*,
*::before,
*::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --bg: #0b0b11;
  --surface: #12121c;
  --card: #181826;
  --border: #262640;
  --text: #e4e4f0;
  --text-secondary: #8585a0;
  --accent: #8b5cf6;
  --accent-hover: #7c3aed;
  --accent-subtle: rgba(139, 92, 246, 0.12);
  --green: #34d399;
  --radius: 8px;
  --radius-lg: 12px;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen,
    Ubuntu, Cantarell, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

a {
  color: var(--accent);
  text-decoration: none;
}

a:hover {
  color: var(--accent-hover);
}

code {
  font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
  background: var(--card);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  font-size: 0.9em;
}

/* ── Header ── */

.site-header {
  border-bottom: 1px solid var(--border);
  padding: 1rem 0;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
}

.logo:hover {
  color: var(--text);
}

.logo-accent {
  color: var(--accent);
}

nav {
  display: flex;
  gap: 1.5rem;
}

nav a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s;
}

nav a:hover,
nav a.active {
  color: var(--text);
}

/* ── Buttons ── */

.btn {
  display: inline-block;
  padding: 0.65rem 1.5rem;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: background 0.15s, transform 0.1s;
  text-align: center;
}

.btn:active:not(:disabled) {
  transform: scale(0.98);
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
}

.btn-secondary {
  background: var(--card);
  color: var(--text);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: var(--border);
  color: var(--text);
}

/* ── Hero ── */

.hero {
  padding: 6rem 0 4rem;
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 1.25rem;
}

.hero-sub {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 2rem;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
}

.hero-version {
  margin-top: 2rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-family: 'SF Mono', 'Fira Code', monospace;
}

/* ── Features ── */

.features {
  padding: 4rem 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 1.5rem;
}

.feature-card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
}

.feature-icon {
  font-size: 1.75rem;
  margin-bottom: 0.75rem;
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── Code Section ── */

.code-section {
  padding: 4rem 0;
}

.code-section h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  text-align: center;
}

.code-section pre {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 1.5rem 2rem;
  overflow-x: auto;
  font-size: 0.85rem;
  line-height: 1.7;
  font-family: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
}

.code-section pre code {
  background: none;
  padding: 0;
  font-size: inherit;
}

.code-section .kw { color: #c084fc; }
.code-section .str { color: #34d399; }
.code-section .lit { color: #f59e0b; }

.code-caption {
  margin-top: 1.25rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.95rem;
  max-width: 640px;
  margin-left: auto;
  margin-right: auto;
}

/* ── CTA ── */

.cta-section {
  padding: 4rem 0 5rem;
  text-align: center;
}

.cta-section h2 {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.cta-section p {
  color: var(--text-secondary);
  max-width: 560px;
  margin: 0 auto 1.5rem;
  font-size: 0.95rem;
  line-height: 1.7;
}

/* ── Footer ── */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0;
  margin-top: auto;
  text-align: center;
}

.site-footer p {
  color: var(--text-secondary);
  font-size: 0.8rem;
}

/* ── Demo Page ── */

.demo-page {
  flex: 1;
  padding: 2rem 0;
}

.demo-header {
  text-align: center;
  margin-bottom: 2rem;
}

.demo-header h1 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
}

.demo-header p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  max-width: 560px;
  margin: 0 auto;
  line-height: 1.7;
}

.character-tabs {
  display: flex;
  gap: 0.5rem;
  max-width: 640px;
  margin: 0 auto 0.75rem;
  padding: 0 0.25rem;
  overflow-x: auto;
}

.char-tab {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, border-color 0.15s;
  white-space: nowrap;
}

.char-tab:hover {
  background: var(--border);
  color: var(--text);
}

.char-tab.active {
  background: var(--accent-subtle);
  color: var(--accent);
  border-color: var(--accent);
}

.char-tab-avatar {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  background: var(--accent-subtle);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.75rem;
  font-weight: 700;
  flex-shrink: 0;
}

.char-tab.active .char-tab-avatar {
  background: var(--accent);
  color: #fff;
}

