/* =========================================
   KNOWLEDGE ARTICLE STYLES
   Extends breed guide design language
   ========================================= */
:root {
  --clr-bg: #0e0e18;
  --clr-surface: #16162a;
  --clr-card: #1e1e38;
  --clr-border: rgba(255,255,255,.06);
  --clr-text: #e8e6f0;
  --clr-text-dim: #9896a8;
  --clr-accent: #ffa032;
  --clr-accent2: #7c5cff;
  --clr-accent3: #33d69f;
  --clr-danger: #ff4757;
  --clr-warn: #f5a623;
  --clr-info: #5b9fff;
  --radius-lg: 20px;
  --radius-md: 14px;
  --radius-sm: 8px;
  --sp-xs: 6px;
  --sp-sm: 10px;
  --sp-md: 16px;
  --sp-lg: 24px;
  --sp-xl: 40px;
  --sp-2xl: 64px;
  --fs-xs: .75rem;
  --fs-sm: .9rem;
  --fs-md: 1rem;
  --fs-lg: 1.15rem;
  --fs-xl: 1.5rem;
  --fs-2xl: 2rem;
  --ff-body: 'Noto Sans TC', sans-serif;
  --ff-display: 'Outfit', 'Noto Sans TC', sans-serif;
}

/* ---------- LIGHT MODE ---------- */
[data-theme="light"] {
  --clr-bg: #f5f3ef; --clr-surface: #eae8e3; --clr-card: #ffffff;
  --clr-border: rgba(0,0,0,.08); --clr-text: #1a1a1a; --clr-text-dim: #555;
  --clr-accent: #d48806; --clr-accent2: #5a46cc; --clr-accent3: #1fa66e;
  --clr-danger: #dc2626; --clr-warn: #d48806; --clr-info: #2563eb;
}
[data-theme="light"] .main-nav { background: rgba(255,255,255,.95); backdrop-filter: blur(20px); -webkit-backdrop-filter: blur(20px); }
[data-theme="light"] .main-nav.scrolled { background: rgba(255,255,255,.95); backdrop-filter: blur(16px); -webkit-backdrop-filter: blur(16px); border-bottom: 1px solid rgba(0,0,0,.06); }
[data-theme="light"] .nav-dropdown { background: #fff; border-color: rgba(0,0,0,.1); box-shadow: 0 8px 32px rgba(0,0,0,.12); }
[data-theme="light"] .article-hero { background: linear-gradient(135deg, #f0ede6 0%, #f5f3ef 100%); }
[data-theme="light"] .article-hero-title { background: linear-gradient(135deg, #1a1a1a, #444); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: var(--ff-body); background: var(--clr-bg); color: var(--clr-text); line-height: 1.7; -webkit-font-smoothing: antialiased; }

/* ── Reading Progress ── */
.reading-progress { position: fixed; top: 0; left: 0; height: 3px; background: linear-gradient(90deg, var(--clr-accent), var(--clr-accent2)); width: 0; z-index: 9999; transition: width .1s linear; }

