/* ═══════════════════════════════════════════════════════════════
   DFMCAD.COM — Main Stylesheet
   Dark industrial. Grid-precision. No bullshit.
   Stack: DM Sans | IBM Plex Sans | JetBrains Mono | Barlow Condensed
   ═══════════════════════════════════════════════════════════════ */

/* ── Reset & Base ──────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:          #080808;
  --surface:     #111111;
  --surface-2:   #191919;
  --surface-3:   #222222;
  --border:      #2a2a2a;
  --border-2:    #333333;
  --text:        #d8d8d8;
  --text-dim:    #888888;
  --text-dimmer: #555555;
  --accent:      #c8ff00;
  --accent-dim:  rgba(200, 255, 0, 0.12);
  --accent-glow: rgba(200, 255, 0, 0.06);
  --accent-border: rgba(200, 255, 0, 0.25);
  --red:         #ff4444;
  --orange:      #ff8844;
  --blue:        #4488ff;
  --white:       #f0f0f0;

  --font-display: 'Barlow Condensed', sans-serif;
  --font-body:    'DM Sans', sans-serif;
  --font-prose:   'IBM Plex Sans', sans-serif;
  --font-mono:    'JetBrains Mono', monospace;

  --nav-h:       60px;
  --max-w:       1200px;
  --max-w-prose: 720px;
  --radius:      4px;
  --radius-lg:   8px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-in-out: cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
  /* Offset anchor scroll targets so they clear the fixed nav */
  scroll-padding-top: calc(var(--nav-h) + 16px);
  -webkit-font-smoothing: antialiased;
}

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

#main { flex: 1; }

a { color: var(--accent); text-decoration: none; transition: opacity 0.15s; }
a:hover { opacity: 0.8; }

/* :focus-visible — keyboard-only focus ring. Shows on Tab navigation,
   hidden on mouse clicks. 2px offset keeps the ring from overlapping content. */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Inputs already have their own focus style (border + box-shadow),
   so suppress the generic outline to avoid doubling up. */
.field input:focus-visible,
.field select:focus-visible {
  outline: none;
}

img { max-width: 100%; display: block; }

/* ── Typography ────────────────────────────────────────────── */
h1, h2, h3, h4, h5 {
  font-family: var(--font-display);
  font-weight: 700;
  letter-spacing: 0.01em;
  line-height: 1.1;
  color: var(--white);
}

h1 { font-size: clamp(2.5rem, 6vw, 4.5rem); }
h2 { font-size: clamp(1.8rem, 4vw, 3rem); }
h3 { font-size: clamp(1.3rem, 3vw, 1.8rem); }
h4 { font-size: 1.1rem; letter-spacing: 0.05em; text-transform: uppercase; }

.label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}

.label-accent {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
}

/* ── Layout Utilities ──────────────────────────────────────── */
.container {
  width: 100%;
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
}

.container-prose {
  width: 100%;
  max-width: var(--max-w-prose);
  margin: 0 auto;
  padding: 0 24px;
}

.section { padding: 80px 0; }
.section-sm { padding: 48px 0; }

/* ── Navigation ────────────────────────────────────────────── */
.site-nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(8, 8, 8, 0.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: border-color 0.3s;
}

.site-nav.scrolled { border-bottom-color: var(--border-2); }

/* Dim logo and hide dot on scroll — keeps nav compact and undistracting */
.site-nav.scrolled .logo-mark,
.site-nav.scrolled .logo-cad { opacity: 0.4; transition: opacity 0.3s; }
.site-nav.scrolled .logo-dot { opacity: 0 !important; animation: none !important; transition: opacity 0.3s; }

.nav-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 24px;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 2px;
  text-decoration: none;
  color: inherit;
}

.logo-mark {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.35rem;
  letter-spacing: 0.05em;
  color: var(--white);
  transition: opacity 0.3s;
}

.logo-cad {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 1.35rem;
  letter-spacing: 0.05em;
  color: var(--accent);
  transition: opacity 0.3s;
}

.logo-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  margin-left: 4px;
  margin-bottom: 2px;
  align-self: flex-end;
  box-shadow: 0 0 8px var(--accent);
  animation: dot-blink 2s step-end infinite;
}

/* CLI cursor blink — hard on/off, 1s cycle, 50/50 duty */
@keyframes dot-blink {
  0%, 50% { opacity: 0.4; }
  50.1%, 100% { opacity: 0; }
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 8px;
  list-style: none;
}

.nav-links a {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--radius);
  transition: color 0.15s, background 0.15s;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--white);
  background: var(--surface-2);
}

.nav-links a.active { color: var(--accent); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-dim);
  border-radius: 2px;
  transition: transform 0.2s, opacity 0.2s;
}

.nav-spacer { height: var(--nav-h); }

/* ── Homepage Hero ─────────────────────────────────────────── */
.hero {
  padding: 96px 0 80px;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(200,255,0,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(200,255,0,0.03) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
}

.hero::after {
  content: '';
  position: absolute;
  bottom: 0; left: 0; right: 0;
  height: 80px;
  background: linear-gradient(transparent, var(--bg));
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 1;
}

