/* ============================================================
   FBATools — visual system
   High-density editorial / tool-feel.
   Deliberately avoids the three AI-default looks:
   1. Cream + terracotta serif (generic)
   2. Black + acid-green (cliched)
   3. Hairline-rule broadsheet (overdone)
   Instead: charcoal + ember + monospace data.
   ============================================================ */

:root {
  /* Color tokens (4 hex values) */
  --bg:        #0E1116;  /* near-black, slight blue cast */
  --surface:   #161B22;  /* one step up for cards */
  --surface-2: #1F2530;  /* hover, borders */
  --ink:       #E6E8EC;  /* primary text */
  --ink-soft:  #9BA3AF;  /* secondary text */
  --ink-dim:   #5C6370;  /* tertiary text */
  --accent:    #FF6B1A;  /* ember orange — NOT Amazon #ff9900 */
  --accent-2:  #FFB454;  /* hover, lighter ember */
  --line:      #252A33;  /* hairlines, dividers */
  --good:      #4ADE80;
  --bad:       #F87171;

  /* Type */
  --font-display: 'IBM Plex Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  --font-body:    'IBM Plex Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-data:    'IBM Plex Mono', ui-monospace, 'SF Mono', monospace;

  /* Spacing scale (4px base) */
  --s-1: 4px; --s-2: 8px; --s-3: 12px; --s-4: 16px;
  --s-5: 24px; --s-6: 32px; --s-7: 48px; --s-8: 64px;

  --radius: 4px;  /* sharp — tool-feel */
  --max-w: 1180px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.55;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-feature-settings: 'cv11', 'ss01';
}

a { color: var(--accent-2); text-decoration: none; transition: color .12s ease; }
a:hover { color: var(--accent); }

h1, h2, h3, h4 { line-height: 1.2; margin: 0 0 var(--s-3); color: var(--ink); font-weight: 600; }
h1 { font-family: var(--font-display); font-size: 2.4rem; letter-spacing: -.02em; font-weight: 600; }
h2 { font-size: 1.35rem; letter-spacing: -.01em; }
h3 { font-size: 1.05rem; }
h4 { font-size: .9rem; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-soft); }

p { margin: 0 0 var(--s-3); }

.container { max-width: var(--max-w); margin: 0 auto; padding: 0 var(--s-5); }

/* ========== HEADER (sticky, monospace) ========== */
.site-header {
  background: rgba(14, 17, 22, .92);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
  position: sticky; top: 0; z-index: 50;
}
.header-inner { display: flex; align-items: center; justify-content: space-between; padding: var(--s-3) var(--s-5); }
.logo {
  display: flex; align-items: center; gap: var(--s-2);
  color: var(--ink); font-family: var(--font-display);
  font-weight: 600; font-size: 1rem;
}
.logo:hover { color: var(--accent); text-decoration: none; }
.logo img { display: block; }
.logo-mark {
  width: 24px; height: 24px;
  background: var(--accent);
  border-radius: 3px;
  display: inline-flex; align-items: center; justify-content: center;
  color: var(--bg); font-weight: 700; font-size: .8rem;
  font-family: var(--font-display);
}
.main-nav { display: flex; gap: var(--s-5); }
.main-nav a {
  color: var(--ink-soft);
  font-family: var(--font-display);
  font-size: .82rem;
  letter-spacing: .02em;
}
.main-nav a:hover { color: var(--ink); text-decoration: none; }
.main-nav a.active { color: var(--accent); }

