/* ===================================================================
   1. RESET & BASE
   =================================================================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; scroll-padding-top: 88px; }
body { min-width: 320px; overflow-x: hidden; }
body.nav-open { overflow: hidden; }
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button { font: inherit; cursor: pointer; border: none; background: none; color: inherit; }
ul { list-style: none; }
svg { display: block; }

/* ===================================================================
   2. DESIGN TOKENS
   =================================================================== */
:root {
  --blueprint-navy: #16233A;
  --elevation-navy: #263F5E;
  --navy-soft: #34506F;
  --roofline-amber: #DD9B3F;
  --roofline-amber-light: #F0C077;
  --concrete: #EEECE5;
  --concrete-dark: #E1DED3;
  --steel: #6B7686;
  --canvas: #FFFFFF;
  --ink: #1C2534;
  --sage: #7E9179;

  --font-display: 'Archivo', sans-serif;
  --font-body: 'Karla', sans-serif;

  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 40px;
  --space-5: 64px;
  --space-6: 100px;

  --radius-sm: 3px;
  --radius-md: 6px;

  --shadow-card: 0 1px 2px rgba(22,35,58,0.05), 0 10px 28px rgba(22,35,58,0.09);
  --shadow-lift: 0 6px 12px rgba(22,35,58,0.08), 0 24px 48px rgba(22,35,58,0.16);

  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --container: 1180px;
}

@keyframes heroFadeUp {
  from { opacity: 0; transform: translateY(28px); }
  to { opacity: 1; transform: translateY(0); }
}
@keyframes statPop {
  from { opacity: 0; transform: translateY(16px) scale(0.96); }
  to { opacity: 1; transform: translateY(0) scale(1); }
}
@keyframes drawSkyline {
  to { stroke-dashoffset: 0; }
}
@keyframes skylineGlowIn {
  from { opacity: 0; }
  to { opacity: 0.35; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ===================================================================
   3. TYPOGRAPHY
   =================================================================== */
body {
  font-family: var(--font-body);
  color: var(--ink);
  background: var(--canvas);
  line-height: 1.6;
  font-size: 16px;
}
h1, h2, h3, h4 {
  font-family: var(--font-display);
  color: var(--blueprint-navy);
  line-height: 1.12;
  font-weight: 800;
  letter-spacing: -0.01em;
}
.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 12.5px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--roofline-amber);
}
.eyebrow::before {
  content: '';
  width: 28px;
  height: 2px;
  background: var(--roofline-amber);
  flex-shrink: 0;
}
.eyebrow--light { color: var(--roofline-amber-light); }

.section-head { max-width: 640px; margin-bottom: var(--space-4); }
.section-head h2 { font-size: clamp(28px, 4vw, 40px); margin-top: 14px; }
.section-head p { margin-top: 16px; color: var(--steel); font-size: 17px; max-width: 560px; }
.section-head--center { margin-left: auto; margin-right: auto; text-align: center; }
.section-head--center .eyebrow { justify-content: center; }
.section-head--center p { margin-left: auto; margin-right: auto; }

/* ===================================================================
   4. LAYOUT UTILITIES
   =================================================================== */
.container { max-width: var(--container); margin: 0 auto; padding: 0 32px; }
.section-pad { padding: var(--space-6) 0; }
.bg-concrete { background: var(--concrete); }
.bg-navy { background: var(--blueprint-navy); color: var(--canvas); }

.blueprint-grid {
  background-image:
    linear-gradient(rgba(22,35,58,0.05) 1px, transparent 1px),
    linear-gradient(90deg, rgba(22,35,58,0.05) 1px, transparent 1px);
  background-size: 26px 26px;
}
.blueprint-grid--dark {
  background-image:
    linear-gradient(rgba(240,192,119,0.09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(240,192,119,0.09) 1px, transparent 1px);
  background-size: 26px 26px;
}

.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity 0.85s var(--ease-out), transform 0.85s var(--ease-out);
  will-change: opacity, transform;
}
.reveal.is-visible { opacity: 1; transform: translateY(0); }
.reveal-delay-1 { transition-delay: 0.08s; }
.reveal-delay-2 { transition-delay: 0.16s; }
.reveal-delay-3 { transition-delay: 0.24s; }

