/* =========================================================
   South African Corruption — editorial single-page
   Palette: ink #22181c · red #e51022 · gold #ffc56e
   ========================================================= */

:root {
  --bg:         #22181c;
  --bg-2:       #2a1f24;
  --bg-3:       #1a1216;
  --ink:        #faf6ec;
  --ink-soft:   #d4c9bd;
  --ink-mute:   #8c7e72;
  --accent:     #e51022;
  --accent-dk:  #b00d1b;
  --gold:       #ffc56e;
  --gold-soft:  #ffd693;
  --line:       rgba(250, 246, 236, 0.08);

  --radius:     12px;
  --radius-lg:  20px;

  --shadow:     0 14px 36px rgba(0, 0, 0, 0.4);
  --shadow-lg:  0 30px 60px rgba(0, 0, 0, 0.55);

  --ease:       cubic-bezier(.4,.0,.2,1);
  --ease-out:   cubic-bezier(.16,1,.3,1);

  --max:        1180px;
}

*, *::before, *::after { box-sizing: border-box; }
html {
  scroll-behavior: smooth;
  scroll-padding-top: 126px;
  -webkit-text-size-adjust: 100%;
}
@media (max-width: 640px) { html { scroll-padding-top: 100px; } }

body {
  margin: 0;
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  font-size: 17px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
}
img, svg { display: block; max-width: 100%; height: auto; }
a { color: var(--gold); text-decoration: none; transition: color .18s var(--ease); }
a:hover { color: var(--gold-soft); }
button { font: inherit; cursor: pointer; }
ul { list-style: none; padding: 0; margin: 0; }
blockquote { margin: 0; }
em, i { font-style: italic; }

.wrap { max-width: var(--max); margin: 0 auto; padding: 0 28px; }
.skip {
  position: absolute; top: -100px; left: 12px;
  background: var(--accent); color: #fff; padding: 10px 16px; border-radius: 8px;
  z-index: 999;
}
.skip:focus { top: 12px; }

/* =========================================================
   Typography
   ========================================================= */
h1, h2, h3 {
  font-family: 'Playfair Display', Georgia, serif;
  font-weight: 900;
  letter-spacing: -0.02em;
  line-height: 1.05;
  margin: 0 0 .4em;
  color: var(--ink);
}
h1 { font-size: clamp(2.4rem, 6.5vw, 5.2rem); }
h2 { font-size: clamp(2rem, 4.6vw, 3.6rem); letter-spacing: -0.01em; }
h3 { font-size: 1.4rem; font-weight: 700; }
p  { margin: 0 0 1em; }

.eyebrow {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78rem;
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.22em;
  color: var(--accent);
  margin: 0 0 18px;
}
/* Section-label eyebrows (Where to buy / The authors) — large editorial chapter mark */
.buy > .wrap > .eyebrow.center,
.authors > .wrap > .eyebrow.center {
  font-size: clamp(1.6rem, 3.6vw, 2.4rem);
  letter-spacing: 0.14em;
  color: var(--gold);
  margin-bottom: 20px;
}
.center { text-align: center; }

.grad {
  background: linear-gradient(110deg, var(--gold) 0%, var(--gold-soft) 60%, #ffe1ad 100%);
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent; color: transparent;
}

.section-sub {
  color: var(--ink-soft);
  font-size: 1.05rem;
  margin: 0 auto 56px;
  max-width: 640px;
}

/* =========================================================
   Sticky nav
   ========================================================= */
.nav {
  position: sticky; top: 0; z-index: 60;
  background: rgba(34, 24, 28, 0.85);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--line);
  transition: background .25s var(--ease), box-shadow .25s var(--ease);
}
.nav.scrolled {
  background: rgba(34, 24, 28, 0.96);
  box-shadow: 0 6px 24px rgba(0,0,0,0.4);
}
.nav-row {
  display: flex; align-items: center; justify-content: space-between;
  padding: 17px 28px;
  gap: 24px;
}

