/* InvoiceGen site — paper-ledger design system */

:root {
  --paper: #F6F1E6;
  --paper-2: #FCFAF4;
  --card: #FFFEF9;
  --ink: #1A2238;
  --ink-2: #3B4358;
  --muted: #6F684F;
  --chop: #2438B8;
  --chop-deep: #1A2A8F;
  --chop-soft: rgba(36, 56, 184, .08);
  --red: #B23A2A;
  --line: #E4DCC6;
  --line-strong: #CFC5A9;
  --shadow: 0 1px 2px rgba(26, 34, 56, .05), 0 12px 40px -12px rgba(26, 34, 56, .18);
  --font-display: "Fraunces", "Times New Roman", serif;
  --font-body: "IBM Plex Sans", -apple-system, "PingFang HK", "Microsoft JhengHei", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SF Mono", Menlo, monospace;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #0D1224;
    --paper-2: #101731;
    --card: #151D3D;
    --ink: #EFEAD8;
    --ink-2: #C8C3AF;
    --muted: #968E74;
    --chop: #8FA0FF;
    --chop-deep: #B0BCFF;
    --chop-soft: rgba(143, 160, 255, .12);
    --red: #E06B57;
    --line: #263052;
    --line-strong: #3A4670;
    --shadow: 0 1px 2px rgba(0, 0, 0, .4), 0 16px 48px -12px rgba(0, 0, 0, .55);
  }
}

* { box-sizing: border-box; }

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 400 16.5px/1.68 var(--font-body);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* paper grain */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  z-index: 0;
  pointer-events: none;
  opacity: .05;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='240' height='240'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3C/filter%3E%3Crect width='240' height='240' filter='url(%23n)' opacity='1'/%3E%3C/svg%3E");
}

body > * { position: relative; z-index: 1; }

::selection { background: var(--chop); color: var(--paper-2); }

a { color: var(--chop); text-decoration-color: color-mix(in srgb, var(--chop) 35%, transparent); text-underline-offset: 3px; }
a:hover { color: var(--chop-deep); text-decoration-color: var(--chop-deep); }

.wrap { max-width: 1120px; margin: 0 auto; padding: 0 28px; }
.wrap-narrow { max-width: 780px; margin: 0 auto; padding: 0 28px; }

/* ---------- header ---------- */

.site-header {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--paper);
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line);
}

.site-header .bar {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 0;
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  text-decoration: none;
  color: var(--ink);
  margin-right: auto;
}

.brand:hover { color: var(--ink); }

.brand svg { display: block; }

.brand .name {
  font: 600 21px/1 var(--font-display);
  letter-spacing: -.01em;
}

.site-nav { display: flex; align-items: center; gap: 26px; }

.site-nav a {
  font: 500 13px/1 var(--font-mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-2);
  text-decoration: none;
  padding: 6px 0;
  border-bottom: 1px solid transparent;
}

.site-nav a:hover, .site-nav a[aria-current="page"] { color: var(--chop); border-bottom-color: var(--chop); }

@media (max-width: 620px) {
  .site-nav { gap: 16px; }
  .site-nav a { letter-spacing: .04em; }
  .site-nav .optional { display: none; }
}

/* ---------- typography helpers ---------- */

.eyebrow {
  font: 500 12.5px/1.4 var(--font-mono);
  letter-spacing: .16em;
  text-transform: uppercase;
  color: var(--chop);
  margin: 0 0 18px;
}

.eyebrow .idx { color: var(--muted); margin-right: 10px; }

h1.display {
  font: 560 clamp(38px, 6.2vw, 62px)/1.06 var(--font-display);
  letter-spacing: -.022em;
  margin: 0 0 22px;
  text-wrap: balance;
}

h1.display em, .statement em {
  font-style: italic;
  font-weight: 480;
  color: var(--chop);
}

.section-title {
  font: 560 clamp(28px, 4vw, 40px)/1.12 var(--font-display);
  letter-spacing: -.018em;
  margin: 0 0 14px;
  text-wrap: balance;
}

.lede { font-size: 19px; line-height: 1.65; color: var(--ink-2); max-width: 56ch; }

.mono-num { font-family: var(--font-mono); font-variant-numeric: tabular-nums; }

/* ---------- buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font: 500 15px/1 var(--font-body);
  padding: 15px 26px;
  border-radius: 10px;
  text-decoration: none;
  border: 1px solid transparent;
  transition: transform .18s ease, box-shadow .18s ease, background .18s ease;
}

.btn-primary { background: var(--chop); color: #FCFAF4; box-shadow: var(--shadow); }
.btn-primary:hover { background: var(--chop-deep); color: #FCFAF4; transform: translateY(-1px); }
@media (prefers-color-scheme: dark) {
  .btn-primary, .btn-primary:hover { color: #0D1224; }
}

