/* === HOBBYMUSIC — Design System 2025 === */

@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700;800&family=Inter:wght@400;500;600&display=swap');

/* === CSS Variables === */
:root {
  --c-bg: #F8F7FF;
  --c-white: #FFFFFF;
  --c-primary: #7C3AED;
  --c-primary-light: #EDE9FE;
  --c-primary-mid: #A78BFA;
  --c-accent: #06B6D4;
  --c-accent-warm: #F59E0B;
  --c-green: #10B981;
  --c-red: #EF4444;
  --c-text: #1E1B4B;
  --c-text-2: #4B5563;
  --c-text-3: #9CA3AF;
  --c-border: rgba(124,58,237,0.12);
  --c-glass: rgba(255,255,255,0.82);
  --c-glass-dark: rgba(124,58,237,0.06);
  --shadow-sm: 0 2px 8px rgba(124,58,237,0.08);
  --shadow-md: 0 8px 32px rgba(124,58,237,0.12);
  --shadow-lg: 0 20px 60px rgba(124,58,237,0.18);
  --shadow-glow: 0 0 40px rgba(124,58,237,0.25);
  --radius-sm: 10px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --radius-xl: 40px;
  --font-head: 'Plus Jakarta Sans', sans-serif;
  --font-body: 'Inter', sans-serif;
  --nav-h: 68px;
  --transition: 0.3s cubic-bezier(0.4,0,0.2,1);
  --transition-bounce: 0.4s cubic-bezier(0.34,1.56,0.64,1);
}

/* === Reset === */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-body);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.6;
  overflow-x: hidden;
  min-height: 100vh;
}
img, svg { max-width: 100%; display: block; }
a { text-decoration: none; color: inherit; }
button { font-family: inherit; cursor: pointer; border: none; outline: none; }
input, select { font-family: inherit; }

/* === Background mesh === */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 20% -10%, rgba(167,139,250,0.18) 0%, transparent 60%),
    radial-gradient(ellipse 60% 40% at 80% 110%, rgba(6,182,212,0.12) 0%, transparent 55%),
    radial-gradient(ellipse 40% 60% at 95% 30%, rgba(245,158,11,0.08) 0%, transparent 50%);
  pointer-events: none;
  z-index: 0;
}
body > * { position: relative; z-index: 1; }

/* === Keyframe Animations === */
@keyframes float {
  0%,100% { transform: translateY(0px) rotate(0deg); }
  33% { transform: translateY(-12px) rotate(1deg); }
  66% { transform: translateY(-6px) rotate(-1deg); }
}
@keyframes float-slow {
  0%,100% { transform: translateY(0px); }
  50% { transform: translateY(-18px); }
}
@keyframes wave-bar {
  0%,100% { transform: scaleY(0.4); }
  50% { transform: scaleY(1); }
}
@keyframes pulse-ring {
  0% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(124,58,237,0.4); }
  70% { transform: scale(1); box-shadow: 0 0 0 18px rgba(124,58,237,0); }
  100% { transform: scale(0.95); box-shadow: 0 0 0 0 rgba(124,58,237,0); }
}
@keyframes gradient-flow {
  0%,100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}
@keyframes slide-up {
  from { transform: translateY(40px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}
@keyframes slide-in-left {
  from { transform: translateX(-30px); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}
@keyframes scale-in {
  from { transform: scale(0.85); opacity: 0; }
  to { transform: scale(1); opacity: 1; }
}
@keyframes shimmer {
  0% { background-position: -400% center; }
  100% { background-position: 400% center; }
}
@keyframes spin-slow {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}
@keyframes blink {
  0%,100% { opacity: 1; }
  50% { opacity: 0.2; }
}
@keyframes note-float {
  0% { transform: translateY(0) rotate(0deg); opacity: 0.7; }
  100% { transform: translateY(-120px) rotate(20deg); opacity: 0; }
}
@keyframes swing-left {
  0%,100% { transform: rotate(28deg) translateZ(0); }
  50% { transform: rotate(-28deg) translateZ(0); }
}
@keyframes beat-flash {
  0% { background: var(--c-primary); transform: scale(1.1); }
  100% { background: var(--c-primary-light); transform: scale(1); }
}
@keyframes needle-swing {
  0%,100% { transform: rotate(-30deg); }
  50% { transform: rotate(30deg); }
}

