/* ==========================================================================
   Zhuocuo — Computer Systems Design
   DARK theme: warm charcoal #171310, light text #F5EDE3
   Accent: burned copper #B85C38  |  Secondary: sand gold #D9A05B  |  Panel: #241D18
   ========================================================================== */

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

:root {
  --bg: #171310;
  --text: #F5EDE3;
  --accent: #B85C38;
  --accent-dark: #8E4629;
  --gold: #D9A05B;
  --panel: #241D18;
  --panel-raise: #2C241C;
  --line: #3A2F26;
  --copper-line: #B85C38;
  --ink: #171310;
}

html { scroll-behavior: smooth; }

body {
  background-color: var(--bg);
  color: var(--text);
  font-size: 16px;
  font-family: "Segoe UI", "Helvetica Neue", Arial, "Noto Sans", sans-serif;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

h1, h2, h3 { line-height: 1.15; color: var(--text); }
h1 { font-size: 2.6rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.25rem; }

.btn {
  display: inline-block;
  padding: 14px 30px;
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.04em;
  border-radius: 2px;
  text-transform: uppercase;
  transition: transform 0.15s ease, background-color 0.15s ease;
}
.btn:hover { transform: translateY(-2px); text-decoration: none; }
.btn-solid {
  background-color: var(--ink);
  color: var(--text);
  border: 1px solid var(--ink);
}
.btn-solid:hover { background-color: #2A2018; }
.btn-outline {
  background-color: transparent;
  color: var(--ink);
  border: 1px solid var(--ink);
}
.btn-outline:hover { background-color: var(--ink); color: var(--text); }
.btn-solid-dark {
  background-color: var(--ink);
  color: var(--text);
  border: 1px solid var(--ink);
}
.btn-solid-dark:hover { background-color: #2A2018; }

/* ==========================================================================
   INDEX-NUMBERED NAVIGATION
   ========================================================================== */

.index-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: var(--bg);
  border-bottom: 2px solid var(--copper-line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 48px;
  min-height: 68px;
}
.index-nav-brand {
  font-size: 22px;
  font-weight: 800;
  letter-spacing: 0.14em;
  color: var(--accent);
  text-decoration: none;
}
.index-nav-brand:hover { color: var(--gold); text-decoration: none; }
.index-nav-links {
  display: flex;
  align-items: center;
  gap: 26px;
}
.index-nav-link {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  color: var(--text);
  font-size: 15px;
  font-weight: 600;
  padding: 8px 0;
  border-bottom: 2px solid transparent;
}
.index-nav-link:hover { color: var(--gold); text-decoration: none; }
.index-nav-link.active {
  color: var(--text);
  border-bottom: 2px solid var(--accent);
}
.index-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 18px;
  height: 18px;
  background-color: var(--accent);
  color: var(--ink);
  font-size: 10px;
  font-weight: 800;
  line-height: 1;
}
.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: transparent;
  border: 0;
  padding: 8px;
  cursor: pointer;
}
.nav-toggle span {
  display: block;
  width: 24px;
  height: 3px;
  background-color: var(--accent);
}

/* ==========================================================================
   TWO-DECK HERO
   ========================================================================== */

.two-deck-hero { border-bottom: 2px solid var(--copper-line); }
.hero-deck { width: 100%; }
.hero-top {
  background-color: var(--accent);
  padding: 84px 48px 72px;
}
.hero-inner { max-width: 980px; margin: 0 auto; }
.eyebrow-chip {
  display: inline-block;
  background-color: var(--gold);
  color: var(--ink);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 8px 16px;
  margin-bottom: 26px;
}
.hero-top h1 {
  color: var(--ink);
  font-size: 3.1rem;
  font-weight: 800;
  max-width: 900px;
}
.hero-sub {
  color: var(--ink);
  font-size: 1.1rem;
  max-width: 720px;
  margin-top: 22px;
}
.hero-actions { margin-top: 30px; display: flex; gap: 16px; flex-wrap: wrap; }
.hero-bottom {
  background-color: var(--panel);
  border-top: 2px solid var(--copper-line);
  padding: 30px 48px;
}
.capability-row {
  max-width: 980px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  flex-wrap: wrap;
}
.capability-chip {
  color: var(--gold);
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  padding: 0 28px;
  border-right: 1px solid var(--copper-line);
}
.capability-chip:first-child { padding-left: 0; }
.capability-chip:last-child { border-right: 0; }

