/* ==========================================================================
   BL Platform -- site stylesheet
   Palette: ink navy / warm paper / amber signal accent / muted clay error
   Type: Fraunces (display) + IBM Plex Sans (UI) + IBM Plex Mono (code)
   ========================================================================== */

:root {
  --ink:        #14171F;
  --ink-soft:   #2A2F3A;
  --paper:      #F5F2E9;
  --paper-dim:  #EAE5D6;
  --line:       #DAD3BE;
  --amber:      #D9A441;
  --amber-dark: #B7842C;
  --clay:       #C1443B;
  --mint:       #3FAE8A;
  --white:      #FFFFFF;

  --font-display: 'Fraunces', Georgia, serif;
  --font-ui: 'IBM Plex Sans', system-ui, sans-serif;
  --font-mono: 'IBM Plex Mono', 'Courier New', monospace;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font-ui);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.5;
}
a { color: inherit; }
img { max-width: 100%; display: block; }

/* ---------- Top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 32px;
  border-bottom: 1px solid var(--line);
  background: var(--paper);
  position: sticky;
  top: 0;
  z-index: 20;
}
.topbar .brand {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.35rem;
  letter-spacing: 0.01em;
  text-decoration: none;
  color: var(--ink);
}
.topbar .brand span { color: var(--amber-dark); }
.topbar nav { display: flex; gap: 28px; align-items: center; }
.topbar nav a {
  text-decoration: none;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--ink-soft);
}
.topbar nav a:hover { color: var(--ink); }
.topbar .cta-btn {
  background: var(--ink);
  color: var(--paper);
  padding: 9px 18px;
  border-radius: 4px;
  font-weight: 600;
  font-size: 0.9rem;
}
.topbar .cta-btn:hover { background: var(--ink-soft); }

/* ---------- Hero ---------- */
.hero {
  max-width: 980px;
  margin: 0 auto;
  padding: 84px 32px 60px;
}
.hero .eyebrow {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--amber-dark);
  margin-bottom: 18px;
}
.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 5vw, 3.6rem);
  line-height: 1.08;
  margin: 0 0 22px;
  font-weight: 600;
  max-width: 14ch;
}
.hero p.lede {
  font-size: 1.18rem;
  color: var(--ink-soft);
  max-width: 56ch;
  margin: 0 0 34px;
}
.hero .actions { display: flex; gap: 16px; flex-wrap: wrap; }
.btn-primary, .btn-secondary {
  display: inline-block;
  padding: 13px 26px;
  border-radius: 4px;
  font-weight: 600;
  text-decoration: none;
  font-size: 0.98rem;
  border: 1px solid transparent;
  cursor: pointer;
}
.btn-primary { background: var(--ink); color: var(--paper); }
.btn-primary:hover { background: var(--ink-soft); }
.btn-secondary { background: transparent; color: var(--ink); border-color: var(--ink); }
.btn-secondary:hover { background: var(--paper-dim); }

/* ---------- side-by-side comparison ---------- */
.compare {
  max-width: 980px;
  margin: 20px auto 90px;
  padding: 0 32px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}
@media (max-width: 720px) { .compare { grid-template-columns: 1fr; } }
.compare .panel {
  background: var(--white);
  border: 1px solid var(--line);
  border-radius: 6px;
  overflow: hidden;
}
.compare .panel-head {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  color: var(--ink-soft);
  display: flex;
  justify-content: space-between;
}
.compare pre {
  margin: 0;
  padding: 18px 16px;
  font-family: var(--font-mono);
  font-size: 0.83rem;
  line-height: 1.65;
  overflow-x: auto;
  white-space: pre-wrap;
}
.compare .panel.bl pre { color: var(--ink); }
.compare .panel.other pre { color: var(--ink-soft); }

