/* =========================================================
   DU AO CHENG — Computer Systems Design
   Light bamboo-green theme (bamboo #4E7A56 / deep forest
   #2F4A36 / light bamboo #A8C3A0 on cream #F8F7F2 with ink)
   ========================================================= */

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

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  font-size: 16px;
  line-height: 1.7;
  background-color: #F8F7F2;
  color: #2A2E24;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

h1, h2, h3, h4 {
  font-family: Georgia, "Times New Roman", Times, serif;
  font-weight: 700;
  line-height: 1.15;
  margin: 0 0 16px;
  color: #2A2E24;
}

p {
  margin: 0 0 16px;
}

a {
  color: #4E7A56;
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

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

/* ---------- GATE-CHIP NAVIGATION ---------- */

.gate-nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: #F8F7F2;
  border-bottom: 2px solid #4E7A56;
}

.gate-nav-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 14px 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.gate-brand {
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 20px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #4E7A56;
  white-space: nowrap;
}

.gate-brand:hover {
  text-decoration: none;
  color: #2F4A36;
}

.gate-chips {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.gate-chip {
  display: inline-block;
  padding: 7px 16px;
  border: 1px solid #4E7A56;
  border-radius: 999px;
  background-color: transparent;
  color: #2A2E24;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.gate-chip:hover {
  background-color: #A8C3A0;
  color: #2A2E24;
  text-decoration: none;
}

.gate-chip.active {
  background-color: #4E7A56;
  color: #FFFFFF;
  border-color: #4E7A56;
}

.gate-toggle {
  display: none;
  background-color: #4E7A56;
  color: #FFFFFF;
  border: none;
  border-radius: 8px;
  padding: 8px 14px;
  font-size: 15px;
  font-weight: 600;
  cursor: pointer;
}

.gate-toggle:hover {
  background-color: #2F4A36;
}

/* ---------- FOLD HERO ---------- */

.fold-hero {
  background-color: #4E7A56;
  padding: 84px 28px 88px;
}

.fold-hero-inner {
  max-width: 1240px;
  margin: 0 auto;
  display: flex;
  align-items: stretch;
  gap: 48px;
}

.fold-hero-main {
  flex: 2 1 0;
  padding-right: 8px;
}

.eyebrow-chip {
  display: inline-block;
  background-color: #F8F7F2;
  color: #2A2E24;
  border-radius: 999px;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 24px;
}

.fold-hero h1 {
  font-size: 54px;
  color: #2A2E24;
  max-width: 20ch;
}

.fold-subcopy {
  font-size: 18px;
  line-height: 1.7;
  color: #2A2E24;
  max-width: 58ch;
  margin-bottom: 32px;
}

.fold-ctas {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
}

.btn {
  display: inline-block;
  padding: 15px 32px;
  border-radius: 999px;
  border: 2px solid transparent;
  font-size: 16px;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  text-align: center;
  transition: background-color 0.2s ease, color 0.2s ease, border-color 0.2s ease;
}

.btn:hover {
  text-decoration: none;
}

.btn-cream {
  background-color: #F8F7F2;
  color: #4E7A56;
  border-color: #F8F7F2;
}

.btn-cream:hover {
  background-color: #FFFFFF;
  color: #2F4A36;
  border-color: #FFFFFF;
}

.btn-outline-cream {
  background-color: transparent;
  color: #F8F7F2;
  border-color: #F8F7F2;
}

.btn-outline-cream:hover {
  background-color: #F8F7F2;
  color: #4E7A56;
  border-color: #F8F7F2;
}

.btn-primary {
  background-color: #4E7A56;
  color: #FFFFFF;
  border-color: #4E7A56;
}

.btn-primary:hover {
  background-color: #2F4A36;
  border-color: #2F4A36;
}

.btn-outline {
  background-color: transparent;
  color: #4E7A56;
  border-color: #4E7A56;
}

.btn-outline:hover {
  background-color: #4E7A56;
  color: #FFFFFF;
}

.fold-panel {
  flex: 1 1 0;
  background-color: #F8F7F2;
  border: 2px solid #4E7A56;
  border-radius: 4px 4px 10px 10px;
  padding: 18px 22px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  box-shadow: 10px 10px 0 rgba(47, 74, 54, 0.14);
}

.fold-panel-line {
  display: block;
  text-align: center;
  color: #4E7A56;
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 0.34em;
  text-transform: uppercase;
  padding: 30px 0;
}

.fold-panel-line + .fold-panel-line {
  border-top: 1px solid #4E7A56;
}

/* ---------- PROMISE STRIP ---------- */

.promise-strip {
  background-color: #F8F7F2;
  border-top: 2px solid #4E7A56;
  padding: 76px 28px;
}