/* === Utility Classes === */
.animate-float { animation: float 4s ease-in-out infinite; }
.animate-float-slow { animation: float-slow 6s ease-in-out infinite; }
.animate-pulse-ring { animation: pulse-ring 2s cubic-bezier(0.455,0.03,0.515,0.955) infinite; }
.animate-shimmer {
  background: linear-gradient(90deg, transparent 25%, rgba(255,255,255,0.6) 50%, transparent 75%);
  background-size: 400% 100%;
  animation: shimmer 2s infinite;
}
.animate-slide-up { animation: slide-up 0.6s ease both; }
.animate-scale-in { animation: scale-in 0.4s var(--transition-bounce) both; }
.reveal { opacity: 0; transform: translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity: 1; transform: translateY(0); }

/* === Navigation === */
.nav {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--nav-h);
  background: rgba(248,247,255,0.85);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom: 1px solid var(--c-border);
  display: flex;
  align-items: center;
  padding: 0 24px;
}
.nav-inner {
  max-width: 1280px;
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 16px;
}
.nav-logo {
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.25rem;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  white-space: nowrap;
  flex-shrink: 0;
}
.nav-tools {
  display: flex;
  align-items: center;
  gap: 4px;
  flex-wrap: nowrap;
  overflow-x: auto;
  scrollbar-width: none;
  flex: 1;
}
.nav-tools::-webkit-scrollbar { display: none; }
.nav-link {
  padding: 7px 14px;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--c-text-2);
  white-space: nowrap;
  transition: var(--transition);
  flex-shrink: 0;
}
.nav-link:hover { background: var(--c-primary-light); color: var(--c-primary); }
.nav-link.active { background: var(--c-primary); color: white; }
.nav-burger {
  display: none;
  width: 40px; height: 40px;
  border-radius: 10px;
  background: var(--c-primary-light);
  color: var(--c-primary);
  align-items: center; justify-content: center;
  font-size: 1.2rem;
  flex-shrink: 0;
  transition: var(--transition);
}
.nav-burger:hover { background: var(--c-primary); color: white; }
.nav-mobile {
  display: none;
  position: fixed;
  top: var(--nav-h);
  left: 0; right: 0;
  background: var(--c-white);
  border-bottom: 1px solid var(--c-border);
  padding: 16px;
  flex-direction: column;
  gap: 4px;
  z-index: 999;
  box-shadow: var(--shadow-lg);
}
.nav-mobile.open { display: flex; animation: slide-up 0.25s ease; }
.nav-mobile .nav-link { padding: 12px 16px; border-radius: var(--radius-sm); font-size: 0.95rem; }

/* === Container === */
.container {
  max-width: 1280px;
  margin: 0 auto;
  padding: 0 24px;
}
.container-sm { max-width: 860px; margin: 0 auto; padding: 0 24px; }

/* === Hero === */
.hero {
  padding: 72px 0 48px;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.hero-deco {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  pointer-events: none;
}
.hero-deco-1 {
  width: 500px; height: 500px;
  background: radial-gradient(circle, rgba(167,139,250,0.25) 0%, transparent 70%);
  top: -200px; left: -100px;
}
.hero-deco-2 {
  width: 400px; height: 400px;
  background: radial-gradient(circle, rgba(6,182,212,0.15) 0%, transparent 70%);
  bottom: -150px; right: -80px;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--c-primary-light);
  color: var(--c-primary);
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-bottom: 20px;
  animation: slide-up 0.5s ease both;
}
.hero h1 {
  font-family: var(--font-head);
  font-size: clamp(2.2rem, 5vw, 3.8rem);
  font-weight: 800;
  line-height: 1.15;
  color: var(--c-text);
  margin-bottom: 18px;
  animation: slide-up 0.5s 0.1s ease both;
}
.hero h1 .grad {
  background: linear-gradient(135deg, var(--c-primary) 0%, var(--c-accent) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero-desc {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--c-text-2);
  max-width: 600px;
  margin: 0 auto 32px;
  animation: slide-up 0.5s 0.2s ease both;
}
.hero-wave {
  display: flex;
  align-items: flex-end;
  gap: 4px;
  justify-content: center;
  height: 40px;
  margin-bottom: 24px;
}
.hero-wave span {
  width: 4px;
  background: linear-gradient(to top, var(--c-primary), var(--c-accent));
  border-radius: 4px;
  animation: wave-bar 1.2s ease-in-out infinite;
}
.hero-wave span:nth-child(2) { animation-delay: 0.1s; height: 60%; }
.hero-wave span:nth-child(3) { animation-delay: 0.2s; height: 100%; }
.hero-wave span:nth-child(4) { animation-delay: 0.3s; height: 75%; }
.hero-wave span:nth-child(5) { animation-delay: 0.4s; height: 90%; }
.hero-wave span:nth-child(6) { animation-delay: 0.5s; height: 55%; }
.hero-wave span:nth-child(7) { animation-delay: 0.6s; height: 80%; }
.hero-wave span:nth-child(8) { animation-delay: 0.7s; height: 40%; }

