/* ============================================================
   GlobalStructure — Design system
   Palette: drafting vellum + blueprint ink + one accent blue.
   No external font dependencies (Phase 1 speed priority).
   ============================================================ */

:root {
  /* Vellum palette (light) */
  --paper: #F7F5EF;
  --paper-2: #FBFAF5;
  --paper-3: #EFECE1;
  --ink: #0F1419;
  --ink-2: #3A3F45;
  --ink-3: #6B7079;
  --hairline: #D4D0C4;
  --hairline-strong: #B8B3A2;

  /* Blueprint accent (precision, calculation) */
  --accent: #1E4F8B;
  --accent-2: #2C63A8;
  --accent-tint: #E7EEF7;

  /* Engineer's stamp accent (approval, warmth, signature) */
  --stamp: #B8501F;
  --stamp-2: #D06B36;
  --stamp-tint: #F7E9DE;

  /* Semantic */
  --ok: #166534;
  --ok-tint: #E4EFE0;
  --warn: #B45309;
  --warn-tint: #F5E9D2;
  --danger: #991B1B;

  /* Typography */
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, "SF Mono", Menlo, Consolas, "Roboto Mono", monospace;
  --font-display: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, ui-serif, serif;

  /* Rhythm — 8px base scale */
  --sp-1: 8px; --sp-2: 16px; --sp-3: 24px; --sp-4: 32px; --sp-6: 48px; --sp-8: 64px; --sp-12: 96px;
  --wrap: 1120px;
  --pad: 24px;
  --radius: 4px;
  --radius-lg: 8px;
  --hairline-w: 0.5px;
}

[data-theme="dark"] {
  --paper: #0E1216;
  --paper-2: #151A20;
  --paper-3: #1D242B;
  --ink: #EEEBE0;
  --ink-2: #B8B3A2;
  --ink-3: #7E8189;
  --hairline: #2A3038;
  --hairline-strong: #3A424C;

  --accent: #6FA3E0;
  --accent-2: #8FBBE8;
  --accent-tint: #1A2A3D;

  --stamp: #E08148;
  --stamp-2: #EDA470;
  --stamp-tint: #33200F;

  --ok: #86C58C;
  --ok-tint: #1B2F1E;
  --warn: #E5A758;
  --warn-tint: #33260F;
  --danger: #E88B8B;
}

@media (prefers-color-scheme: dark) {
  html:not([data-theme]) { color-scheme: dark; }
}

/* ---------- Reset ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  /* Signature: subtle isometric grid on hero band, visible only there */
}
img, svg { display: block; max-width: 100%; }
h1, h2, h3, h4, p, ul, ol, dl, dd { margin: 0; padding: 0; }
ul { list-style: none; }
button { font: inherit; cursor: pointer; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

.visually-hidden {
  position: absolute; width: 1px; height: 1px; padding: 0;
  margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0;
}

.skip-link {
  position: absolute; top: -40px; left: 8px;
  background: var(--ink); color: var(--paper);
  padding: 8px 12px; z-index: 1000; border-radius: var(--radius);
}
.skip-link:focus { top: 8px; }

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 var(--pad);
}

/* ---------- Header ---------- */
.site-header {
  border-bottom: var(--hairline-w) solid var(--hairline);
  background: var(--paper);
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: saturate(1.1);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding-top: 12px; padding-bottom: 12px;
}
.brand {
  display: inline-flex; align-items: center; gap: 10px;
  color: var(--ink);
  font-weight: 500; letter-spacing: -0.01em;
}
.brand:hover { text-decoration: none; }
.brand-mark { width: 26px; height: 26px; color: var(--accent); }
.brand-text { font-size: 17px; }
.brand.small .brand-mark { width: 20px; height: 20px; }
.brand.small .brand-text { font-size: 14px; }

