/* 기본 리셋 및 변수 - 채리를 위한 특별한 색상 💕 */
:root {
  --primary-color: #FF6B9D;
  --primary-hover: #FF4785;
  --danger-color: #E74C3C;
  --danger-hover: #C0392B;
  --text-color: #333;
  --text-secondary: #666;
  --bg-color: #FFF5F8;
  --card-bg: #FFFFFF;
  --border-color: #FFE0E9;
  --star-color: #FFD700;
  --success-color: #27AE60;
  --shadow: 0 2px 8px rgba(255, 107, 157, 0.15);
  --shadow-lg: 0 4px 16px rgba(255, 107, 157, 0.2);
  --radius: 12px;
  --radius-sm: 8px;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-color);
  line-height: 1.5;
  min-height: 100vh;
}

/* 유틸리티 */
.hidden {
  display: none !important;
}

/* 버튼 스타일 */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-size: 16px;
  font-weight: 500;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease;
  min-height: 48px;
}

.btn-primary {
  background-color: var(--primary-color);
  color: white;
}

.btn-primary:hover {
  background-color: var(--primary-hover);
}

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

.btn-secondary:hover {
  background-color: var(--bg-color);
}

.btn-outline {
  background-color: transparent;
  color: var(--text-color);
  border: 2px solid var(--border-color);
}

.btn-outline:hover {
  border-color: var(--primary-color);
  color: var(--primary-color);
}

.btn-text {
  background-color: transparent;
  color: var(--text-secondary);
}

.btn-text:hover {
  color: var(--text-color);
}

.btn-danger {
  background-color: var(--danger-color);
  color: white;
}

.btn-danger:hover {
  background-color: var(--danger-hover);
}

.btn-full {
  width: 100%;
}

.btn-icon {
  background: none;
  border: none;
  padding: 8px;
  cursor: pointer;
  font-size: 18px;
  opacity: 0.7;
  transition: opacity 0.2s;
}

.btn-icon:hover {
  opacity: 1;
}

.btn-back {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: 8px;
  color: var(--text-color);
}

/* 헤더 */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-title {
  font-size: 18px;
  font-weight: 600;
  flex: 1;
  text-align: center;
}

.header-spacer {
  width: 40px;
}

/* 로그인 섹션 */
.login-section {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  padding: 20px;
}

.login-container {
  width: 100%;
  max-width: 400px;
  text-align: center;
}

.app-title {
  font-size: 28px;
  margin-bottom: 8px;
}

.app-subtitle {
  color: var(--text-secondary);
  margin-bottom: 32px;
}

.login-form {
  background-color: var(--card-bg);
  padding: 24px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.login-form label {
  display: block;
  text-align: left;
  margin-bottom: 8px;
  font-weight: 500;
}

.login-form input {
  width: 100%;
  padding: 14px 16px;
  font-size: 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}

.login-form input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.login-hint {
  margin-top: 16px;
  font-size: 14px;
  color: var(--text-secondary);
}

/* 메시지 */
.message {
  margin-top: 16px;
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  font-size: 14px;
}

.message.success {
  background-color: #D5F5E3;
  color: #1E8449;
}

.message.error {
  background-color: #FADBD8;
  color: #C0392B;
}

/* 메인 섹션 */
.main-section {
  min-height: 100vh;
}

.wordbook-list-container {
  padding: 20px;
  max-width: 600px;
  margin: 0 auto;
}

/* 단어장 목록 */
.wordbook-list {
  margin-bottom: 20px;
}

.wordbook-item {
  display: flex;
  align-items: center;
  background-color: var(--card-bg);
  padding: 16px;
  margin-bottom: 12px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.wordbook-info {
  flex: 1;
  cursor: pointer;
}

.wordbook-title {
  font-size: 16px;
  font-weight: 500;
  margin-bottom: 4px;
}

.wordbook-stats {
  font-size: 14px;
  color: var(--text-secondary);
}

.wordbook-actions {
  display: flex;
  gap: 4px;
}

/* 로딩/빈 상태 */
.loading,
.empty-message,
.error-message {
  text-align: center;
  padding: 40px 20px;
  color: var(--text-secondary);
}

.error-message {
  color: var(--danger-color);
}

/* 모달 */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.modal-backdrop {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
  position: relative;
  width: 100%;
  max-width: 400px;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  animation: modalIn 0.2s ease;
}

.modal-large {
  max-width: 500px;
}

@keyframes modalIn {
  from {
    opacity: 0;
    transform: scale(0.95);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

.modal-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  border-bottom: 1px solid var(--border-color);
}

.modal-header h2 {
  font-size: 18px;
  font-weight: 600;
}

.modal-close {
  background: none;
  border: none;
  font-size: 24px;
  cursor: pointer;
  color: var(--text-secondary);
  padding: 4px;
}

