/* ==========================================================================
   Stellant — design tokens
   ========================================================================== */
:root {
  --ink-950: #120d24;
  --ink-900: #1a1333;
  --ink-800: #241b47;
  --violet-700: #4a37c4;
  --violet-600: #5b45dd;
  --violet-500: #6f57ea;
  --violet-300: #a78bfa;
  --violet-200: #c9baf9;
  --violet-100: #ece7fd;
  --violet-50: #f6f4fe;

  --paper: #ffffff;
  --paper-alt: #f7f6fc;
  --line: #e6e2f5;
  --line-strong: #d7d0f0;

  --text: #1c1733;
  --text-muted: #635c7f;
  --text-faint: #8b84a6;
  --text-on-dark: #f3f1fb;
  --text-on-dark-muted: #b9b2d6;

  --shadow-sm: 0 1px 2px rgba(24, 16, 56, 0.06), 0 1px 1px rgba(24, 16, 56, 0.04);
  --shadow-md: 0 12px 24px -12px rgba(30, 20, 70, 0.28);
  --shadow-lg: 0 24px 48px -16px rgba(20, 12, 56, 0.32);

  --radius-sm: 10px;
  --radius-md: 16px;
  --radius-lg: 24px;

  --font-head: "Montserrat", "Segoe UI", sans-serif;
  --font-body: "Inter", "Segoe UI", sans-serif;

  --container: 1180px;
  --section-pad: clamp(4rem, 3.2rem + 3.5vw, 7rem);

  --ease: cubic-bezier(0.16, 1, 0.3, 1);
}

/* ==========================================================================
   Reset
   ========================================================================== */
*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  font-family: var(--font-body);
  color: var(--text);
  background: var(--paper);
  line-height: 1.6;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
img, svg { display: block; max-width: 100%; }
img { height: auto; }
a { color: inherit; text-decoration: none; -webkit-tap-highlight-color: transparent; }
ul { list-style: none; padding: 0; }
button { font: inherit; color: inherit; background: none; border: 0; cursor: pointer; -webkit-tap-highlight-color: transparent; }
a, button { touch-action: manipulation; }
h1, h2, h3, h4, h5 { font-family: var(--font-head); font-weight: 700; line-height: 1.15; letter-spacing: -0.01em; }

@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; scroll-behavior: auto !important; }
}

:focus-visible {
  outline: 2px solid var(--violet-500);
  outline-offset: 3px;
  border-radius: 4px;
}

.skip-link {
  position: absolute;
  top: -48px;
  left: 1rem;
  background: var(--ink-950);
  color: #fff;
  padding: 0.75rem 1.25rem;
  border-radius: var(--radius-sm);
  z-index: 200;
  transition: top 0.2s var(--ease);
}
.skip-link:focus { top: 1rem; }

.container {
  width: 100%;
  max-width: var(--container);
  margin-inline: auto;
  padding-inline: max(clamp(1.25rem, 4vw, 2.5rem), env(safe-area-inset-left) + 1rem) max(clamp(1.25rem, 4vw, 2.5rem), env(safe-area-inset-right) + 1rem);
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--violet-600);
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 2px;
  background: var(--violet-500);
  border-radius: 2px;
}
.eyebrow.on-dark { color: var(--violet-200); }
.eyebrow.on-dark::before { background: var(--violet-300); }

.section { padding-block: var(--section-pad); }
.section-alt { background: var(--paper-alt); }
.section-head {
  max-width: 640px;
  margin-bottom: clamp(2.5rem, 2rem + 2vw, 3.5rem);
}
.section-head h2 { font-size: clamp(1.9rem, 1.6rem + 1.4vw, 2.6rem); margin-top: 0.75rem; }
.section-head p { margin-top: 1rem; color: var(--text-muted); font-size: 1.05rem; }
.section-head.centered { margin-inline: auto; text-align: center; align-items: center; display: flex; flex-direction: column; }