.brand {
  display: inline-flex; align-items: center; gap: 16px;
  color: var(--ink) !important;
  flex-shrink: 0;
}
.brand-mark {
  display: inline-flex; align-items: center; justify-content: center;
  width: 52px; height: 52px;
  border-radius: 12px;
  background: var(--accent);
  overflow: hidden;
  isolation: isolate;
  padding: 6px;
  box-shadow: 0 6px 18px rgba(229, 16, 34, 0.35);
  transition: transform .25s var(--ease-out);
}
.brand-mark img {
  width: 100%; height: 100%;
  object-fit: contain;
  /* invert source (black silhouette → white, white bg → black),
     then lighten-blend so black disappears against red and white shows through */
  filter: invert(1);
  mix-blend-mode: lighten;
}
.brand:hover .brand-mark { transform: rotate(-4deg) scale(1.06); }
.brand-text {
  display: flex; flex-direction: column;
  line-height: 1;
  font-family: 'Playfair Display', serif;
  font-weight: 700;
  letter-spacing: -0.01em;
}
.brand-line1 { font-size: 0.9rem; color: var(--ink-soft); }
.brand-line2 { font-size: 1.38rem; color: var(--ink); margin-top: 2px; }
@media (max-width: 640px) {
  .nav-row { padding: 14px 22px; }
  .brand-mark { width: 44px; height: 44px; border-radius: 10px; padding: 5px; }
  .brand-line1 { font-size: 0.78rem; }
  .brand-line2 { font-size: 1.18rem; }
}

.nav-links { display: flex; align-items: center; gap: 6px; }
.nav-links a {
  position: relative;
  color: var(--ink) !important;
  font-weight: 500;
  font-size: 0.97rem;
  padding: 8px 14px;
  font-family: 'Inter', sans-serif;
}
.nav-links a::after {
  content: ""; position: absolute;
  left: 14px; right: 14px; bottom: 4px;
  height: 2px; background: var(--accent);
  transform: scaleX(0); transform-origin: left;
  transition: transform .35s var(--ease-out);
}
.nav-links a:hover { color: var(--gold) !important; }
.nav-links a:hover::after { transform: scaleX(1); }

.nav-toggle {
  display: none;
  background: none; border: 0; padding: 8px;
  width: 40px; height: 40px;
  flex-direction: column; justify-content: center; gap: 5px;
}
.nav-toggle span {
  display: block; height: 2px; width: 22px;
  background: var(--ink); border-radius: 2px;
  transition: transform .25s var(--ease), opacity .25s var(--ease);
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

.nav-mobile {
  display: none;
  padding: 14px 28px 22px;
  border-top: 1px solid var(--line);
  background: var(--bg-3);
}
.nav-mobile a {
  display: block; padding: 12px 8px;
  color: var(--ink) !important;
  font-weight: 500;
  border-bottom: 1px solid var(--line);
}
.nav-mobile a:last-child { border-bottom: 0; }
.nav-mobile a:hover { color: var(--gold) !important; }
@media (max-width: 760px) {
  .nav-links { display: none; }
  .nav-toggle { display: inline-flex; }
  .nav-mobile.open { display: block; }
}

/* =========================================================
   Buttons
   ========================================================= */
.btn {
  display: inline-flex; align-items: center; justify-content: center;
  gap: 10px;
  padding: 14px 24px;
  border-radius: 999px;
  font-family: 'Inter', sans-serif;
  font-weight: 600;
  font-size: 1rem;
  letter-spacing: -0.005em;
  border: 2px solid transparent;
  cursor: pointer;
  transition: transform .18s var(--ease), background .22s var(--ease), color .22s var(--ease), border-color .22s var(--ease), box-shadow .22s var(--ease);
}
.btn .arr { transition: transform .25s var(--ease); }
.btn:hover .arr { transform: translateX(4px); }
.btn:active { transform: translateY(1px); }
.btn-primary {
  background: var(--accent);
  color: #fff !important;
  box-shadow: 0 10px 26px rgba(229, 16, 34, 0.35);
}
.btn-primary:hover {
  background: var(--gold);
  color: var(--bg) !important;
  box-shadow: 0 14px 34px rgba(255, 197, 110, 0.45);
}
.btn-ghost {
  background: transparent;
  color: var(--ink) !important;
  border-color: rgba(250, 246, 236, 0.3);
}
.btn-ghost:hover {
  border-color: var(--gold);
  color: var(--gold) !important;
}