/* === Buttons === */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 13px 28px;
  border-radius: 50px;
  font-family: var(--font-head);
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  border: none;
  transition: var(--transition-bounce);
  position: relative;
  overflow: hidden;
  outline: none;
}
.btn::after {
  content: '';
  position: absolute;
  inset: 0;
  background: rgba(255,255,255,0.2);
  opacity: 0;
  transition: opacity 0.2s;
}
.btn:hover::after { opacity: 1; }
.btn-primary {
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  background-size: 200% 200%;
  color: white;
  box-shadow: 0 4px 20px rgba(124,58,237,0.35);
}
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 8px 30px rgba(124,58,237,0.45); }
.btn-primary:active { transform: translateY(0); }
.btn-secondary {
  background: var(--c-white);
  color: var(--c-primary);
  box-shadow: var(--shadow-sm);
  border: 1.5px solid var(--c-border);
}
.btn-secondary:hover { background: var(--c-primary-light); transform: translateY(-2px); border-color: var(--c-primary-mid); }
.btn-ghost {
  background: transparent;
  color: var(--c-primary);
  border: 1.5px solid var(--c-primary-mid);
}
.btn-ghost:hover { background: var(--c-primary-light); }
.btn-danger {
  background: linear-gradient(135deg, #EF4444, #F97316);
  color: white;
  box-shadow: 0 4px 20px rgba(239,68,68,0.3);
}
.btn-danger:hover { transform: translateY(-2px); }
.btn-sm { padding: 8px 18px; font-size: 0.82rem; }
.btn-lg { padding: 16px 40px; font-size: 1.05rem; }
.btn-icon {
  width: 44px; height: 44px;
  padding: 0;
  border-radius: 12px;
}
.btn:disabled { opacity: 0.5; pointer-events: none; }

/* === Cards === */
.card {
  background: var(--c-glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  transition: var(--transition);
  overflow: hidden;
}
.card:hover { transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.card-body { padding: 28px; }
.card-header {
  padding: 20px 28px;
  border-bottom: 1px solid var(--c-border);
}
.tool-card {
  background: var(--c-glass);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  padding: 40px 32px;
  backdrop-filter: blur(20px);
}

/* === Tool Wrapper === */
.tool-section {
  padding: 48px 0;
}
.tool-section .container { position: relative; }

/* === SEO Content Sections === */
.seo-section {
  padding: 80px 0;
  background: var(--c-white);
  margin-top: 40px;
}
.seo-section .container-sm { max-width: 800px; }
.seo-section h2 {
  font-family: var(--font-head);
  font-size: clamp(1.5rem, 3vw, 2.1rem);
  font-weight: 800;
  color: var(--c-text);
  margin-bottom: 16px;
  margin-top: 40px;
}
.seo-section h2:first-child { margin-top: 0; }
.seo-section h3 {
  font-family: var(--font-head);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--c-text);
  margin-bottom: 10px;
  margin-top: 28px;
}
.seo-section p {
  color: var(--c-text-2);
  font-size: 1rem;
  line-height: 1.8;
  margin-bottom: 16px;
}
.seo-section ul {
  list-style: none;
  margin-bottom: 20px;
}
.seo-section ul li {
  position: relative;
  padding-left: 24px;
  color: var(--c-text-2);
  line-height: 1.8;
  margin-bottom: 8px;
}
.seo-section ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 10px;
  width: 8px; height: 8px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
}
.faq-item {
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  margin-bottom: 12px;
  overflow: hidden;
  transition: var(--transition);
}
.faq-item:hover { border-color: var(--c-primary-mid); }
.faq-q {
  padding: 18px 22px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  background: var(--c-white);
  transition: var(--transition);
}
.faq-q:hover { background: var(--c-primary-light); color: var(--c-primary); }
.faq-q .icon { font-size: 0.8rem; transition: transform 0.3s; flex-shrink: 0; }
.faq-item.open .faq-q .icon { transform: rotate(180deg); }
.faq-a {
  padding: 0 22px;
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.4s ease, padding 0.3s ease;
  color: var(--c-text-2);
  line-height: 1.8;
}
.faq-item.open .faq-a { max-height: 500px; padding: 0 22px 18px; }

