252525;
  --bg-hover: #333;
  --border: #3a3a3a;
  --text: #f0f0f0;
  --text-muted: #999;
  --accent: #4a9eff;
  --entry: #00ff00;
  --exit: #0099ff;
  --stop: #ff3333;
  --line-width: 3px;
  --hit-tolerance: 8px;
}

html,
body {
  height: 100%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
    "Microsoft YaHei", sans-serif;
  background: var(--bg);
  color: var(--text);
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.toolbar {
  background: var(--bg-panel);
  border-bottom: 1px solid var(--border);
  padding: 12px 20px;
  flex-shrink: 0;
}

.toolbar-title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 10px;
  letter-spacing: 0.02em;
}

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

.toolbar-hint {
  margin-top: 8px;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 7px 14px;
  font-size: 0.875rem;
  border: 1px solid var(--border);
  border-radius: 4px;
  background: var(--bg-hover);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  user-select: none;
  white-space: nowrap;
}

.btn:hover:not(:disabled) {
  background: #404040;
  border-color: #555;
}

.btn:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.btn-primary {
  background: #2d4a3e;
  border-color: #3d6b55;
}

.btn-primary:hover:not(:disabled) {
  background: #3a5c4a;
}

.btn-accent {
  background: #1e3a5f;
  border-color: var(--accent);
}

.btn-accent:hover:not(:disabled) {
  background: #264d7a;
}

.mode-group {
  display: inline-flex;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
}

.mode-btn {
  border: none;
  border-radius: 0;
  border-right: 1px solid var(--border);
  background: transparent;
}

.mode-btn:last-child {
  border-right: none;
}

.mode-btn.active[data-mode="entry"] {
  background: rgba(0, 255, 0, 0.15);
  color: var(--entry);
  box-shadow: inset 0 -2px 0 var(--entry);
}

.mode-btn.active[data-mode="exit"] {
  background: rgba(0, 153, 255, 0.15);
  color: var(--exit);
  box-shadow: inset 0 -2px 0 var(--exit);
}

.mode-btn.active[data-mode="stop"] {
  background: rgba(255, 51, 51, 0.15);
  color: var(--stop);
  box-shadow: inset 0 -2px 0 var(--stop);
}

.workspace {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  overflow: auto;
  min-height: 0;
}

.drop-zone {
  width: 100%;
  max-width: 1400px;
  min-height: 400px;
  border: 2px dashed var(--border);
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: border-color 0.2s, background 0.2s;
}

.drop-zone.drag-over {
  border-color: var(--accent);
  background: rgba(74, 158, 255, 0.06);
}

.drop-placeholder {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-muted);
}

.drop-icon {
  font-size: 3rem;
  display: block;
  margin-bottom: 12px;
}

.drop-sub {
  margin-top: 8px;
  font-size: 0.8rem;
}

.canvas-wrap {
  position: relative;
  line-height: 0;
  max-width: 100%;
}

.hidden {
  display: none !important;
}

.canvas-wrap.hidden {
  display: none;
}

#chart-image {
  display: block;
  max-width: 100%;
  height: auto;
  pointer-events: none;
  user-select: none;
}

#overlay-canvas {
  position: absolute;
  top: 0;
  left: 0;
  cursor: crosshair;
}

#overlay-canvas.can-drag {
  cursor: ns-resize;
}

.footer {
  flex-shrink: 0;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
  padding: 10px 20px;
  font-size: 0.8rem;
  color: var(--text-muted);
  border-top: 1px solid var(--border);
  background: var(--bg-panel);
}

.legend {
  display: inline-block;
  width: 24px;
  height: 3px;
  vertical-align: middle;
  margin-left: 4px;
  border-radius: 1px;
}

.legend.entry {
  background: var(--entry);
}

.legend.exit {
  background: var(--exit);
}

.legend.stop {
  background: var(--stop);
}

.footer-note {
  margin-left: auto;
}

@media (max-width: 640px) {
  .toolbar-actions {
    gap: 6px;
  }

  .btn {
    padding: 6px 10px;
    font-size: 0.8rem;
  }

  .footer-note {
    width: 100%;
    margin-left: 0;
  }
}