/* ============================================================
   AR PIANO VISION — Design System CSS
   File: css/style.css
   Dipendenze: Google Fonts (Outfit, Inter, JetBrains Mono)
   ============================================================ */

/* ── GOOGLE FONTS ── */
@import url('https://fonts.googleapis.com/css2?family=Outfit:wght@300;400;500;600;700;800;900&family=Inter:wght@300;400;500;600&family=JetBrains+Mono:wght@400;500;600&display=swap');

/* ── DESIGN TOKENS ── */
:root {
  /* Backgrounds */
  --bg-base:        #060913;
  --bg:             #060913;
  --bg-surface:     #0c1220;
  --bg-card:        rgba(255, 255, 255, 0.04);
  --bg-card-hover:  rgba(255, 255, 255, 0.07);

  /* Borders */
  --border-subtle:  rgba(255, 255, 255, 0.08);
  --border-mid:     rgba(255, 255, 255, 0.14);
  --border-accent:  rgba(111, 170, 255, 0.32);

  /* Primary palette — Viola/Indaco */
  --clr-primary:      hsl(248, 90%, 68%);
  --clr-primary-glow: hsl(248, 100%, 76%);
  --clr-primary-dim:  rgba(111, 90, 255, 0.15);

  /* Secondary palette — Ciano */
  --clr-cyan:         hsl(190, 80%, 55%);
  --clr-cyan-dim:     rgba(50, 200, 220, 0.12);

  /* Accent palette */
  --clr-accent:    hsl(320, 85%, 65%);
  --clr-gold:      hsl(42,  100%, 65%);
  --clr-green:     hsl(145, 70%, 52%);
  --clr-red:       hsl(5,   85%, 60%);
  --clr-orange:    hsl(28,  90%, 60%);

  /* Difficulty colors */
  --diff-beginner:     hsl(145, 70%, 52%);
  --diff-easy:         hsl(190, 80%, 55%);
  --diff-intermediate: hsl(42,  100%, 65%);
  --diff-advanced:     hsl(5,   85%, 60%);

  /* Text (calibrated for WCAG AA >= 4.5:1 contrast against #060913) */
  --text-primary:   rgba(255, 255, 255, 0.95);
  --text-secondary: rgba(255, 255, 255, 0.72);
  --text-muted:     rgba(255, 255, 255, 0.58);
  --text-code:      hsl(190, 80%, 75%);

  /* Typography */
  --font-display: 'Outfit', sans-serif;
  --font-body:    'Inter', sans-serif;
  --font-mono:    'JetBrains Mono', monospace;

  /* Radius */
  --r-sm:   6px;
  --r-md:   12px;
  --r-lg:   18px;
  --r-xl:   24px;
  --r-pill: 999px;

  /* Shadows */
  --shadow-card:    0 4px 24px rgba(0, 0, 0, 0.5), 0 1px 0 rgba(255, 255, 255, 0.05) inset;
  --shadow-glow-p:  0 0 32px rgba(111, 90, 255, 0.35);
  --shadow-glow-c:  0 0 24px rgba(50, 200, 220, 0.25);
  --shadow-elevated:0 16px 64px rgba(0, 0, 0, 0.6);

  /* Glassmorphism */
  --glass-bg:     rgba(255, 255, 255, 0.045);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-blur:   blur(20px);

  /* Transitions */
  --tr-fast:   0.15s ease;
  --tr-normal: 0.25s ease;
  --tr-slow:   0.4s ease;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  background-color: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-body);
  font-size: 15px;
  line-height: 1.7;
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  animation: pageFadeIn 200ms ease-out forwards;
}

img, video, svg {
  display: block;
  max-width: 100%;
}

button, input, select, textarea {
  font: inherit;
  color: inherit;
}

a { color: inherit; text-decoration: none; }

/* ── GLOBAL BACKGROUND MESH ── */
.bg-mesh {
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 15% 10%,  rgba(111, 90, 255, 0.11) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 85% 85%,  rgba(50, 200, 220, 0.07) 0%, transparent 55%),
    radial-gradient(ellipse 50% 60% at 60% 35%,  rgba(220, 80, 180, 0.05) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}

