:root {
  color-scheme: light;
  --bg-a: #f4f7fb;
  --bg-b: #e3eef8;
  --panel: #ffffff;
  --line: #d5deea;
  --text: #17324d;
  --muted: #5a7088;
  --brand: #0063d1;
  --brand-dark: #004ea8;
  --danger: #c22f3e;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top right, var(--bg-b), var(--bg-a));
  min-height: 100vh;
}

.page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 20px;
}

.panel {
  width: min(800px, 100%);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 16px;
  box-shadow: 0 20px 40px rgba(10, 30, 60, 0.08);
  padding: 20px;
}

.auth-panel {
  width: min(420px, 100%);
  display: grid;
  gap: 10px;
}

h1,
h2,
p {
  margin: 0;
}

.subtitle {
  color: var(--muted);
}

label {
  font-size: 14px;
  color: var(--muted);
}

input,
select,
button {
  font: inherit;
}

input,
select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 10px 12px;
}

button {
  border: none;
  border-radius: 10px;
  background: var(--brand);
  color: #fff;
  padding: 10px 14px;
  cursor: pointer;
  font-weight: 600;
}

button:hover {
  background: var(--brand-dark);
}

button.secondary {
  background: #eef4fb;
  color: var(--text);
  border: 1px solid var(--line);
}

.chat-panel {
  display: grid;
  gap: 12px;
}

.chat-header {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  align-items: center;
}

.toolbar {
  display: flex;
  gap: 10px;
  align-items: center;
}

.toolbar label {
  min-width: 90px;
}

.messages {
  height: 360px;
  overflow-y: auto;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 10px;
  background: #f8fbff;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.bubble {
  max-width: 80%;
  border-radius: 10px;
  padding: 8px 10px;
  border: 1px solid #d0def0;
  background: #ffffff;
}

.bubble.mine {
  align-self: flex-end;
  background: #dcecff;
}

.bubble .meta {
  color: var(--muted);
  font-size: 12px;
  margin-bottom: 4px;
}

.composer {
  display: flex;
  gap: 8px;
}

.composer input {
  flex: 1;
}

.hint {
  color: var(--muted);
  font-size: 14px;
}

.error {
  min-height: 18px;
  color: var(--danger);
  font-size: 14px;
}

.hidden {
  display: none;
}

@media (max-width: 720px) {
  .panel {
    padding: 14px;
  }

  .chat-header {
    flex-direction: column;
    align-items: stretch;
  }

  .toolbar {
    flex-direction: column;
    align-items: stretch;
  }
}