/* === Floating notes deco === */
.notes-deco {
  position: absolute;
  pointer-events: none;
  overflow: hidden;
  inset: 0;
}
.note-particle {
  position: absolute;
  font-size: 1.5rem;
  opacity: 0;
  animation: note-float 4s ease-in-out infinite;
}

/* === Range Sliders === */
input[type=range] {
  -webkit-appearance: none;
  appearance: none;
  width: 100%;
  height: 6px;
  border-radius: 10px;
  background: var(--c-primary-light);
  outline: none;
  cursor: pointer;
}
input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 22px; height: 22px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  box-shadow: 0 2px 8px rgba(124,58,237,0.4);
  transition: transform 0.2s;
}
input[type=range]::-webkit-slider-thumb:hover { transform: scale(1.2); }
input[type=range]::-moz-range-thumb {
  width: 22px; height: 22px;
  border-radius: 50%;
  border: none;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  box-shadow: 0 2px 8px rgba(124,58,237,0.4);
}

/* === Select === */
select {
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--c-border);
  background: var(--c-white);
  color: var(--c-text);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  outline: none;
  -webkit-appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='16' height='16' viewBox='0 0 24 24' fill='none' stroke='%237C3AED' stroke-width='2'%3E%3Cpath d='m6 9 6 6 6-6'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  padding-right: 36px;
}
select:focus { border-color: var(--c-primary); box-shadow: 0 0 0 3px rgba(124,58,237,0.1); }

/* === Tags / Chips === */
.chip {
  display: inline-flex;
  align-items: center;
  padding: 5px 12px;
  border-radius: 50px;
  font-size: 0.78rem;
  font-weight: 600;
  background: var(--c-primary-light);
  color: var(--c-primary);
  gap: 5px;
}
.chip-accent { background: rgba(6,182,212,0.1); color: var(--c-accent); }
.chip-warm { background: rgba(245,158,11,0.1); color: var(--c-accent-warm); }
.chip-green { background: rgba(16,185,129,0.1); color: var(--c-green); }

/* === Tool Grid (index page) === */
.tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 24px;
  padding: 16px 0 60px;
}
.tool-preview-card {
  background: var(--c-white);
  border: 1.5px solid var(--c-border);
  border-radius: var(--radius-lg);
  padding: 28px;
  transition: var(--transition-bounce);
  cursor: pointer;
  text-decoration: none;
  color: inherit;
  display: block;
  position: relative;
  overflow: hidden;
}
.tool-preview-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--c-primary), var(--c-accent));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.3s ease;
}
.tool-preview-card:hover { transform: translateY(-6px); box-shadow: var(--shadow-lg); border-color: var(--c-primary-mid); }
.tool-preview-card:hover::before { transform: scaleX(1); }
.tool-icon {
  width: 56px; height: 56px;
  border-radius: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6rem;
  margin-bottom: 16px;
  background: var(--c-primary-light);
  transition: var(--transition-bounce);
}
.tool-preview-card:hover .tool-icon { transform: scale(1.1) rotate(5deg); }
.tool-preview-card h3 {
  font-family: var(--font-head);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--c-text);
}
.tool-preview-card p {
  font-size: 0.87rem;
  color: var(--c-text-2);
  line-height: 1.6;
  margin-bottom: 16px;
}
.tool-stats {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
}