/* corner registration marks — recurring detail echoing blueprint/drafting marks */
.corner-frame { position: relative; }
.corner-frame::before,
.corner-frame::after {
  content: '';
  position: absolute;
  width: 26px;
  height: 26px;
  border-color: var(--roofline-amber);
  border-style: solid;
  border-width: 0;
  z-index: 2;
  pointer-events: none;
}
.corner-frame::before { top: -9px; left: -9px; border-top-width: 3px; border-left-width: 3px; }
.corner-frame::after { bottom: -9px; right: -9px; border-bottom-width: 3px; border-right-width: 3px; }

/* ===================================================================
   5. BUTTONS
   =================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  letter-spacing: 0.01em;
  padding: 15px 28px;
  border-radius: var(--radius-sm);
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s var(--ease), border-color 0.25s var(--ease);
  white-space: nowrap;
}
.btn svg { width: 18px; height: 18px; flex-shrink: 0; }
.btn--primary {
  background: var(--roofline-amber);
  color: var(--blueprint-navy);
}
.btn--primary:hover { background: var(--roofline-amber-light); transform: translateY(-2px); box-shadow: var(--shadow-lift); }
.btn--outline {
  background: transparent;
  border: 1.5px solid rgba(255,255,255,0.55);
  color: var(--canvas);
}
.btn--outline:hover { border-color: var(--canvas); background: rgba(255,255,255,0.08); transform: translateY(-2px); }
.btn--outline-dark {
  background: transparent;
  border: 1.5px solid rgba(22,35,58,0.25);
  color: var(--blueprint-navy);
}
.btn--outline-dark:hover { border-color: var(--blueprint-navy); background: rgba(22,35,58,0.04); transform: translateY(-2px); }
.btn--block { width: 100%; justify-content: center; }
.btn:focus-visible, a:focus-visible, button:focus-visible { outline: 2px solid var(--roofline-amber); outline-offset: 3px; }

/* ===================================================================
   6. NAV
   =================================================================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid rgba(22,35,58,0.08);
  transition: box-shadow 0.3s var(--ease);
}
.nav.is-scrolled { box-shadow: 0 4px 20px rgba(22,35,58,0.08); }
.nav__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 14px 32px;
  max-width: var(--container);
  margin: 0 auto;
}
.nav__brand { display: flex; align-items: center; gap: 10px; flex-shrink: 0; }
.nav__brand img { height: 44px; width: auto; }
.nav__links { display: flex; align-items: center; gap: 34px; }
.nav__links a {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 14.5px;
  color: var(--blueprint-navy);
  position: relative;
  padding: 4px 0;
}
.nav__links a::after {
  content: '';
  position: absolute;
  left: 0; bottom: -2px;
  width: 0; height: 2px;
  background: var(--roofline-amber);
  transition: width 0.25s var(--ease);
}
.nav__links a:hover::after,
.nav__links a.is-active::after { width: 100%; }
.nav__links a.is-active { color: var(--roofline-amber); }
.nav__right { display: flex; align-items: center; gap: 18px; }
.nav__call {
  display: flex; align-items: center; gap: 8px;
  font-family: var(--font-display); font-weight: 700; font-size: 14px;
  background: var(--blueprint-navy); color: var(--canvas);
  padding: 11px 20px; border-radius: var(--radius-sm);
  transition: background 0.25s var(--ease), transform 0.25s var(--ease);
}
.nav__call:hover { background: var(--elevation-navy); transform: translateY(-1px); }
.nav__call svg { width: 16px; height: 16px; }
.nav__toggle { display: none; width: 26px; height: 20px; position: relative; flex-shrink: 0; }
.nav__toggle span {
  position: absolute; left: 0; width: 100%; height: 2.5px; background: var(--blueprint-navy);
  transition: transform 0.3s var(--ease), opacity 0.3s var(--ease);
}
.nav__toggle span:nth-child(1) { top: 0; }
.nav__toggle span:nth-child(2) { top: 9px; }
.nav__toggle span:nth-child(3) { top: 18px; }
.nav.is-open .nav__toggle span:nth-child(1) { transform: translateY(9px) rotate(45deg); }
.nav.is-open .nav__toggle span:nth-child(2) { opacity: 0; }
.nav.is-open .nav__toggle span:nth-child(3) { transform: translateY(-9px) rotate(-45deg); }

