/* ═══════════════════════════════════════════════════════════════
   OSTech Co. — premium dark corporate theme
   Fonts: Poppins (headings) / Open Sans (body)
   ═══════════════════════════════════════════════════════════════ */

:root {
  --bg: #060b18;
  --bg-alt: #0a1224;
  --surface: rgba(255, 255, 255, 0.04);
  --surface-strong: rgba(255, 255, 255, 0.07);
  --border: rgba(255, 255, 255, 0.09);
  --text: #e6edf7;
  --text-muted: #9fb0c7;
  --accent: #0e9de5;
  --accent-2: #38d4f5;
  --accent-deep: #0369a1;
  --grad: linear-gradient(120deg, #0e9de5 0%, #38d4f5 100%);
  --shadow-card: 0 18px 46px rgba(2, 8, 23, 0.55);
  --radius: 18px;
  --nav-h: 76px;
  --font-head: "Poppins", system-ui, sans-serif;
  --font-body: "Open Sans", system-ui, sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.75;
  color: var(--text);
  background: var(--bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: var(--accent-2); text-decoration: none; }
button { font: inherit; cursor: pointer; }

h1, h2, h3, h4 {
  font-family: var(--font-head);
  line-height: 1.2;
  color: #fff;
  font-weight: 600;
}

::selection { background: rgba(14, 157, 229, 0.4); }

.container { width: min(1200px, 92%); margin-inline: auto; }
.narrow { max-width: 780px; margin-inline: auto; }
.center { text-align: center; }

:focus-visible { outline: 2px solid var(--accent-2); outline-offset: 3px; border-radius: 4px; }

/* ── Buttons ─────────────────────────────────────────────── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.72rem 1.5rem;
  border-radius: 999px;
  border: 1px solid transparent;
  font-family: var(--font-head);
  font-weight: 500;
  font-size: 0.95rem;
  cursor: pointer;
  transition: transform 0.2s var(--ease), box-shadow 0.2s var(--ease), background 0.2s;
  will-change: transform;
}
.btn-lg { padding: 0.9rem 2rem; font-size: 1rem; }
.btn-block { width: 100%; }
.btn-primary {
  background: var(--grad);
  color: #04121f;
  box-shadow: 0 10px 28px rgba(14, 157, 229, 0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 14px 34px rgba(14, 157, 229, 0.5); }
.btn-primary:active { transform: translateY(0) scale(0.98); }
.btn-ghost {
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.22);
  color: #fff;
  backdrop-filter: blur(8px);
}
.btn-ghost:hover { background: rgba(255, 255, 255, 0.12); transform: translateY(-2px); }

/* ── Navbar ──────────────────────────────────────────────── */
.navbar {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 100;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  transition: background 0.3s, box-shadow 0.3s, backdrop-filter 0.3s;
}
.navbar.scrolled {
  background: rgba(6, 11, 24, 0.78);
  backdrop-filter: blur(18px);
  -webkit-backdrop-filter: blur(18px);
  box-shadow: 0 10px 30px rgba(2, 8, 23, 0.5);
  border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }

.brand { display: inline-flex; align-items: center; gap: 0.65rem; }
.brand-logo { width: 44px; height: 44px; object-fit: contain; border-radius: 10px; background: #fff; padding: 4px; }
.brand-text { font-family: var(--font-head); font-weight: 700; font-size: 1.25rem; color: #fff; letter-spacing: 0.3px; }
.brand-text em { font-style: normal; color: var(--accent-2); }

.nav-links { display: flex; align-items: center; gap: 0.35rem; }
.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  padding: 0.55rem 0.95rem;
  border-radius: 10px;
  color: var(--text);
  font-family: var(--font-head);
  font-size: 0.92rem;
  font-weight: 500;
  background: none;
  border: none;
  transition: color 0.2s, background 0.2s;
}
.nav-link:hover, .nav-link.active { color: #fff; background: rgba(255, 255, 255, 0.08); }
.btn-nav { margin-left: 0.6rem; }