/* ── LAYOUT ── */
.page-wrap {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px 80px;
}

.page-wrap--wide { max-width: 1280px; }
.page-wrap--narrow { max-width: 680px; }

/* ── GLASS ── */
.glass {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  backdrop-filter: var(--glass-blur);
  -webkit-backdrop-filter: var(--glass-blur);
}

/* ── DIVIDER ── */
.divider {
  height: 1px;
  background: linear-gradient(90deg,
    transparent,
    var(--border-subtle),
    var(--border-accent),
    var(--border-subtle),
    transparent);
  margin: 40px 0;
}

/* ── BADGE / CHIP ── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--glass-bg);
  border: 1px solid var(--border-accent);
  border-radius: var(--r-pill);
  padding: 6px 18px;
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--clr-primary-glow);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  backdrop-filter: var(--glass-blur);
}

.badge--pulse::before {
  content: '';
  width: 6px; height: 6px;
  background: var(--clr-primary-glow);
  border-radius: 50%;
  animation: blink 2s ease-in-out infinite;
  flex-shrink: 0;
}

.chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--r-pill);
  padding: 4px 12px;
  font-size: 12px;
  color: var(--text-secondary);
  font-family: var(--font-mono);
}

.chip .dot { width: 6px; height: 6px; border-radius: 50%; flex-shrink: 0; }

/* Difficulty tags */
.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 10px;
  padding: 2px 9px;
  border-radius: var(--r-pill);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
}
.tag--beginner    { background: rgba(80,200,100,.13);  color: var(--diff-beginner);    border: 1px solid rgba(80,200,100,.25); }
.tag--easy        { background: rgba(50,200,220,.13);  color: var(--diff-easy);        border: 1px solid rgba(50,200,220,.25); }
.tag--intermediate{ background: rgba(240,180,50,.13);  color: var(--diff-intermediate);border: 1px solid rgba(240,180,50,.25); }
.tag--advanced    { background: rgba(220,80,60,.13);   color: var(--diff-advanced);    border: 1px solid rgba(220,80,60,.25); }

/* ── TYPOGRAPHY ── */
.h-display {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 6vw, 4.2rem);
  font-weight: 800;
  letter-spacing: -0.025em;
  line-height: 1.08;
  background: linear-gradient(135deg, #fff 0%, var(--clr-primary-glow) 45%, var(--clr-cyan) 75%, var(--clr-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.h-title {
  font-family: var(--font-display);
  font-size: clamp(1.4rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--text-primary);
}

.h-section {
  font-family: var(--font-display);
  font-size: clamp(1.1rem, 2.5vw, 1.5rem);
  font-weight: 600;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

.label-mono {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--clr-primary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
}

/* ── BUTTONS ── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: var(--r-pill);
  font-family: var(--font-display);
  font-size: 0.9rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform var(--tr-fast), box-shadow var(--tr-fast), opacity var(--tr-fast);
  position: relative;
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}

.btn:active { transform: scale(0.97); }

/* Ripple effect (T-24) */
.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle, rgba(255, 255, 255, 0.35) 10%, transparent 70%);
  transform: scale(0);
  opacity: 0;
  pointer-events: none;
  transition: transform 0.45s ease-out, opacity 0.45s ease-out;
}
.btn:active::after {
  transform: scale(2.5);
  opacity: 1;
  transition: 0s;
}

.btn--primary {
  background: linear-gradient(135deg, var(--clr-primary) 0%, hsl(270, 85%, 58%) 100%);
  color: #fff;
  box-shadow: 0 4px 20px rgba(111, 90, 255, 0.4);
}
.btn--primary:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-p);
}

.btn--ghost {
  background: var(--glass-bg);
  border: 1px solid var(--border-mid);
  color: var(--text-secondary);
  backdrop-filter: var(--glass-blur);
}
.btn--ghost:hover {
  border-color: var(--border-accent);
  color: var(--text-primary);
  background: var(--bg-card-hover);
}