/* ===================================================================
   7. HERO
   =================================================================== */
.hero{

    position:relative;

    min-height:100vh;

    overflow:hidden;

    isolation: isolate;

    display:flex;

    align-items:center;

}
.hero-bg{

    position:absolute;

    inset:0;

    width:100%;

    height:100%;

    overflow:hidden;

    z-index:0;

}

.hero-bg img{

    position:absolute;

    top:0;

    left:0;

    width:100%;

    height:100%;

    object-fit:cover;

    object-position:center;

    opacity:0;

    transform:scale(1);

    transition:opacity 1.2s ease;

    animation:zoom 10s linear infinite;

}

.hero-bg img.active{

    opacity:1;

}

@keyframes zoom{

    from{

        transform:scale(1);

    }

    to{

        transform:scale(1.08);

    }

}

.hero-bg img.active{
    opacity:1;
}

.hero::before{
    content:"";
    position:absolute;
    inset:0;
    background:rgba(0,0,0,.45);
    z-index:1;
}

.hero-content{
    position:relative;
    z-index:2;
}
.hero__inner {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 32px;
  position: relative;
  z-index: 2;
}
.hero__content { max-width: 640px; padding-bottom: 70px; }
.hero__content > * {
  opacity: 0;
  transform: translateY(28px);
  animation: heroFadeUp 0.95s var(--ease-out) forwards;
}
.hero__content .eyebrow { margin-bottom: 22px; animation-delay: 0.12s; }
.hero__content h1 { animation-delay: 0.24s; }
.hero__content .hero__sub { animation-delay: 0.38s; }
.hero__actions { animation-delay: 0.52s; }
.hero__trust { animation-delay: 0.66s; }
.hero__content h1 {
  font-size: clamp(38px, 5.6vw, 62px);
  color: var(--canvas);
  margin-bottom: 22px;
}
.hero__content p.hero__sub {
  font-size: 18.5px;
  color: rgba(255,255,255,0.78);
  max-width: 520px;
  margin-bottom: 34px;
}
.hero__actions { display: flex; gap: 16px; flex-wrap: wrap; margin-bottom: 40px; }
.hero__trust {
  display: flex; align-items: center; gap: 14px; flex-wrap: wrap;
  font-family: var(--font-display); font-weight: 600; font-size: 13px;
  letter-spacing: 0.04em; text-transform: uppercase;
  color: rgba(255,255,255,0.55);
}
.hero__trust .dot { width: 4px; height: 4px; border-radius: 50%; background: var(--roofline-amber); }

.hero__skyline { position: absolute; left: 0; right: 0; bottom: 0; width: 100%; line-height: 0; z-index: 1; }
.hero__skyline svg { width: 100%; height: auto; display: block; }
.hero__skyline .skyline-main {
  stroke-dasharray: 3200;
  stroke-dashoffset: 3200;
  animation: drawSkyline 2.8s var(--ease-out) 0.55s forwards;
}
.hero__skyline .skyline-glow {
  opacity: 0;
  animation: skylineGlowIn 1.6s var(--ease-out) 1.8s forwards;
}

/* ===================================================================
   8. STATS STRIP
   =================================================================== */
.stats {
  background: var(--canvas);
  border-bottom: 1px solid var(--concrete-dark);
}
.stats__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
}
.stat {
  text-align: center;
  padding: 44px 16px;
  border-left: 1px solid var(--concrete-dark);
}
.stat:first-child { border-left: none; }
.stats.is-visible .stat {
  animation: statPop 0.7s var(--ease-out) backwards;
}
.stats.is-visible .stat:nth-child(1) { animation-delay: 0.05s; }
.stats.is-visible .stat:nth-child(2) { animation-delay: 0.12s; }
.stats.is-visible .stat:nth-child(3) { animation-delay: 0.19s; }
.stats.is-visible .stat:nth-child(4) { animation-delay: 0.26s; }
.stat__num {
  font-family: var(--font-display);
  font-weight: 900;
  font-size: clamp(30px, 4vw, 42px);
  color: var(--blueprint-navy);
  display: block;
}
.stat__num span.suffix { color: var(--roofline-amber); }
.stat__label {
  margin-top: 6px;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 12.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--steel);
}

