/* ==========================================================================
   🎨 PASSION MATE - PREMIUM DESIGN SYSTEM (GLASSMORPHISM & SLICK DARK)
   ========================================================================== */

/* 1. 디자인 시스템 토큰 및 변수 선언 */
:root {
  --bg-primary: #080c14;
  --bg-secondary: #0f1626;
  --bg-tertiary: #17223b;
  
  /* Glassmorphism */
  --glass-bg: rgba(15, 22, 38, 0.55);
  --glass-bg-hover: rgba(23, 34, 59, 0.7);
  --glass-border: rgba(255, 255, 255, 0.06);
  --glass-border-glow: rgba(139, 92, 246, 0.25);
  
  /* Neon Palette */
  --neon-mint: #00f2fe;
  --neon-mint-glow: rgba(0, 242, 254, 0.3);
  --neon-purple: #8b5cf6;
  --neon-purple-glow: rgba(139, 92, 246, 0.4);
  --neon-green: #10b981;
  --neon-green-glow: rgba(16, 185, 129, 0.35);
  --neon-coral: #ff4a5a;
  
  /* Typography Colors */
  --text-main: #f8fafc;
  --text-body: #cbd5e1;
  --text-muted: #64748b;
  
  /* Transitions */
  --transition-smooth: all 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  --font-display: 'Outfit', 'Noto Sans KR', sans-serif;
}

/* 2. 전역 스타일 및 초기화 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: var(--font-display);
  -webkit-tap-highlight-color: transparent; /* 모바일 터치 깜빡임 방지 */
}

body {
  background-color: var(--bg-primary);
  color: var(--text-main);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  overflow-x: hidden;
  background-image: 
    radial-gradient(circle at 10% 20%, rgba(139, 92, 246, 0.08) 0%, transparent 40%),
    radial-gradient(circle at 90% 80%, rgba(0, 242, 254, 0.06) 0%, transparent 40%);
  background-attachment: fixed;
}

/* 스크롤바 커스텀 */
::-webkit-scrollbar {
  width: 5px;
}
::-webkit-scrollbar-track {
  background: var(--bg-primary);
}
::-webkit-scrollbar-thumb {
  background: var(--bg-tertiary);
  border-radius: 10px;
}

/* 3. 모바일 레이아웃 컨테이너 */
.app-container {
  width: 100%;
  max-width: 480px; /* 데스크톱에서 볼 때 스마트폰 비율 고정 */
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: rgba(8, 12, 20, 0.8);
  border-left: 1px solid rgba(255, 255, 255, 0.03);
  border-right: 1px solid rgba(255, 255, 255, 0.03);
  position: relative;
}

/* 4. 고정 헤더 */
.app-header {
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 18px 20px;
  background: rgba(8, 12, 20, 0.7);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--glass-border);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
}

.logo-accent {
  color: var(--neon-mint);
  font-size: 1.3rem;
  text-shadow: 0 0 10px var(--neon-mint-glow);
  animation: logo-pulse 2s infinite alternate;
}

.logo h1 {
  font-size: 1.15rem;
  font-weight: 800;
  letter-spacing: 0.5px;
}

.logo h1 span {
  color: var(--text-muted);
  font-weight: 400;
}

.status-indicator {
  font-size: 0.75rem;
  color: var(--text-body);
  background: rgba(255, 255, 255, 0.04);
  padding: 4px 10px;
  border-radius: 20px;
  border: 1px solid rgba(255, 255, 255, 0.05);
}

.dot {
  display: inline-block;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  margin-right: 4px;
}

.dot.live {
  background-color: var(--neon-green);
  box-shadow: 0 0 8px var(--neon-green-glow);
}

/* 5. 메인 스크롤 콘텐츠 영역 */
.app-content {
  flex: 1;
  padding: 20px 16px 95px 16px; /* 하단 내비게이션 여유 마진 */
  overflow-y: auto;
}

.app-view {
  display: none;
  animation: fade-in 0.4s ease-out forwards;
}

.app-view.active {
  display: block;
}

/* 6. 프리미엄 Glassmorphism 카드 */
.glass-card {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: 18px;
  padding: 20px;
  margin-bottom: 20px;
  backdrop-filter: blur(16px) saturate(180%);
  -webkit-backdrop-filter: blur(16px) saturate(180%);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.25);
  transition: var(--transition-smooth);
}