.site-nav { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }

.selector {
  appearance: none;
  background: var(--paper-2);
  color: var(--ink);
  border: var(--hairline-w) solid var(--hairline);
  border-radius: var(--radius);
  padding: 6px 28px 6px 10px;
  font-size: 13px;
  font-family: var(--font-sans);
  background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='0 0 10 10'><path d='M2 4 L5 7 L8 4' fill='none' stroke='%236B7079' stroke-width='1.2'/></svg>");
  background-repeat: no-repeat;
  background-position: right 8px center;
  min-height: 32px;
  max-width: 220px;
}
.selector:hover { border-color: var(--hairline-strong); }
.selector:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}
.selector option:disabled { color: var(--ink-3); }

.icon-btn {
  background: transparent;
  border: var(--hairline-w) solid var(--hairline);
  color: var(--ink);
  width: 32px; height: 32px;
  border-radius: var(--radius);
  display: inline-flex; align-items: center; justify-content: center;
  transition: background 0.15s ease;
}
.icon-btn:hover { background: var(--paper-3); }

/* ---------- Hero (signature isometric grid + structural illustration) ---------- */
.hero {
  padding: 88px 0 64px;
  position: relative;
  overflow: hidden;
  border-bottom: var(--hairline-w) solid var(--hairline);
  background-color: var(--paper);
}
.hero::before {
  content: "";
  position: absolute; inset: 0;
  background-image:
    linear-gradient(30deg, var(--hairline) 0.5px, transparent 0.5px),
    linear-gradient(-30deg, var(--hairline) 0.5px, transparent 0.5px),
    linear-gradient(90deg, var(--hairline) 0.5px, transparent 0.5px);
  background-size: 48px 28px, 48px 28px, 48px 28px;
  mask-image: linear-gradient(180deg, transparent 0, black 25%, black 65%, transparent 100%);
  pointer-events: none;
  animation: grid-drift 60s linear infinite;
}
@keyframes grid-drift {
  from { background-position: 0 0, 0 0, 0 0; }
  to   { background-position: 480px 0, -480px 0, 0 280px; }
}
@media (prefers-reduced-motion: reduce) { .hero::before { animation: none; } }

.hero .wrap { position: relative; z-index: 1; }
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 420px);
  gap: var(--sp-8);
  align-items: center;
}
@media (max-width: 880px) { .hero-grid { grid-template-columns: 1fr; } .hero-visual { order: -1; max-width: 320px; margin: 0 auto var(--sp-2); } }

.eyebrow {
  font-family: var(--font-mono);
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--stamp);
  margin-bottom: var(--sp-3);
  display: inline-flex; align-items: center; gap: 8px;
}
.eyebrow::before { content: ""; width: 16px; height: 1px; background: var(--stamp); display: inline-block; }

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(36px, 5vw, 58px);
  line-height: 1.06;
  font-weight: 500;
  letter-spacing: -0.01em;
  max-width: 620px;
  margin-bottom: var(--sp-2);
}
.hero-title-em {
  display: block;
  font-style: italic;
  color: var(--stamp);
}
.hero-lead {
  font-size: 18px;
  color: var(--ink-2);
  max-width: 560px;
  margin-bottom: var(--sp-4);
}

.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; margin-bottom: var(--sp-6); }

.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 11px 20px;
  border-radius: var(--radius);
  font-size: 14px; font-weight: 500;
  border: var(--hairline-w) solid transparent;
  transition: background 0.18s ease, border-color 0.18s ease, transform 0.18s ease, box-shadow 0.18s ease;
}
.btn-primary { background: var(--ink); color: var(--paper); border-color: var(--ink); }
.btn-primary:hover { background: var(--stamp); border-color: var(--stamp); text-decoration: none; transform: translateY(-1.5px); box-shadow: 0 6px 16px -6px color-mix(in srgb, var(--stamp) 55%, transparent); }
.btn-ghost { background: transparent; color: var(--ink); border-color: var(--hairline-strong); }
.btn-ghost:hover { background: var(--paper-3); text-decoration: none; border-color: var(--accent); transform: translateY(-1.5px); }