/* ==========================================================================
   STATEMENT SPLIT
   ========================================================================== */

.statement-split {
  max-width: 1200px;
  margin: 0 auto;
  padding: 96px 48px 88px;
  display: grid;
  grid-template-columns: 1fr 1px 1fr;
  gap: 48px;
}
.statement-line {
  color: var(--gold);
  font-size: 2.35rem;
  font-weight: 800;
  line-height: 1.25;
  align-self: center;
}
.statement-left { grid-column: 1; }
.statement-right { grid-column: 3; }
.statement-right { display: flex; flex-direction: column; gap: 22px; }
.statement-right p { color: var(--text); }

/* ==========================================================================
   SERVICE INDEX
   ========================================================================== */

.service-index {
  background-color: var(--panel);
  border-top: 2px solid var(--copper-line);
  border-bottom: 2px solid var(--copper-line);
  padding: 90px 48px 96px;
}
.section-head {
  max-width: 1200px;
  margin: 0 auto 46px;
}
.section-kicker {
  color: var(--gold);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  display: block;
  margin-bottom: 12px;
}
.section-head h2 { margin-bottom: 14px; }
.section-intro { color: var(--text); max-width: 760px; }
.service-grid {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px;
}
.service-card {
  background-color: var(--panel-raise);
  border-top: 3px solid var(--copper-line);
  padding: 38px 34px 34px;
}
.service-index-num {
  display: block;
  color: var(--accent);
  font-size: 15px;
  font-weight: 800;
  margin-bottom: 14px;
  letter-spacing: 0.1em;
}
.service-card h3 { margin-bottom: 14px; }
.service-card p { color: var(--text); }

/* ==========================================================================
   PROCESS RAIL
   ========================================================================== */

.process-rail { padding: 90px 48px 100px; }
.rail-track {
  position: relative;
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 32px;
  padding-top: 34px;
}
.rail-line {
  position: absolute;
  top: 33px;
  left: 4%;
  right: 4%;
  height: 2px;
  background-color: var(--copper-line);
}
.rail-node {
  position: relative;
  z-index: 1;
  text-align: center;
}
.rail-dot {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background-color: var(--copper-line);
  color: var(--ink);
  font-weight: 800;
  font-size: 17px;
  margin-bottom: 20px;
}
.rail-node h3 { margin-bottom: 12px; }
.rail-node p { color: var(--text); font-size: 15px; }

/* ==========================================================================
   METRIC BAND
   ========================================================================== */

.metric-band {
  background-color: var(--panel);
  border-top: 2px solid var(--copper-line);
  border-bottom: 2px solid var(--copper-line);
  padding: 66px 48px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}
.metric-item {
  text-align: center;
  padding: 0 30px;
  border-right: 1px solid var(--copper-line);
}
.metric-item:last-child { border-right: 0; }
.metric-num {
  color: var(--gold);
  font-size: 3.4rem;
  font-weight: 800;
  line-height: 1;
}
.metric-suffix { color: var(--gold); font-size: 2rem; font-weight: 800; }
.metric-label {
  display: block;
  color: var(--text);
  margin-top: 12px;
  font-size: 14px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

/* ==========================================================================
   CTA BAND
   ========================================================================== */

.cta-band {
  background-color: var(--accent);
  padding: 84px 48px;
}
.cta-inner {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
}
.cta-inner h2 { color: var(--ink); margin-bottom: 16px; }
.cta-inner p { color: var(--ink); font-size: 1.05rem; margin-bottom: 30px; }