.btn--cta {
  background: linear-gradient(135deg, var(--clr-cyan) 0%, var(--clr-primary) 100%);
  color: #fff;
  font-size: 1rem;
  padding: 15px 36px;
  box-shadow: 0 6px 30px rgba(50, 200, 220, 0.3);
}
.btn--cta:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow-c);
}

.btn--sm { padding: 8px 18px; font-size: 0.82rem; min-height: 40px; }
.btn--lg { padding: 17px 40px; font-size: 1.05rem; }
.btn--icon { padding: 11px; border-radius: 50%; min-width: 44px; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; }
.btn:disabled { opacity: 0.5; pointer-events: none; }

/* ── CARDS (T-24: scale + glow viola 300ms ease) ── */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--r-lg);
  padding: 24px;
  box-shadow: var(--shadow-card);
  transition: transform 300ms ease, box-shadow 300ms ease, border-color 300ms ease, background 300ms ease;
  will-change: transform;
}

.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(111, 90, 255, 0.4);
  transform: scale(1.02);
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.5), 0 0 24px rgba(111, 90, 255, 0.35);
}

.card--bordered-l  { border-left: 3px solid var(--clr-primary); }
.card--bordered-lc { border-left: 3px solid var(--clr-cyan); }
.card--interactive { cursor: pointer; }
.card--selected {
  border-color: var(--clr-primary) !important;
  background: var(--clr-primary-dim) !important;
  box-shadow: var(--shadow-card), 0 0 0 1px var(--clr-primary-dim);
}

/* ── SONG CARD ── */
.song-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--r-lg);
  padding: 20px;
  cursor: pointer;
  transition: transform 300ms ease, box-shadow 300ms ease, border-color 300ms ease, background 300ms ease;
  position: relative;
  overflow: hidden;
  will-change: transform;
}

.song-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--clr-primary-dim), transparent);
  opacity: 0;
  transition: opacity var(--tr-normal);
}

.song-card:hover::before { opacity: 1; }
.song-card:hover {
  border-color: rgba(111, 90, 255, 0.45);
  transform: scale(1.02);
  box-shadow: 0 12px 36px rgba(0, 0, 0, 0.5), 0 0 24px rgba(111, 90, 255, 0.35);
}

.song-card.selected {
  border-color: var(--clr-primary);
  box-shadow: 0 0 0 1px var(--clr-primary-dim), 0 8px 32px rgba(111, 90, 255, 0.2);
}

/* ── FORM ELEMENTS ── */
.range-wrap { display: flex; flex-direction: column; gap: 6px; }
.range-label { display: flex; justify-content: space-between; font-size: 0.85rem; color: var(--text-secondary); }

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  background: var(--border-subtle);
  border-radius: var(--r-pill);
  outline: none;
  cursor: pointer;
}
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px; height: 18px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--clr-primary), var(--clr-primary-glow));
  box-shadow: 0 0 8px rgba(111, 90, 255, 0.5);
  cursor: pointer;
  transition: transform var(--tr-fast);
}
input[type="range"]::-webkit-slider-thumb:active { transform: scale(1.2); }

.toggle-wrap { display: flex; align-items: center; justify-content: space-between; }

.toggle {
  position: relative;
  width: 44px; height: 24px;
  cursor: pointer;
}
.toggle input { opacity: 0; width: 0; height: 0; }
.toggle-slider {
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0.12);
  border-radius: var(--r-pill);
  transition: background var(--tr-normal);
}
.toggle-slider::before {
  content: '';
  position: absolute;
  width: 18px; height: 18px;
  left: 3px; top: 3px;
  background: #fff;
  border-radius: 50%;
  transition: transform var(--tr-normal);
}
.toggle input:checked + .toggle-slider {
  background: var(--clr-primary);
}
.toggle input:checked + .toggle-slider::before {
  transform: translateX(20px);
}