/* ── Nav ── */
.main-nav {
  position: fixed; top: 0; left: 0; width: 100%;
  z-index: 1000; padding: var(--sp-md) 0;
  background: rgba(14,14,24,.95);
  backdrop-filter: blur(20px) saturate(1.4); -webkit-backdrop-filter: blur(20px) saturate(1.4);
  transition: background .3s, padding .3s;
}
.main-nav.scrolled {
  background: rgba(14,14,24,.95);
  backdrop-filter: blur(20px) saturate(1.6); -webkit-backdrop-filter: blur(20px) saturate(1.6);
  padding: var(--sp-sm) 0;
  border-bottom: 1px solid var(--clr-border);
}
.nav-inner {
  max-width: 1280px; margin: 0 auto; padding: 0 var(--sp-lg);
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  display: flex; align-items: center; gap: 8px;
  font-family: var(--ff-heading); font-weight: 700; font-size: 1.125rem;
  text-decoration: none; color: var(--clr-text);
}
.logo-icon { font-size: 1.6rem; filter: drop-shadow(0 0 8px rgba(244,166,35,.4)); }
.nav-links { display: flex; gap: 24px; list-style: none; }
.nav-links a {
  font-size: var(--fs-sm); font-weight: 500; color: var(--clr-text-dim);
  text-decoration: none; transition: color .15s;
}
.nav-links a:hover { color: var(--clr-accent); }
.nav-links li { position: relative; }
.nav-dropdown-toggle { cursor: pointer; }
.nav-dropdown-toggle::after { content: ' ▾'; font-size: 0.7em; opacity: 0.6; }
.nav-dropdown {
  position: absolute; top: 100%; left: 50%;
  transform: translateX(-50%) translateY(8px);
  min-width: 180px;
  background: #1e1d28;
  border: 1px solid rgba(255,255,255,.1); border-radius: 10px;
  padding: 4px 0;
  opacity: 0; visibility: hidden;
  transition: opacity .15s, visibility .15s, transform .15s;
  z-index: 1001; box-shadow: 0 8px 32px rgba(0,0,0,.6);
}
.nav-links li:hover .nav-dropdown,
.nav-links li.dropdown-open .nav-dropdown {
  opacity: 1; visibility: visible;
  transform: translateX(-50%) translateY(0);
}
.nav-dropdown a {
  display: block; padding: 8px 16px;
  font-size: var(--fs-sm); color: var(--clr-text-dim);
  white-space: nowrap; transition: background .15s, color .15s;
}
.nav-dropdown a:hover { background: rgba(244,166,35,.1); color: var(--clr-accent); }
.theme-toggle {
  background: none; border: 1px solid var(--clr-border);
  border-radius: 999px; width: 36px; height: 36px;
  font-size: 1.1rem; cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background .15s, border-color .15s;
  flex-shrink: 0;
}
.theme-toggle:hover { background: rgba(244,166,35,.12); border-color: var(--clr-accent); }
.guide-nav-title {
  font-size: var(--fs-sm); font-weight: 500; color: var(--clr-text-dim);
  opacity: 0; transition: opacity .3s;
  white-space: nowrap;
  max-width: 280px; overflow: hidden; text-overflow: ellipsis;
  margin-left: 12px; padding-left: 12px;
  border-left: 1px solid var(--clr-border);
}
.main-nav.scrolled .guide-nav-title { opacity: 1; }

/* ── Article Hero ── */
.article-hero { padding: 120px var(--sp-lg) var(--sp-2xl); background: linear-gradient(135deg, #1a1a36 0%, #0e0e18 100%); text-align: center; }
.article-hero-inner { max-width: 720px; margin: 0 auto; }
.article-hero-badge { display: inline-block; padding: var(--sp-xs) var(--sp-md); border-radius: 50px; background: rgba(255,160,50,.12); color: var(--clr-accent); font-size: var(--fs-sm); font-weight: 600; margin-bottom: var(--sp-md); }
.article-hero-title { font-family: var(--ff-display); font-size: clamp(1.8rem, 4vw, 2.8rem); font-weight: 800; line-height: 1.3; margin-bottom: var(--sp-md); background: linear-gradient(135deg, #fff, #c8c6d8); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.article-hero-subtitle { font-size: var(--fs-lg); color: var(--clr-text-dim); margin-bottom: var(--sp-xl); }

/* ── TL;DR (AEO) ── */
.article-tldr { background: linear-gradient(135deg, rgba(124,92,255,.1), rgba(51,214,159,.08)); border: 1px solid rgba(124,92,255,.2); border-radius: var(--radius-md); padding: var(--sp-lg); text-align: left; font-size: var(--fs-md); line-height: 1.8; }
.article-tldr::before { content: '📝 重點摘要（TL;DR）'; display: block; font-weight: 700; font-size: var(--fs-sm); color: var(--clr-accent2); margin-bottom: var(--sp-sm); text-transform: uppercase; letter-spacing: .5px; }