/* ========== HERO ========== */
.hero {
  padding: var(--s-8) 0 var(--s-7);
  border-bottom: 1px solid var(--line);
  position: relative;
  background-image:
    radial-gradient(circle at 80% 20%, rgba(255, 107, 26, .06) 0, transparent 40%),
    linear-gradient(180deg, var(--bg) 0%, var(--surface) 100%);
}
.hero::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 1px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  opacity: .4;
}
.eyebrow {
  display: inline-block;
  font-family: var(--font-display);
  font-size: .72rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: var(--s-3);
  padding: var(--s-1) var(--s-2);
  border: 1px solid var(--accent);
  border-radius: 2px;
}
.hero h1 {
  font-size: clamp(2rem, 4vw, 3rem);
  margin-bottom: var(--s-4);
  max-width: 18ch;
}
.hero h1 .accent { color: var(--accent); }
.hero .lede {
  max-width: 60ch;
  color: var(--ink-soft);
  font-size: 1.05rem;
  margin-bottom: var(--s-5);
}
.hero .meta-line {
  font-family: var(--font-display);
  font-size: .72rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-dim);
  margin-top: var(--s-5);
}
.hero .meta-line .dot { color: var(--accent); margin: 0 6px; }

/* ========== BUTTONS ========== */
.btn {
  display: inline-flex; align-items: center; gap: var(--s-2);
  padding: 10px 18px;
  border-radius: var(--radius);
  font-family: var(--font-display);
  font-size: .85rem;
  font-weight: 500;
  letter-spacing: .02em;
  cursor: pointer;
  transition: all .12s ease;
  border: 1px solid transparent;
}
.btn-primary { background: var(--accent); color: var(--bg); }
.btn-primary:hover { background: var(--accent-2); color: var(--bg); text-decoration: none; transform: translateY(-1px); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--line); }
.btn-ghost:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }

/* ========== SECTIONS ========== */
section { padding: var(--s-7) 0; }
.section-header { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: var(--s-5); flex-wrap: wrap; gap: var(--s-3); }
.section-header h2 { margin: 0; }
.section-tag {
  font-family: var(--font-display);
  font-size: .7rem;
  letter-spacing: .14em;
  text-transform: uppercase;
  color: var(--ink-dim);
}

/* ========== FEATURES (data-row, not cards) ========== */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.feature {
  padding: var(--s-5);
  background: var(--surface);
  border-right: 1px solid var(--line);
}
.feature:last-child { border-right: 0; }
.feature h3 { color: var(--ink); margin-bottom: var(--s-2); font-family: var(--font-display); font-size: .95rem; }
.feature p { color: var(--ink-soft); font-size: .9rem; margin: 0; }
.feature .icon { font-family: var(--font-display); color: var(--accent); font-size: 1.1rem; margin-bottom: var(--s-3); }

/* ========== TOOL GRID ========== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1px;
  background: var(--line);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.tool-card {
  display: block;
  padding: var(--s-5);
  background: var(--surface);
  color: var(--ink);
  transition: background .12s ease, transform .12s ease;
  position: relative;
}
.tool-card:hover {
  background: var(--surface-2);
  text-decoration: none;
  transform: translateY(-1px);
}
.tool-card h3 { font-family: var(--font-display); font-size: 1rem; margin-bottom: var(--s-2); }
.tool-card p { color: var(--ink-soft); font-size: .88rem; margin: 0; }
.tool-card .arrow {
  position: absolute; top: var(--s-5); right: var(--s-5);
  color: var(--accent);
  font-family: var(--font-display);
  font-size: .9rem;
  opacity: 0;
  transition: opacity .12s ease, transform .12s ease;
}
.tool-card:hover .arrow { opacity: 1; transform: translateX(2px); }

/* ========== CALCULATOR ========== */
.calc-page { padding: var(--s-6) 0 var(--s-8); }
.calc-page h1 { font-size: 1.8rem; margin-bottom: var(--s-2); }
.calc-page .subtitle { color: var(--ink-soft); margin-bottom: var(--s-5); font-size: .95rem; }
.calc-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
}
.calc-card {
  padding: var(--s-5);
  background: var(--surface);
}
.calc-card + .calc-card { border-left: 1px solid var(--line); }
.calc-card h2 { font-family: var(--font-display); font-size: .9rem; text-transform: uppercase; letter-spacing: .08em; color: var(--ink-soft); margin-bottom: var(--s-4); }