/* =========================================================
   Hero
   ========================================================= */
.hero {
  position: relative;
  min-height: 88vh;
  display: flex; align-items: center;
  overflow: hidden;
  color: var(--ink);
  isolation: isolate;
}
.hero-bg {
  position: absolute; inset: -4%;
  background: url('images/banner-bookshelf.jpg') center/cover no-repeat;
  filter: grayscale(78%) contrast(1.08) brightness(0.62);
  transform: scale(1.06);
  z-index: -2;
  animation: heroDrift 26s ease-in-out infinite alternate;
}
@keyframes heroDrift {
  0%   { transform: scale(1.06) translate(0, 0); }
  100% { transform: scale(1.1) translate(-1.5%, -1%); }
}
.hero-overlay {
  position: absolute; inset: 0; z-index: -1;
  background:
    linear-gradient(95deg, rgba(26, 18, 22, 0.92) 0%, rgba(26, 18, 22, 0.70) 45%, rgba(26, 18, 22, 0.50) 100%),
    radial-gradient(70% 60% at 100% 100%, rgba(229, 16, 34, 0.22), transparent 65%),
    radial-gradient(60% 50% at 0% 0%, rgba(0, 0, 0, 0.55), transparent 70%);
}
.hero-inner {
  position: relative; z-index: 1;
  padding: 120px 28px 140px;
  max-width: 980px;
}
.hero h1 {
  font-family: 'Playfair Display', serif;
  color: var(--ink);
  font-style: italic;
  font-weight: 900;
}
.hero-line { display: block; }
.hero-sub {
  font-size: clamp(1.05rem, 1.4vw, 1.22rem);
  max-width: 620px;
  margin: 28px 0 36px;
  color: var(--ink-soft);
}
.hero-cta { display: flex; gap: 14px; flex-wrap: wrap; }

.hero-scroll {
  position: absolute; bottom: 28px; left: 50%; transform: translateX(-50%);
  width: 26px; height: 42px;
  border: 2px solid rgba(250, 246, 236, 0.4); border-radius: 999px;
  display: flex; justify-content: center; padding-top: 8px;
}
.hero-scroll span {
  display: block; width: 3px; height: 8px; background: var(--gold); border-radius: 2px;
  animation: scrollHint 1.6s ease-in-out infinite;
}
@keyframes scrollHint {
  0%, 100% { transform: translateY(0); opacity: 1; }
  60%      { transform: translateY(10px); opacity: 0; }
}
@media (max-width: 640px) {
  .hero { min-height: auto; }
  .hero-inner { padding: 80px 24px 90px; }
  .hero-sub { font-size: 1rem; }
  .hero-scroll { display: none; }
  .reveal.from-left { transform: translateX(-30px); transition-duration: 1.2s; }
}

/* =========================================================
   Marquee strip
   ========================================================= */
.marquee {
  background: var(--bg-3);
  color: var(--ink-soft);
  overflow: hidden;
  padding: 16px 0;
  border-block: 1px solid var(--line);
}
.marquee-track {
  display: inline-flex; align-items: center;
  white-space: nowrap;
  animation: marquee 24s linear infinite;
  will-change: transform;
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-weight: 700;
  font-size: 1.02rem;
}
.marquee-set {
  display: inline-flex; align-items: center; gap: 36px;
  padding-right: 36px;
  flex-shrink: 0;
}
.marquee-set .dot { color: var(--accent); font-size: 0.6rem; font-family: 'Inter', sans-serif; }
@keyframes marquee {
  from { transform: translate3d(0, 0, 0); }
  to   { transform: translate3d(-50%, 0, 0); }
}