.hero-label {
  margin-bottom: 20px;
}

.hero-title {
  max-width: 900px;
  margin-bottom: 24px;
}

.hero-title em {
  font-style: normal;
  color: var(--accent);
}

.hero-sub {
  font-family: var(--font-prose);
  font-size: 1.1rem;
  color: var(--text-dim);
  max-width: 560px;
  margin-bottom: 40px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

/* ── Buttons ───────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 11px 22px;
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  text-decoration: none;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #000;
  border-color: var(--accent);
  font-weight: 700;
}

.btn-primary:hover {
  opacity: 1;
  background: #d8ff20;
  box-shadow: 0 0 20px rgba(200,255,0,0.3);
}

.btn-outline {
  background: transparent;
  color: var(--text-dim);
  border-color: var(--border-2);
}

.btn-outline:hover {
  color: var(--white);
  border-color: var(--text-dimmer);
  opacity: 1;
}

/* ── Section Headers ───────────────────────────────────────── */
.section-header {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  margin-bottom: 40px;
  gap: 24px;
}

.section-header-text .label { margin-bottom: 8px; }
.section-header-text h2 { margin-bottom: 0; }

/* Standalone section title — larger than h2 default, used when
   the section has no subtitle or action button beside it. */
.section-title {
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin-bottom: 40px;
}

/* ── Calculator Cards ──────────────────────────────────────── */
.calc-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 1px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.calc-card {
  background: var(--surface);
  padding: 28px;
  text-decoration: none;
  color: inherit;
  display: flex;
  flex-direction: column;
  gap: 12px;
  transition: background 0.15s;
  position: relative;
}

.calc-card:hover {
  background: var(--surface-2);
  opacity: 1;
}

.calc-card:hover .calc-card-icon { color: var(--accent); }

.calc-card-icon {
  font-size: 1.4rem;
  transition: color 0.15s;
  width: 32px;
}

.calc-card-title {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.02em;
}

.calc-card-desc {
  font-size: 0.85rem;
  color: var(--text-dim);
  line-height: 1.5;
  flex: 1;
}

.calc-card-tags {
  display: flex;
  gap: 6px;
  flex-wrap: wrap;
}

.tag {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  padding: 3px 7px;
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text-dimmer);
}

.calc-card.featured {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
}

.calc-card.featured::before {
  content: 'NEW';
  position: absolute;
  top: 12px; right: 12px;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 2px 6px;
  border-radius: 2px;
  border: 1px solid rgba(200,255,0,0.2);
}

/* .live: used on calculator cards that are fully built and accessible.
   These rules were previously only in index.html's inline <style>; they
   belong here so /calculators/ list page also picks them up. */
.calc-card.live {
  background: var(--surface-2);
}

.calc-card.live::before {
  content: 'LIVE';
  position: absolute;
  top: 12px; right: 12px;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  color: var(--accent);
  background: var(--accent-dim);
  padding: 2px 6px;
  border-radius: 2px;
  border: 1px solid var(--accent-border);
}

/* Wide grid variant for DFM Reference and More Coming sections */
.calc-grid.wide {
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
}

/* ── Section hub page title (used on calculators, learn, reference, downloads) */
.page-title { font-size: clamp(1.8rem, 4vw, 3rem); }

/* ── Section hub description */
.page-desc {
  color: var(--text-dim);
  font-family: var(--font-prose);
  margin-bottom: 48px;
  max-width: 560px;
}

/* ── Calculator Page Layout ────────────────────────────────── */
.calc-page {
  padding: 48px 0 96px;
}

.calc-breadcrumb {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 32px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.calc-breadcrumb a { color: var(--text-dimmer); }
.calc-breadcrumb a:hover { color: var(--accent); opacity: 1; }
.calc-breadcrumb span { color: var(--text-dimmer); }

.calc-layout {
  display: grid;
  grid-template-columns: 360px 1fr;
  gap: 2px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  min-height: 520px;
}

.calc-inputs-panel {
  background: var(--surface);
  padding: 36px 32px;
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.calc-results-panel {
  background: var(--surface-2);
  padding: 36px 36px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: relative;
}

.panel-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border);
  margin-bottom: 4px;
}

/* ── Form Controls ─────────────────────────────────────────── */
.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.field label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  /* #999 gives ~5.8:1 on --surface, passing WCAG AA at all text sizes */
  text-transform: uppercase;
  color: #999;
}

.field input[type="number"],
.field input[type="text"],
.field select {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 1rem;
  padding: 10px 14px;
  width: 100%;
  outline: none;
  transition: border-color 0.15s, box-shadow 0.15s;
  -moz-appearance: textfield;
}

.field input::-webkit-outer-spin-button,
.field input::-webkit-inner-spin-button { -webkit-appearance: none; }

.field input:focus,
.field select:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

.field select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%23555' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 36px;
}

.unit-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 8px;
  align-items: end;
}

.unit-toggle {
  display: flex;
  gap: 1px;
  background: var(--surface-3);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  overflow: hidden;
  width: 100%;
}

.unit-btn {
  flex: 1;
  padding: 10px 14px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  background: transparent;
  border: none;
  cursor: pointer;
  transition: all 0.12s;
}