.nav-dropdown { position: relative; }
.dropdown-menu {
  position: absolute;
  top: calc(100% + 10px);
  left: 0;
  min-width: 250px;
  padding: 0.5rem;
  border-radius: 14px;
  background: rgba(10, 18, 36, 0.96);
  backdrop-filter: blur(18px);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-card);
  opacity: 0;
  visibility: hidden;
  transform: translateY(8px);
  transition: opacity 0.22s var(--ease), transform 0.22s var(--ease), visibility 0.22s;
}
.nav-dropdown:hover .dropdown-menu,
.nav-dropdown:focus-within .dropdown-menu { opacity: 1; visibility: visible; transform: translateY(0); }
.dropdown-menu a {
  display: block;
  padding: 0.6rem 0.9rem;
  border-radius: 9px;
  color: var(--text);
  font-size: 0.92rem;
  transition: background 0.15s, color 0.15s;
}
.dropdown-menu a:hover { background: rgba(14, 157, 229, 0.15); color: #fff; }

.nav-burger {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  padding: 10px;
}
.nav-burger span { width: 24px; height: 2px; background: #fff; border-radius: 2px; transition: transform 0.25s, opacity 0.25s; }
.nav-burger[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-burger[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-burger[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ── Hero ────────────────────────────────────────────────── */
.hero {
  position: relative;
  min-height: 100dvh;
  display: flex;
  align-items: center;
  overflow: hidden;
}
.hero-bg { position: absolute; inset: 0; }
.hero-slide {
  position: absolute;
  inset: 0;
  background-size: cover;
  background-position: center;
  opacity: 0;
  transform: scale(1.08);
  transition: opacity 1.6s ease, transform 9s linear;
}
.hero-slide.is-active { opacity: 1; transform: scale(1); }
.hero-overlay {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(100deg, rgba(4, 9, 22, 0.94) 30%, rgba(4, 9, 22, 0.55) 70%, rgba(3, 105, 161, 0.35)),
    radial-gradient(80% 60% at 85% 20%, rgba(14, 157, 229, 0.22), transparent 60%);
}
.hero-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(255, 255, 255, 0.045) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.045) 1px, transparent 1px);
  background-size: 56px 56px;
  mask-image: radial-gradient(70% 60% at 50% 40%, #000 30%, transparent 100%);
  -webkit-mask-image: radial-gradient(70% 60% at 50% 40%, #000 30%, transparent 100%);
}

/* floating 3D orbs */
.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.5;
  animation: float 12s ease-in-out infinite;
  pointer-events: none;
}
.orb-1 { width: 420px; height: 420px; top: -120px; right: -80px; background: radial-gradient(circle at 30% 30%, #0e9de5, transparent 70%); }
.orb-2 { width: 300px; height: 300px; bottom: 6%; left: -100px; background: radial-gradient(circle at 60% 40%, #38d4f5, transparent 70%); animation-delay: -4s; }
.orb-3 { width: 220px; height: 220px; top: 30%; left: 42%; background: radial-gradient(circle at 50% 50%, #0369a1, transparent 70%); animation-delay: -8s; opacity: 0.35; }
@keyframes float {
  0%, 100% { transform: translate3d(0, 0, 0); }
  50% { transform: translate3d(0, -34px, 0); }
}

.hero-content {
  position: relative;
  z-index: 2;
  padding: calc(var(--nav-h) + 3rem) 0 5rem;
  max-width: 860px;
  transform-style: preserve-3d;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.45rem 1.05rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid rgba(255, 255, 255, 0.16);
  backdrop-filter: blur(10px);
  font-family: var(--font-head);
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.4px;
  color: #cfe8fa;
}
.hero-badge svg { color: var(--accent-2); }
.hero-title {
  margin-top: 1.4rem;
  font-size: clamp(2.6rem, 6.4vw, 4.6rem);
  font-weight: 700;
  letter-spacing: -1.5px;
}
.accent-dot { color: var(--accent-2); }
.hero-rotator {
  margin-top: 1.1rem;
  font-family: var(--font-head);
  font-size: clamp(1.05rem, 2.4vw, 1.45rem);
  font-weight: 500;
  color: #d7e5f5;
  min-height: 2.2em;
}
.hero-rotator .typed { color: var(--accent-2); }
.typed-caret {
  display: inline-block;
  width: 2px;
  height: 1.1em;
  margin-left: 3px;
  vertical-align: text-bottom;
  background: var(--accent-2);
  animation: blink 1s step-end infinite;
}
.grad-caret { background: var(--accent); }
@keyframes blink { 50% { opacity: 0; } }
.hero-sub {
  margin-top: 1.2rem;
  max-width: 620px;
  color: var(--text-muted);
  font-size: 1.05rem;
}
.hero-cta { margin-top: 2.2rem; display: flex; flex-wrap: wrap; gap: 0.9rem; }