.hero-stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--sp-3);
  padding-top: var(--sp-3);
  border-top: var(--hairline-w) solid var(--hairline);
  max-width: 820px;
}
.hero-stats > div { display: flex; flex-direction: column; gap: 4px; }
.hero-stats dt { font-size: 12px; color: var(--ink-3); font-family: var(--font-mono); letter-spacing: 0.02em; }
.hero-stats dd { font-family: var(--font-display); font-size: 32px; font-weight: 500; color: var(--ink); font-style: italic; }
.hero-stats dd .stamp-num { color: var(--stamp); }

/* Hero SVG illustration wrapper */
.hero-visual { position: relative; }
.hero-visual svg { width: 100%; height: auto; display: block; }
.hero-visual .stamp-badge {
  position: absolute; top: -14px; right: -14px;
  width: 74px; height: 74px;
}
.hero-visual svg .draw-in {
  stroke-dasharray: 520;
  stroke-dashoffset: 520;
  animation: draw-in 1.5s cubic-bezier(.2,.7,.3,1) 0.4s forwards;
}
.hero-visual svg .draw-in-delay { animation-delay: 1.1s; }
@keyframes draw-in { to { stroke-dashoffset: 0; } }
@media (prefers-reduced-motion: reduce) {
  .hero-visual svg .draw-in { animation: none; stroke-dashoffset: 0; }
}

/* ---------- Reference chip (SIGNATURE) ---------- */
.ref-chip {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 11px;
  padding: 2px 6px;
  border: var(--hairline-w) solid var(--hairline-strong);
  border-radius: 3px;
  color: var(--accent);
  background: var(--accent-tint);
  letter-spacing: 0.02em;
  vertical-align: 1px;
}

/* ---------- Principles ---------- */
.principles { padding: var(--sp-12) 0; border-bottom: var(--hairline-w) solid var(--hairline); }
.principles h2 {
  font-family: var(--font-display);
  font-size: 30px; font-weight: 500; font-style: italic;
  letter-spacing: -0.01em;
  margin-bottom: var(--sp-6);
}
.principles-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: var(--sp-4) var(--sp-5, 40px);
}
.principles article { position: relative; padding-left: 0; }
.principles article .p-num {
  display: inline-flex; align-items: center; justify-content: center;
  width: 30px; height: 30px;
  border: 1.5px solid var(--stamp);
  border-radius: 50%;
  color: var(--stamp);
  font-family: var(--font-mono); font-size: 12px; font-weight: 600;
  transform: rotate(-8deg);
}
.principles article h3 {
  font-size: 16px; font-weight: 500;
  margin: 14px 0 8px;
}
.principles article p { color: var(--ink-2); font-size: 15px; }

/* ---------- Categories ---------- */
.categories { padding: 72px 0; }
.section-head {
  display: flex; align-items: baseline; justify-content: space-between;
  gap: 24px; flex-wrap: wrap;
  margin-bottom: 32px;
}
.categories h2 { font-size: 26px; font-weight: 500; letter-spacing: -0.01em; }

.search {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 12px;
  border: var(--hairline-w) solid var(--hairline);
  border-radius: var(--radius);
  background: var(--paper-2);
  color: var(--ink-3);
  min-width: 260px;
}
.search:focus-within {
  border-color: var(--accent);
  outline: 2px solid var(--accent-tint);
}
.search input {
  border: 0; background: transparent; outline: 0;
  color: var(--ink); font-size: 14px; flex: 1;
  min-width: 0;
}