/* ==========================================================================
   Buttons
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.85rem 1.6rem;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), background 0.25s var(--ease), color 0.25s var(--ease), border-color 0.25s var(--ease);
  white-space: nowrap;
}
.btn-primary {
  background: linear-gradient(135deg, var(--violet-600), var(--violet-700));
  color: #fff;
  box-shadow: var(--shadow-md);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 20px 32px -14px rgba(74, 55, 196, 0.45); }
.btn-ghost {
  background: transparent;
  color: var(--text);
  border: 1.5px solid var(--line-strong);
}
.btn-ghost:hover { border-color: var(--violet-500); color: var(--violet-700); }
.btn-ghost.on-dark { color: #fff; border-color: rgba(255, 255, 255, 0.3); }
.btn-ghost.on-dark:hover { border-color: #fff; }
.btn-sm { padding: 0.6rem 1.1rem; font-size: 0.85rem; }

/* ==========================================================================
   Header
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.78);
  backdrop-filter: blur(14px) saturate(160%);
  -webkit-backdrop-filter: blur(14px) saturate(160%);
  border-bottom: 1px solid transparent;
  transition: border-color 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.site-header.is-scrolled { border-color: var(--line); box-shadow: 0 4px 20px -12px rgba(30, 20, 70, 0.18); }

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  height: 92px;
}
.brand { display: flex; align-items: center; gap: 0.6rem; flex-shrink: 0; }
.brand-mark { height: 72px; width: auto; }
.brand-word {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.2rem;
  letter-spacing: -0.01em;
  color: var(--ink-950);
}

.nav {
  display: flex;
  align-items: center;
  gap: 2rem;
  margin-inline: auto;
}
.nav a {
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  position: relative;
  padding-block: 0.3rem;
  transition: color 0.2s;
}
.nav a::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: -2px;
  height: 2px;
  background: var(--violet-600);
  transform: scaleX(0);
  transform-origin: right;
  transition: transform 0.25s var(--ease);
  border-radius: 2px;
}
.nav a:hover, .nav a.is-active { color: var(--ink-950); }
.nav a:hover::after, .nav a.is-active::after { transform: scaleX(1); transform-origin: left; }

.nav-toggle {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  border-radius: 10px;
  flex-shrink: 0;
  margin-right: -0.4rem;
}
.nav-toggle span, .nav-toggle::before, .nav-toggle::after {
  content: "";
  display: block;
  height: 2px;
  width: 22px;
  margin-inline: auto;
  background: var(--ink-950);
  border-radius: 2px;
  transition: transform 0.25s var(--ease), opacity 0.25s var(--ease);
}
.nav-toggle[aria-expanded="true"]::before { transform: translateY(6.5px) rotate(45deg); }
.nav-toggle[aria-expanded="true"]::after { transform: translateY(-6.5px) rotate(-45deg); }
.nav-toggle[aria-expanded="true"] span { opacity: 0; }

@media (max-width: 860px) {
  .header-inner { height: 104px; }
  .brand-mark { height: 84px; }
  .nav-toggle { display: flex; margin-left: auto; }
  .nav-cta { display: none; }
  .nav {
    position: fixed;
    inset: 104px 0 0 0;
    height: calc(100dvh - 104px);
    background: var(--paper);
    flex-direction: column;
    align-items: flex-start;
    padding: 2rem clamp(1.25rem, 4vw, 2.5rem);
    gap: 0.5rem;
    transform: translateX(100%);
    transition: transform 0.35s var(--ease);
    overflow-y: auto;
  }
  .nav.is-open { transform: translateX(0); }
  .nav a { width: 100%; padding-block: 0.9rem; font-size: 1.1rem; border-bottom: 1px solid var(--line); }
  .nav .nav-cta-mobile { display: inline-flex; margin-top: 1rem; }
}
.nav-cta-mobile { display: none; }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  position: relative;
  padding-top: clamp(4rem, 3rem + 4vw, 6.5rem);
  padding-bottom: clamp(6rem, 4rem + 8vw, 10rem);
  /* Smaller, lighter image by default (mobile-first); swapped for the
     full-resolution version once the viewport can actually show the detail. */
  background:
    linear-gradient(180deg, rgba(18, 13, 36, 0.86) 0%, rgba(18, 13, 36, 0.82) 55%, rgba(18, 13, 36, 0.94) 100%),
    url("images/hero-mobile.jpg") center 30% / cover no-repeat;
  color: var(--text-on-dark);
  overflow: hidden;
}
@media (min-width: 700px) {
  .hero {
    background-image:
      linear-gradient(180deg, rgba(18, 13, 36, 0.86) 0%, rgba(18, 13, 36, 0.82) 55%, rgba(18, 13, 36, 0.94) 100%),
      url("images/a3caefefe1d4b78050fb476baca5d542a03b7bfa133c357f8d64957648614502b347ef8008c26a11b1385dd33cd11cfd90c49b2716421ca0f57cd3_1280.jpg");
  }
}
.hero::before {
  content: "";
  position: absolute;
  top: -20%;
  right: -10%;
  width: 640px;
  height: 640px;
  background: radial-gradient(circle, rgba(111, 87, 234, 0.55), transparent 70%);
  filter: blur(10px);
  pointer-events: none;
}
.hero-inner { position: relative; max-width: 760px; }
.hero-inner h1 {
  margin-top: 1rem;
  font-size: clamp(2.4rem, 1.9rem + 2.5vw, 3.8rem);
  color: #fff;
}
.hero-inner .lede {
  margin-top: 1.4rem;
  font-size: 1.15rem;
  color: var(--text-on-dark-muted);
  max-width: 52ch;
}
.hero-actions { display: flex; flex-wrap: wrap; gap: 1rem; margin-top: 2.2rem; }