/* ── SPINNER / LOADING ── */
.spinner {
  width: 40px; height: 40px;
  border: 3px solid var(--border-subtle);
  border-top-color: var(--clr-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin { to { transform: rotate(360deg); } }

/* ── SKELETON LOADER & SHIMMER (T-24) ── */
.skeleton {
  background: linear-gradient(90deg, rgba(255, 255, 255, 0.04) 25%, rgba(111, 90, 255, 0.16) 50%, rgba(255, 255, 255, 0.04) 75%);
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--r-md);
  will-change: background-position;
}

.skeleton-text {
  height: 14px;
  margin-bottom: 8px;
  border-radius: var(--r-sm);
}

.skeleton-title {
  height: 20px;
  width: 60%;
  margin-bottom: 12px;
  border-radius: var(--r-sm);
}

.skeleton-card {
  height: 80px;
  border-radius: var(--r-lg);
  margin-bottom: 12px;
}

@keyframes shimmer { to { background-position: -200% 0; } }

/* ── DIFFICULTY TAGS & BADGES (T-24) ── */
.tag {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 10px;
  border-radius: var(--r-pill);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  white-space: nowrap;
  transition: transform var(--tr-fast), box-shadow var(--tr-fast);
}

.tag::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: currentColor;
}

/* beginner = verde */
.tag--beginner {
  background: rgba(34, 197, 94, 0.12);
  color: #22c55e;
  border: 1px solid rgba(34, 197, 94, 0.3);
}

/* easy = ciano */
.tag--easy {
  background: rgba(0, 240, 255, 0.12);
  color: #00f0ff;
  border: 1px solid rgba(0, 240, 255, 0.3);
}

/* intermediate = giallo */
.tag--intermediate {
  background: rgba(251, 191, 36, 0.12);
  color: #fbbf24;
  border: 1px solid rgba(251, 191, 36, 0.3);
}

/* advanced = rosso */
.tag--advanced {
  background: rgba(239, 68, 68, 0.12);
  color: #ef4444;
  border: 1px solid rgba(239, 68, 68, 0.3);
}

/* Page Fade-In (T-24) */
@keyframes pageFadeIn {
  from { opacity: 0; }
  to   { opacity: 1; }
}

/* ── PROGRESS BAR ── */
.progress-bar {
  height: 4px;
  background: var(--border-subtle);
  border-radius: var(--r-pill);
  overflow: hidden;
}
.progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--clr-primary), var(--clr-cyan));
  border-radius: var(--r-pill);
  transition: width 0.3s ease;
}

/* ── HORIZONTAL CAROUSEL ── */
.carousel-wrap {
  position: relative;
  overflow: hidden;
}

.carousel {
  display: flex;
  gap: 20px;
  overflow-x: auto;
  scroll-snap-type: x mandatory;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
  padding-bottom: 16px;
}
.carousel::-webkit-scrollbar { display: none; }

.carousel-slide {
  scroll-snap-align: center;
  flex: 0 0 min(340px, 85vw);
}

.carousel-dots {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin-top: 20px;
}
.carousel-dot {
  width: 8px; height: 8px;
  border-radius: 50%;
  background: var(--border-mid);
  border: none;
  cursor: pointer;
  padding: 0;
  transition: background var(--tr-normal), transform var(--tr-normal), width var(--tr-normal);
}
.carousel-dot.active {
  background: var(--clr-primary);
  box-shadow: 0 0 8px var(--clr-primary);
  width: 24px;
  border-radius: var(--r-pill);
}

/* ── ALERT BOXES ── */
.alert {
  display: flex;
  gap: 14px;
  padding: 16px 20px;
  border-radius: var(--r-md);
  font-size: 0.875rem;
  line-height: 1.6;
}
.alert-icon { font-size: 1.2rem; flex-shrink: 0; margin-top: 2px; }
.alert--info    { background: rgba(50,200,220,0.08);  border: 1px solid rgba(50,200,220,0.25);  color: hsl(190,70%,80%); }
.alert--success { background: rgba(80,200,100,0.08);  border: 1px solid rgba(80,200,100,0.25);  color: hsl(145,60%,75%); }
.alert--warning { background: rgba(240,180,50,0.08);  border: 1px solid rgba(240,180,50,0.25);  color: hsl(38,85%,75%); }
.alert--purple  { background: rgba(111,90,255,0.08);  border: 1px solid rgba(111,90,255,0.25);  color: hsl(248,80%,82%); }