/* =========================================================
   Books section
   ========================================================= */
.books { padding: 0; background: var(--bg); }

.book { padding: 110px 0; position: relative; }
.book--rogues { background: var(--bg); }
.book--ballots { background: var(--bg-2); }

.book-grid {
  display: grid;
  grid-template-columns: 0.9fr 1fr;
  gap: 64px;
  align-items: start;
}
.book--alt .book-grid > .book-body { order: 1; }
.book--alt .book-grid > .book-cover { order: 2; }
@media (max-width: 880px) {
  .book-grid { grid-template-columns: 1fr; gap: 40px; }
  .book--alt .book-grid > .book-body { order: 2; }
  .book--alt .book-grid > .book-cover { order: 1; }
}

.book-cover-wrap {
  position: relative;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  transform: rotate(-1deg);
  transition: transform .5s var(--ease-out);
  background: #000;
}
.book--alt .book-cover-wrap { transform: rotate(1deg); }
.book-cover-wrap:hover { transform: rotate(0) scale(1.015); }
.book-cover-wrap::after {
  content: ""; position: absolute; inset: 0;
  background: linear-gradient(135deg, transparent 60%, rgba(229, 16, 34, 0.15) 100%);
  pointer-events: none;
}
.book-cover-wrap img {
  width: 100%; height: auto; display: block;
}

.book-title {
  font-family: 'Playfair Display', serif;
  font-weight: 900;
  font-size: clamp(2.4rem, 5vw, 4.4rem);
  letter-spacing: -0.02em;
  margin: 0 0 14px;
  line-height: 1;
}
.book-subtitle {
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-weight: 700;
  font-size: clamp(1.2rem, 1.6vw, 1.4rem);
  color: var(--ink-soft);
  margin: 0 0 28px;
  line-height: 1.3;
}
.book-blurb p {
  color: var(--ink-soft);
  margin-bottom: 1em;
  font-size: 1.02rem;
}
.book-blurb strong { color: var(--gold); font-weight: 600; }

.book-tags {
  display: flex; flex-wrap: wrap; gap: 8px;
  margin: 28px 0;
}
.book-tags li {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--ink-soft);
  background: rgba(255, 197, 110, 0.04);
  transition: border-color .22s, color .22s, background .22s;
}
.book-tags li:hover {
  border-color: var(--gold);
  color: var(--gold);
  background: rgba(255, 197, 110, 0.1);
}

.book-pullquote {
  margin: 28px 0;
  padding: 22px 26px;
  border-left: 3px solid var(--accent);
  background: rgba(229, 16, 34, 0.06);
  border-radius: 0 var(--radius) var(--radius) 0;
}
.book-pullquote p {
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-size: 1.2rem;
  color: var(--ink);
  margin: 0 0 8px;
}
.book-pullquote footer {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.75rem;
  color: var(--ink-mute);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* Book metadata — small spec list at the bottom of each book section */
.book-spec {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 0;
  margin: 32px 0 0;
  padding-top: 24px;
  border-top: 1px solid var(--line);
}
.book-spec > div { padding: 10px 14px 10px 0; }
.book-spec dt {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.66rem;
  color: var(--ink-mute);
  letter-spacing: 0.14em;
  text-transform: uppercase;
  margin: 0 0 4px;
}
.book-spec dd {
  margin: 0;
  font-family: 'Inter', sans-serif;
  font-weight: 500;
  font-size: 0.95rem;
  color: var(--ink);
}

/* =========================================================
   Where to buy — per-book cards with small covers + retailer links
   ========================================================= */
.buy {
  padding: 110px 0;
  background: var(--bg);
}
.buy h2 { margin-bottom: 12px; }