.promise-strip-inner {
  max-width: 1240px;
  margin: 0 auto;
}

.promise-strip-inner h2 {
  font-size: 34px;
  text-align: center;
  margin-bottom: 12px;
}

.promise-strip-intro {
  max-width: 64ch;
  margin: 0 auto 44px;
  text-align: center;
  font-size: 17px;
  color: #2A2E24;
}

.promise-row {
  display: flex;
  align-items: stretch;
}

.promise-item {
  flex: 1 1 0;
  padding: 28px 34px;
}

.promise-item + .promise-item {
  border-left: 2px solid #4E7A56;
}

.promise-item h3 {
  font-size: 22px;
  margin-bottom: 10px;
}

.promise-item p {
  margin-bottom: 0;
  font-size: 16px;
  color: #2A2E24;
}

/* ---------- SERVICE COLUMNS ---------- */

.service-columns {
  background-color: #FFFFFF;
  padding: 84px 28px;
  border-top: 1px solid #A8C3A0;
}

.service-columns-inner {
  max-width: 1240px;
  margin: 0 auto;
}

.service-columns-inner h2 {
  font-size: 34px;
  text-align: center;
  margin-bottom: 12px;
}

.service-columns-intro {
  max-width: 64ch;
  margin: 0 auto 48px;
  text-align: center;
  font-size: 17px;
  color: #2A2E24;
}

.service-row {
  display: flex;
  align-items: stretch;
  gap: 40px;
}

.service-column {
  flex: 1 1 0;
  background-color: #F8F7F2;
  border: 1px solid #A8C3A0;
  border-top: 6px solid #4E7A56;
  border-radius: 4px 4px 10px 10px;
  padding: 42px 34px;
  display: flex;
  flex-direction: column;
}

.service-number {
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.24em;
  color: #4E7A56;
  margin-bottom: 20px;
}

.service-column h3 {
  font-size: 24px;
  margin-bottom: 14px;
}

.service-column p {
  font-size: 16px;
  line-height: 1.75;
  color: #2A2E24;
}

/* ---------- IMPACT ROW ---------- */

.impact-row {
  background-color: #2F4A36;
  padding: 80px 28px;
}

.impact-row-inner {
  max-width: 1240px;
  margin: 0 auto;
}

.impact-row-inner h2 {
  color: #F8F7F2;
  font-size: 34px;
  text-align: center;
  margin-bottom: 12px;
}

.impact-row-intro {
  color: #F8F7F2;
  font-size: 17px;
  text-align: center;
  max-width: 64ch;
  margin: 0 auto 44px;
}

.impact-grid {
  display: flex;
  align-items: stretch;
}

.impact-item {
  flex: 1 1 0;
  text-align: center;
  padding: 20px 16px;
}

.impact-item + .impact-item {
  border-left: 1px solid #A8C3A0;
}

.impact-num {
  display: block;
  margin-bottom: 10px;
}

.impact-number,
.impact-suffix {
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 60px;
  font-weight: 700;
  line-height: 1;
  color: #A8C3A0;
}

.impact-label {
  display: block;
  color: #F8F7F2;
  font-size: 14px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
}

/* ---------- CTA BAND ---------- */

.cta-band {
  background-color: #4E7A56;
  padding: 72px 28px;
  text-align: center;
}

.cta-band-inner {
  max-width: 820px;
  margin: 0 auto;
}

.cta-band-inner h2 {
  color: #2A2E24;
  font-size: 36px;
  margin-bottom: 12px;
}

.cta-band-inner p {
  color: #2A2E24;
  font-size: 17px;
  margin-bottom: 28px;
}

/* ---------- BAMBOO-GATE FOOTER ---------- */

.gate-footer {
  background-color: #2F4A36;
}

.gate-footer-inner {
  max-width: 1240px;
  margin: 0 auto;
  padding: 52px 28px 44px;
  display: flex;
  align-items: flex-start;
}

.footer-zone {
  flex: 1 1 0;
  padding: 0 36px;
}

.footer-zone + .footer-zone {
  border-left: 1px solid #A8C3A0;
}

.footer-zone:first-child {
  padding-left: 0;
}

.footer-zone:last-child {
  padding-right: 0;
}

.footer-brand {
  display: block;
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 19px;
  font-weight: 700;
  letter-spacing: 0.1em;
  color: #A8C3A0;
  margin-bottom: 10px;
}

.footer-company {
  color: #F8F7F2;
  font-size: 13px;
  line-height: 1.6;
  margin: 0;
}

.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 26px;
}

.footer-links a {
  color: #F8F7F2;
  font-size: 14px;
  font-weight: 600;
}

.footer-links a:hover {
  color: #A8C3A0;
  text-decoration: none;
}

.footer-contact {
  color: #F8F7F2;
  font-size: 14px;
  line-height: 1.8;
  margin: 0;
}