.glass-card:hover {
  background: var(--glass-bg-hover);
  border-color: rgba(255, 255, 255, 0.1);
}

/* 웰컴 카드 타이틀 */
.welcome-card h2 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 6px;
  background: linear-gradient(135deg, var(--text-main) 30%, #a78bfa 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.welcome-card p {
  font-size: 0.85rem;
  color: var(--text-body);
  line-height: 1.4;
  margin-bottom: 18px;
}

/* 7. 학생 선택 디자인 */
.input-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-group label {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-body);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.custom-select-wrapper {
  position: relative;
  width: 100%;
}

.custom-select {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 0.95rem;
  outline: none;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  transition: var(--transition-smooth);
}

.custom-select:focus {
  border-color: var(--neon-purple);
  box-shadow: 0 0 12px rgba(139, 92, 246, 0.25);
}

.custom-select-wrapper::after {
  content: '\f107';
  font-family: 'Font Awesome 6 Free';
  font-weight: 900;
  position: absolute;
  right: 16px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-body);
  pointer-events: none;
}

/* 8. 펄싱 네온 타이머 그래픽 디스플레이 */
.timer-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin: 30px 0;
}

.timer-outer-ring {
  width: 250px;
  height: 250px;
  border-radius: 50%;
  background: conic-gradient(from 0deg, var(--bg-tertiary) 0%, var(--bg-tertiary) 100%);
  display: flex;
  justify-content: center;
  align-items: center;
  transition: var(--transition-smooth);
  box-shadow: 0 0 30px rgba(0, 0, 0, 0.2);
}

/* 타이머 동작 중(ACTIVE)일 때 링 상태 */
.timer-outer-ring.active {
  background: conic-gradient(from 0deg, var(--neon-purple) 0%, var(--neon-mint) 50%, var(--neon-purple) 100%);
  animation: spin-gradient 4s linear infinite;
  box-shadow: 0 0 40px rgba(139, 92, 246, 0.25);
}

.timer-inner-ring {
  width: 236px;
  height: 236px;
  border-radius: 50%;
  background: var(--bg-primary);
  display: flex;
  justify-content: center;
  align-items: center;
}

.timer-display {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.timer-digits {
  font-family: 'Outfit', sans-serif;
  font-size: 2.3rem;
  font-weight: 800;
  letter-spacing: 1px;
  color: var(--text-main);
  text-shadow: 0 0 10px rgba(255, 255, 255, 0.1);
  transition: var(--transition-smooth);
}

.timer-outer-ring.active .timer-digits {
  color: var(--neon-mint);
  text-shadow: 0 0 15px var(--neon-mint-glow);
}

.timer-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 2px;
  margin-top: 4px;
  transition: var(--transition-smooth);
}

.timer-outer-ring.active .timer-label {
  color: var(--neon-green);
  text-shadow: 0 0 8px var(--neon-green-glow);
}

/* 실시간 상태 배지 */
.timer-info-badge {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-top: 20px;
  background: rgba(255, 255, 255, 0.05);
  padding: 6px 14px;
  border-radius: 30px;
  border: 1px solid var(--glass-border);
}

.badge-instrument {
  background: var(--neon-purple);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 8px;
}

.badge-name {
  font-size: 0.85rem;
  font-weight: 600;
}

/* 9. 버튼 제어 */
.timer-controls {
  margin-top: 24px;
  width: 100%;
  max-width: 220px;
}

.btn {
  width: 100%;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  border: none;
  outline: none;
  font-weight: 700;
  font-size: 0.95rem;
  padding: 14px 24px;
  border-radius: 14px;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn-lg {
  padding: 16px 28px;
  border-radius: 16px;
  font-size: 1rem;
}

.btn-primary {
  background: linear-gradient(135deg, var(--neon-purple) 0%, #6d28d9 100%);
  color: var(--text-main);
  box-shadow: 0 6px 20px rgba(139, 92, 246, 0.35);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(139, 92, 246, 0.5);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(1px);
}

