:root {
  color-scheme: dark;
  --bg: #0d1117;
  --panel: #161b22;
  --panel-2: #21262d;
  --border: #30363d;
  --text: #f0f6fc;
  --muted: #8b949e;
  --accent: #2f81f7;
  --accent-hover: #388bfd;
  --user: #1f6feb;
  --bot: #21262d;
  --danger: #f85149;
  --radius: 18px;
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

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

button,
textarea,
input {
  font: inherit;
}

button {
  color: inherit;
}

.app-shell {
  width: min(860px, 100%);
  height: min(820px, calc(100vh - 40px));
  display: grid;
  grid-template-rows: auto 1fr auto auto;
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 24px;
  overflow: hidden;
  box-shadow: 0 24px 80px rgb(0 0 0 / 0.35);
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 18px 22px;
  border-bottom: 1px solid var(--border);
}

.eyebrow {
  margin: 0 0 3px;
  color: var(--muted);
  font-size: 0.78rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-size: 1.3rem;
}

.icon-button {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 12px;
  cursor: pointer;
}

.icon-button:hover {
  background: var(--panel-2);
}

.chat {
  min-height: 0;
  overflow-y: auto;
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 14px;
  scroll-behavior: smooth;
}

.message {
  max-width: min(78%, 620px);
  padding: 12px 15px;
  border-radius: var(--radius);
  line-height: 1.45;
  overflow-wrap: anywhere;
  animation: appear 160ms ease-out;
}

.message.user {
  align-self: flex-end;
  background: var(--user);
  border-bottom-right-radius: 5px;
}

.message.bot {
  align-self: flex-start;
  background: var(--bot);
  border: 1px solid var(--border);
  border-bottom-left-radius: 5px;
}

.message-meta {
  display: block;
  margin-top: 5px;
  color: rgb(255 255 255 / 0.58);
  font-size: 0.7rem;
}

.typing {
  display: inline-flex;
  gap: 5px;
  align-items: center;
  min-height: 20px;
}

.typing span {
  width: 7px;
  height: 7px;
  background: var(--muted);
  border-radius: 50%;
  animation: bounce 1s infinite ease-in-out;
}

.typing span:nth-child(2) {
  animation-delay: 120ms;
}

.typing span:nth-child(3) {
  animation-delay: 240ms;
}

.composer {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  padding: 14px 18px;
  border-top: 1px solid var(--border);
}

textarea {
  min-height: 46px;
  max-height: 160px;
  resize: none;
  padding: 12px 14px;
  color: var(--text);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  outline: none;
}

textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgb(47 129 247 / 0.15);
}

.composer button,
.settings-actions button,
.file-button {
  padding: 10px 15px;
  background: var(--accent);
  border: 0;
  border-radius: 12px;
  font-weight: 650;
  cursor: pointer;
}

.composer button:hover,
.settings-actions button:hover,
.file-button:hover {
  background: var(--accent-hover);
}

.composer button:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.privacy-note {
  margin: 0;
  padding: 0 18px 14px;
  color: var(--muted);
  font-size: 0.75rem;
  text-align: center;
}

.settings-panel {
  position: fixed;
  top: 0;
  right: 0;
  z-index: 10;
  width: min(390px, 92vw);
  height: 100vh;
  padding: 22px;
  background: var(--panel);
  border-left: 1px solid var(--border);
  transform: translateX(105%);
  transition: transform 180ms ease;
  overflow-y: auto;
}

.settings-panel.open {
  transform: translateX(0);
}

.settings-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 28px;
}

.settings-header h2 {
  margin-bottom: 0;
}

.setting-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 10px;
  margin-bottom: 24px;
}

.setting-row input {
  grid-column: 1 / -1;
  width: 100%;
}

.setting-row output {
  color: var(--muted);
}

.stats {
  margin: 26px 0;
  padding: 14px;
  color: var(--muted);
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 14px;
  line-height: 1.8;
}

.settings-actions {
  display: grid;
  gap: 10px;
}

.settings-actions button,
.file-button {
  width: 100%;
  text-align: center;
}

.file-button input {
  display: none;
}

.settings-actions .danger {
  background: transparent;
  color: var(--danger);
  border: 1px solid rgb(248 81 73 / 0.5);
}

.settings-actions .danger:hover {
  background: rgb(248 81 73 / 0.1);
}

.backdrop {
  position: fixed;
  inset: 0;
  z-index: 9;
  background: rgb(0 0 0 / 0.55);
}

@keyframes appear {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
}

@keyframes bounce {
  0%,
  60%,
  100% {
    transform: translateY(0);
  }
  30% {
    transform: translateY(-5px);
  }
}

@media (max-width: 640px) {
  body {
    padding: 0;
  }

  .app-shell {
    height: 100vh;
    border: 0;
    border-radius: 0;
  }

  .chat {
    padding: 18px 14px;
  }

  .message {
    max-width: 88%;
  }

  .composer {
    padding: 12px;
  }
}