/* ── Layout ── */
.guide-layout { display: flex; gap: var(--sp-xl); max-width: 1100px; margin: 0 auto; padding: var(--sp-xl) var(--sp-lg); }
.guide-toc { position: sticky; top: 80px; flex-shrink: 0; width: 200px; height: fit-content; max-height: calc(100vh - 120px); overflow-y: auto; }
.toc-title { font-size: var(--fs-sm); font-weight: 700; color: var(--clr-accent); margin-bottom: var(--sp-md); }
.toc-list { list-style: none; }
.toc-list li { margin-bottom: var(--sp-xs); }
.toc-list a { font-size: var(--fs-xs); color: var(--clr-text-dim); text-decoration: none; padding: var(--sp-xs) var(--sp-sm); display: block; border-radius: var(--radius-sm); transition: all .2s; }
.toc-list a:hover, .toc-list a.active { color: var(--clr-accent); background: rgba(255,160,50,.06); }
.toc-related { margin-top: var(--sp-xl); padding-top: var(--sp-lg); border-top: 1px solid var(--clr-border); }
.toc-related-title { font-size: var(--fs-xs); font-weight: 700; color: var(--clr-text-dim); margin-bottom: var(--sp-sm); text-transform: uppercase; letter-spacing: .5px; }
.toc-related a { font-size: var(--fs-xs); color: var(--clr-accent2); text-decoration: none; display: block; padding: var(--sp-xs) 0; }
.toc-related a:hover { color: var(--clr-accent); }

.guide-main { flex: 1; min-width: 0; }

/* ── Sections ── */
.guide-section { margin-bottom: var(--sp-2xl); }
.guide-section-header { display: flex; align-items: center; gap: var(--sp-md); margin-bottom: var(--sp-lg); }
.guide-section-icon { font-size: 1.6rem; }
.guide-section-title { font-family: var(--ff-display); font-size: var(--fs-xl); font-weight: 700; }

/* ── Cards ── */
.guide-card { background: var(--clr-card); border-radius: var(--radius-md); padding: var(--sp-lg); margin-bottom: var(--sp-md); border: 1px solid var(--clr-border); }
.guide-card h4 { font-size: var(--fs-md); font-weight: 700; margin-bottom: var(--sp-sm); color: var(--clr-accent); }
.guide-card p { font-size: var(--fs-sm); color: var(--clr-text-dim); line-height: 1.8; }
.guide-card ul { list-style: none; }
.guide-card ul li { position: relative; padding: var(--sp-sm) 0 var(--sp-sm) var(--sp-lg); border-bottom: 1px solid var(--clr-border); font-size: var(--fs-sm); line-height: 1.7; color: var(--clr-text); }
.guide-card ul li::before { content: '•'; position: absolute; left: 0; color: var(--clr-accent); font-weight: 700; }
.guide-card ul li:last-child { border-bottom: none; }
.guide-info-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--sp-md); }

/* ── Checklist ── */
.guide-checklist li::before { content: '☐' !important; color: var(--clr-accent3) !important; }

/* ── Alert ── */
.guide-alert { border-radius: var(--radius-md); padding: var(--sp-lg); margin-bottom: var(--sp-md); font-size: var(--fs-sm); line-height: 1.8; }
.guide-alert strong { display: block; margin-bottom: var(--sp-sm); font-size: var(--fs-md); }
.guide-alert.danger { background: rgba(255,71,87,.08); border: 1px solid rgba(255,71,87,.2); color: #ffb3ba; }
.guide-alert.danger strong { color: var(--clr-danger); }
.guide-alert.warn { background: rgba(245,166,35,.08); border: 1px solid rgba(245,166,35,.2); color: #ffd89b; }
.guide-alert.warn strong { color: var(--clr-warn); }
.guide-alert.info { background: rgba(91,159,255,.08); border: 1px solid rgba(91,159,255,.2); color: #b3d4ff; }
.guide-alert.info strong { color: var(--clr-info); }

/* ── Cost Table ── */
.guide-cost-table { width: 100%; border-collapse: collapse; margin-bottom: var(--sp-md); background: var(--clr-card); border-radius: var(--radius-md); overflow: hidden; }
.guide-cost-table th { text-align: left; padding: var(--sp-md); font-size: var(--fs-xs); font-weight: 600; color: var(--clr-text-dim); background: rgba(255,255,255,.03); text-transform: uppercase; letter-spacing: .5px; }
.guide-cost-table td { padding: var(--sp-md); font-size: var(--fs-sm); border-top: 1px solid var(--clr-border); }
.guide-cost-table .cost-val { color: var(--clr-accent); font-weight: 600; text-align: right; }
.guide-cost-total { background: rgba(255,160,50,.06); font-weight: 700; }
.guide-cost-total td { border-top: 2px solid rgba(255,160,50,.2); }