/* ---------- Section shell ---------- */
.section {
  max-width: 980px;
  margin: 0 auto;
  padding: 70px 32px;
  border-top: 1px solid var(--line);
}
.section h2 {
  font-family: var(--font-display);
  font-size: 2rem;
  margin: 0 0 14px;
  font-weight: 600;
}
.section p.section-lede {
  color: var(--ink-soft);
  max-width: 60ch;
  margin: 0 0 40px;
  font-size: 1.05rem;
}

/* ---------- grammar table ---------- */
.grammar-list { display: flex; flex-direction: column; gap: 0; }
.grammar-row {
  display: grid;
  grid-template-columns: 1.1fr 1.4fr;
  gap: 24px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
  align-items: start;
}
@media (max-width: 720px) { .grammar-row { grid-template-columns: 1fr; } }
.grammar-row .cat { font-weight: 600; font-size: 0.95rem; }
.grammar-row .cat small { display:block; color: var(--ink-soft); font-weight: 400; margin-top: 4px; font-size: 0.85rem; }
.grammar-row code {
  display: block;
  font-family: var(--font-mono);
  background: var(--paper-dim);
  padding: 3px 8px;
  border-radius: 4px;
  font-size: 0.82rem;
  margin-bottom: 6px;
  width: fit-content;
}

/* ---------- steps ---------- */
.steps { counter-reset: step; display: flex; flex-direction: column; gap: 26px; }
.step { display: flex; gap: 20px; }
.step .num {
  font-family: var(--font-display);
  font-size: 1.6rem;
  color: var(--amber-dark);
  min-width: 40px;
}
.step h3 { margin: 0 0 6px; font-size: 1.05rem; }
.step p { margin: 0; color: var(--ink-soft); }

/* ---------- footer ---------- */
footer {
  padding: 40px 32px;
  text-align: center;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

/* ==========================================================================
   BUILDER (IDE) PAGE
   ========================================================================== */
.builder-shell {
  display: grid;
  grid-template-columns: 1fr 1fr;
  height: calc(100vh - 61px);
}
@media (max-width: 900px) {
  .builder-shell { grid-template-columns: 1fr; height: auto; }
}

.editor-pane, .preview-pane {
  display: flex;
  flex-direction: column;
  min-height: 0;
}
.editor-pane { background: var(--ink); border-right: 1px solid var(--line); }
.pane-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}
.editor-pane .pane-head { color: var(--paper-dim); border-bottom: 1px solid #2A2F3A; }
.preview-pane .pane-head { color: var(--ink-soft); border-bottom: 1px solid var(--line); }
.pane-head .tools { display: flex; gap: 8px; }
.pane-head select, .pane-head button {
  font-family: var(--font-ui);
  font-size: 0.8rem;
  padding: 5px 10px;
  border-radius: 4px;
  border: 1px solid #3A3F4A;
  background: #1D212B;
  color: var(--paper-dim);
  cursor: pointer;
}
.preview-pane .pane-head select, .preview-pane .pane-head button {
  border-color: var(--line); background: var(--white); color: var(--ink);
}
.pane-head button.primary { background: var(--amber); border-color: var(--amber-dark); color: var(--ink); font-weight: 600; }
.pane-head button.primary:hover { background: var(--amber-dark); color: var(--white); }

#bl-editor {
  flex: 1;
  width: 100%;
  border: none;
  outline: none;
  resize: none;
  background: var(--ink);
  color: #E9E6DA;
  font-family: var(--font-mono);
  font-size: 0.92rem;
  line-height: 1.65;
  padding: 18px 20px;
  tab-size: 4;
}

.preview-frame-wrap { flex: 1; background: var(--paper-dim); padding: 14px; overflow: auto; min-height: 300px; }
#bl-preview {
  width: 100%;
  height: 100%;
  min-height: 480px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: white;
}

.errors-box {
  background: #2A1414;
  color: #F5C3BE;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  padding: 12px 16px;
  border-top: 1px solid var(--clay);
  max-height: 140px;
  overflow-y: auto;
  display: none;
}
.errors-box.visible { display: block; }
.errors-box .ok { color: #B8E2CF; }