.hero-cards {
  position: relative;
  margin-top: clamp(3.5rem, 2.5rem + 4vw, 5rem);
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.25rem;
}
.hero-card {
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  border-radius: var(--radius-md);
  padding: 1.75rem 1.5rem;
  backdrop-filter: blur(6px);
  transition: transform 0.3s var(--ease), background 0.3s var(--ease), border-color 0.3s var(--ease);
}
.hero-card:hover { transform: translateY(-6px); background: rgba(255, 255, 255, 0.1); border-color: rgba(255, 255, 255, 0.28); }
.icon-circle-on-dark { background: rgba(167, 139, 250, 0.16); color: var(--violet-300); }
.hero-card h3 { font-size: 1.05rem; color: #fff; margin-top: 1rem; }
.hero-card p { font-size: 0.9rem; color: var(--text-on-dark-muted); margin-top: 0.5rem; }

@media (max-width: 900px) {
  .hero-cards { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 520px) {
  .hero-cards { grid-template-columns: 1fr; gap: 1rem; }
  .hero-card { padding: 1.4rem; }
}

/* ==========================================================================
   Icons
   ========================================================================== */
.icon { width: 26px; height: 26px; flex-shrink: 0; }
.icon-circle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 52px;
  height: 52px;
  border-radius: 14px;
  background: var(--violet-100);
  color: var(--violet-700);
}

/* ==========================================================================
   Benefits grid
   ========================================================================== */
.benefits-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}
.benefit-card {
  padding: 2rem;
  border-radius: var(--radius-md);
  background: var(--paper);
  border: 1px solid var(--line);
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease), border-color 0.3s var(--ease);
}
.benefit-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-md); border-color: transparent; }
.benefit-card .num {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 0.85rem;
  color: var(--violet-500);
  letter-spacing: 0.05em;
}
.benefit-card h3 { font-size: 1.15rem; margin-top: 0.9rem; }
.benefit-card p { margin-top: 0.6rem; color: var(--text-muted); font-size: 0.95rem; }
.benefit-card.featured {
  background: linear-gradient(155deg, var(--violet-700), var(--ink-900));
  color: #fff;
  border-color: transparent;
}
.benefit-card.featured .num { color: var(--violet-300); }
.benefit-card.featured p { color: var(--text-on-dark-muted); }

@media (max-width: 900px) { .benefits-grid { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 560px) {
  .benefits-grid { grid-template-columns: 1fr; }
  .benefit-card { padding: 1.5rem; }
}

/* ==========================================================================
   About
   ========================================================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1.05fr 0.95fr;
  gap: clamp(2rem, 1.5rem + 2vw, 4rem);
  align-items: center;
}
.about-media {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.about-media img { width: 100%; height: 100%; object-fit: cover; aspect-ratio: 4/3; }
.about-media::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 60%, rgba(18, 13, 36, 0.35));
}
.about-copy p { color: var(--text-muted); margin-top: 1.1rem; font-size: 1.05rem; }

.about-points {
  margin-top: clamp(2.5rem, 2rem + 2vw, 3.5rem);
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.25rem;
}
.about-point {
  padding: 1.75rem;
  border-radius: var(--radius-md);
  background: var(--paper);
  border: 1px solid var(--line);
}
.about-point h4 { font-size: 1rem; font-family: var(--font-body); font-weight: 700; }
.about-point p { margin-top: 0.6rem; color: var(--text-muted); font-size: 0.92rem; }