.form-row { display: flex; flex-direction: column; margin-bottom: var(--s-3); }
.form-row label {
  font-family: var(--font-display);
  font-size: .72rem;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 6px;
}
.form-row .hint { font-size: .78rem; color: var(--ink-dim); margin-top: 4px; }
.form-row input, .form-row select {
  padding: 9px 12px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  font-size: .95rem;
  font-family: var(--font-data);
  color: var(--ink);
  width: 100%;
  transition: border-color .12s ease;
}
.form-row input:focus, .form-row select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(255, 107, 26, .15);
}

.result-row {
  display: flex; justify-content: space-between; align-items: baseline;
  padding: 8px 0;
  border-bottom: 1px dashed var(--line);
  font-size: .9rem;
}
.result-row:last-child { border-bottom: 0; }
.result-row .label { color: var(--ink-soft); font-family: var(--font-display); font-size: .82rem; }
.result-row .value { font-family: var(--font-data); color: var(--ink); font-weight: 500; }
.result-row.negative .value { color: var(--bad); }
.result-row.highlight {
  background: rgba(255, 107, 26, .08);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: var(--s-3);
  margin-top: var(--s-3);
}
.result-row.highlight .label { color: var(--ink); font-weight: 600; }
.result-row.highlight .value { color: var(--accent); font-size: 1.4rem; font-weight: 600; }

@media (max-width: 720px) {
  h1 { font-size: 1.8rem; }
  .hero { padding: var(--s-7) 0 var(--s-6); }
  .calc-layout { grid-template-columns: 1fr; }
  .calc-card + .calc-card { border-left: 0; border-top: 1px solid var(--line); }
  .features { grid-template-columns: 1fr; }
  .feature { border-right: 0; border-bottom: 1px solid var(--line); }
  .feature:last-child { border-bottom: 0; }
  .main-nav { gap: var(--s-3); font-size: .75rem; }
  .header-inner { padding: var(--s-3) var(--s-4); }
  .container { padding: 0 var(--s-4); }
}

/* ========== FAQ ========== */
.faq details {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: var(--s-3) var(--s-4);
  margin-bottom: var(--s-2);
  transition: border-color .12s ease;
}
.faq details[open] { border-color: var(--accent); }
.faq summary {
  cursor: pointer;
  font-family: var(--font-display);
  font-size: .9rem;
  color: var(--ink);
  list-style: none;
  display: flex; align-items: center; justify-content: space-between;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: '+'; color: var(--accent); font-size: 1.2rem; transition: transform .15s ease; }
.faq details[open] summary::after { content: '−'; }
.faq p { margin: var(--s-3) 0 0; color: var(--ink-soft); font-size: .92rem; }

/* ========== BLOG ========== */
.blog-list { list-style: none; padding: 0; margin: 0; }
.blog-list li { padding: var(--s-4) 0; border-bottom: 1px solid var(--line); }
.blog-list li:last-child { border-bottom: 0; }
.blog-list a { font-family: var(--font-display); font-size: 1.05rem; color: var(--ink); }
.blog-list a:hover { color: var(--accent); }
.blog-list .meta { color: var(--ink-dim); font-family: var(--font-data); font-size: .78rem; margin-top: 4px; }
.blog-list .desc { color: var(--ink-soft); font-size: .9rem; margin-top: 6px; }

/* ========== FOOTER ========== */
.site-footer {
  border-top: 1px solid var(--line);
  background: var(--surface);
  padding: var(--s-5) 0;
  margin-top: var(--s-7);
  font-size: .85rem;
  color: var(--ink-soft);
}
.site-footer .container { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: var(--s-3); }
.site-footer nav { display: flex; gap: var(--s-4); }
.site-footer nav a { color: var(--ink-soft); }
.site-footer nav a:hover { color: var(--accent); }
.site-footer p { margin: 0; font-family: var(--font-display); font-size: .78rem; }

/* ========== Reduced motion ========== */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; }
}

/* ========== Focus visible (accessibility) ========== */
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ========== Selection ========== */
::selection { background: var(--accent); color: var(--bg); }