:root {
  --ink: #04342C;
  --green-deep: #0F6E56;
  --green: #1D9E75;
  --green-pale: #E7F3EE;
  --orange: #D85A30;
  --orange-pale: #FBEAE3;
  --paper: #FCFBF7;
  --paper-raised: #FFFFFF;
  --line: #DCE6E1;
  --text: #16302A;
  --text-soft: #4C685F;
  --radius: 10px;
  --serif: 'Fraunces', Georgia, serif;
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --mono: 'IBM Plex Mono', ui-monospace, monospace;
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  background: var(--paper);
  color: var(--text);
  font-family: var(--sans);
  -webkit-font-smoothing: antialiased;
}

a { color: var(--green-deep); }

.page {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 24px 64px;
}

/* ---- top bar ---- */

.topbar {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  padding: 28px 0 18px;
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
  gap: 8px;
}

.brand-mark {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.5rem;
  color: var(--ink);
  letter-spacing: -0.01em;
}

.brand-tag {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-soft);
  margin-left: 12px;
}

.brand-link {
  font-family: var(--mono);
  font-size: 0.82rem;
  text-decoration: none;
  color: var(--green-deep);
  white-space: nowrap;
}
.brand-link:hover { color: var(--orange); }

/* ---- banner ---- */

.banner {
  margin-top: 18px;
  padding: 12px 16px;
  background: var(--orange-pale);
  border: 1px solid #F0C7B4;
  border-radius: var(--radius);
  font-size: 0.9rem;
  color: #8A3A1E;
}

/* ---- intro ---- */

.intro { margin-top: 44px; }

.intro h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-style: italic;
  font-size: clamp(2rem, 5vw, 2.9rem);
  line-height: 1.12;
  margin: 0 0 18px;
  color: var(--ink);
}

.intro p {
  max-width: 60ch;
  font-size: 1.02rem;
  line-height: 1.6;
  color: var(--text-soft);
  margin: 0;
}

/* ---- checkpoint picker ---- */

.checkpoint-picker { margin-top: 40px; }

.picker-label {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-soft);
  margin-bottom: 10px;
}

.tabs {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.tab {
  flex: 1 1 140px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 2px;
  padding: 12px 16px;
  background: var(--paper-raised);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  cursor: pointer;
  font-family: var(--sans);
  text-align: left;
  transition: border-color 0.15s ease, background 0.15s ease, transform 0.1s ease;
}

.tab:hover:not(:disabled) { border-color: var(--green); transform: translateY(-1px); }
.tab:disabled { opacity: 0.55; cursor: default; }

.tab .tab-label {
  font-weight: 600;
  font-size: 0.98rem;
  color: var(--ink);
}
.tab .tab-sub {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-soft);
}

.tab.active {
  background: var(--ink);
  border-color: var(--ink);
}
.tab.active .tab-label { color: var(--paper); }
.tab.active .tab-sub { color: var(--green); }

/* ---- checkpoint load progress ---- */

.load-progress {
  margin-top: 12px;
  height: 5px;
  background: var(--green-pale);
  border-radius: 999px;
  overflow: hidden;
}

.load-progress-fill {
  height: 100%;
  width: 0%;
  background: var(--green);
  border-radius: 999px;
  transition: width 0.15s ease;
}

.tab.loading { position: relative; }
.tab.loading .tab-sub::after {
  content: ' \00b7 loading\2026';
  color: var(--orange);
}

/* ---- chat panel ---- */

.chat-panel {
  margin-top: 22px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--paper-raised);
  overflow: hidden;
}

.chat-log {
  padding: 22px 22px 6px;
  max-height: 420px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.bubble { display: flex; }
.bubble.user { justify-content: flex-end; }
.bubble.model { justify-content: flex-start; }

.bubble-inner {
  max-width: 78%;
  padding: 11px 15px;
  border-radius: 12px;
  line-height: 1.55;
  font-size: 0.98rem;
  white-space: pre-wrap;
}

.bubble.user .bubble-inner {
  background: var(--green-pale);
  color: var(--ink);
  border-bottom-right-radius: 3px;
}

.bubble.model .bubble-inner {
  background: var(--paper);
  border: 1px solid var(--line);
  color: var(--ink);
  font-family: var(--serif);
  font-style: italic;
  font-size: 1.05rem;
  border-bottom-left-radius: 3px;
}

.bubble.model.intro-bubble .bubble-inner {
  font-family: var(--sans);
  font-style: normal;
  color: var(--text-soft);
  font-size: 0.92rem;
}