/* === Metronome specific === */
.metro-display {
  text-align: center;
  padding: 32px;
}
.metro-bpm {
  font-family: var(--font-head);
  font-size: 5rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1;
  margin-bottom: 4px;
}
.metro-bpm-label { font-size: 0.85rem; color: var(--c-text-3); font-weight: 500; letter-spacing: 2px; }
.metro-pendulum-wrap {
  width: 140px; height: 140px;
  margin: 24px auto;
  position: relative;
  transform-origin: top center;
}
.metro-pendulum-arm {
  width: 4px;
  height: 120px;
  background: linear-gradient(to bottom, var(--c-primary), var(--c-primary-mid));
  border-radius: 4px;
  margin: 0 auto;
  transform-origin: top center;
  transition: transform 0.02s linear;
}
.metro-pendulum-bob {
  width: 28px; height: 28px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  margin: 0 auto;
  margin-top: -6px;
  box-shadow: 0 4px 16px rgba(124,58,237,0.5);
  transition: box-shadow 0.1s;
}
.metro-beats {
  display: flex;
  justify-content: center;
  gap: 8px;
  margin: 20px 0;
}
.metro-beat-dot {
  width: 12px; height: 12px;
  border-radius: 50%;
  background: var(--c-primary-light);
  transition: all 0.05s ease;
}
.metro-beat-dot.active {
  background: var(--c-primary);
  box-shadow: 0 0 12px var(--c-primary);
  transform: scale(1.3);
}
.metro-beat-dot.accent {
  width: 16px; height: 16px;
  background: var(--c-accent-warm);
}
.metro-beat-dot.accent.active {
  background: var(--c-accent-warm);
  box-shadow: 0 0 16px var(--c-accent-warm);
}

/* === Tuner specific === */
.tuner-display {
  text-align: center;
  padding: 32px;
}
.tuner-note {
  font-family: var(--font-head);
  font-size: 6rem;
  font-weight: 800;
  line-height: 1;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 4px;
  min-height: 1.2em;
  display: flex;
  align-items: center;
  justify-content: center;
}
.tuner-cents {
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--c-text-2);
  margin-bottom: 20px;
}
.tuner-cents.sharp { color: var(--c-green); }
.tuner-cents.flat { color: var(--c-accent-warm); }
.tuner-gauge {
  position: relative;
  width: 280px;
  margin: 0 auto 20px;
}
.tuner-arc {
  width: 100%;
  height: 140px;
  overflow: visible;
}
.tuner-needle {
  transform-origin: bottom center;
  transition: transform 0.15s ease-out;
}
.tuner-level {
  width: 100%;
  height: 6px;
  background: var(--c-primary-light);
  border-radius: 10px;
  overflow: hidden;
  margin-top: 12px;
}
.tuner-level-bar {
  height: 100%;
  background: linear-gradient(90deg, var(--c-green), var(--c-accent-warm), var(--c-red));
  border-radius: 10px;
  width: 0%;
  transition: width 0.1s ease;
}

/* === Piano specific === */
.piano-wrap {
  overflow-x: auto;
  padding: 16px 0;
}
.piano-keys {
  display: flex;
  align-items: flex-start;
  position: relative;
  height: 160px;
  min-width: 460px;
  gap: 0;
  user-select: none;
}
.piano-key-w {
  width: 40px;
  height: 150px;
  background: var(--c-white);
  border: 1.5px solid #D1D5DB;
  border-radius: 0 0 10px 10px;
  cursor: pointer;
  position: relative;
  z-index: 1;
  transition: background 0.08s, transform 0.08s;
  flex-shrink: 0;
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding-bottom: 8px;
  font-size: 0.65rem;
  color: var(--c-text-3);
  font-weight: 600;
}
.piano-key-w:hover { background: var(--c-primary-light); }
.piano-key-w.pressed { background: var(--c-primary-light); transform: scaleY(0.97); border-color: var(--c-primary); }
.piano-key-b {
  width: 26px;
  height: 100px;
  background: var(--c-text);
  border-radius: 0 0 8px 8px;
  cursor: pointer;
  position: absolute;
  z-index: 2;
  transition: background 0.08s, transform 0.08s;
  margin-left: -13px;
}
.piano-key-b:hover { background: #374151; }
.piano-key-b.pressed { background: var(--c-primary); transform: scaleY(0.97); }
.piano-controls {
  display: flex;
  align-items: center;
  gap: 16px;
  flex-wrap: wrap;
  margin-top: 20px;
}
.piano-oct-display {
  font-family: var(--font-head);
  font-weight: 700;
  color: var(--c-primary);
  font-size: 1rem;
  min-width: 60px;
  text-align: center;
}