.scroll-hint {
  position: absolute;
  left: 50%;
  bottom: 26px;
  translate: -50% 0;
  z-index: 2;
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.25);
  color: #fff;
  background: rgba(255, 255, 255, 0.05);
  animation: bob 2.2s ease-in-out infinite;
}
@keyframes bob { 0%, 100% { transform: translateY(0); } 50% { transform: translateY(8px); } }

/* ── Strip ───────────────────────────────────────────────── */
.strip { background: var(--bg-alt); border-block: 1px solid var(--border); }
.strip-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 2rem;
  flex-wrap: wrap;
  padding: 2.6rem 0;
}
.strip-title { font-size: clamp(1.25rem, 2.6vw, 1.7rem); font-weight: 600; max-width: 640px; }
.strip-sub { color: var(--text-muted); margin-top: 0.4rem; font-size: 0.95rem; }
.grad-text {
  background: var(--grad);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ── Sections ────────────────────────────────────────────── */
.section { padding: 6rem 0; position: relative; }
.section-alt {
  background:
    radial-gradient(60% 50% at 15% 0%, rgba(14, 157, 229, 0.07), transparent 70%),
    var(--bg-alt);
  border-block: 1px solid var(--border);
}
.eyebrow {
  font-family: var(--font-head);
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 2.5px;
  text-transform: uppercase;
  color: var(--accent-2);
  margin-bottom: 0.8rem;
}
.section-title { font-size: clamp(1.7rem, 3.6vw, 2.5rem); letter-spacing: -0.5px; margin-bottom: 1.1rem; }
.section-text { color: var(--text-muted); margin-bottom: 1rem; max-width: 62ch; }
.center .section-text, .section-text.center { margin-inline: auto; }
.anchor-offset { position: relative; top: calc(-1 * var(--nav-h) - 12px); display: block; visibility: hidden; }

/* ── Cards / tilt ────────────────────────────────────────── */
.card {
  position: relative;
  padding: 1.9rem;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-card);
  transition: border-color 0.25s, background 0.25s, transform 0.25s var(--ease);
}
.card h3 { font-size: 1.12rem; margin-bottom: 0.55rem; }
.card p { color: var(--text-muted); font-size: 0.94rem; }

.tilt {
  transform: perspective(900px) rotateX(var(--rx, 0deg)) rotateY(var(--ry, 0deg)) translateZ(0);
  transition: transform 0.18s ease-out, border-color 0.25s, box-shadow 0.25s;
}
.tilt:hover {
  border-color: rgba(56, 212, 245, 0.35);
  box-shadow: 0 24px 60px rgba(2, 8, 23, 0.65), 0 0 0 1px rgba(56, 212, 245, 0.12) inset;
}
.tilt .card-icon, .tilt h3, .tilt p { transform: translateZ(24px); }

.card-icon {
  width: 58px;
  height: 58px;
  display: grid;
  place-items: center;
  border-radius: 15px;
  margin-bottom: 1.2rem;
  color: var(--accent-2);
  background: linear-gradient(140deg, rgba(14, 157, 229, 0.2), rgba(56, 212, 245, 0.08));
  border: 1px solid rgba(56, 212, 245, 0.25);
}

.values-grid {
  margin-top: 2.6rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 1.4rem;
  perspective: 1200px;
}

/* ── Stats ───────────────────────────────────────────────── */
.stats {
  padding: 4.2rem 0;
  background:
    linear-gradient(100deg, rgba(3, 105, 161, 0.25), rgba(6, 11, 24, 0.2)),
    radial-gradient(70% 120% at 50% 0%, rgba(14, 157, 229, 0.18), transparent 70%),
    var(--bg-alt);
  border-block: 1px solid var(--border);
}
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 2rem; text-align: center; }
.stat { display: flex; flex-direction: column; align-items: center; gap: 0.4rem; }
.stat img { height: 52px; width: auto; object-fit: contain; margin-bottom: 0.5rem; }
.stat-number {
  font-family: var(--font-head);
  font-size: clamp(2.4rem, 5vw, 3.4rem);
  font-weight: 700;
  color: #fff;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.stat-label { color: var(--text-muted); font-family: var(--font-head); font-size: 0.95rem; }

/* ── Product split sections ──────────────────────────────── */
.split {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 5vw, 4.5rem);
  align-items: center;
}
.split-flip .split-media { order: -1; }

