:root {
  --bg-color: #f4f4f5;
  --text-color: #18181b;
  --card-bg: #ffffff;
  --primary: #2563eb;
  --danger: #d9363e;
}

body {
  font-family:
    system-ui,
    -apple-system,
    sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  margin: 0;
  padding: 2rem;
  line-height: 1.5;
}

.container {
  max-width: 1000px;
  margin: 0 auto;
}

h1 {
  margin-bottom: 0.5rem;
}

.subtitle {
  margin-top: 0;
  color: #52525b;
}

.controls {
  display: flex;
  gap: 1rem;
  margin: 2rem 0;
  align-items: center;
}

button {
  padding: 0.6rem 1.2rem;
  background: var(--primary);
  color: white;
  border: none;
  border-radius: 6px;
  font-weight: 600;
  cursor: pointer;
  font-size: 1rem;
}

button:disabled {
  background: #94a3b8;
  cursor: not-allowed;
}

button:hover:not(:disabled) {
  background: #1d4ed8;
}

.status-indicator {
  padding: 0.5rem 1rem;
  border-radius: 6px;
  background: #e4e4e7;
  font-family: monospace;
}

.jank-test {
  margin: 2rem 0;
  padding: 1rem;
  background: var(--card-bg);
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  display: flex;
  align-items: center;
  gap: 1rem;
}

.spinner {
  width: 30px;
  height: 30px;
  border: 4px solid #f3f3f3;
  border-top: 4px solid #3498db;
  border-radius: 50%;
  /* animation: spin 1s linear infinite; removed to use JS for blocking demo */
  box-shadow: 0 0 10px #ef4444aa;
  margin-right: 10px;
  display: inline-block;
}

@keyframes spin {
  100% {
    transform: rotate(360deg);
  }
}

.spinner-label {
  font-family: monospace;
  font-size: 1.2em;
  color: var(--danger);
  margin-left: 10px;
}

.info-box {
  margin: 1rem 0;
  padding: 0.75rem 1rem;
  background: #dbeafe;
  border: 1px solid #93c5fd;
  border-radius: 6px;
  font-size: 0.9rem;
  color: #1e40af;
}

.chart-container {
  background: var(--card-bg);
  border-radius: 8px;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.1);
  padding: 1rem;
  height: 400px;
  position: relative;
}