/* ===================================================================
   9. ABOUT
   =================================================================== */
.about__grid {
  display: grid;
  grid-template-columns: 0.85fr 1fr;
  gap: 70px;
  align-items: center;
}
.about__visual {
  border-radius: var(--radius-md);
  padding: 40px;
  position: relative;
}
.about__visual svg { width: 100%; height: auto; }
.about__content .section-head { margin-bottom: 22px; }
.about__content p { color: var(--steel); font-size: 16.5px; margin-bottom: 16px; }
.about__content p:last-of-type { margin-bottom: 30px; }
.about__checklist { display: grid; grid-template-columns: 1fr 1fr; gap: 16px 20px; }
.about__checklist li {
  display: flex; align-items: flex-start; gap: 10px;
  font-family: var(--font-display); font-weight: 600; font-size: 14.5px;
  color: var(--blueprint-navy);
}
.about__checklist svg { width: 20px; height: 20px; flex-shrink: 0; color: var(--roofline-amber); margin-top: 1px; }

/* ===================================================================
   10. WHY US
   =================================================================== */
.why-us__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}
.feature-card {
  background: var(--canvas);
  border: 1px solid var(--concrete-dark);
  border-radius: var(--radius-md);
  padding: 32px 26px;
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}
.feature-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lift); border-color: transparent; }
.feature-card__icon {
  width: 52px; height: 52px;
  background: var(--blueprint-navy);
  border-radius: var(--radius-sm);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 22px;
}
.feature-card__icon svg { width: 26px; height: 26px; color: var(--roofline-amber); }
.feature-card h3 { font-size: 18px; margin-bottom: 10px; }
.feature-card p { color: var(--steel); font-size: 15px; }

/* ===================================================================
   11. PROJECTS
   =================================================================== */
.projects__top {
  display: flex; align-items: flex-end; justify-content: space-between;
  gap: 24px; flex-wrap: wrap; margin-bottom: var(--space-4);
}
.projects__top .section-head { margin-bottom: 0; }
.filter-group { display: flex; gap: 10px; flex-shrink: 0; }
.filter-btn {
  font-family: var(--font-display); font-weight: 600; font-size: 13.5px;
  padding: 10px 20px; border-radius: 999px;
  border: 1.5px solid var(--concrete-dark);
  color: var(--steel);
  transition: all 0.25s var(--ease);
}
.filter-btn:hover { border-color: var(--roofline-amber); color: var(--blueprint-navy); }
.filter-btn.is-active { background: var(--blueprint-navy); border-color: var(--blueprint-navy); color: var(--canvas); }

.projects__grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 30px; }
.project-card {
  transition: opacity 0.45s var(--ease-out), transform 0.45s var(--ease-out);
  transform-origin: center top;
}
.project-card.is-filtered-out {
  opacity: 0;
  transform: translateY(14px) scale(0.97);
  pointer-events: none;
}
.project-card.is-filtered-hidden { display: none; }
.project-card__media {
  position: relative;
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--concrete);
  aspect-ratio: 4 / 3;
}
.project-card__media svg { width: 100%; height: 100%; transition: transform 0.5s var(--ease); }
.project-card:hover .project-card__media svg { transform: scale(1.06); }
.project-card__media::before,
.project-card__media::after {
  content: ''; position: absolute; width: 22px; height: 22px;
  border-color: var(--roofline-amber); border-style: solid; border-width: 0;
  opacity: 0; transition: opacity 0.3s var(--ease); z-index: 2;
}
.project-card__media::before { top: 10px; left: 10px; border-top-width: 3px; border-left-width: 3px; }
.project-card__media::after { bottom: 10px; right: 10px; border-bottom-width: 3px; border-right-width: 3px; }
.project-card:hover .project-card__media::before,
.project-card:hover .project-card__media::after { opacity: 1; }

.project-card__badges { position: absolute; top: 14px; left: 14px; right: 14px; display: flex; justify-content: space-between; z-index: 3; }
.badge {
  font-family: var(--font-display); font-weight: 700; font-size: 10.5px;
  letter-spacing: 0.06em; text-transform: uppercase;
  padding: 6px 11px; border-radius: 999px;
  background: rgba(255,255,255,0.92); color: var(--blueprint-navy);
}
.badge--status-ongoing { background: var(--roofline-amber); color: var(--blueprint-navy); }
.badge--status-done { background: var(--blueprint-navy); color: var(--canvas); }

