/* ── Tokens ─────────────────────────────────────────────────────────────── */
:root {
  --bg-0: #0d1117;
  --bg-1: #161b22;
  --bg-2: #21262d;
  --bg-3: #30363d;

  --text-primary:   #e6edf3;
  --text-secondary: #8b949e;
  --text-dim:       #484f58;

  --accent:      #00e5a0;
  --accent-dim:  rgba(0, 229, 160, 0.15);
  --accent-glow: rgba(0, 229, 160, 0.35);
  --warn:        #f59e0b;
  --warn-dim:    rgba(245, 158, 11, 0.15);
  --danger:      #ef4444;
  --success:     #22c55e;

  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;

  --font: -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
}

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

body {
  background: var(--bg-0);
  color: var(--text-primary);
  font-family: var(--font);
  font-size: 14px;
  line-height: 1.5;
  min-height: 100dvh;
  overflow-x: hidden;
}

/* ── Layout ─────────────────────────────────────────────────────────────── */
.app {
  display: grid;
  grid-template-rows: 56px 1fr;
  height: 100dvh;
}

header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 24px;
  background: var(--bg-1);
  border-bottom: 1px solid var(--bg-3);
}

.logo {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.5px;
  color: var(--accent);
}

.logo-sub {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 400;
}

.header-spacer { flex: 1; }

.side-toggle {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-secondary);
}

.side-toggle label {
  display: flex;
  align-items: center;
  gap: 4px;
  cursor: pointer;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--bg-3);
  transition: background 150ms, color 150ms, border-color 150ms;
}

.side-toggle input[type="radio"] { display: none; }

.side-toggle input[type="radio"]:checked + span {
  color: var(--accent);
}

.side-toggle label:has(input:checked) {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent);
}

main {
  display: grid;
  grid-template-columns: 220px 1fr 260px;
  overflow: hidden;
}

/* ── Exercise panel ─────────────────────────────────────────────────────── */
.exercise-panel {
  background: var(--bg-1);
  border-right: 1px solid var(--bg-3);
  padding: 16px 12px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.panel-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  padding: 0 4px 8px;
  border-bottom: 1px solid var(--bg-3);
  margin-bottom: 4px;
}

.exercise-card {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding: 14px 14px;
  background: var(--bg-2);
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-md);
  cursor: pointer;
  text-align: left;
  color: var(--text-primary);
  transition: background 150ms, border-color 200ms, transform 150ms var(--ease-out);
}

.exercise-card:hover {
  background: var(--bg-3);
  border-color: var(--text-dim);
  transform: translateX(2px);
}

.exercise-card.active {
  background: var(--accent-dim);
  border-color: var(--accent);
}

.exercise-card.active .exercise-name {
  color: var(--accent);
}

.exercise-emoji {
  font-size: 22px;
  line-height: 1;
  margin-bottom: 2px;
}

.exercise-name {
  font-weight: 600;
  font-size: 14px;
  line-height: 1.3;
}

.exercise-name-en {
  font-size: 11px;
  color: var(--text-secondary);
}

.exercise-freq {
  font-size: 11px;
  color: var(--text-dim);
  margin-top: 2px;
}

.calibrate-btn {
  margin-top: auto;
  padding: 10px;
  background: transparent;
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  cursor: pointer;
  font-size: 12px;
  font-family: var(--font);
  transition: background 150ms, color 150ms, border-color 150ms;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.calibrate-btn:hover {
  background: var(--bg-3);
  color: var(--text-primary);
  border-color: var(--text-dim);
}

/* ── Camera section ─────────────────────────────────────────────────────── */
.camera-section {
  position: relative;
  background: #000;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

.camera-wrap {
  position: relative;
  width: 100%;
  height: 100%;
  max-width: 100%;
}

#input-video {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
  transform: scaleX(-1); /* mirror for selfie view */
}

#overlay-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

/* ── Guide overlay (exercise instructions) ─────────────────────────────── */
.guide-overlay {
  position: absolute;
  inset: 0;
  background: rgba(13, 17, 23, 0.92);
  backdrop-filter: blur(6px);
  display: none;
  align-items: center;
  justify-content: center;
  z-index: 20;
  padding: 24px;
  animation: fadeSlide 250ms var(--ease-out);
}

.guide-overlay.visible { display: flex; }

.guide-card {
  background: var(--bg-1);
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  max-width: 520px;
  width: 100%;
  max-height: 90%;
  overflow-y: auto;
  box-shadow: 0 24px 60px rgba(0, 0, 0, 0.5),
              0 0 0 1px rgba(0, 229, 160, 0.08);
}

