/* ==========================================================================
   RC Tax Partners — rctaxpartners.com.au
   Design tokens: ink navy / aged brass / warm paper
   Type: Fraunces + Noto Serif SC (display), IBM Plex Sans + Noto Sans SC (body),
         IBM Plex Mono (ledger figures & labels)
   ========================================================================== */

:root {
  --navy-900: #0b1f38;
  --navy-800: #10294a;
  --navy-700: #1a3a63;
  --navy-100: #dce4ee;
  --brass-600: #a8842f;
  --brass-500: #c6a14b;
  --brass-300: #e6d3a0;
  --paper: #f7f5f0;
  --paper-deep: #efece4;
  --ink: #1c2733;
  --ink-soft: #4a5766;
  --line: #d9d4c8;
  --line-navy: #2c4a75;
  --white: #ffffff;

  --font-display: "Fraunces", "Noto Serif SC", Georgia, serif;
  --font-body: "IBM Plex Sans", "Noto Sans SC", -apple-system, "PingFang SC", "Microsoft YaHei", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --w-max: 1080px;
  --w-text: 720px;
  --sp-1: 0.5rem;
  --sp-2: 1rem;
  --sp-3: 1.5rem;
  --sp-4: 2.5rem;
  --sp-5: 4rem;
  --sp-6: 6rem;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  font-family: var(--font-body);
  font-size: 1.0625rem;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
}

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

a { color: var(--navy-800); text-decoration-color: var(--brass-500); text-underline-offset: 3px; }
a:hover { color: var(--brass-600); }
a:focus-visible, button:focus-visible, summary:focus-visible {
  outline: 3px solid var(--brass-500);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---------- Layout ---------- */

.wrap { max-width: var(--w-max); margin: 0 auto; padding: 0 var(--sp-3); }
.wrap-text { max-width: var(--w-text); margin: 0 auto; padding: 0 var(--sp-3); }

section { padding: var(--sp-6) 0; }
@media (max-width: 640px) { section { padding: var(--sp-5) 0; } }

/* ---------- The bilingual ledger label (signature device) ----------
   A paired EN · 中文 eyebrow separated by a brass hairline, set in mono,
   like the heading row of a bilingual ledger. */

.ledger-label {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--brass-600);
  margin-bottom: var(--sp-3);
}
.ledger-label::after {
  content: "";
  flex: 1;
  height: 1px;
  background: linear-gradient(to right, var(--brass-500), transparent);
}
.ledger-label .zh { letter-spacing: 0.3em; }
.on-navy .ledger-label { color: var(--brass-300); }
.on-navy .ledger-label::after { background: linear-gradient(to right, var(--brass-500), transparent); }

/* ---------- Type ---------- */

h1, h2, h3 { font-family: var(--font-display); font-weight: 600; line-height: 1.15; color: var(--navy-900); }
h1 { font-size: clamp(2.3rem, 5.5vw, 3.6rem); letter-spacing: -0.01em; }
h2 { font-size: clamp(1.7rem, 3.5vw, 2.3rem); margin-bottom: var(--sp-3); }
h3 { font-size: 1.25rem; margin-bottom: var(--sp-1); }
.on-navy h1, .on-navy h2, .on-navy h3 { color: var(--white); }

.lead { font-size: 1.2rem; color: var(--ink-soft); max-width: 38em; }
.on-navy .lead { color: var(--navy-100); }

p + p { margin-top: var(--sp-2); }

.small { font-size: 0.9rem; color: var(--ink-soft); }

/* ---------- Header ---------- */

.site-header {
  background: var(--navy-900);
  border-bottom: 1px solid var(--line-navy);
  position: sticky;
  top: 0;
  z-index: 50;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-2);
  min-height: 64px;
  flex-wrap: wrap;
  padding-top: 0.6rem;
  padding-bottom: 0.6rem;
}
.brand {
  display: flex;
  align-items: baseline;
  gap: 0.6rem;
  text-decoration: none;
  color: var(--white);
}
.brand:hover { color: var(--white); }
.brand-mark {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  color: var(--navy-900);
  background: var(--brass-500);
  padding: 0.1rem 0.45rem;
  border-radius: 2px;
  align-self: center;
}
.brand-name { font-family: var(--font-display); font-weight: 600; font-size: 1.15rem; letter-spacing: 0.01em; }
.brand-sub { font-family: var(--font-mono); font-size: 0.68rem; letter-spacing: 0.18em; color: var(--brass-300); text-transform: uppercase; }