.footer-contact a {
  color: #A8C3A0;
  font-weight: 600;
}

.footer-contact a:hover {
  color: #F8F7F2;
  text-decoration: none;
}

.legal-strip {
  background-color: #F8F7F2;
  border-top: 2px solid #4E7A56;
  text-align: center;
  padding: 14px 24px;
}

.legal-strip p {
  margin: 0;
  color: #2A2E24;
  font-size: 13px;
}

.legal-strip a {
  color: #2F4A36;
  font-weight: 700;
  text-decoration: underline;
}

.legal-strip a:hover {
  color: #4E7A56;
}

/* ---------- SECONDARY PAGE HERO ---------- */

.page-hero {
  background-color: #F8F7F2;
  border-top: 2px solid #4E7A56;
  border-bottom: 1px solid #4E7A56;
  padding: 68px 28px 72px;
}

.page-hero-inner {
  max-width: 1240px;
  margin: 0 auto;
}

.page-hero-chip {
  display: inline-block;
  background-color: #4E7A56;
  color: #FFFFFF;
  border-radius: 999px;
  padding: 8px 18px;
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin-bottom: 22px;
}

.page-hero h1 {
  font-size: 46px;
  max-width: 22ch;
  margin-bottom: 14px;
}

.page-hero p {
  font-size: 18px;
  max-width: 64ch;
  color: #2A2E24;
  margin-bottom: 0;
}

/* ---------- GENERIC PAGE SECTIONS ---------- */

.page-section {
  padding: 76px 28px;
}

.page-section-alt {
  background-color: #FFFFFF;
  border-top: 1px solid #A8C3A0;
  border-bottom: 1px solid #A8C3A0;
}

.page-section-inner {
  max-width: 1060px;
  margin: 0 auto;
}

.page-section-inner h2 {
  font-size: 32px;
  margin-bottom: 18px;
}

.page-section-inner h3 {
  font-size: 22px;
  margin-bottom: 10px;
}

.page-section-inner p,
.page-section-inner li {
  color: #2A2E24;
}

/* ---------- SERVICES PAGE ---------- */

.service-block {
  display: flex;
  gap: 40px;
  padding: 34px 0;
  align-items: flex-start;
}

.service-block + .service-block {
  border-top: 2px solid #4E7A56;
}

.service-block-num {
  flex: 0 0 72px;
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 40px;
  font-weight: 700;
  color: #A8C3A0;
  line-height: 1;
  padding-top: 4px;
}

.service-block-body {
  flex: 1 1 0;
}

.service-block-body h3 {
  font-size: 26px;
  margin-bottom: 10px;
}

.service-block-body p {
  margin-bottom: 0;
}

.process-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.process-list li {
  position: relative;
  padding: 18px 0 18px 56px;
  border-bottom: 1px solid #A8C3A0;
  font-size: 16px;
}

.process-list li:last-child {
  border-bottom: none;
}

.process-list .process-step {
  position: absolute;
  left: 0;
  top: 18px;
  display: inline-block;
  background-color: #4E7A56;
  color: #FFFFFF;
  border-radius: 999px;
  width: 38px;
  height: 38px;
  line-height: 38px;
  text-align: center;
  font-weight: 700;
  font-size: 14px;
}

.process-list strong {
  color: #2F4A36;
}

/* ---------- CONTACT PAGE ---------- */

.contact-grid {
  display: flex;
  gap: 56px;
  align-items: flex-start;
}

.contact-form {
  flex: 3 1 0;
  background-color: #FFFFFF;
  border: 1px solid #A8C3A0;
  border-top: 6px solid #4E7A56;
  border-radius: 4px 4px 10px 10px;
  padding: 36px 36px 40px;
}

.field {
  margin-bottom: 22px;
}

.field label {
  display: block;
  font-size: 14px;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #2F4A36;
  margin-bottom: 8px;
}

.field input,
.field textarea,
.field select {
  width: 100%;
  padding: 13px 16px;
  font-size: 16px;
  font-family: inherit;
  color: #2A2E24;
  background-color: #F8F7F2;
  border: 1px solid #4E7A56;
  border-radius: 8px;
  transition: border-color 0.2s ease, background-color 0.2s ease;
}

.field input:focus,
.field textarea:focus,
.field select:focus {
  outline: none;
  border-color: #2F4A36;
  background-color: #FFFFFF;
}

.field textarea {
  min-height: 150px;
  resize: vertical;
}

.form-status {
  display: none;
  margin-top: 18px;
  padding: 14px 18px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 600;
}

.form-status.show {
  display: block;
}

.form-status.ok {
  background-color: #A8C3A0;
  color: #2A2E24;
  border: 1px solid #4E7A56;
}