.guide-header {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 18px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--bg-3);
}

.guide-emoji {
  font-size: 44px;
  line-height: 1;
}

.guide-header h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.3px;
  margin-bottom: 2px;
}

.guide-subtitle {
  font-size: 13px;
  color: var(--text-secondary);
}

.guide-position {
  display: inline-block;
  font-size: 12px;
  color: var(--accent);
  background: var(--accent-dim);
  border: 1px solid rgba(0, 229, 160, 0.3);
  padding: 5px 12px;
  border-radius: 999px;
  margin-bottom: 18px;
}

.guide-steps {
  list-style: none;
  counter-reset: step-counter;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-bottom: 24px;
}

.guide-steps li {
  counter-increment: step-counter;
  display: flex;
  gap: 14px;
  align-items: flex-start;
  padding: 10px 12px;
  background: var(--bg-2);
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-sm);
  font-size: 13px;
  line-height: 1.5;
  transition: border-color 150ms;
}

.guide-steps li:hover {
  border-color: var(--text-dim);
}

.guide-steps li::before {
  content: counter(step-counter);
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--accent-dim);
  border: 1px solid var(--accent);
  color: var(--accent);
  font-size: 12px;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.guide-step-zh {
  color: var(--text-primary);
  font-weight: 500;
  display: block;
}

.guide-step-en {
  color: var(--text-secondary);
  font-size: 12px;
  display: block;
  margin-top: 2px;
}

.guide-actions {
  display: flex;
  gap: 10px;
  justify-content: flex-end;
  padding-top: 18px;
  border-top: 1px solid var(--bg-3);
}

.guide-btn-primary,
.guide-btn-secondary {
  padding: 11px 22px;
  border-radius: var(--radius-sm);
  font-size: 13px;
  font-weight: 600;
  font-family: var(--font);
  cursor: pointer;
  transition: all 150ms;
  border: 1px solid transparent;
}

.guide-btn-primary {
  background: var(--accent);
  color: var(--bg-0);
  border-color: var(--accent);
  box-shadow: 0 4px 14px var(--accent-glow);
}

.guide-btn-primary:hover {
  background: #00f5ad;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px var(--accent-glow);
}

.guide-btn-secondary {
  background: transparent;
  color: var(--text-secondary);
  border-color: var(--bg-3);
}

.guide-btn-secondary:hover {
  background: var(--bg-2);
  color: var(--text-primary);
  border-color: var(--text-dim);
}

/* ── Step HUD (in-camera step guide) ────────────────────────────────────── */
.step-hud {
  position: absolute;
  top: 20px;
  left: 50%;
  transform: translateX(-50%);
  min-width: 320px;
  max-width: 80%;
  background: rgba(13, 17, 23, 0.82);
  backdrop-filter: blur(8px);
  border: 1px solid rgba(0, 229, 160, 0.25);
  border-radius: var(--radius-md);
  padding: 14px 22px 12px;
  text-align: center;
  z-index: 5;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  display: none;
  animation: fadeSlide 200ms var(--ease-out);
}

.step-hud.visible { display: block; }

.step-hud.advancing {
  animation: phaseAdvance 400ms var(--ease-out);
}

@keyframes phaseAdvance {
  0%   { transform: translateX(-50%) scale(1);    border-color: rgba(0, 229, 160, 0.25); }
  40%  { transform: translateX(-50%) scale(1.04); border-color: var(--accent); box-shadow: 0 8px 32px var(--accent-glow); }
  100% { transform: translateX(-50%) scale(1);    border-color: rgba(0, 229, 160, 0.25); }
}

.step-hud-row {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  margin-bottom: 6px;
}

.step-hud-num {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 3px 10px;
  border-radius: 999px;
}

.step-hud-name {
  font-size: 12px;
  color: var(--text-secondary);
  font-weight: 500;
}

.step-hud-instruction {
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
  margin-bottom: 2px;
}

.step-hud-instruction-en {
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.step-hud-dots {
  display: flex;
  justify-content: center;
  gap: 6px;
}

.step-hud-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--bg-3);
  border: 1px solid var(--bg-3);
  transition: all 200ms;
}

.step-hud-dot.done {
  background: var(--accent);
  border-color: var(--accent);
}