.unit-btn.active {
  background: var(--surface-2);
  color: var(--accent);
}

/* ── Result Display ────────────────────────────────────────── */
.result-primary {
  background: var(--surface-3);
  border: 1px solid var(--border-2);
  border-radius: var(--radius-lg);
  padding: 28px 28px 24px;
}

.result-primary .result-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}

.result-fraction {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  letter-spacing: -0.01em;
  display: flex;
  align-items: flex-end;
  gap: 10px;
  flex-wrap: wrap;
}

.result-fraction .whole { color: var(--white); }
.result-fraction .frac {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}
.result-fraction .frac-num { border-bottom: 3px solid var(--accent); padding-bottom: 2px; }
.result-fraction .frac-den { color: var(--white); opacity: 0.5; font-size: 0.7em; }

.result-decimal {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 10px;
}

.result-error {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  color: var(--text-dimmer);
  margin-top: 6px;
}

.result-error .error-value {
  color: var(--red);
}

.results-pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.result-card {
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px 20px 16px;
}

.result-card .direction {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 10px;
}

.result-card.floor .direction { color: var(--blue); }
.result-card.ceiling .direction { color: var(--orange); }

.result-card .frac-display {
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: -0.01em;
  margin-bottom: 6px;
}

.result-card.floor .frac-display { color: var(--blue); }
.result-card.ceiling .frac-display { color: var(--orange); }

.result-card .sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dimmer);
}

.result-card .sub span { color: var(--text-dim); }

/* ── Copy/Print Bar ─────────────────────────────────────────── */
.action-bar {
  display: flex;
  gap: 8px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  margin-top: auto;
  flex-wrap: wrap;
}

.action-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 7px 14px;
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  cursor: pointer;
  transition: all 0.15s;
  white-space: nowrap;
}

.action-btn:hover {
  color: var(--white);
  border-color: var(--border-2);
  background: var(--surface-2);
}

.action-btn.copied { color: var(--accent); border-color: var(--accent-border); background: var(--accent-dim); }

/* ── Placeholder / Empty State ─────────────────────────────── */
.result-empty {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  height: 100%;
  min-height: 200px;
  gap: 12px;
  color: var(--text-dimmer);
  text-align: center;
}

.result-empty .empty-icon {
  font-size: 2rem;
  opacity: 0.3;
}

.result-empty p {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
}

/* ── Reference Table (for DFM pages) ──────────────────────── */
.ref-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.875rem;
  font-family: var(--font-prose);
}

.ref-table th {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  text-align: left;
  padding: 10px 16px;
  border-bottom: 1px solid var(--border-2);
  background: var(--surface);
  white-space: nowrap;
}

.ref-table td {
  padding: 10px 16px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
}

.ref-table tr:hover td { background: var(--surface-2); }

.ref-table .mono {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--accent);
}

/* ── Info Callout ──────────────────────────────────────────── */
.callout {
  background: var(--accent-dim);
  border: 1px solid rgba(200,255,0,0.15);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 16px 20px;
  font-size: 0.875rem;
  color: var(--text-dim);
  line-height: 1.6;
}

.callout strong { color: var(--white); }

/* ── How It Works Section ──────────────────────────────────── */
.how-it-works {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  margin-top: 32px;
}

.how-it-works h3 {
  font-size: 1rem;
  letter-spacing: 0.08em;
  margin-bottom: 16px;
}

.how-it-works p, .how-it-works li {
  font-family: var(--font-prose);
  font-size: 0.875rem;
  color: var(--text-dim);
  line-height: 1.7;
}

.how-it-works ol {
  padding-left: 20px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.how-it-works code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background: var(--surface-3);
  padding: 1px 5px;
  border-radius: 3px;
  color: var(--accent);
}

/* ── Coming Soon Cards ─────────────────────────────────────── */
.calc-card.soon {
  opacity: 0.55;
  cursor: not-allowed;
  pointer-events: auto !important;
}
.calc-card.soon:hover { background: var(--surface); }
.calc-card.soon .calc-card-icon { color: inherit; }


/* ── Animations ────────────────────────────────────────────── */
.fade-in {
  opacity: 0;
  transform: translateY(10px);
  transition: opacity 0.5s var(--ease-out), transform 0.5s var(--ease-out);
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── Learn Section ─────────────────────────────────────────── */

.learn-section {
  margin-bottom: 56px;
}

.learn-section-header {
  margin-bottom: 20px;
}

.learn-section-header h2 {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 2.5vw, 1.6rem);
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.02em;
  margin-bottom: 4px;
}

.learn-section-sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dimmer);
  letter-spacing: 0.06em;
  text-transform: uppercase;
}


/* ── About Page ───────────────────────────────────────────── */

.about-content {
  max-width: 640px;
}

.about-block {
  margin-bottom: 40px;
}

.about-block h2 {
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--white);
  letter-spacing: 0.02em;
  margin-bottom: 12px;
}

.about-block p {
  font-family: var(--font-prose);
  font-size: 0.92rem;
  color: var(--text-dim);
  line-height: 1.7;
  margin-bottom: 8px;
}


/* ── Calculator cross-link to Learn ───────────────────────── */

.td-learn-link {
  margin-top: 48px;
  padding: 28px 32px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
}

