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

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", sans-serif;
  background: #0a0a0a;
  color: #ffffff;
  overflow: hidden;
}

.app-container {
  display: grid;
  grid-template-columns: 360px 1fr;
  height: 100vh;
}

/* Sidebar */
.sidebar {
  background: #1d1d1f;
  border-right: 1px solid rgba(255,255,255,0.08);
  display: flex;
  flex-direction: column;
}

.sidebar-header {
  padding: 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid rgba(255,255,255,0.08);
}

.user-info {
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  padding: 8px;
  border-radius: 12px;
  transition: background 0.3s;
}

.user-info:hover {
  background: rgba(255,255,255,0.05);
}

.user-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  object-fit: cover;
}

.user-name {
  font-weight: 600;
  font-size: 15px;
}

.btn-new-chat {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
  color: white;
  font-size: 20px;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-new-chat:hover {
  transform: scale(1.1);
}

.search-box {
  padding: 16px 20px;
}

.search-box input {
  width: 100%;
  padding: 12px 16px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 12px;
  color: white;
  font-size: 15px;
  transition: border-color 0.3s;
}

.search-box input:focus {
  outline: none;
  border-color: #667eea;
}

.chat-list {
  flex: 1;
  overflow-y: auto;
}

.chat-item {
  padding: 16px 20px;
  display: flex;
  align-items: center;
  gap: 12px;
  cursor: pointer;
  transition: background 0.3s;
  border-bottom: 1px solid rgba(255,255,255,0.03);
}

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

.chat-item.active {
  background: rgba(102, 126, 234, 0.15);
  border-left: 3px solid #667eea;
}

.chat-avatar {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  object-fit: cover;
}

.chat-item-info {
  flex: 1;
  min-width: 0;
}

.chat-item-name {
  font-weight: 600;
  font-size: 15px;
  margin-bottom: 4px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-item-last {
  color: #86868b;
  font-size: 14px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-item-time {
  font-size: 12px;
  color: #6e6e73;
  margin-left: 8px;
}

.chat-type-badge {
  font-size: 11px;
  padding: 2px 8px;
  border-radius: 980px;
  background: rgba(102, 126, 234, 0.2);
  color: #667eea;
  margin-left: 8px;
}

/* Chat Area */
.chat-area {
  display: flex;
  flex-direction: column;
  background: #0a0a0a;
}

.chat-header {
  padding: 20px 24px;
  border-bottom: 1px solid rgba(255,255,255,0.08);
  background: #1d1d1f;
}

.chat-header-info {
  display: flex;
  align-items: center;
  gap: 16px;
}

.chat-header-avatar {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  object-fit: cover;
}

.chat-header-info h3 {
  font-size: 18px;
  font-weight: 600;
  margin-bottom: 4px;
}

.status {
  font-size: 13px;
  color: #86868b;
}

.status.online {
  color: #34c759;
}

/* Messages */
.messages-container {
  flex: 1;
  overflow-y: auto;
  padding: 24px;
}

.empty-chat {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  text-align: center;
  color: #86868b;
}

.empty-icon {
  font-size: 80px;
  margin-bottom: 24px;
  opacity: 0.5;
}

.empty-chat h3 {
  font-size: 22px;
  color: #f5f5f7;
  margin-bottom: 8px;
}

.messages-list {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.message {
  display: flex;
  gap: 12px;
  max-width: 70%;
  animation: messageSlide 0.3s ease;
}

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

.message.sent {
  align-self: flex-end;
  flex-direction: row-reverse;
}

.message-avatar {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
}

.message-content {
  background: #1d1d1f;
  padding: 12px 16px;
  border-radius: 18px;
  border: 1px solid rgba(255,255,255,0.08);
}

.message.sent .message-content {
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
}

.message-sender {
  font-size: 13px;
  font-weight: 600;
  margin-bottom: 4px;
  color: #667eea;
}

.message.sent .message-sender {
  color: rgba(255,255,255,0.9);
}

.message-text {
  font-size: 15px;
  line-height: 1.5;
  word-wrap: break-word;
}

.message-time {
  font-size: 11px;
  color: #86868b;
  margin-top: 6px;
  text-align: right;
}

.message.sent .message-time {
  color: rgba(255,255,255,0.7);
}

/* Message Input */
.message-input-container {
  padding: 20px 24px;
  border-top: 1px solid rgba(255,255,255,0.08);
  background: #1d1d1f;
  position: relative;
}

.message-input-wrapper {
  display: flex;
  align-items: center;
  gap: 12px;
}

.btn-emoji {
  background: transparent;
  border: none;
  font-size: 24px;
  cursor: pointer;
  padding: 8px;
  border-radius: 50%;
  transition: background 0.3s;
}

