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

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --border: #30363d;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --accent: #58a6ff;
  --accent-dim: #1f6feb;
  --green: #3fb950;
  --orange: #d29922;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  padding: 16px;
  max-width: 1400px;
  margin: 0 auto;
}

header { text-align: center; margin-bottom: 16px; }
header h1 { font-size: 1.4rem; }
.subtitle { color: var(--text-muted); font-size: 0.85rem; }

/* Signal config */
#signal-config { margin-bottom: 12px; }
#config-toggle {
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); padding: 6px 14px; cursor: pointer; border-radius: 6px;
  width: 100%; text-align: left; font-size: 0.85rem;
}
#config-panel {
  display: none; background: var(--surface); border: 1px solid var(--border);
  border-top: none; padding: 12px; border-radius: 0 0 6px 6px;
  gap: 10px; align-items: center;
}
#signal-config:not(.collapsed) #config-panel { display: flex; flex-wrap: wrap; }
#scenario-select, #run-pipeline {
  background: var(--bg); border: 1px solid var(--border);
  color: var(--text); padding: 4px 10px; border-radius: 4px; font-size: 0.85rem;
}
#run-pipeline {
  background: var(--accent-dim); border-color: var(--accent); cursor: pointer;
}

/* Pipeline bar */
#pipeline-bar {
  display: flex; align-items: center; gap: 4px;
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 8px 12px; overflow-x: auto;
  margin-bottom: 8px; flex-wrap: wrap; justify-content: center;
}
.stage-badge {
  padding: 5px 12px; border-radius: 4px; font-size: 0.75rem;
  cursor: pointer; white-space: nowrap; border: 1px solid transparent;
  background: var(--bg); color: var(--text-muted); transition: all 0.15s;
}
.stage-badge:hover { border-color: var(--accent); color: var(--text); }
.stage-badge.active { background: var(--accent-dim); color: #fff; border-color: var(--accent); }
.stage-badge.done { color: var(--green); }
.stage-arrow { color: var(--text-muted); font-size: 0.7rem; user-select: none; }

/* Nav buttons */
#nav-buttons { display: flex; justify-content: space-between; margin-bottom: 12px; }
#nav-buttons button {
  background: var(--surface); border: 1px solid var(--border);
  color: var(--text); padding: 4px 16px; border-radius: 4px;
  cursor: pointer; font-size: 0.8rem;
}
#nav-buttons button:disabled { opacity: 0.3; cursor: default; }

/* Detail panel */
#detail-panel {
  display: grid; grid-template-columns: 1fr 320px; gap: 16px;
  min-height: 400px;
}
@media (max-width: 900px) {
  #detail-panel { grid-template-columns: 1fr; }
}
#plot-area {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 12px; min-height: 380px;
}
#explanation {
  background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 16px; font-size: 0.85rem;
  color: var(--text-muted); overflow-y: auto; max-height: 600px;
}
#explanation h3 { color: var(--text); margin-bottom: 8px; }
#explanation p { margin-bottom: 10px; }
#explanation code {
  background: var(--bg); padding: 1px 5px; border-radius: 3px;
  font-size: 0.8rem;
}