:root {
  color: #17251e;
  background: #eef2ed;
  font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  font-synthesis: none;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  background:
    radial-gradient(circle at 85% 5%, rgba(177, 204, 181, .55), transparent 28rem),
    #eef2ed;
}

button, input, textarea { font: inherit; }

button {
  min-height: 44px;
  border: 0;
  border-radius: 12px;
  padding: 0 18px;
  color: #fff;
  background: #175d3b;
  cursor: pointer;
}

button:hover { background: #0e472c; }
button:focus-visible, input:focus-visible, textarea:focus-visible { outline: 3px solid #e1a73d; outline-offset: 2px; }
button:disabled { cursor: wait; opacity: .55; }

.shell {
  width: min(940px, calc(100% - 32px));
  margin: 32px auto;
}

.masthead {
  display: flex;
  align-items: start;
  justify-content: space-between;
  gap: 24px;
  padding: 28px 32px;
  color: #f8fbf8;
  border-radius: 22px 22px 0 0;
  background: #123d2b;
}

.eyebrow { margin: 0 0 8px; color: #b9d4c2; font-size: .75rem; font-weight: 700; letter-spacing: .16em; }
h1 { margin: 0; font-size: clamp(1.5rem, 4vw, 2.25rem); line-height: 1.2; }
.intro { max-width: 680px; margin: 12px 0 0; color: #dbe8df; line-height: 1.7; }
h2 { margin: 0; font-size: 1rem; }

.quiet-button { color: #194f35; background: #e6eee8; white-space: nowrap; }
.quiet-button:hover { background: #d2e2d7; }

.credential-card {
  display: grid;
  grid-template-columns: 1fr minmax(300px, 1.2fr);
  gap: 10px 24px;
  align-items: center;
  padding: 20px 32px;
  border-bottom: 1px solid #dce4de;
  background: #fff;
}

.credential-card p { margin: 5px 0 0; color: #5d6c63; font-size: .86rem; }
.credential-form { display: flex; gap: 8px; }
.credential-form input { min-width: 0; flex: 1; }
.credential-state { grid-column: 2; }

input, textarea {
  width: 100%;
  border: 1px solid #bdc9c0;
  border-radius: 12px;
  padding: 11px 13px;
  color: #17251e;
  background: #fbfcfb;
}

.conversation {
  overflow: hidden;
  border-radius: 0 0 22px 22px;
  box-shadow: 0 16px 48px rgba(28, 55, 39, .12);
  background: #fff;
}

.messages {
  min-height: 360px;
  max-height: min(58vh, 620px);
  overflow-y: auto;
  padding: 26px 32px;
}

.message {
  width: fit-content;
  max-width: min(78%, 720px);
  margin: 0 0 18px;
  border-radius: 5px 17px 17px;
  padding: 13px 16px;
  line-height: 1.7;
  overflow-wrap: anywhere;
}

.message p { margin: 0; white-space: pre-wrap; }
.assistant-message { border: 1px solid #dce6df; background: #f5f8f6; }
.user-message { margin-left: auto; color: #fff; border-radius: 17px 5px 17px 17px; background: #1d6945; }
.error-message { color: #7b211c; border: 1px solid #e9b9b5; background: #fff2f0; }

.noscript-warning {
  margin: 0;
  padding: 14px 18px;
  color: #7b211c;
  border: 1px solid #e9b9b5;
  background: #fff2f0;
}

.composer { padding: 18px 22px 20px; border-top: 1px solid #e1e7e2; background: #f8faf8; }
.composer textarea { display: block; min-height: 82px; resize: vertical; background: #fff; }
.composer-footer { display: flex; align-items: center; justify-content: space-between; gap: 16px; margin-top: 10px; }
.composer-footer p { margin: 0; color: #68766d; font-size: .82rem; }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0, 0, 0, 0); white-space: nowrap; border: 0; }

@media (max-width: 680px) {
  .shell { width: 100%; margin: 0; }
  .masthead { padding: 22px 18px; border-radius: 0; }
  .intro { font-size: .9rem; }
  .credential-card { grid-template-columns: 1fr; padding: 18px; }
  .credential-form { flex-wrap: wrap; }
  .credential-form input { flex-basis: 100%; }
  .credential-state { grid-column: 1; }
  .conversation { border-radius: 0; box-shadow: none; }
  .messages { min-height: calc(100vh - 480px); padding: 20px 16px; }
  .message { max-width: 92%; }
  .composer { padding: 14px 12px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; }
}