.td-learn-link p {
  font-family: var(--font-prose);
  font-size: 0.9rem;
  color: var(--text-dim);
  line-height: 1.6;
  margin-bottom: 16px;
}

.td-learn-link .label {
  margin-bottom: 8px;
}

.td-learn-link .btn {
  display: inline-block;
}


/* ── Footer ────────────────────────────────────────────────── */
.site-footer {
  border-top: 1px solid var(--border);
  margin-top: auto;
}

.footer-inner {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 60px 24px 40px;
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 48px;
}

.footer-brand .logo-mark { font-family: var(--font-display); font-weight: 800; font-size: 1.2rem; color: var(--white); }
.footer-brand .logo-cad { font-family: var(--font-display); font-weight: 600; font-size: 1.2rem; color: var(--accent); }

.footer-brand p {
  margin-top: 12px;
  font-size: 0.85rem;
  color: var(--text-dimmer);
  line-height: 1.5;
}

.footer-nav {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.footer-col h4 {
  font-size: 0.65rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 14px;
}

.footer-col a {
  display: block;
  font-size: 0.85rem;
  color: var(--text-dim);
  text-decoration: none;
  margin-bottom: 8px;
  transition: color 0.15s;
}

.footer-col a:hover { color: var(--white); opacity: 1; }

.footer-bottom {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 20px 24px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.08em;
  color: var(--text-dimmer);
}

/* ── Selection & Scrollbar ─────────────────────────────────── */
::selection { background: rgba(200,255,0,0.2); color: #fff; }
::-webkit-scrollbar { width: 5px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: var(--surface-3); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--border-2); }

/* ── Responsive ────────────────────────────────────────────── */
/* Two main breakpoints: 768px (tablet) and 480px (mobile).
   Nav collapse stays at 640px — 5 menu items won't fit
   horizontally below that width. */

@media (max-width: 768px) {
  .calc-layout {
    grid-template-columns: 1fr;
  }

  .calc-results-panel {
    border-top: 1px solid var(--border);
  }

  .footer-inner {
    grid-template-columns: 1fr;
    gap: 36px;
  }

  .footer-nav {
    grid-template-columns: repeat(2, 1fr);
  }

  .results-pair { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
    position: fixed;
    top: var(--nav-h);
    left: 0; right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 4px;
  }

  .nav-links.open { display: flex; }

  .nav-toggle { display: flex; }
}

@media (max-width: 480px) {
  .section-header {
    flex-direction: column;
    align-items: flex-start;
  }

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

  .footer-nav { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 6px; text-align: center; }
}

@media print {
  .site-nav, .nav-spacer, .site-footer, .action-bar, .hero-actions { display: none !important; }
  body { background: #fff; color: #000; }
  .calc-layout { border: 1px solid #ccc; }
  .result-fraction, .result-card .frac-display { color: #000 !important; }
}

/* ── prefers-reduced-motion ──────────────────────────────── */
@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;
  }

  /* Logo dot pulse is non-disorienting — exempt from reduced-motion */
  .logo-dot {
    animation-duration:        2s !important;
    animation-iteration-count: infinite !important;
  }
}

/* ── Coming-soon tooltip (injected by main.js) ──────────────── */
/* Floats near cursor on hover over any .calc-card.soon element  */
#cs-tooltip {
  position: fixed;
  z-index: 9999;
  pointer-events: none;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  background: var(--surface-3);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 5px 11px;
  white-space: nowrap;
  display: flex;
  align-items: center;
  gap: 6px;
  opacity: 0;
  transition: opacity 0.12s;
}
#cs-tooltip::before  { content: '◌'; color: var(--accent); }
#cs-tooltip.visible  { opacity: 1; }
#cs-tooltip.fading   { opacity: 0; transition: opacity 0.7s ease; }


/* ═══════════════════════════════════════════════════════════════
   CALCULATOR: Fraction Converter
   ═══════════════════════════════════════════════════════════════ */

/* ── Calculator header (used by fraction-converter) ──────────── */
.calc-header            { margin-bottom: 32px; }
.calc-header h1         { font-size: clamp(1.8rem, 4vw, 2.8rem); margin-bottom: 12px; }
.calc-header p          { color: var(--text-dim); font-family: var(--font-prose); font-size: 0.95rem; max-width: 520px; line-height: 1.7; }

/* ── Exact-match result card ─────────────────────────────────── */
.exact-match-card {
  background: linear-gradient(135deg, rgba(200,255,0,0.1) 0%, rgba(200,255,0,0.04) 100%);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-lg);
  padding: 24px 24px 20px;
  display: none;
  margin-bottom: 14px;
}
.exact-match-card .em-label {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.exact-match-card .em-label::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 6px var(--accent);
}
.exact-match-card .em-frac {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
  display: flex;
  align-items: flex-end;
  gap: 8px;
  flex-wrap: wrap;
}
.em-frac .whole            { color: var(--white); }
.em-frac .frac             { display: inline-flex; flex-direction: column; align-items: center; gap: 2px; }
.em-frac .frac-num         { border-bottom: 3px solid var(--accent); padding-bottom: 2px; }
.em-frac .frac-den         { color: var(--white); opacity: 0.5; font-size: 0.7em; }
.exact-match-card .em-dec  { font-family: var(--font-mono); font-size: 0.82rem; color: var(--text-dim); margin-top: 10px; }

