:root {
  color-scheme: dark;
  --bg: #0d0f12;
  --panel: #15181d;
  --line: #262b33;
  --text: #e8eaed;
  --muted: #8b93a1;
  --accent: #6ea8fe;
  --user: #1e2a3a;
  --err: #ff8a80;
}

* {
  box-sizing: border-box;
}

html, body {
  height: 100%;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.55 system-ui, -apple-system, "Segoe UI", sans-serif;
}

body.center {
  display: grid;
  place-items: center;
  padding: 1rem;
}

.chat {
  width: min(820px, 100%);
  height: 100dvh;
  margin: 0 auto;
  padding: 0 1rem;
  display: flex;
  flex-direction: column;
}

header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--line);
}

h1 {
  margin: 0;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
}
.sub {
  margin: 0.1rem 0 0;
  color: var(--muted);
  font-size: 0.8rem;
}

.actions {
  display: flex;
  gap: 0.4rem;
}
.actions form {
  margin: 0;
}

button {
  border: 1px solid var(--line);
  background: #20252d;
  color: var(--text);
  border-radius: 8px;
  padding: 0.55rem 0.9rem;
  font: inherit;
  cursor: pointer;
}

button:hover {
  border-color: #3a424e;
}
button:disabled {
  opacity: 0.5;
  cursor: default;
}

button.ghost {
  background: transparent;
  padding: 0.4rem 0.7rem;
  font-size: 0.85rem;
  color: var(--muted);
}

#messages {
  flex: 1;
  overflow-y: auto;
  padding: 1.1rem 0;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.empty {
  color: var(--muted);
  margin: auto;
}

.msg {
  max-width: 88%;
  padding: 0.7rem 0.9rem;
  border-radius: 12px;
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.msg.user {
  align-self: flex-end;
  background: var(--user);
  border: 1px solid #2b3d55;
}

.msg.assistant {
  align-self: flex-start;
  background: var(--panel);
  border: 1px solid var(--line);
}

.msg.streaming::after {
  content: "▍";
  color: var(--accent);
  animation: blink 1s steps(1) infinite;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

#composer {
  display: flex;
  gap: 0.6rem;
  align-items: flex-end;
  border-top: 1px solid var(--line);
  padding: 0.8rem 0 0.2rem;
}

textarea {
  flex: 1;
  resize: none;
  max-height: 40dvh;
  background: var(--panel);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.65rem 0.8rem;
  font: inherit;
}

textarea:focus, input:focus {
  outline: 1px solid var(--accent);
}

.hint {
  color: var(--muted);
  font-size: 0.72rem;
  margin: 0.3rem 0 0.6rem;
}
.err {
  color: var(--err);
  font-size: 0.85rem;
  margin: 0.2rem 0;
}

.login {
  width: min(380px, 100%);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1.6rem;
}

.login h1 {
  font-size: 1.3rem;
}
.login .sub {
  margin-bottom: 1.2rem;
}

.login form {
  display: flex;
  gap: 0.5rem;
}

.login input {
  flex: 1;
  min-width: 0;
  background: #0f1216;
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 0.55rem 0.7rem;
  color: var(--text);
  font: inherit;
}

.login .err {
  margin-top: 0.9rem;
}