.check-list { list-style: none; margin-top: 1.3rem; display: grid; gap: 0.75rem; }
.check-list.two-col { grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }
.check-list li {
  position: relative;
  padding-left: 2rem;
  color: var(--text-muted);
  font-size: 0.96rem;
}
.check-list li strong { color: var(--text); font-weight: 600; }
.check-list li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.32em;
  width: 18px;
  height: 18px;
  border-radius: 6px;
  background:
    url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 24 24" fill="none" stroke="%2304121f" stroke-width="3.4" stroke-linecap="round" stroke-linejoin="round"><path d="M20 6 9 17l-5-5"/></svg>') center / 11px no-repeat,
    var(--grad);
  box-shadow: 0 4px 12px rgba(14, 157, 229, 0.35);
}

.media-3d {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: var(--shadow-card);
  background: var(--surface);
  padding: 10px;
}
.media-3d img { border-radius: calc(var(--radius) - 8px); width: 100%; height: auto; object-fit: cover; }

/* ── About ───────────────────────────────────────────────── */
.about-grid { display: grid; grid-template-columns: 1.15fr 0.85fr; gap: clamp(2rem, 5vw, 4rem); align-items: start; }
.about-side { display: grid; gap: 1.3rem; }

/* ── Solutions cards ─────────────────────────────────────── */
.solutions-grid {
  margin-top: 2.8rem;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
  perspective: 1400px;
}
.sol-card {
  display: flex;
  flex-direction: column;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-card);
}
.sol-media { aspect-ratio: 16 / 10; overflow: hidden; }
.sol-media img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.6s var(--ease); }
.sol-card:hover .sol-media img { transform: scale(1.06); }
.sol-body { padding: 1.5rem; display: flex; flex-direction: column; flex: 1; }
.sol-body h3 { font-size: 1.08rem; margin-bottom: 0.6rem; }
.sol-body p { color: var(--text-muted); font-size: 0.92rem; flex: 1; }
.sol-link {
  margin-top: 1.1rem;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 0.9rem;
  color: var(--accent-2);
  transition: gap 0.2s var(--ease);
}
.sol-link:hover { gap: 0.75rem; }

/* ── Marquee ─────────────────────────────────────────────── */
.marquee {
  margin-top: 3.6rem;
  overflow: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.03);
  mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 8%, #000 92%, transparent);
}
.marquee-track {
  display: flex;
  align-items: center;
  gap: 4rem;
  padding: 1.6rem 2rem;
  width: max-content;
  animation: marquee 26s linear infinite;
}
.marquee:hover .marquee-track { animation-play-state: paused; }
.marquee-track img {
  height: 56px;
  width: auto;
  object-fit: contain;
  border-radius: 8px;
  background: #fff;
  padding: 6px 12px;
  opacity: 0.9;
  transition: opacity 0.2s, transform 0.2s;
}
.marquee-track img:hover { opacity: 1; transform: translateY(-3px); }
@keyframes marquee { to { transform: translateX(-50%); } }

/* ── Contact ─────────────────────────────────────────────── */
.contact { background: radial-gradient(70% 60% at 80% 10%, rgba(14, 157, 229, 0.08), transparent 70%); }
.contact-list { list-style: none; margin-top: 2rem; display: grid; gap: 1.5rem; }
.contact-list li { display: flex; gap: 1rem; align-items: flex-start; }
.contact-list h3 { font-size: 1rem; margin-bottom: 0.2rem; }
.contact-list p { color: var(--text-muted); font-size: 0.93rem; }
.contact-icon {
  flex: 0 0 auto;
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 13px;
  color: var(--accent-2);
  background: linear-gradient(140deg, rgba(14, 157, 229, 0.2), rgba(56, 212, 245, 0.07));
  border: 1px solid rgba(56, 212, 245, 0.25);
}

.contact-form { padding: 2.2rem; }
.form-title { font-size: 1.25rem; margin-bottom: 1.4rem; }
.field { margin-bottom: 1.1rem; }
.field label {
  display: block;
  font-family: var(--font-head);
  font-size: 0.86rem;
  font-weight: 500;
  margin-bottom: 0.4rem;
  color: #d5e2f2;
}
.req { color: var(--accent-2); }
.optional { color: var(--text-muted); font-weight: 400; }
.field input, .field textarea {
  width: 100%;
  padding: 0.8rem 1rem;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(6, 11, 24, 0.6);
  color: var(--text);
  font: inherit;
  font-size: 0.95rem;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.field textarea { resize: vertical; min-height: 120px; }
.field input:focus, .field textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(14, 157, 229, 0.22);
}
.field input.invalid, .field textarea.invalid { border-color: #f87171; }

