:root {
  --bg: #0b1120;
  --card: #111c33;
  --panel: #1b2942;
  --accent: #38bdf8;
  --accent-2: #818cf8;
  --text: #e2e8f0;
  --muted: #94a3b8;
}

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

body {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  background: radial-gradient(1200px 600px at 50% -10%, #1e293b, var(--bg));
  color: var(--text);
  padding: 20px;
}

.card {
  width: 100%;
  max-width: 420px;
  background: var(--card);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 24px;
  padding: 32px 28px 24px;
  text-align: center;
  box-shadow: 0 30px 60px rgba(0, 0, 0, 0.5);
}

h1 {
  font-size: 34px;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.bolt { -webkit-text-fill-color: initial; }

.subtitle { color: var(--muted); margin: 6px 0 24px; font-size: 14px; }

.gauge {
  position: relative;
  width: 200px;
  height: 200px;
  margin: 0 auto 24px;
  border-radius: 50%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: conic-gradient(var(--accent) 0deg, var(--accent-2) 0deg, var(--panel) 0deg);
  transition: background 0.2s linear;
}

.gauge::before {
  content: "";
  position: absolute;
  inset: 14px;
  border-radius: 50%;
  background: var(--card);
}

.gauge-value { position: relative; font-size: 48px; font-weight: 800; line-height: 1; }
.gauge-unit { position: relative; color: var(--muted); font-size: 14px; margin-top: 2px; }
.gauge-phase {
  position: relative;
  color: var(--accent);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  margin-top: 8px;
  min-height: 14px;
}

.metrics { display: flex; gap: 10px; margin-bottom: 22px; }

.metric {
  flex: 1;
  background: var(--panel);
  border-radius: 14px;
  padding: 12px 6px;
}

.metric-label { color: var(--muted); font-size: 12px; margin-bottom: 6px; }
.metric-num { font-size: 20px; font-weight: 700; color: var(--accent); }
.metric-num small { font-size: 11px; color: var(--muted); font-weight: 400; }

#startBtn {
  width: 100%;
  padding: 14px;
  font-size: 16px;
  font-weight: 700;
  color: #06121f;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  border: none;
  border-radius: 14px;
  cursor: pointer;
  transition: transform 0.1s, opacity 0.2s;
}

#startBtn:hover { transform: translateY(-1px); }
#startBtn:disabled { opacity: 0.5; cursor: not-allowed; transform: none; }

.footer { color: var(--muted); font-size: 11px; margin-top: 16px; }