* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: Arial, sans-serif;
  background: #f5f7f8;
  color: #172026;
}

.app-shell {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  padding: 32px 16px;
}

.chat-panel {
  width: min(860px, 100%);
  min-height: calc(100vh - 64px);
  display: grid;
  grid-template-rows: auto 1fr auto;
  background: #ffffff;
  border: 1px solid #d9e1e5;
  border-radius: 8px;
  overflow: hidden;
}

.chat-header {
  padding: 18px 20px;
  border-bottom: 1px solid #d9e1e5;
}

.chat-header h1 {
  margin: 0 0 6px;
  font-size: 20px;
}

.chat-header p {
  margin: 0;
  color: #5b6b73;
  font-size: 14px;
}

.messages {
  padding: 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.message {
  max-width: 78%;
  padding: 10px 12px;
  border-radius: 8px;
  line-height: 1.45;
  white-space: pre-wrap;
}

.message.user {
  align-self: flex-end;
  background: #234b55;
  color: #ffffff;
}

.message.assistant {
  align-self: flex-start;
  background: #eef3f5;
  color: #172026;
}

.composer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 16px;
  border-top: 1px solid #d9e1e5;
}

textarea {
  resize: none;
  padding: 10px 12px;
  font: inherit;
  border: 1px solid #b9c6cc;
  border-radius: 8px;
}

button {
  padding: 0 18px;
  border: 0;
  border-radius: 8px;
  background: #234b55;
  color: #ffffff;
  font: inherit;
  cursor: pointer;
}

button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.message.assistant table {
  width: 100%;
  border-collapse: collapse;
  margin: 10px 0;
  font-size: 14px;
}

.message.assistant th,
.message.assistant td {
  border: 1px solid #c9d4da;
  padding: 8px;
  text-align: left;
  vertical-align: top;
}

.message.assistant th {
  background: #dfe8ec;
}