.buy-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}
@media (max-width: 800px) { .buy-grid { grid-template-columns: 1fr; } }

.buy-card {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 26px;
  align-items: start;
  padding: 28px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  transition: transform .35s var(--ease-out), border-color .35s var(--ease-out);
}
.buy-card:hover { transform: translateY(-3px); border-color: rgba(255, 197, 110, 0.25); }
@media (max-width: 520px) {
  .buy-card { grid-template-columns: 1fr; }
  .buy-cover { max-width: 200px; }
}

.buy-cover {
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: 0 12px 30px rgba(0,0,0,0.4);
  transform: rotate(-1.5deg);
  transition: transform .35s var(--ease-out);
}
.buy-card:hover .buy-cover { transform: rotate(0); }
.buy-cover img { width: 100%; height: auto; display: block; }

.buy-title {
  font-family: 'Playfair Display', serif;
  font-weight: 800;
  font-size: 1.55rem;
  color: var(--ink);
  margin: 0 0 4px;
  letter-spacing: -0.01em;
}
.buy-sub {
  font-family: 'Playfair Display', serif;
  font-style: italic;
  font-weight: 700;
  font-size: 0.92rem;
  color: var(--ink-mute);
  margin: 0 0 18px;
}

.buy-links { display: flex; flex-direction: column; gap: 2px; }
.buy-links a {
  display: flex; align-items: center; justify-content: space-between;
  gap: 12px;
  padding: 11px 0;
  border-bottom: 1px solid var(--line);
  color: var(--ink) !important;
  font-size: 0.96rem;
  font-weight: 500;
  transition: color .18s var(--ease), padding .18s var(--ease);
}
.buy-links li:last-child a { border-bottom: 0; }
.buy-links a:hover { color: var(--gold) !important; padding-left: 4px; }
.buy-links a .arr {
  color: var(--accent);
  transition: transform .25s var(--ease), color .25s var(--ease);
}
.buy-links a:hover .arr { transform: translateX(4px); color: var(--gold); }

/* =========================================================
   Authors
   ========================================================= */
.authors {
  padding: 110px 0 120px;
  background: var(--bg-2);
}
.authors h2 { margin-bottom: 50px; }
.author-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 28px;
}
@media (max-width: 760px) {
  .author-grid { grid-template-columns: 1fr; }
}
.author-card {
  display: flex; flex-direction: column;
  align-items: center;
  text-align: center;
  padding: 40px 32px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: var(--radius-lg);
  transition: transform .35s var(--ease-out), border-color .35s var(--ease-out);
}
.author-card:hover {
  transform: translateY(-4px);
  border-color: rgba(255, 197, 110, 0.25);
}
.author-portrait {
  width: 168px; height: 168px;
  border-radius: 50%;
  margin-bottom: 26px;
  overflow: hidden;
  border: 4px solid var(--accent);
  box-shadow: 0 18px 38px rgba(229, 16, 34, 0.35);
  background: var(--bg-3);
  transition: transform .3s var(--ease-out), border-color .3s var(--ease-out);
}
.author-card:hover .author-portrait { transform: scale(1.04); border-color: var(--gold); }
.author-portrait img {
  width: 100%; height: 100%;
  object-fit: cover;
  object-position: center 30%;
  display: block;
}
@media (max-width: 640px) {
  .author-portrait { width: 140px; height: 140px; }
}
.author-name {
  font-family: 'Playfair Display', serif;
  font-weight: 800;
  font-size: 1.7rem;
  color: var(--ink);
  margin: 0 0 4px;
}
.author-role {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.16em;
  color: var(--accent);
  margin: 0 0 18px;
}
.author-bio {
  color: var(--ink-soft);
  font-size: 0.98rem;
  margin: 0;
  max-width: 36ch;
}
.author-link {
  margin: 22px 0 0;
  font-size: 0.95rem;
  color: var(--ink-soft);
}
.author-link a {
  color: var(--gold);
  font-weight: 600;
  border-bottom: 1px solid transparent;
  transition: color .18s var(--ease), border-color .18s var(--ease);
}
.author-link a:hover {
  color: var(--gold-soft);
  border-bottom-color: var(--gold-soft);
}
.author-link .arr {
  color: var(--accent);
  display: inline-block;
  transition: transform .25s var(--ease);
}
.author-link:hover .arr { transform: translateX(3px); }