/* ==========================================================================
   LEDGER-STRIP FOOTER
   ========================================================================== */

.ledger-footer { border-top: 2px solid var(--copper-line); }
.ledger-top {
  background-color: var(--bg);
  padding: 44px 48px 40px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}
.ledger-brand { display: flex; flex-direction: column; gap: 6px; }
.ledger-wordmark {
  color: var(--accent);
  font-size: 20px;
  font-weight: 800;
  letter-spacing: 0.14em;
}
.ledger-wordmark:hover { color: var(--gold); text-decoration: none; }
.ledger-company { color: var(--text); font-size: 14px; }
.ledger-links {
  display: flex;
  gap: 30px;
  flex-wrap: wrap;
}
.ledger-links a { color: var(--text); font-size: 15px; }
.ledger-links a:hover { color: var(--gold); }
.ledger-bottom {
  background-color: var(--accent);
  padding: 22px 48px;
  text-align: center;
}
.ledger-bottom p { color: var(--ink); font-size: 14px; font-weight: 600; }
.ledger-bottom a { color: var(--ink); text-decoration: underline; }
.ledger-bottom a:hover { color: var(--panel); }

/* ==========================================================================
   SECONDARY PAGE HERO (Services / Contact)
   ========================================================================== */

.page-hero {
  background-color: var(--accent);
  border-bottom: 2px solid var(--copper-line);
  padding: 76px 48px 66px;
}
.page-hero-inner { max-width: 980px; margin: 0 auto; }
.page-hero h1 { color: var(--ink); font-size: 2.9rem; }
.page-hero .hero-sub { color: var(--ink); }

/* ==========================================================================
   SERVICE DETAIL (Services page)
   ========================================================================== */

.service-detail {
  max-width: 1040px;
  margin: 0 auto;
  padding: 84px 48px 40px;
  display: flex;
  flex-direction: column;
  gap: 56px;
}
.detail-block {
  border-left: 3px solid var(--copper-line);
  padding-left: 34px;
}
.detail-num {
  display: inline-block;
  background-color: var(--accent);
  color: var(--ink);
  font-size: 12px;
  font-weight: 800;
  padding: 5px 12px;
  margin-bottom: 16px;
  letter-spacing: 0.08em;
}
.detail-block h2 { margin-bottom: 16px; }
.detail-block p { margin-bottom: 18px; color: var(--text); }

/* ==========================================================================
   PROCESS OVERVIEW (Services page)
   ========================================================================== */

.process-overview {
  background-color: var(--panel);
  border-top: 2px solid var(--copper-line);
  border-bottom: 2px solid var(--copper-line);
  padding: 84px 48px 88px;
}
.process-intro {
  max-width: 1200px;
  margin: 0 auto 40px;
  color: var(--text);
}
.process-list {
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}
.process-step {
  background-color: var(--panel-raise);
  border-top: 3px solid var(--copper-line);
  padding: 30px 28px;
}
.process-num {
  display: inline-block;
  color: var(--gold);
  font-weight: 800;
  font-size: 14px;
  letter-spacing: 0.1em;
  margin-bottom: 12px;
}
.process-step h3 { margin-bottom: 12px; }
.process-step p { color: var(--text); font-size: 15px; }

/* ==========================================================================
   CONTACT LAYOUT (Contact page)
   ========================================================================== */

.contact-layout {
  max-width: 1200px;
  margin: 0 auto;
  padding: 84px 48px 72px;
  display: grid;
  grid-template-columns: 1.3fr 1fr;
  gap: 36px;
}
.contact-form-panel,
.contact-info-panel {
  background-color: var(--panel);
  border-top: 3px solid var(--copper-line);
  padding: 38px 36px;
}
.contact-form-panel h2,
.contact-info-panel h2 { margin-bottom: 22px; }
.form-field { margin-bottom: 20px; }
.form-field label {
  display: block;
  color: var(--gold);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 8px;
}
.form-field input,
.form-field textarea {
  width: 100%;
  background-color: var(--bg);
  border: 1px solid var(--line);
  color: var(--text);
  padding: 12px 14px;
  font-size: 16px;
  font-family: inherit;
  border-radius: 2px;
}
.form-field input:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--copper-line);
}
.form-status { margin-top: 16px; color: var(--gold); font-size: 15px; font-weight: 700; }
.form-status.error { color: #E08B6B; }