.btn-emoji:hover {
  background: rgba(255,255,255,0.1);
}

.emoji-picker {
  position: absolute;
  bottom: 80px;
  left: 24px;
  background: #1d1d1f;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 16px;
  padding: 16px;
  display: none;
  box-shadow: 0 10px 40px rgba(0,0,0,0.4);
  z-index: 100;
}

.emoji-picker.active {
  display: block;
}

.emoji-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
}

.emoji-item {
  font-size: 24px;
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  transition: background 0.3s;
}

.emoji-item:hover {
  background: rgba(255,255,255,0.1);
}

.message-input {
  flex: 1;
  padding: 14px 20px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,0.1);
  border-radius: 980px;
  color: white;
  font-size: 15px;
  transition: border-color 0.3s;
}

.message-input:focus {
  outline: none;
  border-color: #667eea;
}

.btn-send {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
  color: white;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s;
}

.btn-send:hover {
  transform: scale(1.1);
}

/* Modal */
.modal {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  backdrop-filter: blur(10px);
  z-index: 1000;
  justify-content: center;
  align-items: center;
}

.modal.active {
  display: flex;
}

.modal-content {
  background: #1d1d1f;
  border-radius: 24px;
  padding: 32px;
  width: 100%;
  max-width: 480px;
  border: 1px solid rgba(255,255,255,0.1);
  position: relative;
  max-height: 80vh;
  overflow-y: auto;
}

.modal-close {
  position: absolute;
  top: 16px;
  right: 16px;
  background: transparent;
  border: none;
  color: #86868b;
  font-size: 28px;
  cursor: pointer;
  width: 32px;
  height: 32px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  transition: all 0.3s;
}

.modal-close:hover {
  background: rgba(255,255,255,0.1);
  color: white;
}

.modal-content h2 {
  font-size: 24px;
  margin-bottom: 24px;
}

.modal-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 24px;
}

.tab {
  flex: 1;
  padding: 12px;
  background: transparent;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 12px;
  color: #86868b;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.3s;
}

.tab.active {
  background: linear-gradient(135deg, #667eea, #764ba2);
  border-color: transparent;
  color: white;
}

.user-list {
  display: flex;
  flex-direction: column;
  gap: 8px;
  max-height: 300px;
  overflow-y: auto;
}

.user-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px;
  border-radius: 12px;
  cursor: pointer;
  transition: background 0.3s;
}

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

.user-item-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
}

.user-item-name {
  font-weight: 500;
}

.modal-input {
  width: 100%;
  padding: 14px 18px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 12px;
  color: white;
  font-size: 16px;
  margin-bottom: 16px;
}

.modal-input:focus {
  outline: none;
  border-color: #667eea;
}

.btn-submit {
  width: 100%;
  padding: 16px;
  background: linear-gradient(135deg, #667eea, #764ba2);
  border: none;
  border-radius: 12px;
  color: white;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-submit:hover {
  transform: translateY(-2px);
  box-shadow: 0 10px 30px rgba(102, 126, 234, 0.4);
}

/* Settings */
.settings-content {
  max-width: 420px;
}

.settings-avatar {
  display: flex;
  flex-direction: column;
  align-items: center;
  margin-bottom: 32px;
}

.settings-avatar img {
  width: 100px;
  height: 100px;
  border-radius: 50%;
  margin-bottom: 16px;
}

.btn-change-avatar {
  padding: 8px 20px;
  background: transparent;
  border: 1px solid rgba(255,255,255,0.2);
  border-radius: 980px;
  color: #667eea;
  font-size: 14px;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-change-avatar:hover {
  border-color: #667eea;
  background: rgba(102, 126, 234, 0.1);
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 14px;
  color: #86868b;
  margin-bottom: 8px;
  font-weight: 500;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 14px 18px;
  background: #0a0a0a;
  border: 1px solid rgba(255,255,255,0.15);
  border-radius: 12px;
  color: white;
  font-size: 16px;
  font-family: inherit;
  transition: border-color 0.3s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: #667eea;
}

.btn-logout {
  width: 100%;
  padding: 16px;
  margin-top: 20px;
  background: transparent;
  border: 2px solid #ff3b30;
  border-radius: 12px;
  color: #ff3b30;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.3s;
}

.btn-logout:hover {
  background: #ff3b30;
  color: white;
}

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

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

::-webkit-scrollbar-thumb {
  background: rgba(255,255,255,0.1);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: rgba(255,255,255,0.2);
}

/* Responsive */
@media (max-width: 768px) {
  .app-container {
    grid-template-columns: 1fr;
  }

  .sidebar {
    display: none;
  }

  .sidebar.mobile-active {
    display: flex;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 100;
  }
}