/* ── UTILITY ── */
.hidden { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px; overflow: hidden; clip: rect(0,0,0,0); border: 0; }
.text-center { text-align: center; }
.text-muted { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }
.mono { font-family: var(--font-mono); }

/* ── ANIMATIONS ── */
@keyframes blink {
  0%, 100% { opacity: 1; box-shadow: 0 0 8px var(--clr-primary-glow); }
  50%       { opacity: 0.3; box-shadow: none; }
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fade-in-fast {
  from { opacity: 0; }
  to   { opacity: 1; }
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50%       { transform: translateY(-8px); }
}

@keyframes glow-pulse {
  0%, 100% { box-shadow: var(--shadow-glow-p); }
  50%       { box-shadow: 0 0 60px rgba(111,90,255,0.5); }
}

.anim-fade-in { animation: fade-in 0.5s ease both; }
.anim-fade-in-fast { animation: fade-in-fast 0.3s ease both; }
.anim-float   { animation: float 3s ease-in-out infinite; }

/* Staggered children */
.stagger > *:nth-child(1) { animation-delay: 0.05s; }
.stagger > *:nth-child(2) { animation-delay: 0.12s; }
.stagger > *:nth-child(3) { animation-delay: 0.19s; }
.stagger > *:nth-child(4) { animation-delay: 0.26s; }
.stagger > *:nth-child(5) { animation-delay: 0.33s; }
.stagger > *:nth-child(6) { animation-delay: 0.40s; }

/* Scroll reveal */
.reveal {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}
.reveal.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ── RESPONSIVE ── */
@media (max-width: 640px) {
  .page-wrap { padding: 0 16px 64px; }
  .btn { padding: 12px 22px; }
  .btn--lg { padding: 14px 28px; font-size: 0.95rem; }
  .card { padding: 18px; }
}

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

/* ══════════════════════════════════════════════════════════════
   LUXURY TOP NAVIGATION & PWA INSTALL MODAL (T-PWA)
   ══════════════════════════════════════════════════════════════ */
.luxury-top-nav {
  position: sticky;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(6, 9, 19, 0.88);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border-subtle);
  padding: 12px 20px;
}

.top-nav-wrap {
  max-width: 1200px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--text-primary);
}

.nav-brand-icon {
  font-size: 1.5rem;
  line-height: 1;
}

.nav-brand-name {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  letter-spacing: -0.01em;
  background: linear-gradient(135deg, #ffffff 40%, hsl(248, 90%, 80%));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.nav-badge {
  font-family: var(--font-mono);
  font-size: 0.65rem;
  font-weight: 700;
  padding: 2px 7px;
  border-radius: 999px;
  background: rgba(111, 90, 255, 0.16);
  border: 1px solid rgba(111, 90, 255, 0.35);
  color: hsl(248, 90%, 80%);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 16px;
}

.nav-link {
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  padding: 6px 12px;
  border-radius: var(--r-sm);
  transition: color var(--tr-fast), background var(--tr-fast);
}

.nav-link:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.05);
}

.nav-link-ar {
  color: hsl(190, 85%, 65%);
  background: rgba(50, 200, 220, 0.08);
  border: 1px solid rgba(50, 200, 220, 0.22);
}

.nav-link-ar:hover {
  background: rgba(50, 200, 220, 0.16);
  color: #fff;
}

.nav-btn-install {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-display);
  font-size: 0.88rem;
  font-weight: 700;
  color: #ffffff;
  background: linear-gradient(135deg, hsl(248, 90%, 65%), hsl(280, 85%, 60%));
  border: 1px solid rgba(255, 255, 255, 0.25);
  padding: 8px 18px;
  border-radius: 999px;
  cursor: pointer;
  box-shadow: 0 0 20px rgba(111, 90, 255, 0.4);
  transition: transform var(--tr-fast), box-shadow var(--tr-fast);
}

