:root {
  --bg-start: #f5efe2;
  --bg-end: #d7ece7;
  --panel: #ffffffde;
  --text: #1e2a31;
  --muted: #4f6873;
  --accent: #0f8b8d;
  --accent-strong: #126782;
  --border: #c6dde0;
  --bubble-user: #e7f4f5;
  --bubble-assistant: #f6f1ff;
  --shadow: 0 24px 60px -34px rgba(15, 139, 141, 0.55);
}

:root[data-theme="dark"] {
  --bg-start: #18242e;
  --bg-end: #222c3d;
  --panel: #141d25e6;
  --text: #e9f0f4;
  --muted: #a3bbc4;
  --accent: #34c6be;
  --accent-strong: #48a9e6;
  --border: #324654;
  --bubble-user: #1d2f38;
  --bubble-assistant: #2c2b48;
  --shadow: 0 24px 60px -34px rgba(10, 28, 35, 0.8);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  color: var(--text);
  background: linear-gradient(130deg, var(--bg-start), var(--bg-end));
}

body {
  padding: 24px;
}

.shell {
  width: min(980px, 100%);
  margin: 0 auto;
  display: grid;
  gap: 16px;
  background: var(--panel);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 18px;
  box-shadow: var(--shadow);
}

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

h1 {
  margin: 0;
  font-size: 1.25rem;
  letter-spacing: 0.02em;
}

.toggles {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.toggle {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  font-size: 0.86rem;
  color: var(--muted);
  background: #ffffff3d;
}

.toggle select {
  border: 1px solid var(--border);
  border-radius: 8px;
  background: transparent;
  color: var(--text);
  padding: 2px 6px;
}

.checkbox-toggle input {
  accent-color: var(--accent);
}

.messages {
  min-height: 360px;
  max-height: 52vh;
  overflow-y: auto;
  border-radius: 16px;
  border: 1px solid var(--border);
  padding: 12px;
  background: linear-gradient(180deg, #ffffff26, #ffffff08);
  display: grid;
  gap: 10px;
}

.message-row {
  border-radius: 14px;
  border: 1px solid var(--border);
  padding: 10px 12px;
  background: var(--bubble-user);
  transform: translateY(0);
  opacity: 1;
  transition: transform 200ms ease, opacity 200ms ease;
}

.message-row.assistant {
  background: var(--bubble-assistant);
}

.message-row.new {
  opacity: 0;
  transform: translateY(6px);
}

.message-author {
  margin: 0 0 6px;
  font-weight: 700;
  font-size: 0.82rem;
  color: var(--accent-strong);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.message-text {
  margin: 0;
  white-space: pre-wrap;
  word-break: break-word;
  font-family: "JetBrains Mono", Consolas, monospace;
  font-size: 0.92rem;
}

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

.field-label {
  font-size: 0.86rem;
  color: var(--muted);
}

input,
textarea,
button {
  font: inherit;
}

input,
textarea {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px 12px;
  background: #ffffffa8;
  color: var(--text);
}

:root[data-theme="dark"] input,
:root[data-theme="dark"] textarea {
  background: #0f171f;
}

textarea {
  resize: vertical;
}

button {
  justify-self: end;
  border: none;
  border-radius: 12px;
  padding: 10px 14px;
  font-weight: 700;
  background: linear-gradient(120deg, var(--accent), var(--accent-strong));
  color: #fff;
  cursor: pointer;
}

button:disabled {
  opacity: 0.65;
  cursor: not-allowed;
}

body.reduce-motion * {
  transition: none !important;
  animation: none !important;
}

@media (max-width: 720px) {
  body {
    padding: 10px;
  }

  .shell {
    padding: 12px;
    border-radius: 14px;
  }

  .messages {
    min-height: 300px;
    max-height: 48vh;
  }

  button {
    width: 100%;
    justify-self: stretch;
  }
}