.chat-container {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  max-width: 640px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.chat-npc-info {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 1rem 1.25rem;
  border-bottom: 1px solid var(--border);
  background: var(--card);
}

.npc-avatar {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent-subtle);
  color: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.npc-name {
  font-weight: 600;
  font-size: 0.95rem;
}

.npc-meta {
  font-size: 0.75rem;
  color: var(--text-secondary);
  font-family: 'SF Mono', 'Fira Code', monospace;
}

.chat-messages {
  flex: 1;
  min-height: 320px;
  max-height: 420px;
  overflow-y: auto;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.system-message {
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.85rem;
  padding: 2rem 0;
}

.message {
  max-width: 85%;
  padding: 0.6rem 0.9rem;
  border-radius: var(--radius);
  font-size: 0.9rem;
  line-height: 1.5;
  animation: fadeIn 0.2s ease;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}

.message.npc {
  background: var(--card);
  border: 1px solid var(--border);
  align-self: flex-start;
}

.message.npc .message-sender {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 0.2rem;
}

.message.player {
  background: var(--accent);
  color: #fff;
  align-self: flex-end;
}

.chat-input-area {
  display: flex;
  gap: 0.5rem;
  padding: 1rem 1.25rem;
  border-top: 1px solid var(--border);
}

.chat-input-area input {
  flex: 1;
  padding: 0.6rem 0.8rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 0.9rem;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s;
}

.chat-input-area input:focus {
  border-color: var(--accent);
}

.chat-input-area input:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.chat-input-area button {
  padding: 0.6rem 1.2rem;
  border-radius: var(--radius);
  background: var(--accent);
  color: #fff;
  font-weight: 600;
  font-size: 0.9rem;
  border: none;
  cursor: pointer;
  transition: background 0.15s;
}

.chat-input-area button:hover:not(:disabled) {
  background: var(--accent-hover);
}

.chat-input-area button:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.chat-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 0.75rem 1.25rem;
  border-top: 1px solid var(--border);
  background: var(--card);
}

.chat-status {
  font-size: 0.8rem;
  color: var(--text-secondary);
  font-family: 'SF Mono', 'Fira Code', monospace;
}

.chat-hint {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-align: center;
  padding: 0 1.25rem 0.6rem;
}

.summary-notice {
  background: rgba(245, 158, 11, 0.08);
  border: 1px solid rgba(245, 158, 11, 0.25);
  border-radius: var(--radius);
  padding: 0.6rem 0.9rem;
  font-size: 0.8rem;
  line-height: 1.5;
  animation: fadeIn 0.2s ease;
  align-self: center;
  max-width: 95%;
}

.summary-notice-title {
  font-weight: 700;
  color: #f59e0b;
  margin-bottom: 0.3rem;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.03em;
}

.summary-notice-body {
  color: var(--text-secondary);
  font-size: 0.8rem;
}

/* ── Welcome Overlay ── */

.welcome-overlay {
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 2rem;
}

.welcome-card,
.welcome-dialog {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 2.5rem;
  max-width: 460px;
  width: 90%;
  text-align: center;
}

.welcome-card h1,
.welcome-dialog h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.welcome-card p,
.welcome-dialog p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
  margin-bottom: 1.5rem;
}

.welcome-input-row {
  display: flex;
  gap: 0.5rem;
}

.welcome-input-row input {
  flex: 1;
  padding: 0.65rem 0.9rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  font-size: 0.95rem;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s;
}

.welcome-input-row input:focus {
  border-color: var(--accent);
}

.welcome-status {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  min-height: 1.2em;
}

.welcome-disclaimer {
  margin-top: 1.25rem;
  font-size: 0.75rem;
  color: var(--text-secondary);
  opacity: 0.7;
}

.welcome-dialog-actions {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  flex-wrap: wrap;
}

/* ── Responsive ── */

@media (max-width: 600px) {
  .hero h1 {
    font-size: 2rem;
  }

  .hero-sub {
    font-size: 1rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .code-section pre {
    font-size: 0.75rem;
    padding: 1rem;
  }
}