* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--color-bg);
  color: var(--color-ink);
  font-family: var(--font-body);
  font-size: var(--text-base);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

main { max-width: 60rem; margin: 0 auto; padding: 0 1.5rem; }

h1, h2 { font-family: var(--font-display); font-weight: 600; font-optical-sizing: auto; letter-spacing: -0.01em; }

/* ---------- Header ---------- */
.site-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.85rem clamp(1.5rem, 4vw, 3rem);
  border-bottom: 1px solid var(--color-line);
  position: sticky; top: 0; z-index: 20;
  background: oklch(98% 0.005 95 / 0.82);
  backdrop-filter: blur(12px);
}
.brand { display: flex; gap: 0.65rem; align-items: center; text-decoration: none; color: inherit; }
.brand-mark {
  font-family: var(--font-display); font-weight: 600; font-size: 0.95rem;
  color: var(--color-surface); background: var(--color-brand);
  width: 2rem; height: 2rem; display: grid; place-items: center;
  border-radius: 7px; letter-spacing: 0; line-height: 1;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.2; }
.brand-text strong { font-family: var(--font-display); font-weight: 600; font-size: 1rem; }
.brand-text small { color: var(--color-ink-faint); font-size: 0.72rem; letter-spacing: 0.01em; }

.site-header nav { display: flex; align-items: center; gap: 1.4rem; }
.site-header nav a {
  color: var(--color-ink-soft); text-decoration: none; font-size: 0.85rem; font-weight: 500;
  position: relative; padding: 0.2rem 0;
  transition: color var(--duration) var(--ease);
}
.site-header nav a::after {
  content: ""; position: absolute; left: 0; right: 0; bottom: -2px; height: 1.5px;
  background: var(--color-accent); transform: scaleX(0); transform-origin: left;
  transition: transform var(--duration) var(--ease);
}
.site-header nav a:hover { color: var(--color-ink); }
.site-header nav a:hover::after, .site-header nav a:focus-visible::after { transform: scaleX(1); }

.lang-switch { display: flex; gap: 1px; background: var(--color-line); border: 1px solid var(--color-line); border-radius: 999px; overflow: hidden; }
.lang-switch button {
  border: 0; background: var(--color-surface); padding: 0.28rem 0.7rem; font: inherit; font-size: 0.76rem; font-weight: 500;
  cursor: pointer; color: var(--color-ink-soft); transition: background var(--duration) var(--ease), color var(--duration) var(--ease);
}
.lang-switch button:hover { color: var(--color-ink); }
.lang-switch button.is-active { background: var(--color-ink); color: var(--color-bg); }

/* ---------- Hero ---------- */
.hero { padding: var(--space-section) 0 calc(var(--space-section) * 0.7); max-width: 42rem; }
.eyebrow {
  color: var(--color-accent); font-family: var(--font-mono); font-size: var(--text-xs);
  letter-spacing: 0.16em; text-transform: uppercase; font-weight: 500; margin: 0 0 0.75rem;
}
.hero h1 { font-size: var(--text-hero); line-height: 1.08; margin: 0 0 1.1rem; }
.lede { color: var(--color-ink-soft); max-width: 36rem; margin: 0; font-size: 1.02rem; }

/* ---------- Sections & form ---------- */
.builder, .optimize { padding: calc(var(--space-section) * 0.45) 0; }
.section-heading { margin-bottom: 1.1rem; }
.section-heading h2 { font-size: var(--text-h2); margin: 0 0 0.3rem; }
.section-heading .hint { color: var(--color-ink-faint); font-size: var(--text-sm); margin: 0; }
.builder-heading { display: flex; align-items: center; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.builder-heading > div { min-width: 0; }
.builder-heading h2 { margin: 0; }

.prompt-form {
  display: grid; gap: 0.9rem;
  background: var(--color-surface); border: 1px solid var(--color-line); border-radius: var(--radius);
  padding: clamp(1.1rem, 2.5vw, 1.6rem);
  box-shadow: 0 1px 2px oklch(40% 0.03 235 / 0.04), 0 8px 28px oklch(40% 0.04 235 / 0.05);
}
.field { display: flex; flex-direction: column; gap: 0.35rem; }
.field > span, .safeguards legend {
  font-size: var(--text-sm); font-weight: 600; color: var(--color-ink);
}
.field em { color: var(--color-accent); font-style: normal; font-weight: 700; }
.field-row { display: grid; grid-template-columns: 1fr 1fr; gap: 0.9rem; }

