/* ==========================================
   0. CSS 변수 및 전역 스타일
   ========================================== */
:root {
  --bg-color: #0b0d19; /* 매우 세련된 딥 블루 블랙 */
  --card-bg-active: rgba(255, 255, 255, 0.15);
  --card-bg-inactive: rgba(255, 255, 255, 0.04);
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --neon-green: #39ff14;
  --neon-blue: #00f0ff;
  --neon-gold: #ffd700;
  --neon-pink: #ff007f;
  
  --glass-border: rgba(255, 255, 255, 0.08);
  --glass-shadow: 0 8px 32px 0 rgba(0, 0, 0, 0.37);
  --glass-blur: blur(20px);
  
  --font-title: 'Outfit', 'Noto Sans KR', sans-serif;
  --font-body: 'Noto Sans KR', sans-serif;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent; /* 모바일 터치 하이라이트 투명화 */
  user-select: none; /* 텍스트 선택 방지 */
  -webkit-user-select: none;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden; /* 스크롤바 방지 */
  background-color: var(--bg-color);
  font-family: var(--font-body);
  color: var(--text-primary);
}

/* ==========================================
   1. 레이아웃 구조 (App Container)
   ========================================== */
#app-container {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  position: relative;
  background: radial-gradient(circle at 50% 30%, #151a30 0%, #0b0d19 80%);
}

/* ==========================================
   2. 상단 HUD 헤더 스타일
   ========================================== */
#hud-header {
  padding: 1.25rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  z-index: 10;
  background: linear-gradient(to bottom, rgba(11, 13, 25, 0.8), rgba(11, 13, 25, 0));
  backdrop-filter: blur(5px);
  -webkit-backdrop-filter: blur(5px);
}

.logo-area h1 {
  font-family: var(--font-title);
  font-size: 1.4rem;
  font-weight: 800;
  letter-spacing: 0.1rem;
  background: linear-gradient(135deg, #00f0ff, #ff007f);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  text-shadow: 0 0 15px rgba(0, 240, 255, 0.2);
}

.logo-area .sub-logo {
  font-family: var(--font-title);
  font-size: 0.75rem;
  font-weight: 400;
  color: var(--text-secondary);
  letter-spacing: 0.15rem;
  text-transform: uppercase;
  display: block;
}

.control-panel {
  display: flex;
  gap: 0.75rem;
}

.hud-btn {
  background: var(--card-bg-inactive);
  border: 1px solid var(--glass-border);
  color: var(--text-secondary);
  width: 2.75rem;
  height: 2.75rem;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: var(--glass-shadow);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
}

.hud-btn:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 255, 255, 0.2);
  color: var(--text-primary);
}

.hud-btn.active {
  color: #00f0ff;
  border-color: rgba(0, 240, 255, 0.3);
  background: rgba(0, 240, 255, 0.08);
  box-shadow: 0 0 15px rgba(0, 240, 255, 0.15);
}

#btn-freeze-toggle.active {
  color: #a5f3fc;
  border-color: rgba(165, 243, 252, 0.4);
  background: rgba(165, 243, 252, 0.12);
  box-shadow: 0 0 18px rgba(165, 243, 252, 0.35);
  animation: pulseFreeze 2s infinite ease-in-out;
}

@keyframes pulseFreeze {
  0%, 100% { box-shadow: 0 0 10px rgba(165, 243, 252, 0.2); }
  50% { box-shadow: 0 0 22px rgba(165, 243, 252, 0.5); }
}

.hud-btn.reset-btn:active {
  transform: rotate(180deg) scale(0.9);
}

/* ==========================================
   3. 중앙 시뮬레이션 영역 (Viewport)
   ========================================== */
.viewport-area {
  flex-grow: 1;
  position: relative;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  touch-action: none; /* 브라우저 드래그 및 줌 원천 차단 */
}

#physics-canvas {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  touch-action: none;
}

/* 플로팅 상태 카드 */
.status-floating-card {
  position: absolute;
  top: 1rem;
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  padding: 0.5rem 1rem;
  display: flex;
  align-items: center;
  gap: 0.75rem;
  box-shadow: var(--glass-shadow);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  pointer-events: none; /* 마우스 이벤트 무시 */
  transition: all 0.3s ease;
}