/* ── Dimmed state when exact match supersedes floor/ceiling ───── */
.result-card.is-exact { opacity: 0.5; }

/* ── Input echo row ─────────────────────────────────────────── */
.echo-row {
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
  margin-top: 4px;
}

/* ── Action button extra state (fraction-converter active toggle) */
.action-btn.active-state { color: var(--accent); border-color: var(--accent-border); background: var(--accent-dim); }

/* ── Embed code panel ───────────────────────────────────────── */
.embed-panel           { display: none; margin-top: 16px; background: var(--surface); border: 1px solid var(--border-2); border-radius: var(--radius-lg); padding: 24px; }
.embed-panel.open      { display: block; }
.embed-panel h4        { font-family: var(--font-display); font-size: 0.95rem; margin-bottom: 8px; }
.embed-panel p         { font-family: var(--font-prose); font-size: 0.82rem; color: var(--text-dim); line-height: 1.6; margin-bottom: 14px; }
.embed-code-block {
  background: var(--surface-3);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 14px 16px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  white-space: pre-wrap;
  word-break: break-all;
  line-height: 1.5;
  margin-bottom: 12px;
  user-select: all;
  cursor: text;
}

/* ── Quick-select denominator grid ─────────────────────────── */
.quick-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 5px; }

/* ── How It Works / Education section ──────────────────────── */
.how-section                        { background: var(--surface); border: 1px solid var(--border); border-radius: var(--radius-lg); padding: 32px; margin-top: 32px; }
.how-section p,
.how-section li                     { font-family: var(--font-prose); font-size: 0.875rem; color: var(--text-dim); line-height: 1.7; }
.how-section ol                     { padding-left: 20px; display: flex; flex-direction: column; gap: 6px; margin-top: 12px; }
.how-section code                   { font-family: var(--font-mono); font-size: 0.8rem; background: var(--surface-3); padding: 1px 5px; border-radius: 3px; color: var(--accent); }
.how-section p + p                  { margin-top: 10px; }
.how-section .note                  { font-size: 0.8rem; color: var(--text-dimmer); font-style: italic; margin-top: 8px; }

/* ── Tap Drill Education ──────────────────────────────────── */
.td-education > * + * { margin-top: 28px; }

/* The one rule */
.td-edu-rule {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 24px;
}
.td-edu-rule-label,
.td-edu-diagram-label,
.td-edu-keys-label,
.td-edu-engage-label {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 14px;
}
.td-edu-formula-hero {
  font-family: var(--font-mono);
  font-size: clamp(1rem, 3vw, 1.5rem);
  font-weight: 700;
  color: var(--white);
  padding: 16px 0;
  letter-spacing: 0.02em;
}
.td-edu-examples {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 16px;
}
.td-edu-example {
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.td-edu-example-label {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 4px;
}
.td-edu-example span {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text);
}
.td-edu-example strong {
  color: var(--accent);
}
.td-edu-check {
  color: var(--text-dimmer) !important;
  font-size: 0.72rem !important;
}

/* Thread diagram */
.td-edu-diagram-wrap {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 24px;
}
.td-edu-diagram {
  width: 100%;
  max-width: 540px;
  height: auto;
  margin: 0 auto 16px;
  display: block;
}

/* Key relationships grid */
.td-edu-keys {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 24px;
}
.td-edu-key-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.td-edu-key {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 12px 14px;
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.td-edu-key code {
  font-size: 0.82rem;
  background: none;
  padding: 0;
  color: var(--white);
}
.td-edu-key span {
  font-family: var(--font-prose);
  font-size: 0.75rem;
  color: var(--text-dimmer);
  line-height: 1.5;
}

/* Engagement bar chart */
.td-edu-engage {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  padding: 24px;
}
.td-edu-bar-chart {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
}
.td-edu-bar-row {
  display: grid;
  grid-template-columns: 40px 1fr 100px;
  align-items: center;
  gap: 10px;
}
.td-edu-bar-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-dim);
  text-align: right;
}
.td-edu-bar-track {
  height: 14px;
  background: var(--surface-3);
  border-radius: 2px;
  overflow: hidden;
}
.td-edu-bar-fill {
  height: 100%;
  background: var(--text-dimmer);
  border-radius: 2px;
  transition: width 0.3s var(--ease-out);
}
.td-edu-bar-accent {
  background: var(--accent);
}
.td-edu-bar-val {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dimmer);
}
.td-edu-bar-highlight .td-edu-bar-label {
  color: var(--accent);
  font-weight: 600;
}
.td-edu-bar-highlight .td-edu-bar-val {
  color: var(--accent);
}

@media (max-width: 480px) {
  .td-edu-examples { grid-template-columns: 1fr; }
  .td-edu-key-grid { grid-template-columns: 1fr; }
  .td-edu-bar-row  { grid-template-columns: 36px 1fr 80px; }
}

/* ── Number line visualization ──────────────────────────────── */
.fc-viz-panel {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 14px 18px 10px;
}

.fc-viz-header {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.fc-viz-header::before {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 5px var(--accent);
  flex-shrink: 0;
}

