:root {
  color-scheme: light;
  --bg: #f3f0e7;
  --bg-soft: #faf7f0;
  --panel: rgba(255, 252, 246, 0.94);
  --panel-strong: #fffdf8;
  --panel-muted: #f0e8da;
  --text: #243029;
  --muted: #5f6f65;
  --heading: #1e2a23;
  --accent: #456b57;
  --accent-strong: #2e5140;
  --accent-soft: #d9e5db;
  --warning-bg: #f7edd8;
  --warning-border: #caa867;
  --border: rgba(88, 110, 95, 0.22);
  --shadow: 0 18px 40px rgba(61, 74, 62, 0.09);
  --shadow-soft: 0 10px 24px rgba(61, 74, 62, 0.06);
  --radius-lg: 24px;
  --radius-md: 16px;
  --radius-sm: 12px;
  --space-xxl: 5rem;
  --space-xl: 3rem;
  --space-lg: 2rem;
  --space-md: 1.25rem;
  --space-sm: 0.85rem;
  --space-xs: 0.5rem;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(174, 194, 178, 0.32), transparent 28%),
    radial-gradient(circle at top right, rgba(231, 220, 194, 0.28), transparent 22%),
    linear-gradient(180deg, #f7f4ec 0%, #f3f0e7 55%, #ede6d8 100%);
  color: var(--text);
  font-family: Georgia, "Iowan Old Style", "Palatino Linotype", "Book Antiqua", "Times New Roman", serif;
  line-height: 1.6;
}

a {
  color: var(--accent-strong);
  text-decoration-thickness: 0.08em;
  text-underline-offset: 0.15em;
}

a:hover,
a:focus-visible {
  color: var(--heading);
}

img {
  max-width: 100%;
  height: auto;
}

button,
input,
textarea {
  font: inherit;
}

.container {
  width: min(1120px, calc(100vw - 2rem));
  margin: 0 auto;
}

.top-bar {
  position: sticky;
  top: 0;
  z-index: 10;
  backdrop-filter: blur(10px);
  background: rgba(248, 245, 237, 0.88);
  border-bottom: 1px solid rgba(88, 110, 95, 0.12);
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-md);
  padding: 1rem 0;
}

.brand {
  display: inline-flex;
  align-items: baseline;
  gap: 0.55rem;
  color: var(--heading);
  font-weight: 700;
  text-decoration: none;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 2rem;
  height: 2rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-strong);
  font-size: 0.88rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
}

.brand-text {
  font-size: 1.05rem;
}

.nav-links {
  display: flex;
  gap: var(--space-md);
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-links a {
  color: var(--muted);
  text-decoration: none;
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-size: 0.95rem;
  font-weight: 600;
}

main {
  padding: 2rem 0 var(--space-xxl);
}

.page-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.6fr) minmax(280px, 0.9fr);
  gap: 1.5rem;
  align-items: start;
}

.hero,
.chat-panel,
.info-card,
.footer-panel {
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  background: var(--panel);
  box-shadow: var(--shadow);
}

.hero {
  padding: clamp(1.6rem, 3vw, 2.6rem);
}

.eyebrow {
  margin: 0 0 var(--space-sm);
  color: var(--accent-strong);
  font-size: 0.82rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-weight: 700;
}

h1,
h2,
h3 {
  color: var(--heading);
  line-height: 1.15;
}

h1 {
  margin: 0;
  font-size: clamp(2.4rem, 5vw, 4rem);
  max-width: 12ch;
}

.subtitle {
  margin: 1rem 0 0;
  max-width: 60ch;
  color: var(--muted);
  font-size: 1.08rem;
}

.hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.meta-pill {
  display: inline-flex;
  align-items: center;
  padding: 0.5rem 0.85rem;
  border-radius: 999px;
  background: var(--bg-soft);
  border: 1px solid rgba(88, 110, 95, 0.14);
  color: var(--muted);
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-size: 0.92rem;
}

.sidebar {
  display: grid;
  gap: 1rem;
}

.info-card {
  padding: 1.25rem;
}

.info-card h2,
.info-card h3 {
  margin: 0 0 0.75rem;
  font-size: 1.2rem;
}

.info-card p,
.info-card li {
  margin: 0;
  color: var(--muted);
  font-size: 0.98rem;
}

.info-card p + p,
.info-card ul {
  margin-top: 0.75rem;
}

.info-card ul {
  padding-left: 1.2rem;
}

.warning-card {
  background: linear-gradient(180deg, rgba(247, 237, 216, 0.95), rgba(255, 250, 240, 0.96));
  border-color: rgba(202, 168, 103, 0.5);
}

.warning-card p,
.warning-card li {
  color: #66522b;
}

.chat-wrap {
  margin-top: 1.5rem;
}

.chat-panel {
  padding: clamp(1.2rem, 2vw, 1.6rem);
}

.chat-header {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1rem;
}

.chat-header h2 {
  margin: 0 0 0.45rem;
  font-size: 1.6rem;
}

.lede {
  margin: 0;
  max-width: 64ch;
  color: var(--muted);
}

.chat-note {
  display: inline-flex;
  align-items: center;
  padding: 0.45rem 0.75rem;
  border-radius: 999px;
  background: var(--panel-muted);
  color: var(--accent-strong);
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-size: 0.88rem;
  font-weight: 600;
  white-space: nowrap;
}

