:root {
  color-scheme: light;
  font-family: Arial, sans-serif;
  line-height: 1.4;
  background: #f4f7f9;
  color: #1b2430;
}

body {
  margin: 0;
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  padding: 1rem;
  background: #0c4a6e;
  color: #fff;
  position: sticky;
  top: 0;
}

.topbar nav {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.topbar a {
  color: #e0f2fe;
  text-decoration: none;
}

main {
  max-width: 1100px;
  margin: 0 auto;
  padding: 1rem;
  display: grid;
  gap: 1rem;
}

.card {
  background: #fff;
  border-radius: 0.75rem;
  padding: 1rem;
  box-shadow: 0 8px 25px rgba(12, 74, 110, 0.08);
}

.grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

button {
  background: #0369a1;
  color: #fff;
  border: 0;
  border-radius: 0.5rem;
  padding: 0.65rem 0.9rem;
  cursor: pointer;
}

input,
textarea,
select {
  width: 100%;
  padding: 0.6rem;
  border-radius: 0.45rem;
  border: 1px solid #b7c7d6;
  box-sizing: border-box;
}

.stack {
  display: grid;
  gap: 0.6rem;
}

.chat-log {
  border: 1px solid #d8e0e8;
  border-radius: 0.5rem;
  padding: 0.75rem;
  min-height: 120px;
  max-height: 200px;
  overflow-y: auto;
  margin-bottom: 0.75rem;
  background: #f9fbfc;
}

.chat-line {
  margin: 0 0 0.5rem;
}

.chat-line strong {
  color: #0c4a6e;
}

.row {
  display: flex;
  gap: 0.5rem;
}

.result {
  font-weight: 700;
}

@media (min-width: 900px) {
  .grid {
    grid-template-columns: 1fr 1fr;
  }
}