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

:root {
  --bg: #0f0f0f;
  --surface: #1a1a1a;
  --border: rgba(255, 255, 255, 0.08);
  --text: #ffffff;
  --muted: rgba(255, 255, 255, 0.45);
  --accent: #84cc16;
  --level-ok: #4ade80;
}

html, body {
  height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  user-select: none;
  overflow: hidden;
}

.level {
  position: fixed;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2.5rem;
  padding: 4rem 1rem 3rem;
}

#level-svg {
  width: min(88vw, 65vh, 500px);
  height: auto;
  filter: drop-shadow(0 12px 32px rgba(0,0,0,0.6));
}

.target { transition: stroke 0.25s ease, opacity 0.25s ease; opacity: 0.55; }
.target-outer { opacity: 0.3; }

.crosshair {
  stroke: #8bc34a;
  stroke-width: 0.8;
  opacity: 0.22;
}

#bubble-group {
  will-change: transform;
}
#bubble { transition: fill 0.25s ease; }

.level.is-level .target { stroke: var(--level-ok); opacity: 0.9; }
.level.is-level .target-outer { opacity: 0.55; }
.level.is-level #bubble { fill: url(#bubbleGradOk); }

.readout {
  font-family: 'SF Mono', ui-monospace, Menlo, Consolas, monospace;
  font-size: 1.05rem;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
  letter-spacing: 0.04em;
  display: flex;
  align-items: baseline;
  gap: 0.55rem;
  min-height: 1.4em;
  transition: color 0.25s ease;
}
.readout .axis { color: rgba(255,255,255,0.3); font-weight: 700; }
.readout .dot { color: rgba(255,255,255,0.2); }
.level.is-level .readout { color: var(--level-ok); }
.level.is-level .readout .axis { color: rgba(74, 222, 128, 0.7); }

/* Top bar */
.top-bar {
  position: fixed;
  top: env(safe-area-inset-top, 0);
  right: env(safe-area-inset-right, 0);
  padding: 0.85rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.55rem;
  z-index: 20;
}

.back-link {
  color: var(--muted);
  font-size: 0.65rem;
  font-weight: 600;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 0.4rem 0.5rem;
  transition: color 0.15s ease;
}
.back-link:hover { color: var(--text); }

.cal-btn {
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  font: inherit;
  font-size: 0.65rem;
  font-weight: 700;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  padding: 0.42rem 0.7rem;
  border-radius: 6px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}
.cal-btn:hover { color: var(--text); border-color: var(--muted); }

/* Modal */
.modal {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(4px);
  -webkit-backdrop-filter: blur(4px);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.25rem;
}
.modal[hidden] { display: none; }

.modal-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.5rem;
  max-width: 380px;
  width: 100%;
}

.modal-panel h2 {
  font-size: 1.2rem;
  font-weight: 800;
  letter-spacing: -0.01em;
  margin-bottom: 0.5rem;
}

.modal-hint {
  font-size: 0.82rem;
  color: var(--muted);
  line-height: 1.55;
  margin-bottom: 1.25rem;
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.5rem;
}

.btn-primary {
  font: inherit;
  font-size: 0.8rem;
  font-weight: 700;
  padding: 0.6rem 1.15rem;
  border-radius: 6px;
  cursor: pointer;
  border: 1px solid var(--accent);
  background: var(--accent);
  color: #0f0f0f;
  letter-spacing: 0.02em;
}