.site-nav { display: flex; align-items: center; gap: 1.4rem; flex-wrap: wrap; }
.site-nav a {
  color: var(--navy-100);
  text-decoration: none;
  font-size: 0.95rem;
  padding: 0.3rem 0;
  border-bottom: 2px solid transparent;
}
.site-nav a:hover { color: var(--white); border-bottom-color: var(--brass-500); }
.site-nav a[aria-current="page"] { color: var(--white); border-bottom-color: var(--brass-500); }
.lang-switch {
  font-family: var(--font-mono);
  font-size: 0.8rem !important;
  letter-spacing: 0.08em;
  border: 1px solid var(--line-navy);
  border-radius: 3px;
  padding: 0.35rem 0.7rem !important;
  border-bottom: 1px solid var(--line-navy) !important;
}
.lang-switch:hover { border-color: var(--brass-500) !important; }

/* ---------- Hero ---------- */

.hero {
  background: var(--navy-900);
  color: var(--white);
  padding: var(--sp-6) 0;
  border-bottom: 4px solid var(--brass-500);
}
.hero-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.5fr) minmax(0, 1fr);
  gap: var(--sp-5);
  align-items: center;
}
@media (max-width: 820px) { .hero-grid { grid-template-columns: 1fr; gap: var(--sp-4); } }

.hero-zh-line {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 3vw, 1.9rem);
  color: var(--brass-300);
  margin-top: 0.6rem;
  letter-spacing: 0.08em;
}
.hero .lead { margin-top: var(--sp-3); }
.hero-ctas { display: flex; gap: var(--sp-2); margin-top: var(--sp-4); flex-wrap: wrap; }

/* Credentials ledger card */
.ledger-card {
  background: var(--navy-800);
  border: 1px solid var(--line-navy);
  border-top: 3px solid var(--brass-500);
  padding: var(--sp-3);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  line-height: 1.5;
}
.ledger-card h2, .ledger-card .ledger-title {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--brass-300);
  margin-bottom: var(--sp-2);
}
.ledger-card ul { list-style: none; }
.ledger-card li {
  display: flex;
  justify-content: space-between;
  gap: var(--sp-2);
  padding: 0.55rem 0;
  border-bottom: 1px dashed var(--line-navy);
  color: var(--navy-100);
}
.ledger-card li:last-child { border-bottom: none; }
.ledger-card li span:last-child { color: var(--brass-300); text-align: right; }

/* ---------- Buttons ---------- */

.btn {
  display: inline-block;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 1rem;
  text-decoration: none;
  padding: 0.8rem 1.6rem;
  border-radius: 3px;
  border: 1px solid transparent;
}
.btn-gold { background: var(--brass-500); color: var(--navy-900); }
.btn-gold:hover { background: var(--brass-300); color: var(--navy-900); }
.btn-ghost { border-color: var(--line-navy); color: var(--white); }
.btn-ghost:hover { border-color: var(--brass-500); color: var(--brass-300); }
.btn-navy { background: var(--navy-900); color: var(--white); }
.btn-navy:hover { background: var(--navy-700); color: var(--white); }

/* ---------- Audience trio ---------- */

.trio {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--sp-4);
}
@media (max-width: 820px) { .trio { grid-template-columns: 1fr; } }
.trio-item { border-top: 2px solid var(--navy-900); padding-top: var(--sp-2); }
.trio-item .zh-tag { font-family: var(--font-mono); font-size: 0.8rem; color: var(--brass-600); letter-spacing: 0.2em; display: block; margin-bottom: 0.3rem; }
.trio-item p { color: var(--ink-soft); font-size: 0.98rem; margin-top: 0.4rem; }
.trio-item a { font-weight: 600; font-size: 0.95rem; }

/* ---------- Service ledger list ---------- */

.service-list { border-top: 1px solid var(--line); }
.service-row {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(0, 1.7fr);
  gap: var(--sp-3);
  padding: var(--sp-3) 0;
  border-bottom: 1px solid var(--line);
}
@media (max-width: 640px) { .service-row { grid-template-columns: 1fr; gap: 0.5rem; } }
.service-row h3 { margin-bottom: 0.2rem; }
.service-row .zh-tag { font-family: var(--font-mono); font-size: 0.82rem; color: var(--brass-600); letter-spacing: 0.15em; }
.service-row p { color: var(--ink-soft); font-size: 0.98rem; }
.service-row ul { margin: 0.6rem 0 0 1.1rem; color: var(--ink-soft); font-size: 0.95rem; }
.service-row li + li { margin-top: 0.25rem; }

/* ---------- Navy band ---------- */

.band {
  background: var(--navy-900);
  color: var(--white);
  padding: var(--sp-5) 0;
}
.band .wrap { display: grid; grid-template-columns: minmax(0, 1.6fr) auto; gap: var(--sp-4); align-items: center; }
@media (max-width: 720px) { .band .wrap { grid-template-columns: 1fr; } }
.band p { color: var(--navy-100); }