/* 연습 종료 모드의 네온 코랄 버튼 */
.btn-primary.end-mode {
  background: linear-gradient(135deg, var(--neon-coral) 0%, #dc2626 100%);
  box-shadow: 0 6px 20px rgba(255, 74, 90, 0.35);
}

.btn-primary.end-mode:hover:not(:disabled) {
  box-shadow: 0 8px 25px rgba(255, 74, 90, 0.5);
}

.btn:disabled {
  background: var(--bg-tertiary);
  color: var(--text-muted);
  box-shadow: none;
  cursor: not-allowed;
  opacity: 0.6;
}

.btn-secondary {
  background: var(--bg-tertiary);
  color: var(--text-main);
  border: 1px solid var(--glass-border);
}

.btn-secondary:hover {
  background: var(--glass-bg-hover);
  border-color: var(--text-muted);
}

/* 10. 이력 및 리스트 스타일 */
.history-card h3, .dashboard-card h3 {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-body);
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 6px;
}

.history-list, .active-list, .timeline-container {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.history-item, .active-item, .timeline-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.03);
  padding: 12px 16px;
  border-radius: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.item-left {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.item-title {
  font-size: 0.88rem;
  font-weight: 600;
}

.item-subtitle {
  font-size: 0.75rem;
  color: var(--text-muted);
}

.item-right {
  display: flex;
  align-items: center;
  gap: 6px;
}

.duration-tag {
  background: rgba(0, 242, 254, 0.08);
  color: var(--neon-mint);
  border: 1px solid rgba(0, 242, 254, 0.15);
  padding: 3px 8px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 700;
}

.empty-placeholder {
  text-align: center;
  padding: 24px 0;
  color: var(--text-muted);
  font-size: 0.8rem;
}

.empty-placeholder i {
  font-size: 1.5rem;
  margin-bottom: 8px;
  display: block;
}

/* 11. 교사 대시보드 - 요약 그리드 */
.dashboard-stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-bottom: 20px;
}

.stat-item {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 14px;
  margin-bottom: 0; /* 그리드 마진 상쇄 */
}

.stat-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 1.25rem;
}

.icon-neon-green {
  background: rgba(16, 185, 129, 0.1);
  color: var(--neon-green);
  border: 1px solid rgba(16, 185, 129, 0.2);
}

.icon-neon-purple {
  background: rgba(139, 92, 246, 0.1);
  color: var(--neon-purple);
  border: 1px solid rgba(139, 92, 246, 0.2);
}

.stat-content {
  display: flex;
  flex-direction: column;
}

.stat-value {
  font-size: 1.4rem;
  font-weight: 800;
  line-height: 1.1;
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 2px;
}

/* 실시간 현황 헤더 */
.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}

.card-header h3 {
  margin-bottom: 0;
}

.pulse-indicator {
  display: inline-block;
  width: 8px;
  height: 8px;
  background-color: var(--neon-green);
  border-radius: 50%;
  animation: pulse-ring 1.5s infinite;
  margin-right: 4px;
}

.badge {
  font-size: 0.65rem;
  font-weight: 800;
  padding: 2px 6px;
  border-radius: 4px;
  letter-spacing: 0.5px;
}

.badge-live {
  background: rgba(16, 185, 129, 0.15);
  color: var(--neon-green);
  border: 1px solid rgba(16, 185, 129, 0.3);
}

/* 실시간 연습 중 학생 리스트 */
.active-item {
  border-left: 3px solid var(--neon-green);
  box-shadow: 0 4px 15px rgba(16, 185, 129, 0.05);
}

.active-time-elapsed {
  color: var(--neon-green);
  font-size: 0.75rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 4px;
}

/* 12. 랭킹 디자인 (왕관 등) */
.ranking-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.ranking-item {
  display: flex;
  align-items: center;
  gap: 12px;
  position: relative;
}

.rank-number {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background: var(--bg-tertiary);
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 0.8rem;
  font-weight: 700;
}