@media (max-width: 860px) {
  .about-grid { grid-template-columns: 1fr; }
  .about-points { grid-template-columns: 1fr; }
}

/* ==========================================================================
   Approach
   ========================================================================== */
.approach-list { border-top: 1px solid var(--line); margin-top: 1rem; }
.approach-row {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 2rem;
  padding-block: 2rem;
  border-bottom: 1px solid var(--line);
  transition: background 0.3s var(--ease);
}
.approach-row:hover { background: var(--paper-alt); }
.approach-row .step-label {
  display: flex;
  align-items: baseline;
  gap: 0.75rem;
  color: var(--violet-600);
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 1.15rem;
}
.approach-row .step-label span:first-child { color: var(--text-faint); font-size: 0.85rem; }
.approach-row p { color: var(--text-muted); font-size: 1.02rem; max-width: 62ch; }

@media (max-width: 700px) {
  .approach-row { grid-template-columns: 1fr; gap: 0.6rem; }
}

/* ==========================================================================
   Feature split (server & network)
   ========================================================================== */
.feature-split {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  margin-inline: clamp(1.25rem, 4vw, 2.5rem);
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  min-height: 420px;
}
.feature-split .media {
  background: url("images/network-mobile.jpg") center / cover no-repeat;
  position: relative;
}
@media (min-width: 700px) {
  .feature-split .media { background-image: url("images/vbt-min.jpg"); }
}
.feature-split .media::after { content: ""; position: absolute; inset: 0; background: linear-gradient(90deg, rgba(18,13,36,0.15), rgba(18,13,36,0.55)); }
.feature-split .panel {
  background: var(--ink-950);
  color: #fff;
  padding: clamp(2.25rem, 1.75rem + 2vw, 3.5rem);
  display: flex;
  flex-direction: column;
  justify-content: center;
}
.feature-split .panel h3 { font-size: 1.6rem; }
.feature-split .tag-list {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  margin-top: 1.5rem;
}
.feature-split .tag-list li {
  font-size: 0.85rem;
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.14);
  color: var(--text-on-dark-muted);
}
@media (max-width: 780px) {
  .feature-split { grid-template-columns: 1fr; }
  .feature-split .media { min-height: 240px; }
}

/* ==========================================================================
   Philosophy / quote
   ========================================================================== */
.philosophy {
  background: var(--ink-950);
  color: var(--text-on-dark);
  position: relative;
  overflow: hidden;
}
.philosophy::before {
  content: "";
  position: absolute;
  left: 50%;
  top: 0;
  width: 900px;
  height: 900px;
  transform: translate(-50%, -55%);
  background: radial-gradient(circle, rgba(111, 87, 234, 0.28), transparent 70%);
}
.philosophy-head { position: relative; max-width: 780px; margin-inline: auto; text-align: center; }
.philosophy-head h2 { font-size: clamp(1.9rem, 1.5rem + 2vw, 2.8rem); color: #fff; margin-top: 1rem; }
.philosophy-grid {
  position: relative;
  margin-top: clamp(2.5rem, 2rem + 2vw, 4rem);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: clamp(2rem, 1.5rem + 2vw, 4rem);
  padding-top: clamp(2rem, 1.5rem + 2vw, 3rem);
  border-top: 1px solid rgba(255, 255, 255, 0.14);
}
.philosophy-grid p { color: var(--text-on-dark-muted); font-size: 1.05rem; }
.philosophy-grid ul { margin-top: 1.25rem; display: flex; flex-direction: column; gap: 0.6rem; }
.philosophy-grid li {
  font-family: var(--font-head);
  font-weight: 600;
  font-size: 1.05rem;
  color: #fff;
  padding-left: 1.4rem;
  position: relative;
}
.philosophy-grid li::before {
  content: "";
  position: absolute;
  left: 0; top: 0.55em;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--violet-300);
}
@media (max-width: 780px) { .philosophy-grid { grid-template-columns: 1fr; } }