.modal-body {
  padding: 20px;
}

.modal-body label {
  display: block;
  margin-bottom: 8px;
  font-weight: 500;
}

.modal-body input[type="text"],
.modal-body input[type="email"] {
  width: 100%;
  padding: 12px 14px;
  font-size: 16px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  margin-bottom: 16px;
}

.modal-body input:focus {
  outline: none;
  border-color: var(--primary-color);
}

.modal-actions {
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  margin-top: 8px;
}

/* 대량 추가 */
.bulk-hint {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 12px;
  line-height: 1.6;
}

.bulk-textarea {
  width: 100%;
  padding: 12px 14px;
  font-size: 14px;
  font-family: monospace;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  resize: vertical;
  min-height: 150px;
}

.bulk-textarea:focus {
  outline: none;
  border-color: var(--primary-color);
}

.bulk-preview {
  margin-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.preview-success {
  color: var(--success-color);
  font-size: 14px;
}

.preview-error {
  color: var(--danger-color);
  font-size: 14px;
}

/* 단어장 상세 */
.wordbook-detail {
  padding-bottom: 200px;
}

.tab-filter {
  display: flex;
  padding: 12px 20px;
  gap: 8px;
  background-color: var(--card-bg);
  border-bottom: 1px solid var(--border-color);
}

.tab-btn {
  flex: 1;
  padding: 10px 16px;
  font-size: 14px;
  font-weight: 500;
  background-color: var(--bg-color);
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s;
}

.tab-btn.active {
  background-color: var(--primary-color);
  color: white;
}

/* 단어 목록 */
.word-list {
  padding: 16px 20px;
}

.word-item {
  display: flex;
  align-items: center;
  background-color: var(--card-bg);
  padding: 14px 16px;
  margin-bottom: 8px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow);
}

.word-item.difficult {
  border-left: 3px solid var(--star-color);
}

.word-star {
  font-size: 20px;
  cursor: pointer;
  padding: 4px 8px 4px 0;
  user-select: none;
}

.word-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.word-english {
  font-weight: 500;
  font-size: 16px;
}

.word-korean {
  color: var(--text-secondary);
  font-size: 14px;
}

.btn-delete {
  opacity: 0.5;
}

.word-item:hover .btn-delete {
  opacity: 0.8;
}

/* 하단 버튼 영역 */
.bottom-actions {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  padding: 16px 20px;
  background-color: var(--card-bg);
  border-top: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.add-buttons {
  display: flex;
  gap: 12px;
}

.add-buttons .btn {
  flex: 1;
}

/* 학습 화면 */
.study-header {
  justify-content: space-between;
}

.progress-text {
  font-size: 16px;
  font-weight: 500;
  color: var(--text-secondary);
}

.study-container {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  min-height: calc(100vh - 60px);
  padding: 20px;
}

.empty-state {
  text-align: center;
  color: var(--text-secondary);
}

.empty-state p {
  margin-bottom: 20px;
}

/* 카드 컨테이너 */
.card-container {
  width: 100%;
  max-width: 400px;
  margin-bottom: 40px;
  position: relative;
}

/* 플래시카드 */
.flashcard {
  width: 100%;
  aspect-ratio: 3/2;
  perspective: 1000px;
  cursor: pointer;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.5s ease;
  transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
  transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
  position: absolute;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background-color: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  backface-visibility: hidden;
  padding: 24px;
}

.flashcard-back {
  transform: rotateY(180deg);
  background-color: #E8F4FD;
}

.card-text {
  font-size: 28px;
  font-weight: 600;
  text-align: center;
  word-break: keep-all;
}

.card-hint {
  margin-top: 16px;
  font-size: 14px;
  color: var(--text-secondary);
}

.flashcard-back .card-hint {
  display: none;
}

/* 어려움 표시 */
.difficult-indicator {
  position: absolute;
  top: -10px;
  right: -10px;
  font-size: 32px;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% {
    transform: scale(1);
  }
  50% {
    transform: scale(1.1);
  }
}

/* 학습 컨트롤 */
.study-controls {
  width: 100%;
  max-width: 400px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 16px;
}

.control-row {
  display: flex;
  gap: 12px;
  width: 100%;
}

.control-row .btn {
  flex: 1;
}

/* 반응형 */
@media (min-width: 768px) {
  .login-container {
    padding: 40px;
  }

  .wordbook-list-container {
    padding: 32px;
  }

  .word-list {
    padding: 24px 32px;
  }

  .bottom-actions {
    padding: 20px 32px;
  }

  .card-text {
    font-size: 36px;
  }
}

/* 다크모드 지원 (선택적) */
@media (prefers-color-scheme: dark) {
  :root {
    --text-color: #E5E5E5;
    --text-secondary: #A0A0A0;
    --bg-color: #1A1A2E;
    --card-bg: #252542;
    --border-color: #3A3A5C;
  }

  .flashcard-back {
    background-color: #2D2D4A;
  }
}