* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: system-ui, sans-serif;
  background: #0f1115;
  color: #e6e6e6;
}

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

.contacts {
  width: 280px;
  border-right: 1px solid #23262e;
  padding: 16px;
  overflow-y: auto;
}

.contacts h1 {
  font-size: 16px;
  margin: 0 0 12px;
}

.contacts ul {
  list-style: none;
  margin: 0;
  padding: 0;
}

.contact-item {
  padding: 10px;
  border-radius: 8px;
  cursor: pointer;
  margin-bottom: 4px;
}

.contact-item:hover,
.contact-item.active {
  background: #1c1f27;
}

.contact-item .name {
  font-weight: 600;
  font-size: 14px;
}

.contact-item .preview {
  font-size: 12px;
  color: #8b8f99;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.conversation {
  flex: 1;
  padding: 16px 24px;
  overflow-y: auto;
}

.conversation h2 {
  font-size: 16px;
  margin-top: 0;
}

#message-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.message {
  max-width: 60%;
  padding: 8px 12px;
  border-radius: 10px;
  font-size: 14px;
  line-height: 1.4;
}

.message.user {
  align-self: flex-start;
  background: #1c1f27;
}

.message.agent {
  align-self: flex-end;
  background: #2f6f4f;
}