* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}
body {
  font-family: system-ui, sans-serif;
  background: linear-gradient(135deg, #1e3c72, #2a5298);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  color: #fff;
}
.speed-app {
  background: rgba(255, 255, 255, 0.1);
  backdrop-filter: blur(10px);
  padding: 2.5rem;
  border-radius: 20px;
  text-align: center;
  max-width: 400px;
  width: 100%;
}
h1 {
  margin-bottom: 1.5rem;
}
.gauge {
  background: rgba(255, 255, 255, 0.15);
  border-radius: 50%;
  width: 220px;
  height: 220px;
  margin: 0 auto 1.5rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  border: 4px solid #38bdf8;
}
.gauge span {
  font-size: 3rem;
  font-weight: 700;
}
.gauge small {
  font-size: 1rem;
  color: #94a3b8;
}
.status {
  min-height: 1.5rem;
  margin-bottom: 1rem;
}
button {
  padding: 0.75rem 2rem;
  background: #38bdf8;
  color: #0f172a;
  border: none;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
}
button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}
.history {
  margin-top: 1rem;
  color: #94a3b8;
  font-size: 0.9rem;
}