.nav-btn-install:hover {
  transform: translateY(-1px) scale(1.02);
  box-shadow: 0 0 28px rgba(111, 90, 255, 0.6);
}

.install-pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: hsl(145, 80%, 55%);
  box-shadow: 0 0 8px hsl(145, 100%, 60%);
  animation: pulse-dot 1.8s infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.4; transform: scale(1.3); }
}

/* Modal Install Guide */
.modal-backdrop {
  position: fixed;
  inset: 0;
  z-index: 10000;
  background: rgba(4, 6, 14, 0.82);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.modal-backdrop.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  width: 100%;
  max-width: 540px;
  background: linear-gradient(180deg, #0e1428 0%, #080c18 100%);
  border: 1px solid rgba(111, 90, 255, 0.35);
  border-radius: 24px;
  box-shadow: 0 24px 80px rgba(0, 0, 0, 0.8), 0 0 40px rgba(111, 90, 255, 0.2);
  padding: 28px 24px;
  position: relative;
  transform: scale(0.95) translateY(12px);
  transition: transform 0.25s ease;
  max-height: 90vh;
  overflow-y: auto;
}

.modal-backdrop.open .modal-card {
  transform: scale(1) translateY(0);
}

.modal-close-btn {
  position: absolute;
  top: 18px;
  right: 18px;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-secondary);
  font-size: 1.1rem;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background var(--tr-fast), color var(--tr-fast);
}

.modal-close-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  color: #fff;
}

.modal-header {
  margin-bottom: 20px;
  padding-right: 32px;
}

.modal-title {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 800;
  color: #fff;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.modal-subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.modal-tabs {
  display: flex;
  gap: 6px;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: 14px;
  padding: 4px;
  margin-bottom: 22px;
}

.modal-tab-btn {
  flex: 1;
  padding: 8px 10px;
  font-family: var(--font-body);
  font-size: 0.82rem;
  font-weight: 600;
  border-radius: 10px;
  background: transparent;
  color: var(--text-muted);
  border: none;
  cursor: pointer;
  transition: all var(--tr-fast);
  text-align: center;
  white-space: nowrap;
}

.modal-tab-btn.active {
  background: rgba(111, 90, 255, 0.22);
  color: #fff;
  border: 1px solid rgba(111, 90, 255, 0.4);
}

.modal-step-list {
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 24px;
}

.modal-step-item {
  display: flex;
  gap: 14px;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 14px;
  padding: 14px;
  align-items: flex-start;
}

.modal-step-num {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, hsl(248, 90%, 65%), hsl(190, 85%, 55%));
  color: #fff;
  font-family: var(--font-mono);
  font-size: 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.modal-step-text strong {
  display: block;
  font-size: 0.9rem;
  color: var(--text-primary);
  margin-bottom: 2px;
}

.modal-step-text p {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.4;
  margin: 0;
}

.modal-actions {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.modal-btn-native {
  width: 100%;
  padding: 14px;
  border-radius: 14px;
  border: none;
  background: linear-gradient(135deg, hsl(248, 90%, 65%), hsl(280, 85%, 60%));
  color: #fff;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(111, 90, 255, 0.4);
  transition: transform var(--tr-fast);
}

.modal-btn-native:hover {
  transform: translateY(-1px);
}

.modal-btn-browser {
  width: 100%;
  padding: 12px;
  border-radius: 14px;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-secondary);
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 500;
  cursor: pointer;
  transition: background var(--tr-fast), color var(--tr-fast);
}

.modal-btn-browser:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #fff;
}

@media (max-width: 680px) {
  .nav-links .nav-link { display: none; }
  .nav-brand-name { font-size: 1rem; }
  .nav-btn-install { padding: 6px 14px; font-size: 0.8rem; }
}