.cat-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--sp-2);
}

.cat-card {
  display: flex; flex-direction: column; gap: 8px;
  padding: var(--sp-3);
  background: var(--paper-2);
  border: var(--hairline-w) solid var(--hairline);
  border-radius: var(--radius-lg);
  color: inherit;
  transition: border-color 0.2s ease, transform 0.2s ease, box-shadow 0.2s ease;
  position: relative;
  min-height: 158px;
  overflow: hidden;
}
.cat-card::after {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(120px 120px at 0% 0%, color-mix(in srgb, var(--stamp) 10%, transparent), transparent 70%);
  opacity: 0;
  transition: opacity 0.25s ease;
  pointer-events: none;
}
.cat-card:hover {
  border-color: var(--stamp);
  text-decoration: none;
  transform: translateY(-3px);
  box-shadow: 0 14px 28px -18px color-mix(in srgb, var(--ink) 35%, transparent);
}
.cat-card:hover::after { opacity: 1; }
.cat-card .cat-icon {
  width: 26px; height: 26px;
  color: var(--accent);
  transition: color 0.2s ease, transform 0.2s ease;
}
.cat-card:hover .cat-icon { color: var(--stamp); transform: scale(1.08) rotate(-4deg); }
.cat-card .letter {
  position: absolute; top: 18px; right: 18px;
  font-family: var(--font-mono); font-size: 12px;
  color: var(--ink-3);
}
.cat-card h3 { font-size: 17px; font-weight: 500; letter-spacing: -0.01em; margin-top: 4px; }
.cat-card p { font-size: 14px; color: var(--ink-2); }
.cat-card .cat-meta {
  margin-top: auto;
  display: flex; gap: 8px; flex-wrap: wrap;
  font-family: var(--font-mono); font-size: 11px; color: var(--ink-3);
}
.cat-card.disabled { opacity: 0.5; pointer-events: none; }

/* Entrance animation — pure CSS, runs unconditionally on paint. Never
   depends on JS/IntersectionObserver, so content can never be stuck
   invisible (see js/app.js initScrollReveal note). */
@keyframes gs-fade-in { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: translateY(0); } }
@keyframes gs-fade-in-dim { from { opacity: 0; transform: translateY(8px); } to { opacity: 0.5; transform: translateY(0); } }
.cat-card, .principles article {
  animation: gs-fade-in 0.45s ease both;
}
.cat-card.disabled {
  animation: gs-fade-in-dim 0.45s ease both;
  pointer-events: none;
}
@media (prefers-reduced-motion: reduce) {
  .cat-card, .principles article { animation: none; }
  .cat-card.disabled { opacity: 0.5; }
}

.empty-state {
  color: var(--ink-3);
  text-align: center;
  padding: 48px 0;
}

/* ---------- About / code sample ---------- */
.about { padding: 72px 0; border-top: var(--hairline-w) solid var(--hairline); background: var(--paper-2); }
.about h2 { font-size: 26px; font-weight: 500; letter-spacing: -0.01em; margin-bottom: 32px; }
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 40px;
}
.two-col p { color: var(--ink-2); margin-bottom: 12px; font-size: 15px; }
.code-sample {
  background: var(--paper);
  border: var(--hairline-w) solid var(--hairline);
  border-radius: var(--radius-lg);
  padding: 20px;
  overflow-x: auto;
  margin: 0;
}
.code-sample pre { margin: 0; }
.code-sample code {
  font-family: var(--font-mono);
  font-size: 13px;
  line-height: 1.8;
  color: var(--ink);
  white-space: pre;
}
.code-sample .ref {
  display: inline;
  color: var(--accent);
  font-size: 11px;
  padding-left: 4px;
}

@media (max-width: 720px) {
  .two-col { grid-template-columns: 1fr; gap: 24px; }
}

/* ---------- Disclaimer band ---------- */
.disclaimer {
  padding: 24px 0;
  background: var(--warn-tint);
  border-top: var(--hairline-w) solid var(--warn);
  border-bottom: var(--hairline-w) solid var(--warn);
}
.disclaimer p {
  font-size: 14px;
  color: var(--ink);
  max-width: 820px;
}