/* ── Timeline ── */
.guide-timeline { padding-left: var(--sp-lg); border-left: 2px solid var(--clr-border); }
.guide-tl-item { position: relative; margin-bottom: var(--sp-xl); }
.guide-tl-dot { position: absolute; left: calc(-1 * var(--sp-lg) - 16px); width: 30px; height: 30px; display: flex; align-items: center; justify-content: center; font-size: 1rem; background: var(--clr-surface); border: 2px solid var(--clr-border); border-radius: 50%; }
.guide-tl-card { background: var(--clr-card); border-radius: var(--radius-md); padding: var(--sp-lg); border: 1px solid var(--clr-border); }
.guide-tl-header { display: flex; align-items: center; gap: var(--sp-md); margin-bottom: var(--sp-md); }
.guide-tl-stage { font-weight: 700; font-size: var(--fs-md); }
.guide-tl-age { font-size: var(--fs-sm); color: var(--clr-accent); background: rgba(255,160,50,.1); padding: 2px var(--sp-sm); border-radius: 50px; }
.guide-tl-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: var(--sp-md); }
.guide-tl-info h5 { font-size: var(--fs-xs); font-weight: 600; margin-bottom: 4px; }
.guide-tl-info p { font-size: var(--fs-xs); color: var(--clr-text-dim); line-height: 1.6; }
.guide-tl-warning { margin-top: var(--sp-md); padding: var(--sp-sm) var(--sp-md); background: rgba(255,71,87,.06); border-radius: var(--radius-sm); font-size: var(--fs-xs); color: #ffb3ba; line-height: 1.6; }

/* ── FAQ ── */
.guide-faq details { margin-bottom: var(--sp-md); background: var(--clr-card); border-radius: var(--radius-md); border: 1px solid var(--clr-border); overflow: hidden; }
.guide-faq summary { cursor: pointer; font-weight: 600; font-size: var(--fs-sm); padding: var(--sp-md) var(--sp-lg); color: var(--clr-text); list-style: none; display: flex; align-items: center; justify-content: space-between; transition: background .2s; }
.guide-faq summary:hover { background: rgba(255,255,255,.02); }
.guide-faq summary::after { content: '+'; font-size: 1.2rem; color: var(--clr-accent); transition: transform .3s; }
.guide-faq details[open] summary::after { content: '−'; }
.guide-faq .faq-answer { padding: 0 var(--sp-lg) var(--sp-lg); font-size: var(--fs-sm); color: var(--clr-text-dim); line-height: 1.8; }

/* ── Comparison Table ── */
.guide-compare-table { width: 100%; border-collapse: collapse; background: var(--clr-card); border-radius: var(--radius-md); overflow: hidden; margin-bottom: var(--sp-md); }
.guide-compare-table th { padding: var(--sp-md); font-size: var(--fs-xs); font-weight: 600; color: var(--clr-accent); background: rgba(255,160,50,.06); text-align: left; }
.guide-compare-table td { padding: var(--sp-md); font-size: var(--fs-sm); border-top: 1px solid var(--clr-border); }
.guide-compare-table tr:nth-child(even) td { background: rgba(255,255,255,.01); }