.info-row {
  padding: 16px 0;
  border-bottom: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  gap: 4px;
}
.info-row:first-of-type { padding-top: 0; }
.info-label {
  color: var(--gold);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}
.info-value { color: var(--text); font-size: 15px; }
.info-value a { color: var(--text); }
.info-value a:hover { color: var(--gold); }

/* ==========================================================================
   FAQ (Contact page)
   ========================================================================== */

.faq-section {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 48px 96px;
}
.faq-list {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.faq-item {
  background-color: var(--panel);
  border-left: 3px solid var(--copper-line);
}
.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  background: transparent;
  border: 0;
  color: var(--text);
  font-size: 17px;
  font-weight: 700;
  text-align: left;
  padding: 22px 26px;
  cursor: pointer;
  font-family: inherit;
}
.faq-question:hover { color: var(--gold); }
.faq-indicator {
  color: var(--accent);
  font-size: 24px;
  font-weight: 700;
  line-height: 1;
  transition: transform 0.2s ease;
}
.faq-item.open .faq-indicator { transform: rotate(45deg); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}
.faq-answer p {
  color: var(--text);
  padding: 0 26px 24px;
  font-size: 15px;
}

/* ==========================================================================
   SCROLL REVEAL
   ========================================================================== */

.fade-up {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.fade-up.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */

@media (max-width: 1024px) {
  .statement-split { grid-template-columns: 1fr; }
  .statement-right { grid-column: 1; }
  .statement-line { font-size: 2rem; }
  .service-grid { grid-template-columns: 1fr; }
  .rail-track { grid-template-columns: repeat(2, 1fr); row-gap: 40px; }
  .rail-line { display: none; }
  .metric-band { grid-template-columns: repeat(2, 1fr); row-gap: 40px; }
  .metric-item:nth-child(2) { border-right: 0; }
  .contact-layout { grid-template-columns: 1fr; }
}

@media (max-width: 768px) {
  .index-nav { padding: 0 20px; min-height: 60px; }
  .nav-toggle { display: flex; }
  .index-nav-links {
    position: absolute;
    top: 60px;
    left: 0;
    right: 0;
    background-color: var(--panel);
    border-bottom: 2px solid var(--copper-line);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
  }
  .index-nav-links.open { max-height: 420px; }
  .index-nav-link {
    padding: 15px 20px;
    border-bottom: 1px solid var(--line);
    border-left: 0;
  }
  .index-nav-link.active { border-bottom: 1px solid var(--line); border-left: 3px solid var(--accent); }
  .hero-top { padding: 56px 20px 48px; }
  .hero-top h1 { font-size: 2.2rem; }
  .hero-bottom { padding: 24px 20px; }
  .capability-chip { padding: 0 14px; }
  .statement-split,
  .process-rail { padding: 64px 20px; }
  .service-index { padding: 64px 20px; }
  .metric-band { padding: 48px 20px; }
  .cta-band { padding: 64px 20px; }
  .ledger-top { padding: 36px 20px; }
  .ledger-bottom { padding: 20px 20px; }
  .page-hero { padding: 56px 20px 48px; }
  .page-hero h1 { font-size: 2.2rem; }
  .service-detail { padding: 64px 20px 32px; }
  .process-overview { padding: 64px 20px; }
  .process-list { grid-template-columns: 1fr; }
  .contact-layout { padding: 64px 20px; }
  .faq-section { padding: 0 20px 64px; }
}