/* ---------- Footer ---------- */
.site-footer {
  padding: 48px 0 32px;
  border-top: var(--hairline-w) solid var(--hairline);
  background: var(--paper);
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 32px;
}
.footer-tag { color: var(--ink-3); font-size: 13px; margin-top: 8px; }
.site-footer h3 { font-size: 12px; font-weight: 500; color: var(--ink-3); text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 12px; }
.site-footer li { margin-bottom: 6px; }
.site-footer a { color: var(--ink-2); font-size: 14px; }
.site-footer a:hover { color: var(--accent); }
.copyright {
  padding-top: 24px;
  border-top: var(--hairline-w) solid var(--hairline);
  font-size: 12px; color: var(--ink-3);
  font-family: var(--font-mono);
}
@media (max-width: 720px) {
  .footer-grid { grid-template-columns: 1fr; gap: 24px; }
}

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

/* ---------- Print (calculator reports) ---------- */
@media print {
  .site-header, .site-footer, .disclaimer, .hero-actions { display: none; }
  body { background: white; color: black; }
}

/* ── RTL SUPPORT (Arabic, etc.) ─────────────────────────────────────────── */
html[dir="rtl"] .site-header .wrap,
html[dir="rtl"] .tw,
html[dir="rtl"] .hub,
html[dir="rtl"] .tool-wrap  { direction: rtl; }

html[dir="rtl"] .brand       { flex-direction: row-reverse; }
html[dir="rtl"] .site-nav    { flex-direction: row-reverse; }
html[dir="rtl"] .crumbs      { direction: rtl; }
html[dir="rtl"] .crumbs a::after { content: " /"; }
html[dir="rtl"] .crumbs a::before { content: none; }

/* Input fields stay LTR for numbers */
html[dir="rtl"] input[type="number"],
html[dir="rtl"] input[type="text"],
html[dir="rtl"] .font-mono,
html[dir="rtl"] .ref-chip    { direction: ltr; unicode-bidi: embed; }

/* Flip flex rows */
html[dir="rtl"] .result-line,
html[dir="rtl"] .rl          { flex-direction: row-reverse; }

/* User-must-supply field marker (used by JP/GB/IR packs for unverified NDP-style inputs) */
.user-supply { border-left: 3px solid #c04040; padding-left: 11px; margin-left: -14px; background: rgba(192,64,64,0.04); }
html[dir="rtl"] .user-supply { border-left: 0; border-right: 3px solid #c04040; padding-left: 0; padding-right: 11px; margin-left: 0; margin-right: -14px; }

/* Border-left → border-right for RTL step boxes */
html[dir="rtl"] .step-box    { border-left: none; border-right: 3px solid var(--accent); border-radius: var(--radius) 0 0 var(--radius); padding: 9px 13px 9px 9px; }

/* Card grids remain LTR internally */
html[dir="rtl"] .card-grid   { direction: rtl; }

/* Footer & actions */
html[dir="rtl"] .acts        { flex-direction: row-reverse; }
html[dir="rtl"] .field-row   { direction: rtl; }

/* --- Ortak altbilgi (footer.js tarafından enjekte edilir) --- */
.site-footer.compact{
  margin-top:48px;padding:20px 0;
  border-top:1px solid var(--line,#d8d2c4);
  font-size:12px;color:var(--ink-3,#6b6656);
}
.site-footer.compact .wrap{
  display:flex;flex-wrap:wrap;gap:10px 18px;
  align-items:center;justify-content:space-between;
}
.site-footer.compact .footer-legal-links{display:flex;flex-wrap:wrap;gap:14px}
.site-footer.compact .footer-legal-links a{color:inherit;text-decoration:none}
.site-footer.compact .footer-legal-links a:hover{text-decoration:underline}
.site-footer.compact .copyright{margin:0}
@media print{.site-footer.compact .footer-legal-links{display:none}}