/* ── Bottom CTA ── */
.guide-bottom-cta { padding: var(--sp-2xl) var(--sp-lg); text-align: center; background: linear-gradient(180deg, transparent, rgba(124,92,255,.04)); }
.guide-cta-inner h2 { font-family: var(--ff-display); font-size: var(--fs-xl); font-weight: 700; margin-bottom: var(--sp-sm); }
.guide-cta-inner p { color: var(--clr-text-dim); margin-bottom: var(--sp-lg); }
.guide-cta-buttons { display: flex; gap: var(--sp-md); justify-content: center; flex-wrap: wrap; }
.guide-cta-btn { padding: var(--sp-sm) var(--sp-lg); border-radius: 50px; text-decoration: none; font-size: var(--fs-sm); font-weight: 600; color: var(--clr-text); background: var(--clr-card); border: 1px solid var(--clr-border); transition: all .2s; }
.guide-cta-btn:hover { border-color: var(--clr-accent); color: var(--clr-accent); }
.guide-cta-btn.primary { background: linear-gradient(135deg, var(--clr-accent), #e88a20); color: #1a1a2e; border: none; }
.guide-cta-btn.primary:hover { transform: translateY(-2px); box-shadow: 0 4px 20px rgba(255,160,50,.3); }

/* ── Footer ── */
.guide-footer { padding: var(--sp-xl) var(--sp-lg); text-align: center; font-size: var(--fs-xs); color: var(--clr-text-dim); border-top: 1px solid var(--clr-border); }

/* ── Article Illustration ── */
.article-illustration {
  margin: var(--sp-lg) 0;
  border-radius: var(--radius-lg);
  overflow: hidden;
  animation: fadeInIllust .6s ease both;
}
.article-illustration img {
  width: 100%;
  height: auto;
  display: block;
  border-radius: var(--radius-lg);
}
@keyframes fadeInIllust {
  from { opacity: 0; transform: scale(.97); }
  to { opacity: 1; transform: scale(1); }
}

/* ── Map Embed ── */
.article-map-embed {
  background: var(--clr-card);
  border: 1px solid var(--clr-border);
  border-radius: var(--radius-lg);
  padding: var(--sp-lg);
  margin-bottom: var(--sp-md);
}
.article-map-title {
  font-weight: 700; font-size: var(--fs-md);
  margin-bottom: var(--sp-xs);
}
.article-map-desc {
  font-size: var(--fs-sm); color: var(--clr-text-dim);
  margin-bottom: var(--sp-md);
}
.article-map-frame {
  border-radius: 12px;
  overflow: hidden;
}

/* ── CTA Tool Cards ── */
.cta-tools-section { background: linear-gradient(135deg, rgba(124,92,255,.04), rgba(51,214,159,.03)); border: 1px solid rgba(124,92,255,.12); border-radius: var(--radius-lg); padding: var(--sp-xl); }
.cta-tools-intro { font-size: var(--fs-sm); color: var(--clr-text-dim); margin-bottom: var(--sp-lg); }
.cta-tools-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: var(--sp-md); }
.cta-tool-card {
  display: flex; flex-direction: column; gap: var(--sp-xs);
  padding: var(--sp-lg);
  background: var(--clr-card); border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  text-decoration: none; color: var(--clr-text);
  transition: all .25s ease; position: relative; overflow: hidden;
}
.cta-tool-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(255,160,50,.06), rgba(124,92,255,.06));
  opacity: 0; transition: opacity .25s;
}
.cta-tool-card:hover { border-color: var(--clr-accent); transform: translateY(-3px); box-shadow: 0 8px 24px rgba(0,0,0,.3); }
.cta-tool-card:hover::before { opacity: 1; }
.cta-tool-icon { font-size: 1.8rem; z-index: 1; }
.cta-tool-name { font-weight: 700; font-size: var(--fs-md); z-index: 1; }
.cta-tool-desc { font-size: var(--fs-xs); color: var(--clr-text-dim); line-height: 1.6; z-index: 1; flex: 1; }
.cta-tool-arrow {
  align-self: flex-end; font-size: 1.2rem; color: var(--clr-accent);
  opacity: 0; transform: translateX(-8px);
  transition: all .25s; z-index: 1;
}
.cta-tool-card:hover .cta-tool-arrow { opacity: 1; transform: translateX(0); }