.project-card__body { padding: 22px 4px 0; }
.project-card__title { font-size: 20px; margin-bottom: 6px; }
.project-card__meta {
  display: flex; align-items: center; gap: 6px;
  font-size: 13px; color: var(--steel); margin-bottom: 12px;
  font-family: var(--font-display); font-weight: 600; letter-spacing: 0.02em;
}
.project-card__meta svg { width: 14px; height: 14px; color: var(--roofline-amber); flex-shrink: 0; }
.project-card__desc { color: var(--steel); font-size: 15px; margin-bottom: 16px; }
.project-card__link {
  display: inline-flex; align-items: center; gap: 7px;
  font-family: var(--font-display); font-weight: 700; font-size: 14px;
  color: var(--blueprint-navy); border-bottom: 1.5px solid var(--roofline-amber); padding-bottom: 2px;
  transition: gap 0.25s var(--ease), color 0.25s var(--ease);
}
.project-card__link svg { width: 15px; height: 15px; transition: transform 0.25s var(--ease); }
.project-card__link:hover { color: var(--roofline-amber); }
.project-card__link:hover svg { transform: translateX(3px); }

/* ===================================================================
   12. FOUNDER
   =================================================================== */
.founder__grid {
  display: grid;
  grid-template-columns: 0.7fr 1fr;
  gap: 80px;
  align-items: center;
}
.founder__photo {
  width:380px;

    aspect-ratio:4/5;

    overflow:hidden;

    border-radius:12px;

    box-shadow:0 20px 60px rgba(0,0,0,.25);
}
.founder__photo svg { width: 84px; height: 84px; color: rgba(240,192,119,0.5); }
.founder__photo svg circle,
.founder__photo svg path { fill: currentColor; }
.founder__photo span {
  font-family: var(--font-display); font-weight: 700; font-size: 12px;
  letter-spacing: 0.14em; text-transform: uppercase; color: rgba(255,255,255,0.4);
}
.founder__eyebrow { margin-bottom: 20px; }
.founder__content h2 { color: var(--canvas); font-size: clamp(28px, 4vw, 38px); margin-bottom: 4px; }
.founder__role {
  font-family: var(--font-display); font-weight: 600; font-size: 14.5px;
  color: var(--roofline-amber-light); margin-bottom: 26px; display: block;
}
.founder__content p { color: rgba(255,255,255,0.72); font-size: 16px; margin-bottom: 16px; }
.founder__quote {
  margin-top: 26px;
  padding: 24px 26px;
  border-left: 3px solid var(--roofline-amber);
  background: rgba(255,255,255,0.04);
}
.founder__quote p { font-family: var(--font-display); font-weight: 600; font-style: italic; color: var(--canvas); font-size: 17px; margin-bottom: 12px; line-height: 1.5; }
.founder__quote cite { font-style: normal; font-size: 13.5px; color: rgba(255,255,255,0.5); font-family: var(--font-body); }

/* ===================================================================
   13. CONTACT
   =================================================================== */
.contact__inner { text-align: center; }
.contact__inner .section-head { margin: 0 auto var(--space-4); }
.contact__actions { display: flex; gap: 18px; justify-content: center; flex-wrap: wrap; margin-bottom: var(--space-5); }
.contact__actions .btn { padding: 18px 36px; font-size: 16px; }
.contact-info { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--concrete-dark); border: 1px solid var(--concrete-dark); border-radius: var(--radius-md); overflow: hidden; text-align: left; }
.contact-info__item { background: var(--canvas); padding: 28px 26px; }
.contact-info__item svg { width: 22px; height: 22px; color: var(--roofline-amber); margin-bottom: 14px; }
.contact-info__item h4 { font-family: var(--font-display); font-weight: 700; font-size: 12.5px; letter-spacing: 0.08em; text-transform: uppercase; color: var(--steel); margin-bottom: 6px; }
.contact-info__item p { font-family: var(--font-display); font-weight: 600; font-size: 15px; color: var(--blueprint-navy); line-height: 1.4; }