.form-status.err {
  background-color: #F2D8D5;
  color: #7A2E28;
  border: 1px solid #A8524A;
}

.contact-info {
  flex: 2 1 0;
}

.contact-info-block {
  background-color: #FFFFFF;
  border: 1px solid #A8C3A0;
  border-radius: 10px;
  padding: 26px 28px;
  margin-bottom: 24px;
}

.contact-info-block h3 {
  font-size: 19px;
  margin-bottom: 10px;
  color: #2F4A36;
}

.contact-info-block p {
  margin-bottom: 0;
  font-size: 15px;
  color: #2A2E24;
}

.contact-info-block a {
  font-weight: 700;
}

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

.faq-list {
  max-width: 820px;
  margin: 0 auto;
}

.faq-item {
  background-color: #FFFFFF;
  border: 1px solid #A8C3A0;
  border-radius: 10px;
  margin-bottom: 16px;
  overflow: hidden;
}

.faq-q {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 20px 26px;
  font-family: Georgia, "Times New Roman", Times, serif;
  font-size: 19px;
  font-weight: 700;
  color: #2A2E24;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
}

.faq-q::after {
  content: "+";
  flex: 0 0 auto;
  color: #4E7A56;
  font-size: 26px;
  font-weight: 700;
  line-height: 1;
  transition: transform 0.2s ease;
}

.faq-item.open .faq-q::after {
  transform: rotate(45deg);
}

.faq-q:hover {
  background-color: #F8F7F2;
}

.faq-a {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease;
}

.faq-a p {
  padding: 0 26px 22px;
  margin: 0;
  color: #2A2E24;
  font-size: 16px;
}

/* ---------- SCROLL REVEAL ---------- */

.fade-up {
  opacity: 0;
  transform: translateY(26px);
  transition: opacity 0.65s ease, transform 0.65s ease;
}

.fade-up.visible {
  opacity: 1;
  transform: none;
}

@media (prefers-reduced-motion: reduce) {
  .fade-up {
    opacity: 1;
    transform: none;
    transition: none;
  }
}

/* ---------- RESPONSIVE ---------- */

@media (max-width: 960px) {
  .fold-hero-inner {
    flex-direction: column;
    gap: 36px;
  }

  .fold-hero h1 {
    font-size: 44px;
  }

  .service-row {
    flex-direction: column;
    gap: 28px;
  }

  .service-column {
    padding: 32px 26px;
  }

  .impact-grid {
    flex-wrap: wrap;
  }

  .impact-item {
    flex: 1 1 40%;
  }

  .impact-item + .impact-item {
    border-left: none;
  }

  .impact-item:nth-child(even) {
    border-left: 1px solid #A8C3A0;
  }

  .promise-row {
    flex-direction: column;
  }

  .promise-item + .promise-item {
    border-left: none;
    border-top: 2px solid #4E7A56;
  }

  .gate-footer-inner {
    flex-direction: column;
    gap: 32px;
  }

  .footer-zone + .footer-zone {
    border-left: none;
    border-top: 1px solid #A8C3A0;
    padding-top: 26px;
  }

  .footer-zone {
    padding: 0;
  }

  .contact-grid {
    flex-direction: column;
  }
}

@media (max-width: 860px) {
  .gate-toggle {
    display: inline-block;
  }

  .gate-chips {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    background-color: #F8F7F2;
    border-bottom: 2px solid #4E7A56;
    padding: 16px 20px;
    gap: 10px;
    box-shadow: 0 12px 20px rgba(47, 74, 54, 0.12);
  }

  .gate-nav.chips-open .gate-chips {
    display: flex;
  }

  .gate-chip {
    text-align: center;
    padding: 12px 16px;
    font-size: 15px;
  }
}

@media (max-width: 720px) {
  .fold-hero {
    padding: 60px 20px 64px;
  }

  .fold-hero h1 {
    font-size: 38px;
  }

  .fold-subcopy {
    font-size: 16px;
  }

  .fold-panel {
    padding: 12px 16px;
  }

  .fold-panel-line {
    padding: 20px 0;
  }

  .page-hero h1 {
    font-size: 36px;
  }

  .page-hero {
    padding: 52px 20px 56px;
  }

  .page-section {
    padding: 56px 20px;
  }

  .service-block {
    flex-direction: column;
    gap: 12px;
  }

  .service-block-num {
    font-size: 32px;
  }

  .impact-number,
  .impact-suffix {
    font-size: 46px;
  }

  .cta-band {
    padding: 56px 20px;
  }

  .cta-band-inner h2 {
    font-size: 30px;
  }

  .fold-ctas .btn {
    width: 100%;
  }

  .contact-form {
    padding: 26px 22px 30px;
  }
}