.chatlog {
  border: 1px solid rgba(88, 110, 95, 0.16);
  border-radius: var(--radius-md);
  padding: 1rem;
  background: linear-gradient(180deg, rgba(255, 253, 248, 0.92), rgba(247, 243, 235, 0.92));
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.7);
  min-height: 320px;
  max-height: 65vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  margin-bottom: 1rem;
}

.msg-row {
  display: flex;
  width: 100%;
}

.msg-row.user {
  justify-content: flex-end;
}

.msg-row.assistant {
  justify-content: flex-start;
}

.msg-bubble {
  max-width: min(720px, 100%);
  padding: 0.85rem 1rem;
  border-radius: 1.1rem;
  border: 1px solid rgba(88, 110, 95, 0.14);
  background: var(--panel-strong);
  box-shadow: var(--shadow-soft);
}

.msg-row.user .msg-bubble {
  background: linear-gradient(180deg, #edf4ee, #e3eee5);
  border-color: rgba(69, 107, 87, 0.2);
}

.msg-content {
  color: var(--text);
  font-size: 1rem;
  line-height: 1.65;
  word-break: break-word;
}

.msg-content p {
  margin: 0 0 var(--space-xs);
}

.msg-content p:last-child {
  margin-bottom: 0;
}

.msg-content code {
  background: rgba(69, 107, 87, 0.09);
  padding: 0.12em 0.36em;
  border-radius: 6px;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 0.92em;
}

.msg-content pre {
  background: #f5f1e8;
  border: 1px solid rgba(88, 110, 95, 0.14);
  padding: var(--space-sm);
  border-radius: 10px;
  overflow-x: auto;
}

.msg-content .katex {
  color: var(--text);
}

.msg-content .katex-display {
  margin: var(--space-sm) 0;
  padding: var(--space-xs);
  border-radius: 10px;
  background: rgba(69, 107, 87, 0.04);
  overflow-x: auto;
}

.msg-content .katex-display > .katex {
  white-space: normal;
}

#chatform {
  display: flex;
  gap: 0.75rem;
  align-items: stretch;
}

#msg {
  flex: 1;
  min-width: 0;
  padding: 0.9rem 1rem;
  border-radius: 999px;
  border: 1px solid rgba(88, 110, 95, 0.2);
  background: #fffdf9;
  color: var(--text);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.9);
}

#msg:focus-visible {
  outline: 2px solid rgba(69, 107, 87, 0.22);
  outline-offset: 2px;
  border-color: rgba(69, 107, 87, 0.42);
}

#chatform button {
  padding: 0.9rem 1.3rem;
  border: 1px solid rgba(46, 81, 64, 0.1);
  border-radius: 999px;
  background: var(--accent);
  color: #f8f7f3;
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-weight: 700;
  cursor: pointer;
  transition: background-color 160ms ease, transform 160ms ease;
}

#chatform button:hover,
#chatform button:focus-visible {
  background: var(--accent-strong);
  transform: translateY(-1px);
}

.thinking {
  display: inline-flex;
  gap: 6px;
  align-items: center;
}

.thinking .dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--muted);
  opacity: 0.6;
  animation: thinking 1.4s infinite ease-in-out;
}

.thinking .d1 {
  animation-delay: 0.1s;
}

.thinking .d2 {
  animation-delay: 0.25s;
}

@keyframes thinking {
  0%,
  80%,
  100% {
    transform: scale(0.8);
    opacity: 0.4;
  }

  40% {
    transform: scale(1);
    opacity: 0.9;
  }
}

.footer {
  padding: 0 0 2rem;
}

.footer-panel {
  padding: 1.1rem 1.25rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-links {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer a {
  color: var(--muted);
  text-decoration: none;
  font-family: "Segoe UI", "SF Pro Text", system-ui, sans-serif;
  font-size: 0.93rem;
}

.footer a:hover,
.footer a:focus-visible {
  color: var(--heading);
}

.micro {
  margin: 0;
  color: var(--muted);
  font-size: 0.9rem;
}

@media (max-width: 900px) {
  .page-grid {
    grid-template-columns: 1fr;
  }

  .sidebar {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  }
}

@media (max-width: 720px) {
  .container {
    width: min(100vw - 1.2rem, 1120px);
  }

  .nav {
    flex-direction: column;
    align-items: flex-start;
  }

  .nav-links {
    flex-wrap: wrap;
    gap: 0.85rem;
  }

  .hero,
  .chat-panel,
  .info-card,
  .footer-panel {
    border-radius: 18px;
  }

  .chat-header {
    flex-direction: column;
  }

  #chatform {
    flex-direction: column;
  }

  #chatform button {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}