/* ---------- Books shelf ---------- */

.shelf {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(210px, 1fr));
  gap: var(--sp-3);
  align-items: stretch;
}
.book-card { display: flex; flex-direction: column; }
.book-cover {
  aspect-ratio: 5 / 7;
  padding: 1.4rem 1.2rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  border-radius: 2px;
  box-shadow: inset 6px 0 0 rgba(0,0,0,0.18), 0 6px 18px rgba(11,31,56,0.18);
}
.book-cover.navy { background: linear-gradient(160deg, var(--navy-800), var(--navy-900)); color: var(--white); }
.book-cover.brass { background: linear-gradient(160deg, #cfa952, #a8842f); color: var(--navy-900); }
.book-cover .book-title { font-family: var(--font-display); font-weight: 700; font-size: 1.2rem; line-height: 1.25; }
.book-cover .book-author { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.18em; text-transform: uppercase; opacity: 0.85; }
.book-cover .book-rule { width: 2.2rem; height: 2px; background: currentColor; opacity: 0.6; margin: 0.7rem 0; }
.book-meta { padding: var(--sp-2) 0.2rem 0; }
.book-meta .small { display: block; font-family: var(--font-mono); font-size: 0.78rem; }
.book-meta p { font-size: 0.95rem; color: var(--ink-soft); margin-top: 0.4rem; }
.book-meta a { font-weight: 600; font-size: 0.95rem; }

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

.faq { border-top: 1px solid var(--line); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary {
  cursor: pointer;
  list-style: none;
  padding: var(--sp-2) 2rem var(--sp-2) 0;
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--navy-900);
  position: relative;
}
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after {
  content: "+";
  position: absolute;
  right: 0.3rem;
  top: 50%;
  transform: translateY(-50%);
  font-family: var(--font-mono);
  color: var(--brass-600);
  font-size: 1.2rem;
}
.faq details[open] summary::after { content: "\2212"; }
.faq .faq-a { padding: 0 0 var(--sp-3); color: var(--ink-soft); max-width: 60em; }

/* ---------- Articles ---------- */

.article { padding: var(--sp-5) 0; border-bottom: 1px solid var(--line); }
.article:last-of-type { border-bottom: none; }
.article .meta { font-family: var(--font-mono); font-size: 0.8rem; color: var(--brass-600); letter-spacing: 0.12em; text-transform: uppercase; margin-bottom: var(--sp-2); }
.article h2 { max-width: 20em; }
.article p, .article ul, .article ol { max-width: var(--w-text); }
.article ul, .article ol { margin: var(--sp-2) 0 0 1.2rem; color: var(--ink); }
.article li + li { margin-top: 0.4rem; }
.article .takeaway {
  border-left: 3px solid var(--brass-500);
  background: var(--paper-deep);
  padding: var(--sp-2) var(--sp-3);
  margin-top: var(--sp-3);
  max-width: var(--w-text);
}

/* ---------- Contact ---------- */

.contact-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(0, 1fr);
  gap: var(--sp-5);
}
@media (max-width: 820px) { .contact-grid { grid-template-columns: 1fr; } }
.nap {
  background: var(--white);
  border: 1px solid var(--line);
  border-top: 3px solid var(--navy-900);
  padding: var(--sp-3);
}
.nap dt { font-family: var(--font-mono); font-size: 0.72rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--brass-600); margin-top: var(--sp-2); }
.nap dt:first-child { margin-top: 0; }
.nap dd { margin: 0.2rem 0 0; }

/* ---------- Footer ---------- */

.site-footer {
  background: var(--navy-900);
  color: var(--navy-100);
  padding: var(--sp-5) 0 var(--sp-3);
  border-top: 4px solid var(--brass-500);
  margin-top: 0;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: var(--sp-4);
  padding-bottom: var(--sp-4);
  border-bottom: 1px solid var(--line-navy);
}
@media (max-width: 720px) { .footer-grid { grid-template-columns: 1fr; } }
.site-footer h3 { color: var(--white); font-size: 1rem; font-family: var(--font-mono); letter-spacing: 0.15em; text-transform: uppercase; font-weight: 500; }
.site-footer ul { list-style: none; margin-top: var(--sp-2); }
.site-footer li { margin-top: 0.45rem; }
.site-footer a { color: var(--navy-100); }
.site-footer a:hover { color: var(--brass-300); }
.footer-slogan { font-family: var(--font-display); font-size: 1.15rem; color: var(--brass-300); margin-top: var(--sp-2); letter-spacing: 0.05em; }
.footer-legal { padding-top: var(--sp-3); font-size: 0.82rem; color: #8b9bb0; max-width: 70em; }
.footer-legal p + p { margin-top: 0.5rem; }

/* ---------- Page intro ---------- */

.page-intro {
  background: var(--navy-900);
  color: var(--white);
  padding: var(--sp-5) 0;
  border-bottom: 4px solid var(--brass-500);
}
.page-intro .lead { margin-top: var(--sp-2); }

/* ---------- Utility ---------- */

.mt-2 { margin-top: var(--sp-2); }
.mt-3 { margin-top: var(--sp-3); }
.mt-4 { margin-top: var(--sp-4); }
.center { text-align: center; }
.alt { background: var(--paper-deep); }