/* ==========================================================================
   Work / portfolio
   ========================================================================== */
.work-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.75rem;
}
.work-card {
  border-radius: var(--radius-lg);
  overflow: hidden;
  background: var(--paper);
  border: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  transition: transform 0.3s var(--ease), box-shadow 0.3s var(--ease);
}
.work-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); }
.work-media { aspect-ratio: 4/3; overflow: hidden; }
.work-media img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s var(--ease); }
.work-card:hover .work-media img { transform: scale(1.06); }
.work-body { padding: 1.75rem; display: flex; flex-direction: column; gap: 0.75rem; flex: 1; }
.work-body h3 { font-size: 1.15rem; }
.work-body p { color: var(--text-muted); font-size: 0.92rem; flex: 1; }
.work-link {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--violet-700);
  margin-top: 0.25rem;
}
.work-link .icon { width: 16px; height: 16px; transition: transform 0.25s var(--ease); }
.work-card:hover .work-link .icon { transform: translate(2px, -2px); }

@media (max-width: 900px) { .work-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 620px) { .work-grid { grid-template-columns: 1fr; } }

/* ==========================================================================
   Contact
   ========================================================================== */
.contact-section {
  position: relative;
  color: #fff;
  background:
    linear-gradient(180deg, rgba(18, 13, 36, 0.92), rgba(18, 13, 36, 0.88)),
    url("images/contact-mobile.jpg") center / cover no-repeat;
}
@media (min-width: 700px) {
  .contact-section {
    background-image:
      linear-gradient(180deg, rgba(18, 13, 36, 0.92), rgba(18, 13, 36, 0.88)),
      url("images/fgfg-min.jpg");
  }
}
.contact-grid {
  display: grid;
  grid-template-columns: 0.9fr 1.1fr;
  gap: clamp(2rem, 1.5rem + 2vw, 4rem);
  align-items: start;
}
.contact-intro h2 { font-size: clamp(1.9rem, 1.5rem + 1.6vw, 2.6rem); color: #fff; margin-top: 1rem; }
.contact-intro p { margin-top: 1.1rem; color: var(--text-on-dark-muted); font-size: 1.05rem; max-width: 42ch; }
.contact-intro .btn { margin-top: 2rem; }

.contact-cards { display: grid; grid-template-columns: 1fr 1fr; gap: 1.25rem; }
.contact-card {
  padding: 1.75rem;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.14);
  backdrop-filter: blur(6px);
  transition: transform 0.3s var(--ease), background 0.3s var(--ease);
}
.contact-card:hover { transform: translateY(-4px); background: rgba(255, 255, 255, 0.1); }
.contact-card .icon-circle { background: rgba(167, 139, 250, 0.18); color: var(--violet-200); }
.contact-card h3 { font-size: 1rem; margin-top: 1rem; }
.contact-card p, .contact-card a { margin-top: 0.5rem; color: var(--text-on-dark-muted); font-size: 0.95rem; }
.contact-card a:hover { color: #fff; }

@media (max-width: 900px) { .contact-grid { grid-template-columns: 1fr; } }
@media (max-width: 520px) { .contact-cards { grid-template-columns: 1fr; } }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer { background: var(--ink-950); color: var(--text-on-dark-muted); }
.footer-inner {
  padding-block: 3rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 1.5rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
}
.footer-brand { display: flex; align-items: center; gap: 0.6rem; }
.footer-brand img { height: 46px; filter: brightness(0) invert(1); opacity: 0.9; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 1.5rem; }
.footer-nav a { font-size: 0.9rem; transition: color 0.2s; }
.footer-nav a:hover { color: #fff; }
.footer-fine { font-size: 0.85rem; }

/* ==========================================================================
   Back to top
   ========================================================================== */
.back-to-top {
  position: fixed;
  right: max(1.5rem, env(safe-area-inset-right) + 0.5rem);
  bottom: max(1.5rem, env(safe-area-inset-bottom) + 0.5rem);
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--ink-950);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
  transition: opacity 0.3s var(--ease), transform 0.3s var(--ease), background 0.3s var(--ease);
  z-index: 90;
}
.back-to-top.is-visible { opacity: 1; transform: translateY(0); pointer-events: auto; }
.back-to-top:hover { background: var(--violet-600); }

/* ==========================================================================
   Reveal-on-scroll
   Visible by default so content never depends on JS running. The "js-reveal"
   class is added by script.js only once its IntersectionObserver is armed.
   ========================================================================== */
.js-reveal [data-reveal] {
  opacity: 0;
  transform: translateY(18px);
  transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.js-reveal [data-reveal].is-visible { opacity: 1; transform: translateY(0); }