.step-hud-dot.active {
  background: var(--accent-dim);
  border-color: var(--accent);
  box-shadow: 0 0 8px var(--accent-glow);
  transform: scale(1.3);
}

/* ── Manual calibration overlay ─────────────────────────────────────────── */
.manual-calib-overlay {
  position: absolute;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  background: rgba(13, 17, 23, 0.92);
  backdrop-filter: blur(10px);
  z-index: 12;
  padding: 24px;
}

.manual-calib-overlay.visible { display: flex; }

.manual-calib-card {
  width: min(560px, 100%);
  max-height: 92%;
  overflow-y: auto;
  background: linear-gradient(180deg, var(--bg-1), var(--bg-0));
  border: 1px solid rgba(0, 229, 160, 0.25);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  text-align: center;
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.6), 0 0 60px rgba(0, 229, 160, 0.08);
  animation: fadeSlide 240ms var(--ease-out);
}

.manual-calib-card h2 {
  font-size: 22px;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.manual-calib-sub {
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 14px;
}

.manual-calib-help {
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.55;
  margin-bottom: 18px;
}

.manual-calib-stage {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 28px;
  background: var(--bg-0);
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-md);
  padding: 18px 12px;
  margin-bottom: 18px;
}

.manual-calib-avatar {
  width: 160px;
  height: 208px;
  flex-shrink: 0;
}

.manual-calib-readout {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 6px;
}

.manual-calib-pct {
  font-size: 56px;
  font-weight: 800;
  line-height: 1;
  color: var(--accent);
  text-shadow: 0 0 20px var(--accent-glow);
  font-variant-numeric: tabular-nums;
}

.manual-calib-pct-label {
  font-size: 11px;
  color: var(--text-dim);
  line-height: 1.4;
}

.manual-calib-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 8px;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent) 0%, var(--accent) var(--val, 50%), var(--bg-3) var(--val, 50%), var(--bg-3) 100%);
  outline: none;
  margin-bottom: 8px;
}

.manual-calib-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-0);
  cursor: pointer;
  box-shadow: 0 0 12px var(--accent-glow);
  transition: transform 120ms;
}

.manual-calib-slider::-webkit-slider-thumb:hover {
  transform: scale(1.15);
}

.manual-calib-slider::-moz-range-thumb {
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--accent);
  border: 3px solid var(--bg-0);
  cursor: pointer;
  box-shadow: 0 0 12px var(--accent-glow);
}

.manual-calib-scale {
  display: flex;
  justify-content: space-between;
  font-size: 10px;
  color: var(--text-dim);
  line-height: 1.4;
  margin-bottom: 22px;
}

.manual-calib-actions {
  display: flex;
  gap: 12px;
  justify-content: flex-end;
}

.manual-calib-btn-primary,
.manual-calib-btn-secondary {
  padding: 11px 22px;
  border-radius: var(--radius-md);
  border: 1px solid transparent;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: all 160ms var(--ease-out);
  font-family: inherit;
}

.manual-calib-btn-primary {
  background: var(--accent);
  color: var(--bg-0);
  box-shadow: 0 4px 16px var(--accent-glow);
}

.manual-calib-btn-primary:hover {
  background: #00f5ad;
  transform: translateY(-1px);
  box-shadow: 0 6px 22px var(--accent-glow);
}

.manual-calib-btn-secondary {
  background: transparent;
  color: var(--text-secondary);
  border-color: var(--bg-3);
}

.manual-calib-btn-secondary:hover {
  background: var(--bg-2);
  color: var(--text-primary);
  border-color: var(--text-dim);
}

/* ── Calibration overlay ────────────────────────────────────────────────── */
.calib-overlay {
  position: absolute;
  inset: 0;
  background: rgba(13, 17, 23, 0.88);
  backdrop-filter: blur(4px);
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 20px;
  z-index: 10;
  padding: 32px;
  text-align: center;
}

.calib-overlay.visible { display: flex; }

.calib-phase {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-secondary);
}

.calib-message {
  font-size: 17px;
  font-weight: 500;
  line-height: 1.6;
  color: var(--text-primary);
  max-width: 360px;
}

.calib-progress-track {
  width: 240px;
  height: 4px;
  background: var(--bg-3);
  border-radius: 2px;
  overflow: hidden;
}

.calib-progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 2px;
  width: 0%;
  transition: width 100ms linear;
  box-shadow: 0 0 8px var(--accent-glow);
}