.field input, .field textarea, .field select, .safeguards > input, .access-field input {
  font: inherit; color: var(--color-ink);
  border: 1px solid var(--color-line-strong); border-radius: var(--radius-sm);
  padding: 0.5rem 0.65rem; background: var(--color-bg-tint);
  transition: border-color var(--duration) var(--ease), box-shadow var(--duration) var(--ease), background var(--duration) var(--ease);
}
.field textarea { resize: vertical; line-height: 1.5; }
.field input::placeholder, .field textarea::placeholder { color: var(--color-ink-faint); }
.field input:focus-visible, .field textarea:focus-visible, .field select:focus-visible,
.safeguards > input:focus-visible, .access-field input:focus-visible {
  outline: none; border-color: var(--color-accent); background: var(--color-surface);
  box-shadow: 0 0 0 3px var(--color-accent-ring);
}
.field select { cursor: pointer; appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--color-ink-soft) 50%), linear-gradient(135deg, var(--color-ink-soft) 50%, transparent 50%);
  background-position: calc(100% - 16px) 1.05em, calc(100% - 11px) 1.05em; background-size: 5px 5px, 5px 5px; background-repeat: no-repeat;
}

.safeguards { border: 1px solid var(--color-line); border-radius: var(--radius-sm); padding: 0.75rem 0.9rem 0.85rem; margin: 0; background: var(--color-accent-soft); }
.safeguards legend { padding: 0 0.35rem; }
.checkbox-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(10.5rem, 1fr)); gap: 0.35rem 0.9rem; margin-bottom: 0.65rem; }
.checkbox-grid label { display: flex; gap: 0.45rem; align-items: center; font-size: var(--text-sm); cursor: pointer; }
.checkbox-grid input { accent-color: var(--color-accent); width: 0.95rem; height: 0.95rem; }
.safeguards > input { width: 100%; background: var(--color-surface); }

.form-actions { display: flex; align-items: end; justify-content: space-between; gap: 1rem; flex-wrap: wrap; margin-top: 0.2rem; }
.access-field { display: flex; flex-direction: column; gap: 0.3rem; }
.access-field > span { font-size: var(--text-sm); font-weight: 600; color: var(--color-ink); }
.access-field input { max-width: 16rem; padding: 0.5rem 0.65rem; }
.access-hint { font-size: var(--text-xs); color: var(--color-ink-faint); font-weight: 400; line-height: 1.5; }

.button {
  font: inherit; font-weight: 600; font-size: 0.9rem; cursor: pointer; border-radius: 999px;
  padding: 0.6rem 1.4rem; border: 1px solid transparent; letter-spacing: 0.01em;
  transition: transform var(--duration) var(--ease), background var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
}
.button-primary { background: var(--color-accent); color: white; box-shadow: 0 2px 10px var(--color-accent-ring); }
.button-primary:hover { background: var(--color-accent-deep); transform: translateY(-1px); box-shadow: 0 6px 18px var(--color-accent-ring); }
.button-primary:disabled { opacity: 0.45; cursor: not-allowed; transform: none; box-shadow: none; }
.button-secondary { background: transparent; color: var(--color-panel-text); border-color: var(--color-panel-line); }
.button-secondary:hover { background: var(--color-panel-2); }
.button-ghost { background: oklch(32% 0.03 205); color: var(--color-panel-text); border-color: var(--color-panel-line); padding: 0.5rem 1.1rem; font-size: 0.85rem; }
.button-ghost:hover { background: var(--color-panel-2); }
.button-ghost:disabled { opacity: 0.5; cursor: wait; }

.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; border: 0; }
.workbench { padding: calc(var(--space-section) * 0.4) 0; }

/* refine bar inside the dark result panel */
.refine { display: flex; gap: 0.6rem; align-items: end; margin-top: 1.4rem; padding-top: 1.2rem; border-top: 1px solid var(--color-panel-line); }
.refine .field { flex: 1; gap: 0.35rem; }
.refine .field > span { font-size: var(--text-sm); font-weight: 600; color: var(--color-panel-soft); }
/* id selector so the dark-panel styling always beats the light .field input rule */
#refineInput {
  font: inherit; width: 100%;
  color: #ffffff; background: oklch(18% 0.025 205);
  border: 1px solid var(--color-panel-line); border-radius: var(--radius-sm);
  padding: 0.5rem 0.7rem;
  transition: border-color var(--duration) var(--ease), box-shadow var(--duration) var(--ease);
}
#refineInput::placeholder { color: oklch(62% 0.02 205); }
#refineInput:focus-visible { outline: none; border-color: var(--color-panel-soft); box-shadow: 0 0 0 3px oklch(74% 0.018 200 / 0.18); }