.btn-ghost { border-color: var(--line-strong); color: var(--ink); }
.btn-ghost:hover { border-color: var(--chop); color: var(--chop); }

.badge-soon {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font: 500 12px/1 var(--font-mono);
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--red);
  border: 1px solid color-mix(in srgb, var(--red) 45%, transparent);
  border-radius: 999px;
  padding: 7px 14px;
}

.badge-soon::before {
  content: "";
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--red);
}

/* ---------- ledger rules / dividers ---------- */

.rule { border: 0; border-top: 1px solid var(--line); margin: 0; }

.tear {
  height: 14px;
  background-image: radial-gradient(circle at 8px 0, transparent 7px, var(--paper-2) 7.5px);
  background-size: 24px 14px;
  background-repeat: repeat-x;
}

/* ---------- sections ---------- */

.section { padding: 104px 0; }
.section + .section { border-top: 1px solid var(--line); }

@media (max-width: 720px) { .section { padding: 72px 0; } }

/* ---------- cards ---------- */

.grid { display: grid; gap: 22px; }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-2 { grid-template-columns: repeat(2, 1fr); }

@media (max-width: 940px) { .grid-3 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 640px) { .grid-3, .grid-2 { grid-template-columns: 1fr; } }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 30px 28px;
  box-shadow: 0 1px 2px rgba(26, 34, 56, .04);
  transition: transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}

.card:hover {
  transform: translateY(-3px);
  border-color: var(--line-strong);
  box-shadow: var(--shadow);
}

.card .idx {
  font: 500 12px/1 var(--font-mono);
  letter-spacing: .14em;
  color: var(--muted);
  display: block;
  margin-bottom: 20px;
}

.card h3 {
  font: 600 20px/1.3 var(--font-display);
  letter-spacing: -.01em;
  margin: 0 0 10px;
}

.card p { margin: 0; color: var(--ink-2); font-size: 15.5px; }

.card .zh {
  display: block;
  margin-top: 14px;
  font-size: 13.5px;
  color: var(--muted);
}

/* ---------- footer ---------- */

.site-footer {
  border-top: 1px solid var(--line);
  padding: 56px 0 72px;
  background: var(--paper-2);
}

.site-footer .cols {
  display: flex;
  flex-wrap: wrap;
  gap: 32px;
  justify-content: space-between;
  align-items: flex-start;
}

.site-footer nav { display: flex; gap: 24px; flex-wrap: wrap; }

.site-footer a { color: var(--ink-2); text-decoration: none; font-size: 14.5px; }
.site-footer a:hover { color: var(--chop); }

.site-footer .fine { margin-top: 30px; color: var(--muted); font-size: 13px; }

/* ---------- prose (legal / support pages) ---------- */

.doc-head { padding: 72px 0 40px; }

.doc-head .meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
  font: 500 12.5px/1.6 var(--font-mono);
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--muted);
  margin-top: 18px;
}

.doc-head .meta strong { color: var(--red); font-weight: 500; }

.prose { padding-bottom: 110px; }

.prose h2 {
  font: 600 22px/1.35 var(--font-display);
  letter-spacing: -.012em;
  margin: 46px 0 12px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.prose h2 .no {
  font: 500 12px/1 var(--font-mono);
  letter-spacing: .14em;
  color: var(--muted);
  display: block;
  margin-bottom: 10px;
}

.prose p, .prose li { color: var(--ink-2); }
.prose strong { color: var(--ink); }
.prose ul { padding-left: 22px; }
.prose li { margin: 7px 0; }
.prose .lede { font-size: 18px; }

/* ---------- FAQ ---------- */

.faq details {
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--card);
  margin: 12px 0;
  overflow: hidden;
  transition: border-color .2s ease;
}

.faq details:hover { border-color: var(--line-strong); }
.faq details[open] { border-color: var(--chop); }

.faq summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: baseline;
  gap: 14px;
  padding: 19px 22px;
  font: 600 16.5px/1.4 var(--font-body);
  color: var(--ink);
}

.faq summary::-webkit-details-marker { display: none; }

.faq summary::before {
  content: "＋";
  content: "＋" / "";
  font: 400 15px/1 var(--font-mono);
  color: var(--chop);
  flex: none;
  translate: 0 -1px;
}

.faq details[open] summary::before { content: "－"; content: "－" / ""; }

.faq .a { padding: 0 22px 20px 51px; color: var(--ink-2); font-size: 15.5px; }
.faq .a p { margin: 0 0 10px; }
.faq .a p:last-child { margin-bottom: 0; }

/* ---------- reveal animation ---------- */

@media (prefers-reduced-motion: no-preference) {
  .reveal {
    opacity: 0;
    transform: translateY(22px);
    transition: opacity .7s cubic-bezier(.2, .65, .25, 1), transform .7s cubic-bezier(.2, .65, .25, 1);
  }
  .reveal.in { opacity: 1; transform: none; }
}