/* ── No camera notice ───────────────────────────────────────────────────── */
.no-camera {
  position: absolute;
  inset: 0;
  display: none;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 8px;
  color: var(--text-secondary);
  font-size: 14px;
  text-align: center;
  padding: 24px;
}

.no-camera.visible { display: flex; }
.no-camera .icon { font-size: 40px; }

/* ── Feedback panel ─────────────────────────────────────────────────────── */
.feedback-panel {
  background: var(--bg-1);
  border-left: 1px solid var(--bg-3);
  padding: 20px 16px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  overflow-y: auto;
}

/* Rep counter */
.rep-section {}

.rep-label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 12px;
}

.rep-display {
  display: flex;
  align-items: baseline;
  gap: 6px;
  margin-bottom: 12px;
}

#rep-count {
  font-size: 64px;
  font-weight: 800;
  line-height: 1;
  color: var(--accent);
  letter-spacing: -2px;
  transition: transform 200ms var(--ease-out);
}

#rep-count.celebrate {
  transform: scale(1.25);
}

#rep-target {
  font-size: 20px;
  color: var(--text-secondary);
  font-weight: 500;
}

.rep-progress-track {
  height: 6px;
  background: var(--bg-3);
  border-radius: 3px;
  overflow: hidden;
}

.rep-progress-fill {
  height: 100%;
  background: var(--accent);
  border-radius: 3px;
  width: 0%;
  transition: width 300ms var(--ease-out);
  box-shadow: 0 0 8px var(--accent-glow);
}

/* Goal selector */
.goal-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--text-secondary);
}

.goal-row select {
  background: var(--bg-2);
  border: 1px solid var(--bg-3);
  border-radius: var(--radius-sm);
  color: var(--text-primary);
  padding: 4px 8px;
  font-size: 13px;
  font-family: var(--font);
  cursor: pointer;
}

/* State label */
.state-label {
  font-size: 13px;
  font-weight: 500;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-2);
  border: 1px solid var(--bg-3);
  color: var(--text-secondary);
  text-align: center;
  transition: background 200ms, color 200ms, border-color 200ms;
}

.state-label.state-moving {
  background: var(--accent-dim);
  border-color: var(--accent);
  color: var(--accent);
}

.state-label.state-at_peak {
  background: rgba(0, 229, 160, 0.25);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 700;
}

.state-label.state-returning {
  background: var(--warn-dim);
  border-color: var(--warn);
  color: var(--warn);
}

/* Divider */
.divider {
  height: 1px;
  background: var(--bg-3);
}

/* Feedback list */
.feedback-section {}

.feedback-title {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-secondary);
  margin-bottom: 10px;
}

.feedback-list {
  display: flex;
  flex-direction: column;
  gap: 6px;
  min-height: 60px;
}

.feedback-item {
  padding: 9px 12px;
  border-radius: var(--radius-sm);
  font-size: 12px;
  line-height: 1.5;
  border: 1px solid transparent;
  animation: fadeSlide 200ms var(--ease-out);
}

.feedback-item.good {
  background: rgba(34, 197, 94, 0.1);
  border-color: rgba(34, 197, 94, 0.3);
  color: #4ade80;
}

.feedback-item.warn {
  background: var(--warn-dim);
  border-color: rgba(245, 158, 11, 0.3);
  color: var(--warn);
}

.feedback-item.success {
  background: rgba(0, 229, 160, 0.12);
  border-color: var(--accent-glow);
  color: var(--accent);
  font-weight: 600;
}

.feedback-item.flash {
  animation: flashIn 300ms var(--ease-out);
}

@keyframes fadeSlide {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes flashIn {
  0%   { opacity: 0; transform: scale(0.95); }
  60%  { opacity: 1; transform: scale(1.03); }
  100% { transform: scale(1); }
}

/* ── Responsive ─────────────────────────────────────────────────────────── */
@media (max-width: 900px) {
  main {
    grid-template-columns: 1fr;
    grid-template-rows: auto 1fr auto;
  }

  .exercise-panel {
    flex-direction: row;
    overflow-x: auto;
    border-right: none;
    border-bottom: 1px solid var(--bg-3);
    padding: 12px;
    gap: 10px;
  }

  .exercise-card { min-width: 140px; }
  .calibrate-btn { min-width: 120px; margin-top: 0; align-self: center; }
  .panel-title   { display: none; }

  .feedback-panel {
    border-left: none;
    border-top: 1px solid var(--bg-3);
    flex-direction: row;
    flex-wrap: wrap;
  }

  #rep-count { font-size: 42px; }
}