/* ===================================================================
   14. FOOTER
   =================================================================== */
.footer { background: var(--blueprint-navy); color: rgba(255,255,255,0.65); padding-top: 80px; }
.footer__grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 50px; padding-bottom: 56px; border-bottom: 1px solid rgba(255,255,255,0.1); }
.footer__brand img { height: 60px;

    width: auto;

    object-fit: contain;

    filter: none; }
.footer__brand p { font-size: 14.5px; max-width: 320px; line-height: 1.7; }
.footer h5 { font-family: var(--font-display); color: var(--canvas); font-size: 13px; letter-spacing: 0.1em; text-transform: uppercase; margin-bottom: 20px; }
.footer__links li { margin-bottom: 12px; }
.footer__links a { font-size: 14.5px; transition: color 0.2s var(--ease); }
.footer__links a:hover { color: var(--roofline-amber-light); }
.footer__contact li { display: flex; gap: 10px; margin-bottom: 14px; font-size: 14.5px; }
.footer__contact svg { width: 17px; height: 17px; color: var(--roofline-amber); flex-shrink: 0; margin-top: 2px; }
.footer__bottom { display: flex; justify-content: space-between; align-items: center; padding: 26px 0; font-size: 13.5px; flex-wrap: wrap; gap: 12px; }
.footer__social { display: flex; gap: 12px; }
.footer__social a { width: 36px; height: 36px; border: 1px solid rgba(255,255,255,0.18); border-radius: 50%; display: flex; align-items: center; justify-content: center; transition: all 0.25s var(--ease); }
.footer__social a:hover { background: var(--roofline-amber); border-color: var(--roofline-amber); }
.footer__social svg { width: 16px; height: 16px; }

/* ===================================================================
   15. BACK TO TOP
   =================================================================== */
.back-to-top {
  position: fixed; bottom: 28px; right: 28px; z-index: 90;
  width: 48px; height: 48px; border-radius: 50%;
  background: var(--blueprint-navy); color: var(--roofline-amber-light);
  display: flex; align-items: center; justify-content: center;
  box-shadow: var(--shadow-lift);
  opacity: 0; visibility: hidden; transform: translateY(10px);
  transition: all 0.3s var(--ease);
}
.back-to-top.is-visible { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top svg { width: 20px; height: 20px; }
.back-to-top:hover { background: var(--elevation-navy); transform: translateY(-3px); }
.back-to-top:active { transform: translateY(0); }

/* ===================================================================
   16. RESPONSIVE
   =================================================================== */
@media (max-width: 968px) {
  .nav { position: sticky; }
  .nav__inner { flex-wrap: wrap; position: relative; }
  .nav__links, .nav__call { display: none; }
  .nav__toggle { display: block; }
  .nav.is-open .nav__links {
    display: flex; flex-direction: column; align-items: flex-start; gap: 4px;
    order: 3; width: 100%;
    background: var(--canvas); padding: 10px 0 12px; border-top: 1px solid var(--concrete-dark);
  }
  .nav.is-open .nav__links a { padding: 10px 0; width: 100%; }
  .nav.is-open .nav__call {
    display: flex; order: 4; width: 100%;
    justify-content: center; margin: 0 0 18px;
  }

  .about__grid, .founder__grid { grid-template-columns: 1fr; gap: 44px; }
  .founder__photo { max-width: 340px; margin: 0 auto; }
  .why-us__grid { grid-template-columns: 1fr 1fr; }
  .projects__grid { grid-template-columns: 1fr 1fr; }
  .stats__grid { grid-template-columns: 1fr 1fr; }
  .stat:nth-child(3) { border-left: none; }
  .stat { padding: 30px 16px; }
  .contact-info { grid-template-columns: 1fr 1fr; }
  .footer__grid { grid-template-columns: 1fr; gap: 40px; }
}

@media (max-width: 640px) {
  .container { padding: 0 22px; }
  .hero__inner, .nav__inner { padding-left: 22px; padding-right: 22px; }
  .section-pad { padding: 64px 0; }
  :root { --space-6: 64px; }
  .why-us__grid, .projects__grid { grid-template-columns: 1fr; }
  .stats__grid { grid-template-columns: 1fr 1fr; }
  .about__checklist { grid-template-columns: 1fr; }
  .contact-info { grid-template-columns: 1fr; }
  .contact__actions { flex-direction: column; width: 100%; }
  .contact__actions .btn { width: 100%; justify-content: center; }
  .hero__actions { flex-direction: column; width: 100%; }
  .hero__actions .btn { width: 100%; justify-content: center; }
  .footer__bottom { flex-direction: column; text-align: center; }
  .projects__top { flex-direction: column; align-items: flex-start; }
}