.hp { position: absolute; left: -9999px; opacity: 0; height: 0; overflow: hidden; }

.captcha-q { color: var(--accent-2); font-weight: 600; }
.captcha-row { display: flex; gap: 0.6rem; }
.captcha-row input { flex: 1; }
.captcha-refresh {
  flex: 0 0 auto;
  width: 48px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-muted);
  display: grid;
  place-items: center;
  transition: color 0.2s, border-color 0.2s, transform 0.3s var(--ease);
}
.captcha-refresh:hover { color: var(--accent-2); border-color: var(--accent); transform: rotate(90deg); }

.btn-spinner {
  display: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 2px solid rgba(4, 18, 31, 0.3);
  border-top-color: #04121f;
  animation: spin 0.7s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }
.btn.loading { pointer-events: none; opacity: 0.85; }
.btn.loading .btn-spinner { display: inline-block; }

.form-status { margin-top: 0.9rem; font-size: 0.92rem; min-height: 1.4em; }
.form-status.ok { color: #4ade80; }
.form-status.err { color: #f87171; }

/* ── Footer ──────────────────────────────────────────────── */
.footer { background: #040815; border-top: 1px solid var(--border); padding: 3rem 0 2rem; }
.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.6rem;
  flex-wrap: wrap;
  padding-bottom: 1.8rem;
  border-bottom: 1px solid var(--border);
}
.footer-links { display: flex; gap: 1.6rem; flex-wrap: wrap; }
.footer-links a { color: var(--text-muted); font-family: var(--font-head); font-size: 0.9rem; transition: color 0.2s; }
.footer-links a:hover { color: #fff; }
.socials { list-style: none; display: flex; gap: 0.7rem; }
.socials a {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  border-radius: 11px;
  color: var(--text-muted);
  border: 1px solid var(--border);
  background: var(--surface);
  transition: color 0.2s, border-color 0.2s, transform 0.2s;
}
.socials a:hover { color: #fff; border-color: var(--accent); transform: translateY(-3px); }
.footer-bottom { padding-top: 1.6rem; text-align: center; color: var(--text-muted); font-size: 0.85rem; }
.footer-tag { margin-top: 0.35rem; font-size: 0.78rem; opacity: 0.75; }

/* ── Back to top ─────────────────────────────────────────── */
.back-to-top {
  position: fixed;
  right: 22px;
  bottom: 22px;
  z-index: 90;
  width: 48px;
  height: 48px;
  display: grid;
  place-items: center;
  border-radius: 14px;
  border: 1px solid rgba(56, 212, 245, 0.3);
  background: rgba(10, 18, 36, 0.85);
  backdrop-filter: blur(12px);
  color: var(--accent-2);
  opacity: 0;
  visibility: hidden;
  transform: translateY(12px);
  transition: opacity 0.25s, transform 0.25s, visibility 0.25s;
}
.back-to-top.show { opacity: 1; visibility: visible; transform: translateY(0); }
.back-to-top:hover { background: rgba(14, 157, 229, 0.2); }

/* ── Reveal animations ───────────────────────────────────── */
.reveal { opacity: 0; transform: translateY(28px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* ── Responsive ──────────────────────────────────────────── */
@media (max-width: 960px) {
  .split, .about-grid { grid-template-columns: 1fr; }
  .split-flip .split-media { order: 0; }
  .section { padding: 4.2rem 0; }
}

@media (max-width: 820px) {
  .nav-links {
    position: fixed;
    top: var(--nav-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0.3rem;
    padding: 1rem 4%;
    background: rgba(6, 11, 24, 0.97);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: opacity 0.25s, transform 0.25s, visibility 0.25s;
  }
  .nav-links.open { opacity: 1; visibility: visible; transform: translateY(0); }
  .nav-burger { display: flex; }
  .btn-nav { margin: 0.5rem 0 0; }
  .nav-dropdown { display: contents; }
  .dropdown-toggle { display: none; }
  .dropdown-menu {
    position: static;
    opacity: 1;
    visibility: visible;
    transform: none;
    background: none;
    border: none;
    box-shadow: none;
    padding: 0 0 0 0.9rem;
  }
  .hero-cta .btn { flex: 1 1 auto; }
  .scroll-hint { display: none; }
}

/* ── Reduced motion ──────────────────────────────────────── */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  .reveal { opacity: 1; transform: none; }
  .hero-slide { transform: none; }
  .marquee-track { animation: none; }
}