/* ── Responsive ─────────────────────────────────────────────── */
@media (max-width: 480px) {
  .quick-grid { grid-template-columns: repeat(3, 1fr); }
}
@media print {
  .action-bar,
  .embed-panel { display: none !important; }
}


/* ═══════════════════════════════════════════════════════════════
   CALCULATOR: Tap Drill Finder
   ═══════════════════════════════════════════════════════════════ */

/* ── Engagement slider + number input row ──────────────────── */
.td-engage-row {
  display: grid;
  grid-template-columns: 1fr 60px auto;
  gap: 10px;
  align-items: center;
}

.td-engage-row input[type="number"] {
  background: var(--surface-2);
  border: 1px solid var(--border-2);
  border-radius: var(--radius);
  color: var(--white);
  font-family: var(--font-mono);
  font-size: 0.9rem;
  padding: 6px 8px;
  width: 100%;
  outline: none;
  text-align: center;
  -moz-appearance: textfield;
}
.td-engage-row input[type="number"]::-webkit-outer-spin-button,
.td-engage-row input[type="number"]::-webkit-inner-spin-button { -webkit-appearance: none; }
.td-engage-row input[type="number"]:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-dim);
}

/* ── Range slider styling ──────────────────────────────────── */
.td-slider {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 4px;
  background: var(--surface-3);
  border-radius: 2px;
  outline: none;
  cursor: pointer;
}
.td-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  margin-top: -7px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
  box-shadow: 0 0 6px rgba(200,255,0,0.3);
}
.td-slider::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
  border: 2px solid var(--bg);
  box-shadow: 0 0 6px rgba(200,255,0,0.3);
}
.td-slider::-webkit-slider-runnable-track { height: 4px; }
.td-slider::-moz-range-track { height: 4px; background: var(--surface-3); border: none; border-radius: 2px; }

/* ── Primary result card ───────────────────────────────────── */
.td-primary-result {
  background: linear-gradient(135deg, rgba(200,255,0,0.1) 0%, rgba(200,255,0,0.04) 100%);
  border: 1px solid var(--accent-border);
  border-radius: var(--radius-lg);
  padding: 24px 24px 20px;
}
.td-primary-label {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.15em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.td-primary-label::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 6px var(--accent);
}
.td-drill-dia {
  font-family: var(--font-display);
  font-size: clamp(2.2rem, 4vw, 3.2rem);
  font-weight: 800;
  color: var(--accent);
  line-height: 1;
}
.td-drill-sub {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--text-dim);
  margin-top: 10px;
}

/* ── Standard drill name in result cards ───────────────────── */
.td-drill-name {
  font-family: var(--font-display);
  font-size: 1.6rem;
  font-weight: 800;
  color: var(--white);
  letter-spacing: -0.01em;
  margin-bottom: 6px;
}
.result-card.floor .td-drill-name  { color: var(--blue); }
.result-card.ceiling .td-drill-name { color: var(--orange); }

/* Exact match highlight on drill cards */
.result-card.td-exact {
  border-color: var(--accent-border);
  background: linear-gradient(135deg, rgba(200,255,0,0.06) 0%, var(--surface-3) 100%);
}
.result-card.td-exact .td-drill-name { color: var(--accent); }
.result-card.td-exact .direction { color: var(--accent); }

/* ── Thread data reference grid ────────────────────────────── */
.td-thread-data {
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 20px;
}
.td-data-label {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.td-data-label::before {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 5px var(--accent);
  flex-shrink: 0;
}
.td-data-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.td-data-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.td-data-key {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}
.td-data-val {
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--white);
}

/* ── Thread data sub-note ──────────────────────────────────── */
.td-data-note {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--text-dimmer);
  margin-top: 10px;
  line-height: 1.5;
}

/* ── Tapping material note ─────────────────────────────────── */
.td-mat-note {
  background: var(--surface-3);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 14px 18px;
}
.td-mat-note-label {
  font-family: var(--font-mono);
  font-size: 0.58rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 8px;
}
.td-mat-note p {
  font-family: var(--font-prose);
  font-size: 0.82rem;
  color: var(--text-dim);
  line-height: 1.6;
}

/* ── Quick reference table ──────────────────────────────────── */
.td-ref-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px 32px;
  margin-top: 32px;
}
.td-ref-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 20px;
  gap: 16px;
}
.td-ref-sub {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-dimmer);
  margin-top: 6px;
  letter-spacing: 0.04em;
  line-height: 1.8;
}
#td-ref-engage {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--accent);
}
.td-ref-controls {
  display: flex;
  flex-direction: column;
  gap: 4px;
  min-width: 180px;
}
.td-ref-mat-label {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}
.td-ref-controls select {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background: var(--surface-3);
  color: var(--text);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px 10px;
  cursor: pointer;
}
.td-ref-scroll {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}
.td-combined-table {
  min-width: 420px;
}
.td-combined-table th,
.td-combined-table td {
  white-space: nowrap;
}
.td-combined-table td.mono {
  font-size: 0.8rem;
}

/* Tap drill columns — slightly wider for drill names */
.td-ref-drill-col {
  min-width: 72px;
}