/* ---------- Result / anatomy (dark galley-proof panel) ---------- */
.result {
  background:
    radial-gradient(40rem 18rem at 90% -20%, oklch(32% 0.05 200 / 0.6), transparent),
    var(--color-panel);
  color: var(--color-panel-text);
  border-radius: var(--radius); padding: clamp(1.4rem, 3vw, 2.2rem);
  margin: 0.5rem 0 1rem;
  box-shadow: 0 12px 40px oklch(25% 0.04 205 / 0.25);
}
.result-head { display: flex; justify-content: space-between; align-items: start; gap: 1rem; flex-wrap: wrap; }
.result-head .eyebrow { color: var(--color-panel-soft); }
.result-head h2 { margin: 0; font-size: var(--text-h2); color: var(--color-panel-text); }
.result-actions { display: flex; gap: 0.9rem; align-items: center; }
.result-badge {
  font-family: var(--font-mono); font-size: var(--text-xs); letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--color-panel-soft); border: 1px solid var(--color-panel-line); border-radius: 999px; padding: 0.2rem 0.6rem;
}

.placeholder-tip {
  margin: 1.4rem 0 0; padding: 0.55rem 0.85rem;
  font-size: var(--text-sm); color: oklch(82% 0.09 88);
  background: oklch(45% 0.08 88 / 0.18); border-left: 3px solid oklch(78% 0.11 88);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.anatomy-preamble {
  margin: 1.4rem 0 0; padding: 0.7rem 0.9rem;
  font-family: var(--font-display); font-style: italic; font-size: 1.02rem;
  color: var(--color-panel-text); line-height: 1.45;
  border-left: 3px solid var(--color-brand);
  background: oklch(from var(--color-brand) 30% 0.06 h / 0.18);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}
.anatomy { display: grid; gap: 0.55rem; margin-top: 0.9rem; }
.anatomy-row {
  display: grid; grid-template-columns: 3px 8.5rem 1fr; gap: 0.9rem; align-items: start;
  padding: 0.5rem 0; border-top: 1px solid var(--color-panel-line);
  animation: rise 0.35s var(--ease) both;
}
.anatomy-row:first-child { border-top: 0; }
.anatomy-bar { width: 3px; border-radius: 2px; align-self: stretch; min-height: 1.4rem; background: var(--bar, var(--color-accent)); }
.anatomy-label {
  font-family: var(--font-mono); font-weight: 500; font-size: 0.7rem; letter-spacing: 0.06em; text-transform: uppercase;
  padding-top: 0.15rem; color: oklch(from var(--bar) 80% 0.08 h);
}
.anatomy-text { margin: 0; white-space: pre-wrap; font-size: 0.92rem; line-height: 1.55; color: oklch(90% 0.008 200); }
@keyframes rise { from { opacity: 0; transform: translateY(5px); } }

.result-notes {
  margin: 1.3rem 0 0; padding-top: 0.9rem; border-top: 1px solid var(--color-panel-line);
  font-size: var(--text-sm); color: var(--color-panel-soft); font-style: italic;
}
.form-error { color: oklch(52% 0.16 14); font-size: var(--text-sm); margin: 0.7rem 0 0; }
.result-error {
  margin: 1.2rem 0 0; padding: 0.6rem 0.85rem;
  font-size: var(--text-sm); color: oklch(82% 0.09 30);
  background: oklch(45% 0.1 25 / 0.22); border-left: 3px solid oklch(60% 0.16 25);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
}

.site-footer {
  border-top: 1px solid var(--color-line); margin-top: var(--space-section);
  padding: 1.4rem clamp(1.5rem, 4vw, 3rem);
  font-size: var(--text-xs); color: var(--color-ink-faint);
}

@media (max-width: 640px) {
  .field-row { grid-template-columns: 1fr; }
  .anatomy-row { grid-template-columns: 3px 1fr; gap: 0.5rem 0.8rem; }
  .anatomy-text { grid-column: 2; }
  .access-field input { width: 100%; }
  .access-field { flex: 1; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .anatomy-row { animation: none; }
  .button-primary:hover { transform: none; }
}