.exer-stage {
  background: var(--glass);
  -webkit-backdrop-filter: blur(20px);
  backdrop-filter: blur(20px);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  box-shadow: 0 0 64px 3px color-mix(in srgb, var(--accent) 11%, transparent);
  padding: 24px 18px;
  text-align: center;
  margin-bottom: 14px;
  min-height: 380px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.exer-ring {
  position: relative;
  width: 180px;
  height: 180px;
  margin-bottom: 16px;
}

.exer-ring-svg {
  width: 100%;
  height: 100%;
  transform: rotate(-90deg);
}

.ring-bg {
  fill: none;
  stroke: var(--border);
  stroke-width: 8;
}

.ring-fg {
  fill: none;
  stroke: var(--accent);
  stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 339.292;
  stroke-dashoffset: 0;
  transition: stroke-dashoffset 1s linear, stroke 0.3s;
}

.exer-stage.physical .ring-fg { stroke: #e44a8f; }
.exer-stage.mental .ring-fg { stroke: var(--accent); }

.exer-ring-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  pointer-events: none;
}

.exer-timer {
  font-size: 48px;
  font-weight: 800;
  line-height: 1;
  color: var(--text);
}

.exer-timer-unit {
  font-size: 12px;
  color: var(--text-dim);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-top: 4px;
}

.exer-instruction {
  font-size: 22px;
  font-weight: 700;
  margin-bottom: 8px;
  min-height: 56px;
  display: flex;
  align-items: center;
}

.exer-stage.physical .exer-instruction { color: #e44a8f; }

.exer-motion {
  font-size: 13px;
  color: var(--text-dim);
  min-height: 18px;
}

.exer-motion.detected { color: var(--good); font-weight: 600; }

.exer-math {
  width: 100%;
  margin-top: 8px;
}

.exer-math.hidden { display: none; }

.exer-problem {
  font-size: 38px;
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: 2px;
}

.exer-choices {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.exer-choice {
  background: var(--bg);
  border: 2px solid var(--border);
  color: var(--text);
  border-radius: 12px;
  padding: 14px;
  font-size: 22px;
  font-weight: 700;
  cursor: pointer;
  transition: all 0.1s;
}

.exer-choice:hover { border-color: var(--accent-dim); }
.exer-choice:active { transform: scale(0.97); }
.exer-choice.good { background: rgba(74, 222, 128, 0.2); border-color: var(--good); }
.exer-choice.bad { background: rgba(228, 74, 74, 0.2); border-color: var(--bad); }

.exer-stage.rest {
  background: color-mix(in srgb, var(--accent) 45%, transparent);
}

#motion-status {
  display: inline-block;
  margin-left: 8px;
  font-size: 12px;
  color: var(--text-dim);
}

#motion-status.ok { color: var(--good); }
#motion-status.no { color: var(--bad); }