.ranking-item:nth-child(1) .rank-number {
  background: #fbbf24;
  color: #78350f;
  box-shadow: 0 0 10px rgba(251, 191, 36, 0.4);
}
.ranking-item:nth-child(2) .rank-number {
  background: #cbd5e1;
  color: #334155;
}
.ranking-item:nth-child(3) .rank-number {
  background: #b45309;
  color: #fff;
}

.rank-details {
  flex: 1;
}

.rank-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 5px;
}

.rank-name {
  font-size: 0.85rem;
  font-weight: 600;
}

.rank-instrument {
  font-size: 0.7rem;
  color: var(--text-muted);
  margin-left: 4px;
}

.rank-time {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--neon-mint);
}

/* 누적 프로그레스 바 */
.rank-progress-bg {
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 10px;
  overflow: hidden;
}

.rank-progress-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--neon-purple) 0%, var(--neon-mint) 100%);
  border-radius: 10px;
  width: 0; /* JS로 조절 */
  transition: width 1s ease-out;
}

/* 13. 신규 입시생 등록 관리자 폼 */
.admin-card {
  border-color: rgba(139, 92, 246, 0.15);
}

.admin-form {
  margin-top: 10px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr auto;
  gap: 8px;
  align-items: center;
}

.form-row input {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 10px 14px;
  border-radius: 10px;
  font-size: 0.85rem;
  outline: none;
  transition: var(--transition-smooth);
}

.form-row input:focus {
  border-color: var(--neon-purple);
  box-shadow: 0 0 8px rgba(139, 92, 246, 0.2);
}

.form-row button {
  padding: 10px 16px;
  font-size: 0.85rem;
  border-radius: 10px;
  width: auto;
}

/* 14. 하단 고정 내비게이션 바 */
.app-navbar {
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  z-index: 100;
  height: 75px;
  background: rgba(15, 22, 38, 0.85);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-top: 1px solid var(--glass-border);
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  padding: 8px 10px;
}

.nav-item {
  background: none;
  border: none;
  outline: none;
  color: var(--text-muted);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 4px;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.nav-icon {
  font-size: 1.25rem;
  transition: var(--transition-smooth);
}

.nav-text {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.5px;
}

/* 선택된 탭 활성화 상태 */
.nav-item.active {
  color: var(--neon-mint);
  text-shadow: 0 0 10px var(--neon-mint-glow);
}

.nav-item.active .nav-icon {
  transform: translateY(-2px);
  color: var(--neon-mint);
}

/* 15. 토스트 알림 메시지 */
#toast-container {
  position: fixed;
  bottom: 90px; /* 탭바 바로 위 */
  left: 50%;
  transform: translateX(-50%);
  z-index: 1000;
  width: 90%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}

.toast {
  background: rgba(15, 22, 38, 0.95);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 12px 18px;
  border-radius: 12px;
  font-size: 0.85rem;
  font-weight: 500;
  display: flex;
  align-items: center;
  gap: 10px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.35);
  backdrop-filter: blur(10px);
  animation: slide-up 0.35s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
  pointer-events: auto;
}

.toast.success {
  border-left: 3px solid var(--neon-green);
}
.toast.success i {
  color: var(--neon-green);
}

.toast.error {
  border-left: 3px solid var(--neon-coral);
}
.toast.error i {
  color: var(--neon-coral);
}

/* ==========================================================================
   🌀 KEYFRAME ANIMATIONS (DYNAMIC EFFECTS)
   ========================================================================== */

@keyframes logo-pulse {
  from {
    opacity: 0.8;
    text-shadow: 0 0 8px var(--neon-mint-glow);
  }
  to {
    opacity: 1;
    text-shadow: 0 0 15px var(--neon-mint);
  }
}

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes slide-up {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes spin-gradient {
  0% {
    background: conic-gradient(from 0deg, var(--neon-purple) 0%, var(--neon-mint) 50%, var(--neon-purple) 100%);
  }
  100% {
    background: conic-gradient(from 360deg, var(--neon-purple) 0%, var(--neon-mint) 50%, var(--neon-purple) 100%);
  }
}

@keyframes pulse-ring {
  0% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7);
  }
  70% {
    transform: scale(1);
    box-shadow: 0 0 0 6px rgba(16, 185, 129, 0);
  }
  100% {
    transform: scale(0.95);
    box-shadow: 0 0 0 0 rgba(16, 185, 129, 0);
  }
}