.status-badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 0.25rem 0.5rem;
  background: rgba(0, 240, 255, 0.15);
  color: #00f0ff;
  border-radius: 6px;
  text-transform: uppercase;
  letter-spacing: 0.05rem;
  border: 1px solid rgba(0, 240, 255, 0.2);
}

.ball-name {
  font-family: var(--font-title);
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-primary);
}

/* 첫 시작 안내 오버레이 */
.guide-overlay {
  position: absolute;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  pointer-events: none;
  animation: fadeOut 0.5s ease forwards;
  animation-play-state: paused; /* 사용자가 터치하면 실행 */
  z-index: 5;
}

.finger-animation {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  border: 2px solid rgba(255, 255, 255, 0.4);
  position: relative;
  animation: pulseTouch 2s infinite ease-in-out;
}

.finger-animation::after {
  content: '';
  width: 16px;
  height: 16px;
  background: rgba(0, 240, 255, 0.5);
  border-radius: 50%;
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  box-shadow: 0 0 15px #00f0ff;
}

.guide-overlay p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  text-shadow: 0 2px 10px rgba(0, 0, 0, 0.5);
  text-align: center;
}

/* ==========================================
   4. 하단 스킨 선택 푸터
   ========================================== */
#skin-selection-footer {
  padding: 1.5rem;
  z-index: 10;
  background: linear-gradient(to top, rgba(11, 13, 25, 0.9), rgba(11, 13, 25, 0));
}

.deck-scroll-container {
  display: flex;
  gap: 1rem;
  overflow-x: auto;
  padding: 0.5rem 0.25rem;
  scrollbar-width: none; /* Firefox 스크롤바 숨김 */
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
}

.deck-scroll-container::-webkit-scrollbar {
  display: none; /* Chrome 스크롤바 숨김 */
}

.skin-card {
  flex: 0 0 auto;
  width: 140px;
  background: var(--card-bg-inactive);
  border: 1px solid var(--glass-border);
  border-radius: 16px;
  padding: 0.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  cursor: pointer;
  transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
  scroll-snap-align: center;
  box-shadow: var(--glass-shadow);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
  outline: none;
}

.skin-card:hover {
  transform: translateY(-6px);
  border-color: rgba(255, 255, 255, 0.15);
}

.skin-card.active {
  background: var(--card-bg-active);
  border-color: rgba(0, 240, 255, 0.4);
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.15), inset 0 0 10px rgba(0, 240, 255, 0.05);
}

.skin-card.active .skin-title {
  color: #00f0ff;
  font-weight: 700;
}

/* 스킨 썸네일 그래픽 */
.skin-thumbnail {
  width: 70px;
  height: 70px;
  border-radius: 50%;
  margin-bottom: 0.75rem;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 2px 10px rgba(255, 255, 255, 0.2), 0 4px 10px rgba(0,0,0,0.3);
  background-color: #333;
}

/* 1. 청사과 썸네일 */
.apple-thumb {
  background: radial-gradient(circle at 35% 35%, #76ff03 0%, #33691e 80%);
}
.apple-thumb .inner-liquid {
  width: 40px;
  height: 40px;
  background: rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  position: absolute;
  top: 10px;
  left: 10px;
  filter: blur(2px);
}
.apple-thumb .mini-apples {
  width: 10px;
  height: 10px;
  background: #d84315;
  border-radius: 50%;
  position: absolute;
  bottom: 12px;
  right: 12px;
  box-shadow: -15px -15px 0 #2e7d32, -25px 0 0 #fff;
}

/* 2. 버터바 썸네일 */
.butter-thumb {
  border-radius: 8px !important;
  background: linear-gradient(135deg, #fff9c4 0%, #fbc02d 100%);
  display: flex;
  align-items: center;
  justify-content: center;
}
.butter-label {
  font-family: var(--font-title);
  font-size: 0.65rem;
  font-weight: 800;
  color: #0d47a1;
  border: 1px solid #0d47a1;
  padding: 2px 4px;
  border-radius: 3px;
  transform: rotate(-10deg);
}