/* ── Responsive overrides ──────────────────────────────────── */
@media (max-width: 768px) {
  .td-data-grid { grid-template-columns: 1fr 1fr; }
  .td-ref-section { padding: 20px 16px; }
  .td-ref-header { flex-direction: column; }
  .td-ref-controls { min-width: 100%; }
}
@media (max-width: 480px) {
  .td-engage-row { grid-template-columns: 1fr 56px auto; }
  .td-data-grid  { grid-template-columns: 1fr; }
}

/* ── Calculator utility classes ───────────────────────────── */
/* Inline toggle/section label — mono, uppercase, dim.
   Replaces repeated style= attributes on "Thread System",
   "Solve For", "Torque Unit" spans, etc. */
.calc-field-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
}

/* Hint text below inputs — "75% is standard...", etc. */
.calc-hint {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  color: var(--text-dimmer);
}

/* Unit suffix next to input fields — "ft·lbf", "%", "in" */
.calc-input-unit {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dimmer);
  white-space: nowrap;
}

/* ── Layout utility classes ───────────────────────────────── */

/* Centered page — 404, coming-soon */
.centered-page {
  min-height: 60vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 80px 24px;
  text-align: center;
}
.centered-page .page-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 20px;
}
.centered-page h1 {
  font-size: clamp(2rem, 5vw, 3.5rem);
  margin-bottom: 16px;
}
.centered-page .page-desc {
  font-family: var(--font-prose);
  color: var(--text-dim);
  font-size: 1rem;
  max-width: 420px;
  margin: 0 auto 36px;
  line-height: 1.7;
}
.centered-page .btn-row {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

/* Prose single page — about, generic content */
.prose-page { padding: 48px 0 96px; }
.prose-page .label { margin-bottom: 16px; }
.prose-page h1 { margin-bottom: 24px; }
.prose-page .how-it-works {
  background: transparent;
  border: none;
  padding: 0;
}

/* Disabled nav link */
.nav-disabled { opacity: 0.45; }

/* Echo row labels and values — used in input echo displays */
.calc-echo-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dimmer);
}
.calc-echo-val {
  font-family: var(--font-mono);
  font-size: 1.05rem;
  color: var(--white);
}
.calc-echo-val.accent { color: var(--accent); }

/* Converted display hint (fraction converter) */
.calc-converted-hint {
  font-family: var(--font-mono);
  font-size: 0.68rem;
  color: var(--text-dimmer);
  min-height: 1em;
}

/* ── Fraction Converter styles ────────────────────────────── */
/* Extracted from layouts/partials/calculators/fraction-converter.html */

#fc-frac-input {
  width: 100%; padding: 10px 14px; background: var(--surface);
  border: 1px solid var(--border); border-radius: var(--radius);
  color: var(--text); font-family: var(--font-mono); font-size: 0.95rem;
}
#fc-frac-input:focus {
  outline: none; border-color: var(--accent-border);
  box-shadow: 0 0 0 2px var(--accent-dim);
}
#fc-frac-input::placeholder { color: var(--text-dimmer); }

.fc-reverse-result { text-align: center; padding: 24px 16px; }
.fc-rev-value {
  font-family: var(--font-mono); font-size: 2rem;
  color: #fff; font-weight: 600;
}
.fc-rev-sub {
  font-family: var(--font-mono); font-size: 0.85rem;
  color: var(--text-dim); margin-top: 6px;
}
.fc-rev-meta {
  font-family: var(--font-mono); font-size: 0.72rem;
  color: var(--text-dimmer); margin-top: 16px;
}

.fc-alldenoms { margin-top: 8px; }
.fc-alldenoms-toggle {
  width: 100%; background: var(--surface); border: 1px solid var(--border);
  color: var(--text-dim); font-family: var(--font-mono); font-size: 0.72rem;
  padding: 8px 12px; border-radius: var(--radius); cursor: pointer;
  text-align: left; letter-spacing: 0.04em; text-transform: uppercase;
}
.fc-alldenoms-toggle:hover { border-color: var(--border-2); color: var(--text); }
.fc-alldenoms-toggle.open { border-color: var(--accent-border); color: var(--accent); }
.fc-alldenoms table {
  width: 100%; border-collapse: collapse;
  font-family: var(--font-mono); font-size: 0.75rem; margin-top: 8px;
}
.fc-alldenoms th {
  color: var(--text-dimmer); font-weight: 400; text-align: left;
  padding: 6px 8px; border-bottom: 1px solid var(--border);
  font-size: 0.65rem; text-transform: uppercase; letter-spacing: 0.08em;
}
.fc-alldenoms td {
  padding: 5px 8px; border-bottom: 1px solid rgba(42,42,42,0.5); color: var(--text-dim);
}
.fc-alldenoms tr.exact-denom td { color: var(--accent); }
.fc-alldenoms tr.active-denom { background: var(--accent-dim); }
.fc-alldenoms tr.active-denom td { color: var(--text); }

/* ── Bolt Torque styles ───────────────────────────────────── */
/* Extracted from layouts/partials/calculators/bolt-torque.html */