/* 미디어 쿼리 - 뷰포트 확대 축소 시 유연하게 대처 */
@media (max-height: 700px) {
  .timer-outer-ring {
    width: 200px;
    height: 200px;
  }
  .timer-inner-ring {
    width: 188px;
    height: 188px;
  }
  .timer-digits {
    font-size: 1.9rem;
  }
  .timer-section {
    margin: 15px 0;
  }
}

/* ==========================================================================
   🤖 PASSION AI TUTOR CHATBOARD UI (PREMIUM STYLING)
   ========================================================================== */

.chat-card {
  display: flex;
  flex-direction: column;
  height: 480px;
  padding: 15px !important;
  border-color: var(--glass-border-glow);
}

.chat-messages-container {
  flex: 1;
  overflow-y: auto;
  padding-right: 4px;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 12px;
}

.chat-message {
  display: flex;
  width: 100%;
}

.chat-message.tutor {
  justify-content: flex-start;
}

.chat-message.user {
  justify-content: flex-end;
}

.message-bubble {
  max-width: 85%;
  padding: 12px 16px;
  font-size: 0.88rem;
  line-height: 1.5;
  border-radius: 16px;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
  word-break: break-word;
  white-space: pre-line;
}

.chat-message.tutor .message-bubble {
  background: var(--bg-tertiary);
  color: var(--text-main);
  border: 1px solid var(--glass-border);
  border-top-left-radius: 4px;
}

.chat-message.user .message-bubble {
  background: linear-gradient(135deg, var(--neon-purple) 0%, #6d28d9 100%);
  color: #ffffff;
  border-top-right-radius: 4px;
  box-shadow: 0 4px 15px var(--neon-purple-glow);
}

/* AI 타이핑 인디케이터 (Typing Indicator) */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 4px;
  padding: 8px 12px;
}

.typing-dot {
  width: 6px;
  height: 6px;
  background-color: var(--text-muted);
  border-radius: 50%;
  animation: typing-bounce 1.4s infinite ease-in-out both;
}

.typing-dot:nth-child(1) {
  animation-delay: -0.32s;
}

.typing-dot:nth-child(2) {
  animation-delay: -0.16s;
}

@keyframes typing-bounce {
  0%, 80%, 100% {
    transform: scale(0);
    opacity: 0.4;
  }
  40% {
    transform: scale(1);
    opacity: 1;
  }
}

/* 채팅 입력 폼 디자인 */
.chat-input-form {
  display: flex;
  gap: 8px;
  background: rgba(8, 12, 20, 0.5);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  padding: 6px;
  align-items: center;
}

.chat-input-form input {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-main);
  font-size: 0.9rem;
  padding: 8px 12px;
}

.chat-input-form input::placeholder {
  color: var(--text-muted);
}

.btn-chat-send {
  background: linear-gradient(135deg, var(--neon-purple) 0%, var(--neon-mint) 100%);
  border: none;
  outline: none;
  color: #ffffff;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  transition: var(--transition-smooth);
}

.btn-chat-send:hover {
  transform: scale(1.05);
  box-shadow: 0 0 10px var(--neon-mint-glow);
}

.btn-chat-send:active {
  transform: scale(0.95);
}

/* 모바일 키보드 대응 및 스크롤 패딩 */
@media (max-height: 740px) {
  .chat-card {
    height: 380px;
  }
}

/* ==========================================================================
   📋 PASSION STUDENT PRACTICE PLAN CHECKLIST (PREMIUM STYLING)
   ========================================================================== */

.plan-card {
  border-color: rgba(0, 242, 254, 0.18) !important;
  box-shadow: 0 10px 30px rgba(0, 242, 254, 0.05);
}

.plan-list {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 15px;
}

.plan-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid rgba(255, 255, 255, 0.03);
  padding: 14px 16px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  transition: var(--transition-smooth);
}

.plan-item:hover {
  background: rgba(255, 255, 255, 0.04);
  border-color: rgba(0, 242, 254, 0.15);
}