/* 3. 미니 왁볼 썸네일 */
.balloon-thumb {
  background: rgba(255, 255, 255, 0.08);
  border: 2px solid rgba(255, 255, 255, 0.2);
}
.balloon-thumb .bead {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  position: absolute;
  box-shadow: inset 0 2px 4px rgba(255, 255, 255, 0.3);
}
.bead.pink { background: #ff4081; top: 12px; left: 15px; }
.bead.blue { background: #00e5ff; bottom: 12px; left: 25px; }
.bead.yellow { background: #ffea00; top: 25px; right: 12px; }

/* 4. 초코 바나나 썸네일 */
.choco-thumb {
  background: radial-gradient(circle at 35% 35%, #4e342e 0%, #271206 90%);
}
.choco-thumb .inner-banana {
  width: 25px;
  height: 25px;
  background: #ffeb3b;
  border-radius: 50%;
  position: absolute;
  bottom: 8px;
  left: 8px;
  filter: blur(1px);
}

/* 카드 텍스트 정보 */
.skin-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.skin-title {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
  transition: color 0.3s ease;
}

.skin-desc {
  font-size: 0.6rem;
  color: var(--text-secondary);
}

/* ==========================================
   5. 키프레임 애니메이션
   ========================================== */
@keyframes pulseTouch {
  0% {
    transform: scale(0.9);
    opacity: 0.8;
  }
  50% {
    transform: scale(1.1);
    opacity: 0.4;
    box-shadow: 0 0 20px rgba(0, 240, 255, 0.4);
  }
  100% {
    transform: scale(0.9);
    opacity: 0.8;
  }
}

@keyframes fadeOut {
  from {
    opacity: 1;
    transform: scale(1);
  }
  to {
    opacity: 0;
    transform: scale(0.9);
    visibility: hidden;
  }
}

/* ==========================================
   6. 가로형 데스크톱 및 반응형 스타일
   ========================================== */
@media (min-width: 768px) {
  .logo-area h1 {
    font-size: 1.6rem;
  }
  
  .hud-btn {
    width: 3rem;
    height: 3rem;
  }

  .deck-scroll-container {
    justify-content: center;
    gap: 1.5rem;
  }

  .skin-card {
    width: 160px;
    padding: 1rem;
  }

  .skin-title {
    font-size: 0.95rem;
  }

  .skin-desc {
    font-size: 0.65rem;
  }
}

/* ==========================================
   7. 클레이 늘이기 인터페이스 핸들 스타일
   ========================================== */
.handles-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 5;
}

.handles-overlay.hidden {
  display: none;
}

.clay-handle {
  position: absolute;
  top: 50%;
  width: 52px;
  height: 52px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.72);
  border: 2px solid rgba(255, 255, 255, 0.95);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.25), inset 0 0 8px rgba(255, 255, 255, 0.8);
  cursor: grab;
  pointer-events: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  touch-action: none;
  z-index: 6;
  opacity: 0;
}

#handle-left {
  left: 12%;
  transform: translate(-50%, -50%);
  animation: handleLeftFadeIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

#handle-right {
  right: 12%;
  transform: translate(50%, -50%);
  animation: handleRightFadeIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
}

.clay-handle:active {
  cursor: grabbing;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: 0 6px 20px rgba(0, 240, 255, 0.35), inset 0 0 10px rgba(255, 255, 255, 1.0);
  border-color: #00f0ff;
}

.handle-inner {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.12);
  transition: all 0.2s ease;
}

.clay-handle:active .handle-inner {
  background: #00f0ff;
  transform: scale(1.2);
  box-shadow: 0 0 8px #00f0ff;
}

.clay-handle.returning {
  transition: transform 0.38s cubic-bezier(0.175, 0.885, 0.32, 1.275), background 0.3s ease;
}

@keyframes handleLeftFadeIn {
  from {
    opacity: 0;
    transform: translate(-150%, -50%) scale(0.6);
  }
  to {
    opacity: 1;
    transform: translate(-50%, -50%) scale(1);
  }
}

@keyframes handleRightFadeIn {
  from {
    opacity: 0;
    transform: translate(150%, -50%) scale(0.6);
  }
  to {
    opacity: 1;
    transform: translate(50%, -50%) scale(1);
  }
}