/* PhysicsUK Stacker — M1 physics toy shell. Brand tokens from BRAND_BRIEF.md. */
:root {
  --green: #22c670;
  --deep-green: #119655;
  --night-green: #061914;
  --ink: #122033;
  --mint: #f4fbf7;
  --line-green: #d4e9dd;
  --coral: #dc4c55;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--night-green);
  color: var(--ink);
  font-family: system-ui, -apple-system, "Segoe UI", sans-serif;
  overscroll-behavior: none;
}

.toy-shell {
  min-height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
  padding: max(10px, env(safe-area-inset-top)) max(10px, env(safe-area-inset-right))
           max(10px, env(safe-area-inset-bottom)) max(10px, env(safe-area-inset-left));
}

.stage {
  position: relative;
  width: min(100vw - 20px, calc((100vh - 90px) * (400 / 720)));
  aspect-ratio: 400 / 720;
  background: var(--mint);
  border-radius: 14px;
  overflow: hidden;
  box-shadow: 0 10px 40px rgba(0, 0, 0, .45);
  touch-action: none;
}

#game, #game canvas {
  position: absolute;
  inset: 0;
  width: 100% !important;
  height: 100% !important;
}

.hud {
  position: absolute;
  top: 0; left: 0; right: 0;
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding: 10px 12px;
  pointer-events: none;
}

.hud-block { display: flex; flex-direction: column; gap: 2px; }
.hud-right { align-items: flex-end; }

.eyebrow {
  font-size: 10px;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--deep-green);
  font-weight: 700;
}

#hud-score { font-size: 26px; line-height: 1; }
.hud-sub { font-size: 12px; color: #5c7a6b; }
#hud-lives { color: var(--coral); font-size: 18px; letter-spacing: 2px; }

#btn-pause {
  pointer-events: auto;
  min-width: 64px;
  min-height: 34px;
  border: 1px solid var(--line-green);
  background: #fff;
  border-radius: 8px;
  font-weight: 600;
  cursor: pointer;
}

#toast {
  position: absolute;
  top: 84px;
  left: 50%;
  transform: translateX(-50%);
  max-width: 90%;
  font-size: 13px;
  font-weight: 600;
  color: var(--deep-green);
  background: rgba(255, 255, 255, .85);
  border-radius: 999px;
  padding: 4px 14px;
  pointer-events: none;
  white-space: nowrap;
}

#toast:empty { display: none; }

#hud-streak {
  color: var(--deep-green);
  font-weight: 800;
}

#drop-timer {
  position: absolute;
  bottom: 102px;
  left: 50%;
  transform: translateX(-50%);
  width: 58%;
  height: 7px;
  border-radius: 999px;
  background: rgba(212, 233, 221, .55);
  overflow: hidden;
  pointer-events: none;
}

#drop-timer[hidden] { display: none; }

#drop-timer-fill {
  height: 100%;
  width: 100%;
  border-radius: 999px;
  background: var(--green);
}

#drop-timer-fill.warn { background: var(--coral); }

.control-strip {
  position: absolute;
  bottom: 34px;
  left: 0; right: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 14px;
  padding: 0 12px;
}

.control-strip button {
  min-width: 56px;
  min-height: 56px;
  border-radius: 14px;
  border: 1.5px solid var(--line-green);
  background: #fff;
  font-size: 24px;
  color: var(--ink);
  cursor: pointer;
  touch-action: manipulation;
}

.control-strip .drop {
  min-width: 132px;
  background: var(--green);
  border-color: var(--deep-green);
  color: #fff;
  font-size: 18px;
  font-weight: 800;
  letter-spacing: .06em;
}

.control-strip button:active { transform: translateY(1px); filter: brightness(.94); }

.hint {
  position: absolute;
  bottom: 8px;
  left: 0; right: 0;
  text-align: center;
  font-size: 11px;
  color: #5c7a6b;
  margin: 0;
  pointer-events: none;
}

.overlay {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(6, 25, 20, .55);
  z-index: 10;
}