.bt-mode-toggle { width: 100%; }
.bt-mode-toggle .unit-btn { flex: 1; }

.bt-slider-row {
  display: flex;
  align-items: center;
  gap: 10px;
}
.bt-slider {
  flex: 1;
  -webkit-appearance: none;
  appearance: none;
  height: 4px;
  background: var(--border-2);
  border-radius: 2px;
  outline: none;
}
.bt-slider::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  cursor: pointer;
}
.bt-slider::-moz-range-thumb {
  width: 16px; height: 16px;
  border-radius: 50%;
  background: var(--accent);
  border: none;
  cursor: pointer;
}

.bt-primary-result {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
}
.bt-primary-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 8px;
}
.bt-primary-value {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--white);
  line-height: 1.1;
}
.bt-primary-unit {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--text-dim);
  margin-top: 4px;
}

.bt-data-section {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.bt-data-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}
.bt-data-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.bt-data-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.bt-data-key {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}
.bt-data-val {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--text);
}

.bt-warning {
  background: rgba(255, 136, 68, 0.06);
  border: 1px solid rgba(255, 136, 68, 0.2);
  border-radius: var(--radius);
  padding: 12px 14px;
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--orange);
  line-height: 1.5;
}
.bt-warning-label {
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 0.6rem;
  margin-bottom: 4px;
}

.bt-yield-bar-wrap { margin-top: 8px; }
.bt-yield-track {
  height: 6px;
  background: var(--border);
  border-radius: 3px;
  position: relative;
}
.bt-yield-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.3s var(--ease-out), background 0.3s;
}
.bt-yield-tick {
  position: absolute;
  top: -3px;
  width: 2px;
  height: 12px;
  background: var(--text-dim);
  border-radius: 1px;
  transition: left 0.3s var(--ease-out);
  z-index: 1;
}
.bt-yield-label {
  display: flex;
  justify-content: space-between;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  color: var(--text-dimmer);
  margin-top: 4px;
}
.bt-rec-ref {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-dim);
  margin-top: 8px;
  line-height: 1.5;
}

.bt-edu-rule {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin: 24px 0;
}
.bt-edu-rule-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}
.bt-edu-formula-hero {
  font-family: var(--font-mono);
  font-size: 1.3rem;
  color: var(--accent);
  padding: 16px 0;
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  margin-bottom: 12px;
  text-align: center;
}
.bt-edu-keys {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 28px;
  margin: 24px 0;
}
.bt-edu-keys-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 16px;
}
.bt-edu-key-grid {
  display: grid;
  gap: 16px;
}
.bt-edu-key {
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.bt-edu-key code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
}
.bt-edu-key span {
  font-size: 0.82rem;
  color: var(--text-dim);
  line-height: 1.5;
}

.bt-k-table {
  width: 100%;
  border-collapse: collapse;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  margin: 16px 0;
}
.bt-k-table th {
  text-align: left;
  font-size: 0.6rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
}
.bt-k-table td {
  padding: 8px 10px;
  border-bottom: 1px solid var(--border);
  color: var(--text-dim);
}
.bt-k-table tr:last-child td { border-bottom: none; }
.bt-k-table .bt-k-val { color: var(--accent); }

@media (max-width: 480px) {
  .bt-primary-value { font-size: 1.6rem; }
  .bt-data-grid { grid-template-columns: 1fr; }
}

/* ── GD&T Bonus Tolerance styles ─────────────────────────── */

/* Education section spacing (reuses td-edu-* shared classes) */
.gdt-education > * + * { margin-top: 28px; }

.gdt-input-row {
  display: flex;
  align-items: center;
  gap: 8px;
}
.gdt-input-row input[type="text"] {
  flex: 1;
  min-width: 0;
}

.gdt-primary-result {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 24px;
  text-align: center;
}
.gdt-primary-label {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-dim);
  margin-bottom: 8px;
}
.gdt-primary-value {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--white);
  line-height: 1.1;
}
.gdt-primary-sub {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  color: var(--text-dim);
  margin-top: 6px;
}

/* Key values grid */
.gdt-key-values {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.gdt-kv {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.gdt-kv-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}
.gdt-kv-value {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--text);
}
.gdt-kv-accent {
  color: var(--accent);
}

/* SVG visualization */
.gdt-viz-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.gdt-viz-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}
.gdt-viz {
  width: 100%;
  height: auto;
}

/* Size lookup */
.gdt-lookup {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.gdt-lookup-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}
.gdt-lookup-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}
.gdt-lookup-input-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-dim);
  white-space: nowrap;
}
.gdt-lookup-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.gdt-lookup-item {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.gdt-lookup-key {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-dimmer);
}
.gdt-lookup-val {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  color: var(--text);
}

/* Breakdown table */
.gdt-table-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 20px;
}
.gdt-table-label {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-dimmer);
  margin-bottom: 12px;
}
.gdt-breakdown-table {
  width: 100%;
}
.gdt-row-zero td {
  color: var(--text);
  font-weight: 600;
}
.gdt-row-max td {
  color: var(--accent);
  font-weight: 600;
}

@media (max-width: 480px) {
  .gdt-primary-value { font-size: 1.6rem; }
  .gdt-key-values { grid-template-columns: 1fr; }
  .gdt-lookup-grid { grid-template-columns: 1fr; }
}