:root {
  --bg: #0a0b0f;
  --bg-elevated: #12141b;
  --border: #1f2330;
  --text: #e8e9ee;
  --text-dim: #8b8fa3;
  --accent: #5b8cff;
  --accent-glow: #7fb0ff;
  --accent-soft: rgba(91, 140, 255, 0.15);
  --danger: #ff6b6b;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  height: 100%;
  overflow-x: hidden;
}

body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

/* ---------- Login page ---------- */

.login-wrap {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.login-card {
  width: 100%;
  max-width: 360px;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 28px;
}

.login-card h1 {
  font-size: 1.4rem;
  margin: 0 0 4px;
  letter-spacing: 0.02em;
}

.login-card .subtitle {
  color: var(--text-dim);
  font-size: 0.85rem;
  margin: 0 0 24px;
}

.login-card label {
  display: block;
  font-size: 0.8rem;
  color: var(--text-dim);
  margin: 16px 0 6px;
}

.login-card input {
  width: 100%;
  padding: 12px 14px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #0e0f15;
  color: var(--text);
  font-size: 1rem;
}

.login-card input:focus {
  outline: none;
  border-color: var(--accent);
}

.login-card button {
  width: 100%;
  margin-top: 24px;
  padding: 13px;
  border-radius: 10px;
  border: none;
  background: var(--accent);
  color: #06070a;
  font-weight: 600;
  font-size: 1rem;
  cursor: pointer;
}

.login-card button:active { transform: scale(0.98); }

.error {
  color: var(--danger);
  font-size: 0.85rem;
  margin-top: 16px;
}

/* ---------- App shell ---------- */

.topbar {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 14px 16px 10px;
}

.mode-toggle {
  display: flex;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px;
  gap: 4px;
}

.mode-toggle button {
  border: none;
  background: transparent;
  color: var(--text-dim);
  font-size: 0.85rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 8px 18px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 0.2s, color 0.2s;
}

.mode-toggle button.active {
  background: var(--accent-soft);
  color: var(--accent-glow);
}

.nucleus-wrap {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 10px 0 4px;
}

#nucleus-canvas {
  width: 220px;
  height: 220px;
  max-width: 50vw;
  max-height: 50vw;
}

.tiles {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  padding: 8px 14px 4px;
}

.tile {
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 10px 4px;
  text-align: center;
  font-size: 0.62rem;
  color: var(--text-dim);
  line-height: 1.3;
}

.tile .tile-label {
  display: block;
  color: var(--text);
  font-size: 0.68rem;
  font-weight: 600;
  margin-bottom: 2px;
}

.thread {
  flex: 1;
  overflow-y: auto;
  padding: 14px 14px 8px;
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 120px;
}

.msg {
  max-width: 86%;
  padding: 10px 14px;
  border-radius: 14px;
  font-size: 0.92rem;
  line-height: 1.4;
  white-space: pre-wrap;
  word-wrap: break-word;
}

.msg.user {
  align-self: flex-end;
  background: var(--accent);
  color: #06070a;
  border-bottom-right-radius: 4px;
}

.msg.assistant {
  align-self: flex-start;
  background: var(--bg-elevated);
  border: 1px solid var(--border);
  border-bottom-left-radius: 4px;
}

.msg.error {
  align-self: center;
  color: var(--danger);
  font-size: 0.8rem;
  background: transparent;
}

.composer {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  padding: 10px 14px calc(14px + env(safe-area-inset-bottom));
  border-top: 1px solid var(--border);
  background: var(--bg);
}

.composer textarea {
  flex: 1;
  resize: none;
  max-height: 120px;
  padding: 12px 14px;
  border-radius: 14px;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text);
  font-size: 0.95rem;
  font-family: inherit;
}

.composer textarea:focus {
  outline: none;
  border-color: var(--accent);
}

.send-btn {
  width: 44px;
  height: 44px;
  flex-shrink: 0;
  border-radius: 50%;
  border: none;
  background: var(--accent);
  color: #06070a;
  font-size: 1.1rem;
  cursor: pointer;
}

.send-btn:disabled {
  opacity: 0.4;
  cursor: default;
}

.talk-row {
  display: flex;
  justify-content: center;
  padding: 6px 14px 10px;
}

.talk-btn {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  border: 1px solid var(--border);
  background: var(--bg-elevated);
  color: var(--text-dim);
  font-size: 0.62rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  cursor: not-allowed;
}

.talk-btn[disabled] { opacity: 0.55; }

@media (min-width: 720px) {
  body { align-items: center; }
  .app-shell {
    width: 100%;
    max-width: 520px;
    margin: 0 auto;
    border-left: 1px solid var(--border);
    border-right: 1px solid var(--border);
    min-height: 100vh;
  }
}