.overlay[hidden] { display: none; }

.overlay-card {
  background: #fff;
  border-radius: 16px;
  padding: 22px 26px;
  width: min(84%, 300px);
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.overlay-card h2 { margin: 0; color: var(--night-green); }
.overlay-card p { margin: 0; font-size: 14px; color: #40544a; }
.over-stats { line-height: 1.7; }

.overlay-card button {
  min-height: 46px;
  border-radius: 10px;
  border: none;
  background: var(--green);
  color: #fff;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
}

.settings-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin: 4px 0;
}

.overlay-card button.toggle {
  background: var(--mint);
  color: var(--ink);
  border: 1.5px solid var(--line-green);
  font-weight: 600;
  font-size: 13.5px;
  min-height: 42px;
  position: relative;
}

.overlay-card button.toggle::after {
  content: 'off';
  position: absolute;
  right: 12px;
  font-size: 11px;
  font-weight: 800;
  color: #9ab3a5;
}

.overlay-card button.toggle[aria-pressed="true"] {
  border-color: var(--green);
}

.overlay-card button.toggle[aria-pressed="true"]::after {
  content: 'on';
  color: var(--deep-green);
}

.leaderboard-panel {
  border-top: 1px solid var(--line-green);
  margin-top: 4px;
  padding-top: 10px;
  text-align: left;
}

.leaderboard-panel[hidden] { display: none; }

.leaderboard-panel h3 {
  margin: 0 0 6px;
  font-size: 12px;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--deep-green);
}

#leaderboard-list {
  margin: 0;
  padding: 0 0 0 20px;
  font-size: 13px;
  line-height: 1.6;
}

#leaderboard-list li.you { font-weight: 800; color: var(--deep-green); }

.leaderboard-note {
  margin: 6px 0 0;
  font-size: 11.5px;
  color: #7fa891;
}

.overlay-card button.secondary {
  background: #fff;
  color: var(--ink);
  border: 1.5px solid var(--line-green);
}

.question-card {
  width: min(92%, 340px);
  text-align: left;
  gap: 8px;
  max-height: 86%;
  overflow-y: auto;
}

.q-tag {
  font-size: 10px;
  letter-spacing: .1em;
  text-transform: uppercase;
  color: #9ab3a5;
  margin: 0;
}

.question-card h2 {
  font-size: 17px;
  line-height: 1.35;
  color: var(--ink);
}

.q-options {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.overlay-card button.q-option {
  display: flex;
  align-items: center;
  gap: 10px;
  min-height: 48px;
  padding: 8px 12px;
  border: 1.5px solid var(--line-green);
  border-radius: 10px;
  background: var(--mint);
  color: var(--ink);
  font-size: 14px;
  text-align: left;
  cursor: pointer;
}

.overlay-card button.q-option:hover, .overlay-card button.q-option:focus-visible {
  border-color: var(--green);
  outline: none;
}

.q-letter {
  color: var(--ink);
  flex: 0 0 auto;
  width: 26px;
  height: 26px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  background: #fff;
  border: 1.5px solid var(--line-green);
  font-weight: 700;
  font-size: 12px;
}

.q-feedback { display: flex; flex-direction: column; gap: 8px; }
.q-feedback[hidden] { display: none; }

.q-verdict { font-size: 17px; font-weight: 800; margin: 0; }
.q-verdict.correct { color: var(--deep-green); }
.q-verdict.incorrect { color: var(--coral); }

.q-explanation { font-size: 13.5px; line-height: 1.5; color: #40544a; margin: 0; }

.q-earned {
  font-size: 12px;
  font-weight: 700;
  letter-spacing: .05em;
  color: var(--deep-green);
  background: var(--mint);
  border-radius: 8px;
  padding: 8px 10px;
  margin: 0;
}

#q-continue:disabled { opacity: .45; cursor: default; }

.control-strip button:disabled {
  opacity: .4;
  cursor: default;
}

#hud-band {
  display: inline-block;
  margin-left: 4px;
  padding: 1px 7px;
  border-radius: 999px;
  background: var(--green);
  color: #fff;
  font-size: 9px;
  font-weight: 800;
  letter-spacing: .03em;
  vertical-align: middle;
}