/* =========================================================
   Footer
   ========================================================= */
.footer {
  background: var(--bg-3);
  padding: 56px 0 28px;
  color: var(--ink-soft);
}
.footer-row {
  display: flex; justify-content: space-between; align-items: flex-start;
  gap: 32px; flex-wrap: wrap;
  padding-bottom: 32px;
  border-bottom: 1px solid var(--line);
}
.footer-title {
  font-family: 'Playfair Display', serif;
  font-weight: 800;
  font-size: 1.4rem;
  color: var(--ink);
  display: block;
  margin-bottom: 8px;
}
.footer-tag { margin: 0; font-size: 0.92rem; color: var(--ink-mute); max-width: 380px; }
.footer-meta { display: flex; gap: 22px; flex-wrap: wrap; font-size: 0.95rem; }
.footer-meta a { color: var(--ink-soft); }
.footer-meta a:hover { color: var(--gold); }
.footer-copy {
  padding-top: 24px;
  font-size: 0.82rem;
  color: var(--ink-mute);
}

/* =========================================================
   Scroll reveals
   ========================================================= */
.reveal {
  opacity: 0;
  transform: translateY(28px);
  transition: opacity .9s var(--ease-out), transform .9s var(--ease-out);
}
.reveal.in-view {
  opacity: 1;
  transform: translateY(0);
}
.reveal.from-left {
  transform: translateX(-80px);
  transition: opacity 1.4s var(--ease-out), transform 1.4s var(--ease-out);
}
.reveal.from-left.in-view { transform: translateX(0); }

@media (prefers-reduced-motion: reduce) {
  * { animation: none !important; transition: none !important; scroll-behavior: auto !important; }
  .reveal { opacity: 1; transform: none; }
}

/* =========================================================
   Focus visible
   ========================================================= */
:focus-visible {
  outline: 3px solid var(--gold);
  outline-offset: 3px;
  border-radius: 4px;
}

/* =========================================================
   Back-to-top button
   ========================================================= */
.back-to-top {
  position: fixed;
  right: 22px; bottom: 22px;
  width: 56px; height: 56px;
  border-radius: 18px;
  background: var(--accent);
  color: #fff;
  border: 0;
  display: inline-flex; align-items: center; justify-content: center;
  box-shadow: 0 14px 34px rgba(229, 16, 34, 0.45), 0 0 0 1px rgba(0,0,0,0.15) inset;
  cursor: pointer;
  opacity: 0; visibility: hidden;
  transform: translateY(20px) scale(0.9);
  transition: opacity .3s var(--ease), transform .3s var(--ease), background .2s var(--ease), color .2s var(--ease), box-shadow .2s var(--ease);
  z-index: 70;
}
.back-to-top.visible {
  opacity: 1; visibility: visible;
  transform: translateY(0) scale(1);
}
.back-to-top:hover {
  background: var(--gold);
  color: var(--bg);
  transform: translateY(-3px) scale(1.04);
  box-shadow: 0 18px 40px rgba(255, 197, 110, 0.45);
}
.back-to-top:active { transform: translateY(0) scale(0.98); }
@media (prefers-reduced-motion: reduce) {
  .back-to-top { transition: opacity .2s, visibility .2s; transform: none; }
  .back-to-top.visible, .back-to-top:hover, .back-to-top:active { transform: none; }
}
@media (max-width: 640px) {
  .back-to-top { right: 16px; bottom: 16px; width: 48px; height: 48px; border-radius: 14px; }
}