/* 기본 리셋 및 변수 */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg-primary: #1a1a2e;
  --bg-secondary: #16213e;
  --bg-chat: #0f0f23;
  --text-primary: #eaeaea;
  --text-secondary: #a0a0a0;
  --accent: #4f46e5;
  --accent-hover: #6366f1;
  --user-msg: #3730a3;
  --ai-msg: #1e1e3f;
  --border: #2a2a4a;
  --success: #10b981;
  --danger: #ef4444;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
}

.app {
  display: flex;
  height: 100vh;
}

/* 사이드바 */
.sidebar {
  width: 280px;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding: 20px;
  border-bottom: 1px solid var(--border);
}

.sidebar-header h1 {
  font-size: 1.25rem;
  margin-bottom: 16px;
  color: var(--text-primary);
}

.session-list {
  flex: 1;
  overflow-y: auto;
  padding: 12px;
}

.session-item {
  padding: 12px 16px;
  border-radius: 8px;
  cursor: pointer;
  margin-bottom: 8px;
  transition: background 0.2s;
}

.session-item:hover {
  background: rgba(255, 255, 255, 0.05);
}

.session-item.active {
  background: var(--accent);
}

.session-item-title {
  font-size: 0.9rem;
  margin-bottom: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.session-item-meta {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.session-item.active .session-item-meta {
  color: rgba(255, 255, 255, 0.7);
}

/* 버튼 */
.btn-primary {
  background: var(--accent);
  color: white;
  border: none;
  padding: 10px 20px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.9rem;
  transition: background 0.2s;
  width: 100%;
}

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

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-large {
  padding: 16px 32px;
  font-size: 1.1rem;
}

/* 채팅 영역 */
.chat-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  background: var(--bg-chat);
}

.empty-state {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 40px;
}

.empty-state h2 {
  font-size: 1.5rem;
  margin-bottom: 12px;
}

.empty-state p {
  color: var(--text-secondary);
  margin-bottom: 24px;
  max-width: 400px;
}

.empty-state .btn-primary {
  width: auto;
}

/* 채팅 컨테이너 */
.chat-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  min-height: 0;
  overflow: hidden;
}

.chat-header {
  padding: 16px 24px;
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 12px;
}

.chat-header h2 {
  font-size: 1.1rem;
  flex: 1;
}

.editable-title {
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
  transition: background 0.2s;
}

.editable-title:hover {
  background: rgba(255, 255, 255, 0.1);
}

.title-input {
  flex: 1;
  font-size: 1.1rem;
  font-weight: bold;
  padding: 4px 8px;
  background: var(--bg-secondary);
  border: 1px solid var(--accent);
  border-radius: 4px;
  color: var(--text-primary);
  font-family: inherit;
}

.title-input:focus {
  outline: none;
}

.session-status {
  font-size: 0.75rem;
  padding: 4px 8px;
  border-radius: 4px;
  background: var(--success);
}

.btn-secondary {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border);
  padding: 8px 16px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all 0.2s;
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--accent);
}

/* 모달 */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.7);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
}

.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: 12px;
  width: 90%;
  max-width: 600px;
  max-height: 80vh;
  display: flex;
  flex-direction: column;
}

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

.modal-header h3 {
  font-size: 1.1rem;
  color: var(--text-primary);
}

.modal-close {
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 0;
  line-height: 1;
}

.modal-close:hover {
  color: var(--text-primary);
}

.modal-body {
  padding: 20px;
  overflow-y: auto;
  flex: 1;
  line-height: 1.7;
  white-space: pre-wrap;
  color: var(--text-primary);
}

/* 메시지 영역 */
.messages {
  flex: 1;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 24px;
  min-height: 0;
}

.message {
  margin-bottom: 20px;
  max-width: 80%;
}

.message.user {
  margin-left: auto;
}

.message-content {
  padding: 14px 18px;
  border-radius: 16px;
  line-height: 1.6;
  white-space: pre-wrap;
}

.message.assistant .message-content {
  background: var(--ai-msg);
  border-bottom-left-radius: 4px;
}

.message.user .message-content {
  background: var(--user-msg);
  border-bottom-right-radius: 4px;
}

.message-time {
  font-size: 0.7rem;
  color: var(--text-secondary);
  margin-top: 6px;
}

.message.user .message-time {
  text-align: right;
}

/* 입력 영역 */
.input-area {
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 12px;
}

.input-area textarea {
  flex: 1;
  padding: 14px;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  font-size: 0.95rem;
  resize: none;
  font-family: inherit;
}

.input-area textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.input-area .btn-primary {
  width: auto;
  padding: 14px 24px;
}

/* 로딩 상태 */
.loading-message {
  color: var(--text-secondary);
  font-style: italic;
}

.loading-text {
  display: inline;
}

.loading-dots::after {
  content: '';
  animation: dots 1.5s infinite;
}

@keyframes dots {
  0% { content: ''; }
  25% { content: '.'; }
  50% { content: '..'; }
  75% { content: '...'; }
  100% { content: ''; }
}

/* 스크롤바 */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: transparent;
}

::-webkit-scrollbar-thumb {
  background: var(--border);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-secondary);
}

/* 모바일 헤더 */
.mobile-header {
  display: none;
  padding: 12px 16px;
  background: var(--bg-secondary);
  border-bottom: 1px solid var(--border);
  align-items: center;
  gap: 12px;
}

.menu-btn {
  background: none;
  border: none;
  color: var(--text-primary);
  font-size: 1.5rem;
  cursor: pointer;
  padding: 4px 8px;
}

/* 세션 삭제 버튼 */
.session-item {
  position: relative;
}

.session-delete {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--text-secondary);
  font-size: 1rem;
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.2s;
  padding: 4px 8px;
}

.session-item:hover .session-delete {
  opacity: 1;
}

.session-delete:hover {
  color: var(--danger);
}

/* 오버레이 */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(0, 0, 0, 0.5);
  z-index: 99;
}

.sidebar-overlay.open {
  display: block;
}

/* 사이드바 푸터 */
.sidebar-footer {
  padding: 16px;
  border-top: 1px solid var(--border);
  background: var(--bg-secondary);
}

.user-info-content {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.user-name {
  font-size: 0.9rem;
  color: var(--text-primary);
  font-weight: 500;
}

.user-actions {
  display: flex;
  gap: 8px;
}

.settings-link {
  flex: 1;
  padding: 8px 12px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.85rem;
  text-align: center;
  transition: all 0.2s;
}

.settings-link:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: var(--accent);
}

.logout-btn {
  flex: 1;
  padding: 8px 12px;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--text-secondary);
  font-size: 0.85rem;
  cursor: pointer;
  transition: all 0.2s;
}

.logout-btn:hover {
  background: rgba(239, 68, 68, 0.1);
  color: var(--danger);
  border-color: var(--danger);
}

/* 반응형 */
@media (max-width: 768px) {
  .mobile-header {
    display: flex;
  }

  .sidebar {
    position: fixed;
    left: -280px;
    height: 100%;
    z-index: 100;
    transition: left 0.3s;
  }

  .sidebar.open {
    left: 0;
  }

  .message {
    max-width: 90%;
  }

  .session-delete {
    opacity: 1;
  }
}