#hud-band:empty { display: none; }

.band-card { text-align: left; gap: 10px; }

.band-buttons {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.overlay-card button.band-row {
  min-height: 48px;
  padding: 0 16px;
  border-radius: 10px;
  border: 1.5px solid var(--line-green);
  background: var(--mint);
  color: var(--ink);
  font-size: 15px;
  font-weight: 700;
  text-align: left;
  cursor: pointer;
}

.overlay-card button.band-row:hover,
.overlay-card button.band-row:focus-visible {
  border-color: var(--green);
  outline: none;
}

.band-note {
  font-size: 12px;
  color: #5c7a6b;
  margin: 0;
  text-align: center;
}

.choice-card { text-align: center; }

.choice-sub {
  font-size: 12.5px;
  color: var(--deep-green);
  font-weight: 700;
  margin: 0;
}

.choice-buttons {
  display: flex;
  gap: 10px;
}

.overlay-card button.choice {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  min-height: 110px;
  padding: 12px 8px;
  background: var(--mint);
  color: var(--ink);
  border: 1.5px solid var(--line-green);
  border-radius: 12px;
  cursor: pointer;
}

.overlay-card button.choice:hover,
.overlay-card button.choice:focus-visible {
  border-color: var(--green);
  outline: none;
}

.choice-shape {
  display: block;
  border-radius: 3px;
  border: 1.5px solid rgba(18, 32, 51, .45);
}

.choice-name { font-size: 13px; font-weight: 800; }
.choice-hint { font-size: 11px; color: #5c7a6b; }

#tutorial-prompt {
  position: absolute;
  bottom: 122px;
  left: 50%;
  transform: translateX(-50%);
  margin: 0;
  max-width: 88%;
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--night-green);
  color: #fff;
  font-size: 14.5px;
  font-weight: 700;
  text-align: center;
  pointer-events: none;
  z-index: 7;
}

#tutorial-prompt[hidden] { display: none; }

#btn-skip-tutorial {
  position: absolute;
  top: 64px;
  right: 10px;
  min-height: 44px;
  min-width: 44px;
  padding: 0 14px;
  border-radius: 10px;
  border: 1.5px solid var(--line-green);
  background: rgba(255, 255, 255, .92);
  color: var(--ink);
  font-size: 13px;
  font-weight: 600;
  cursor: pointer;
  z-index: 7;
}

#btn-skip-tutorial[hidden] { display: none; }

@keyframes stacker-pulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(34, 198, 112, .55); }
  50% { box-shadow: 0 0 0 10px rgba(34, 198, 112, 0); }
}

.control-strip button.pulse {
  animation: stacker-pulse 1.1s ease-out infinite;
  border-color: var(--green);
}

@media (prefers-reduced-motion: reduce) {
  .control-strip button.pulse { animation: none; outline: 3px solid var(--green); }
}

#debug-panel {
  position: absolute;
  top: 70px;
  left: 8px;
  margin: 0;
  padding: 8px 10px;
  background: rgba(6, 25, 20, .82);
  color: #a3e635;
  font-size: 10px;
  line-height: 1.5;
  border-radius: 8px;
  pointer-events: none;
  z-index: 9;
}

.debug-toggle {
  position: absolute;
  bottom: 34px;
  right: 8px;
  min-width: 34px;
  min-height: 24px;
  font-size: 10px;
  border-radius: 6px;
  border: 1px solid var(--line-green);
  background: rgba(255, 255, 255, .8);
  color: #5c7a6b;
  cursor: pointer;
  z-index: 8;
}

.note {
  max-width: 420px;
  text-align: center;
  font-size: 11px;
  color: #7fa891;
  margin: 0;
}

.note code { color: #a3e635; }

.note-link {
  color: #a3e635;
  font-weight: 700;
  text-decoration: none;
  margin-left: 6px;
}

.note-link:hover { text-decoration: underline; }