.bubble.model.intro-bubble em { color: var(--green-deep); font-style: italic; }

/* ---- composer ---- */

.composer {
  border-top: 1px solid var(--line);
  padding: 16px 22px 14px;
  background: var(--paper);
}

.composer-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

.composer-row + .controls-row { margin-top: 10px; }

#seed-input {
  flex: 1;
  font-family: var(--serif);
  font-style: italic;
  font-size: 1rem;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--paper-raised);
  color: var(--ink);
}
#seed-input:focus { outline: 2px solid var(--green); outline-offset: 1px; }

#send-btn {
  font-family: var(--sans);
  font-weight: 600;
  font-size: 0.92rem;
  padding: 10px 18px;
  background: var(--ink);
  color: var(--paper);
  border: none;
  border-radius: 9px;
  cursor: pointer;
  white-space: nowrap;
  transition: background 0.15s ease;
}
#send-btn:hover:not(:disabled) { background: var(--green-deep); }
#send-btn:disabled { opacity: 0.5; cursor: default; }

.temp-control {
  display: flex;
  align-items: center;
  gap: 10px;
  width: 100%;
}
.temp-name {
  font-family: var(--mono);
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-soft);
  white-space: nowrap;
}
#temp-slider {
  flex: 1;
  accent-color: var(--orange);
}
.temp-readout {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-soft);
  white-space: nowrap;
  min-width: 96px;
  text-align: right;
}
.temp-mood { color: var(--orange); }

.status-line {
  font-family: var(--mono);
  font-size: 0.76rem;
  color: var(--text-soft);
  padding: 10px 22px 16px;
  border-top: 1px solid var(--line);
}

/* ---- how panel ---- */

.how-panel { margin-top: 56px; }
.how-panel h2 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.5rem;
  color: var(--ink);
  margin: 0 0 18px;
}

.how-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.how-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-raised);
}

.how-num {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--green);
}

.how-card h3 {
  font-family: var(--sans);
  font-size: 1rem;
  margin: 6px 0 6px;
  color: var(--ink);
}

.how-card p {
  font-size: 0.88rem;
  line-height: 1.5;
  color: var(--text-soft);
  margin: 0;
}

/* ---- footer ---- */

.foot {
  margin-top: 56px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: 0.82rem;
  color: var(--text-soft);
  line-height: 1.6;
}

/* ---- responsive ---- */

@media (max-width: 640px) {
  .how-grid { grid-template-columns: 1fr; }
  .tabs { flex-direction: column; }
  .tab { flex: 1 1 auto; }
  .landing-links { flex-direction: column; }
}

/* ---- landing page ---- */

.landing-hero { margin-top: 44px; }

.landing-kicker {
  font-family: var(--mono);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--green-deep);
  margin-bottom: 14px;
}

.landing-hero h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: clamp(1.7rem, 4.2vw, 2.5rem);
  line-height: 1.28;
  margin: 0 0 20px;
  color: var(--ink);
  max-width: 22ch;
}

.landing-hero .subhead {
  max-width: 62ch;
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text-soft);
  margin: 0 0 28px;
}

.landing-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin-bottom: 8px;
}

.landing-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 16px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--paper-raised);
  color: var(--ink);
  text-decoration: none;
  font-family: var(--sans);
  font-weight: 500;
  font-size: 0.92rem;
  transition: border-color 0.15s ease, transform 0.1s ease;
}
.landing-link:hover { border-color: var(--green); transform: translateY(-1px); color: var(--green-deep); }

.landing-link.primary {
  background: var(--ink);
  border-color: var(--ink);
  color: var(--paper);
}
.landing-link.primary:hover { background: var(--green-deep); border-color: var(--green-deep); color: var(--paper); }

.landing-tagline {
  margin-top: 56px;
  padding: 32px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.landing-tagline h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-style: italic;
  font-size: clamp(1.8rem, 4.5vw, 2.6rem);
  line-height: 1.15;
  margin: 0 0 16px;
  color: var(--ink);
}

.landing-tagline p {
  max-width: 60ch;
  font-size: 1.02rem;
  line-height: 1.6;
  color: var(--text-soft);
  margin: 0;
}

.landing-cta {
  margin-top: 40px;
  text-align: center;
}

.landing-cta .landing-link.primary {
  padding: 14px 28px;
  font-size: 1rem;
}

/* ---- reduced motion ---- */

@media (prefers-reduced-motion: reduce) {
  .tab { transition: none; }
}