/* 네온 커스텀 체크박스 라벨 컨테이너 */
.checkbox-container {
  display: flex;
  align-items: center;
  position: relative;
  padding-left: 32px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 500;
  user-select: none;
  width: 100%;
}

/* 기본 체크박스 숨기기 */
.checkbox-container input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

/* 커스텀 체크박스 형태 */
.checkmark {
  position: absolute;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  height: 20px;
  width: 20px;
  background-color: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.15);
  border-radius: 6px;
  transition: var(--transition-smooth);
}

/* 호버 시 테두리 민트 네온 효과 */
.checkbox-container:hover input ~ .checkmark {
  border-color: var(--neon-mint);
  box-shadow: 0 0 8px rgba(0, 242, 254, 0.25);
}

/* 체크되었을 때 스타일 */
.checkbox-container input:checked ~ .checkmark {
  background-color: var(--neon-mint);
  border-color: var(--neon-mint);
  box-shadow: 0 0 10px var(--neon-mint-glow);
}

/* 체크 표시 아이콘 구현 (가상 요소) */
.checkmark:after {
  content: "";
  position: absolute;
  display: none;
}

.checkbox-container input:checked ~ .checkmark:after {
  display: block;
}

.checkbox-container .checkmark:after {
  left: 7px;
  top: 3px;
  width: 5px;
  height: 10px;
  border: solid #080c14; /* 어두운 백그라운드 색상으로 체크 모양 가독성 확보 */
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

/* 체크 시 텍스트 스타일 변환 (완료 취소선 & 흐리게 효과) */
.plan-text {
  color: var(--text-main);
  transition: var(--transition-smooth);
  line-height: 1.4;
  flex: 1;
}

.checkbox-container input:checked ~ .plan-text {
  text-decoration: line-through;
  opacity: 0.5;
  color: var(--text-muted);
}

/* ==========================================================================
   🔑 PASSION STUDENT LOGIN & LOGOUT FORM (PREMIUM STYLING)
   ========================================================================== */

.login-input-wrapper {
  display: flex;
  gap: 10px;
  width: 100%;
  margin-top: 5px;
}

.custom-input-text {
  flex: 1;
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 12px 16px;
  border-radius: 12px;
  font-size: 0.95rem;
  outline: none;
  transition: var(--transition-smooth);
}

.custom-input-text:focus {
  border-color: var(--neon-purple);
  box-shadow: 0 0 12px rgba(139, 92, 246, 0.25);
}

.btn-login-submit {
  width: 80px !important;
  padding: 12px 16px !important;
  font-size: 0.9rem !important;
  border-radius: 12px !important;
  background: linear-gradient(135deg, var(--neon-purple) 0%, #6d28d9 100%) !important;
  color: var(--text-main) !important;
  box-shadow: 0 4px 15px rgba(139, 92, 246, 0.25) !important;
  font-weight: 700;
  border: none !important;
}

.btn-login-submit:hover {
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(139, 92, 246, 0.45) !important;
}

.btn-logout {
  background: rgba(255, 74, 90, 0.08);
  border: 1px solid rgba(255, 74, 90, 0.2);
  color: var(--neon-coral);
  padding: 4px 10px;
  border-radius: 8px;
  font-size: 0.72rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: var(--transition-smooth);
  margin-left: auto; /* 우측 정렬 */
}

.btn-logout:hover {
  background: rgba(255, 74, 90, 0.18);
  box-shadow: 0 0 8px rgba(255, 74, 90, 0.25);
  transform: translateY(-1px);
}

.btn-logout:active {
  transform: translateY(1px);
}

/* ==========================================================================
   📥 PASSION STUDENT & TEACHER Q&A (PREMIUM STYLING)
   ========================================================================== */

.custom-textarea {
  width: 100%;
  background: var(--bg-tertiary);
  border: 1px solid var(--glass-border);
  color: var(--text-main);
  padding: 12px;
  border-radius: 12px;
  font-size: 0.9rem;
  font-family: var(--font-display);
  outline: none;
  transition: var(--transition-smooth);
}

.custom-textarea:focus {
  border-color: var(--neon-mint);
  box-shadow: 0 0 12px rgba(0, 242, 254, 0.25);
}