/* ── Related Article Cards ── */
.cta-related-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: var(--sp-md); }
.cta-related-card {
  display: flex; align-items: center; gap: var(--sp-md);
  padding: var(--sp-md) var(--sp-lg);
  background: var(--clr-card); border: 1px solid var(--clr-border);
  border-radius: var(--radius-md);
  text-decoration: none; color: var(--clr-text);
  transition: all .2s;
}
.cta-related-card:hover { border-color: var(--clr-accent2); background: rgba(124,92,255,.06); transform: translateX(4px); }
.cta-related-badge { flex-shrink: 0; font-size: var(--fs-xs); padding: 2px var(--sp-sm); background: rgba(124,92,255,.12); border-radius: 50px; color: var(--clr-accent2); white-space: nowrap; }
.cta-related-title { font-size: var(--fs-sm); font-weight: 600; }

/* ── Article Meta Line (E-E-A-T) ── */
.article-meta-line {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-sm);
  margin-top: var(--sp-md);
  font-size: var(--fs-xs);
  color: var(--clr-text-dim);
  opacity: .8;
}
.article-meta-line a {
  color: var(--clr-accent);
  text-decoration: underline;
  text-underline-offset: 2px;
}
.article-meta-line a:hover { color: #ffb74d; }

/* ── Inline Expandable Why-Tips ── */
.why-inline {
  display: inline;
  cursor: pointer;
}
.why-inline > summary {
  display: inline;
  color: var(--clr-accent);
  border-bottom: 1.5px dashed var(--clr-accent);
  cursor: pointer;
  font-weight: 600;
  list-style: none;
  transition: color .2s, border-color .2s;
}
.why-inline > summary::-webkit-details-marker { display: none; }
.why-inline > summary::marker { display: none; content: ''; }
.why-inline > summary::after {
  content: ' ❓';
  font-size: .75em;
  opacity: .7;
  transition: opacity .2s;
}
.why-inline > summary:hover { color: #ffb74d; border-color: #ffb74d; }
.why-inline > summary:hover::after { opacity: 1; }
.why-inline[open] > summary { color: #ffb74d; border-color: transparent; }
.why-inline[open] > summary::after { content: ' ✕'; opacity: .5; }
.why-inline > .why-body {
  display: block;
  margin: var(--sp-sm) 0;
  padding: var(--sp-md) var(--sp-lg);
  background: linear-gradient(135deg, rgba(255,160,50,.08), rgba(124,92,255,.06));
  border-left: 3px solid var(--clr-accent);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-size: var(--fs-sm);
  line-height: 1.8;
  color: var(--clr-text);
  animation: whyFadeIn .25s ease;
}
.why-body strong { color: var(--clr-accent); }
.why-body cite {
  display: block;
  margin-top: var(--sp-sm);
  padding-top: var(--sp-xs);
  border-top: 1px solid rgba(255,255,255,.06);
  font-size: var(--fs-xs);
  color: var(--clr-text-dim);
  font-style: normal;
  opacity: .7;
}
@keyframes whyFadeIn {
  from { opacity: 0; transform: translateY(-4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .guide-layout { flex-direction: column; padding: var(--sp-lg); }
  .guide-toc { position: static; width: 100%; max-height: none; display: none; }
  .nav-links { display: none; }
  .guide-tl-grid { grid-template-columns: 1fr; }
  .guide-info-grid { grid-template-columns: 1fr; }
  .article-hero { padding: 80px var(--sp-md) var(--sp-xl); }
  .cta-tools-grid { grid-template-columns: 1fr; }
  .cta-related-grid { grid-template-columns: 1fr; }
  .back-to-top { bottom: 16px; right: 16px; width: 40px; height: 40px; font-size: 1rem; }
}

/* ── Back to Top ── */
.back-to-top {
  position: fixed; bottom: 30px; right: 24px;
  width: 44px; height: 44px; border-radius: 50%;
  background: linear-gradient(135deg, var(--clr-accent), #e8923a);
  color: #0f0e13; border: none;
  font-size: 1.2rem; font-weight: 700; cursor: pointer;
  z-index: 900;
  opacity: 0; pointer-events: none; transform: translateY(20px);
  transition: all .3s cubic-bezier(.16,1,.3,1);
  box-shadow: 0 4px 16px rgba(244,166,35,.3);
}
.back-to-top.visible { opacity: 1; pointer-events: auto; transform: translateY(0); }
.back-to-top:hover { transform: translateY(-3px); box-shadow: 0 6px 24px rgba(244,166,35,.5); }