:root {
  --ui-space-1: 8px;
  --ui-space-2: 12px;
  --ui-space-3: 16px;
  --ui-space-4: 20px;
  --ui-space-5: 24px;
  --ui-popup-max-width: 520px;
  --ui-popup-max-height: calc((var(--vh, 1vh) * 100) - 120px);
  --ui-touch-target: 44px;
}

body.game-ux .ux-back-button,
body.game-ux .back-btn,
body.game-ux .back-button,
body.game-ux #backButton {
  min-height: var(--ui-touch-target) !important;
  min-width: var(--ui-touch-target) !important;
  z-index: 10020 !important;
}

body.game-ux .dashboard-btn,
body.game-ux .gallery-btn {
  border: 0;
  border-radius: 10px;
  color: #fff;
  font-weight: 700;
  padding: 12px 18px;
  min-height: var(--ui-touch-target) !important;
  cursor: pointer;
}

body.game-ux .dashboard-btn {
  background: linear-gradient(45deg, #27ae60, #2ecc71);
}

body.game-ux .gallery-btn {
  background: linear-gradient(45deg, #f39c12, #e67e22);
}

body.game-ux .ux-back-button {
  position: fixed;
  top: calc(var(--safe-top, 0px) + 88px);
  left: 12px;
  border: 0;
  border-radius: 999px;
  background: linear-gradient(45deg, #667eea, #764ba2);
  color: #fff;
  font-weight: bold;
  padding: 10px 16px;
  cursor: pointer;
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.35);
  transition: opacity 0.2s ease, transform 0.2s ease;
}

body.game-ux .gnb {
  transition: transform 0.22s ease, opacity 0.22s ease !important;
}

body.game-ux.is-playing {
  padding-top: 0 !important;
}

body.game-ux.is-playing .gnb {
  transform: translateY(-120%) !important;
  opacity: 0 !important;
  pointer-events: none !important;
}

body.game-ux.is-playing .ux-back-button,
body.game-ux.is-playing .back-btn,
body.game-ux.is-playing .back-button,
body.game-ux.is-playing #backButton {
  opacity: 0 !important;
  visibility: hidden !important;
  pointer-events: none !important;
  transform: translateY(-8px) !important;
}

body.game-ux.is-overlay .ux-back-button,
body.game-ux.is-overlay .back-btn,
body.game-ux.is-overlay .back-button,
body.game-ux.is-overlay #backButton {
  opacity: 1 !important;
  visibility: visible !important;
  pointer-events: auto !important;
}

@media (max-width: 767px) {
  .game-start,
  .game-over,
  .game-over-popup,
  #startScreen,
  #gameOver,
  #stageSummary,
  #gameStartPopup,
  #gameOverPopup {
    max-height: var(--ui-popup-max-height) !important;
    overflow-y: auto !important;
    -webkit-overflow-scrolling: touch;
    width: min(100%, calc(100dvw - 16px)) !important;
    max-width: var(--ui-popup-max-width) !important;
  }

  .start-btn,
  .login-btn,
  .play-btn,
  .restart-btn,
  .game-over-btn,
  .popup-button,
  #continueBtn,
  .filter-btn,
  .feedback-form button {
    min-height: var(--ui-touch-target) !important;
    font-size: 14px !important;
  }

  .popup-content,
  .feedback-form {
    gap: var(--ui-space-2);
  }

  .popup-content li,
  .feedback-form label {
    line-height: 1.4;
  }
}

@media (max-width: 430px) {
  :root {
    --ui-popup-max-width: calc(100dvw - 12px);
  }
}