.qa-history-list {
  margin-top: 10px;
}

.qa-history-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--glass-border);
  border-radius: 12px;
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  transition: var(--transition-smooth);
}

.qa-history-item:hover {
  background: rgba(255, 255, 255, 0.04);
  border-color: rgba(255, 255, 255, 0.1);
}

.qa-history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.qa-time {
  font-size: 0.72rem;
  color: var(--text-muted);
}

.qa-status-badge {
  font-size: 0.72rem;
  font-weight: 600;
  padding: 3px 8px;
  border-radius: 6px;
  border: 1px solid transparent;
}

.qa-status-badge.waiting {
  background: rgba(251, 191, 36, 0.08);
  color: #fbbf24;
  border-color: rgba(251, 191, 36, 0.15);
}

.qa-status-badge.answered {
  background: rgba(16, 185, 129, 0.08);
  color: var(--neon-green);
  border-color: rgba(16, 185, 129, 0.15);
}

.qa-text {
  font-size: 0.88rem;
  color: var(--text-body);
  line-height: 1.4;
  word-break: break-all;
}

/* Teacher Dashboard Q&A Cards */
.qa-card-item {
  background: rgba(255, 255, 255, 0.02);
  border: 1px solid var(--glass-border);
  border-radius: 14px;
  padding: 15px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transition: var(--transition-smooth);
}

.qa-card-item:hover {
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--glass-border-glow);
  box-shadow: 0 4px 20px rgba(139, 92, 246, 0.08);
}

.qa-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.qa-card-student-info {
  display: flex;
  align-items: center;
  gap: 8px;
}

.qa-student-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.qa-student-instrument {
  font-size: 0.72rem;
  background: rgba(139, 92, 246, 0.1);
  color: var(--neon-purple);
  padding: 2px 6px;
  border-radius: 6px;
  font-weight: 500;
}

.qa-btn-resolve {
  background: rgba(16, 185, 129, 0.08);
  border: 1px solid rgba(16, 185, 129, 0.2);
  color: var(--neon-green);
  padding: 6px 14px;
  border-radius: 8px;
  font-size: 0.8rem;
  font-weight: 600;
  cursor: pointer;
  align-self: flex-end;
  display: flex;
  align-items: center;
  gap: 4px;
  transition: var(--transition-smooth);
  border: none;
}

.qa-btn-resolve:hover {
  background: rgba(16, 185, 129, 0.18);
  box-shadow: 0 0 10px rgba(16, 185, 129, 0.25);
  transform: translateY(-1px);
}

/* 🔮 실시간 Q&A 피드백 트랜지션 애니메이션 효과 */
.qa-history-item {
  animation: slideInUp 0.5s cubic-bezier(0.16, 1, 0.3, 1) both;
  transition: all 0.4s ease;
  margin-bottom: 12px;
}

.qa-answer-block {
  animation: fadeInDown 0.6s cubic-bezier(0.16, 1, 0.3, 1) both;
  box-shadow: 0 4px 20px rgba(16, 185, 129, 0.1);
}

@keyframes slideInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* 📶 학원 와이파이 불안정 및 오프라인 상태 감지 안심 배너 스타일 */
.network-status-banner {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 9999;
  background: rgba(239, 68, 68, 0.95);
  color: #ffffff;
  text-align: center;
  padding: 8px 16px;
  font-size: 0.8rem;
  font-weight: 700;
  box-shadow: 0 4px 15px rgba(239, 68, 68, 0.4);
  backdrop-filter: blur(8px);
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 8px;
  transform: translateY(-100%);
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  pointer-events: none;
}

.network-status-banner.active {
  transform: translateY(0);
  pointer-events: auto;
}

.wifi-pulse-dot {
  width: 8px;
  height: 8px;
  background: #ffffff;
  border-radius: 50%;
  box-shadow: 0 0 8px #ffffff;
  animation: wifi-pulse-key 1.5s infinite;
}

@keyframes wifi-pulse-key {
  0% { transform: scale(0.9); opacity: 0.6; }
  50% { transform: scale(1.1); opacity: 1; box-shadow: 0 0 12px #ffffff; }
  100% { transform: scale(0.9); opacity: 0.6; }
}