/* === Drum Machine specific === */
.drum-grid {
  display: grid;
  gap: 8px;
}
.drum-row {
  display: grid;
  grid-template-columns: 90px repeat(16, 1fr);
  gap: 6px;
  align-items: center;
}
.drum-label {
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--c-text-2);
  letter-spacing: 0.5px;
  text-transform: uppercase;
}
.drum-step {
  aspect-ratio: 1;
  border-radius: 8px;
  border: 1.5px solid var(--c-border);
  background: var(--c-white);
  cursor: pointer;
  transition: all 0.15s ease;
  min-height: 32px;
}
.drum-step.on {
  background: linear-gradient(135deg, var(--c-primary), var(--c-primary-mid));
  border-color: var(--c-primary);
  box-shadow: 0 2px 8px rgba(124,58,237,0.35);
}
.drum-step.on:hover { opacity: 0.85; }
.drum-step:not(.on):hover { background: var(--c-primary-light); border-color: var(--c-primary-mid); }
.drum-step.playing { outline: 3px solid var(--c-accent); outline-offset: 2px; }
.drum-step.on.accent {
  background: linear-gradient(135deg, var(--c-accent-warm), #F97316);
  border-color: var(--c-accent-warm);
  box-shadow: 0 2px 8px rgba(245,158,11,0.4);
}
.drum-divider { border-left: 2px solid var(--c-border); }
.drum-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}
.drum-bpm-display {
  font-family: var(--font-head);
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--c-primary);
  min-width: 50px;
  text-align: center;
}

/* === Chord Finder specific === */
.chord-display {
  text-align: center;
  padding: 24px;
}
.chord-name {
  font-family: var(--font-head);
  font-size: 3rem;
  font-weight: 800;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 8px;
}
.chord-notes-list {
  display: flex;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}
.chord-note-pill {
  padding: 6px 14px;
  border-radius: 50px;
  background: var(--c-primary-light);
  color: var(--c-primary);
  font-weight: 700;
  font-size: 0.9rem;
  font-family: var(--font-head);
}
.mini-piano {
  display: flex;
  position: relative;
  height: 80px;
  justify-content: center;
  margin: 16px auto;
  user-select: none;
}
.mpk-w {
  width: 22px; height: 70px;
  background: white;
  border: 1px solid #D1D5DB;
  border-radius: 0 0 5px 5px;
  position: relative;
  z-index: 1;
  flex-shrink: 0;
}
.mpk-w.hl { background: linear-gradient(to bottom, var(--c-primary), var(--c-primary-mid)); border-color: var(--c-primary); }
.mpk-b {
  width: 14px; height: 45px;
  background: #1E1B4B;
  border-radius: 0 0 4px 4px;
  position: absolute;
  z-index: 2;
  margin-left: -7px;
}
.mpk-b.hl { background: var(--c-primary); }

/* === Fretboard SVG === */
.fretboard-wrap { overflow-x: auto; margin-top: 20px; }
.fretboard-svg { display: block; margin: 0 auto; }

/* === Scales specific === */
.scale-notes-bar {
  display: flex;
  gap: 8px;
  justify-content: center;
  flex-wrap: wrap;
  margin: 16px 0;
}
.scale-note {
  width: 44px; height: 44px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 800;
  font-family: var(--font-head);
  font-size: 0.85rem;
  background: var(--c-primary-light);
  color: var(--c-primary);
  transition: var(--transition-bounce);
}
.scale-note.root {
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: white;
  transform: scale(1.15);
  box-shadow: 0 4px 16px rgba(124,58,237,0.4);
}

/* === Ear Training specific === */
.et-status {
  text-align: center;
  font-family: var(--font-head);
  font-size: 1.4rem;
  font-weight: 800;
  padding: 16px;
  border-radius: var(--radius-md);
  margin-bottom: 20px;
  min-height: 60px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}
.et-status.correct { background: rgba(16,185,129,0.12); color: var(--c-green); }
.et-status.wrong { background: rgba(239,68,68,0.1); color: var(--c-red); }
.et-status.waiting { background: var(--c-primary-light); color: var(--c-primary); }
.et-choices {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px;
  margin-bottom: 20px;
}
.et-choice {
  padding: 14px;
  border-radius: var(--radius-md);
  border: 2px solid var(--c-border);
  background: var(--c-white);
  font-weight: 700;
  font-size: 0.95rem;
  cursor: pointer;
  transition: var(--transition-bounce);
  font-family: var(--font-head);
  color: var(--c-text);
}
.et-choice:hover:not(:disabled) { border-color: var(--c-primary); background: var(--c-primary-light); color: var(--c-primary); transform: scale(1.03); }
.et-choice.correct-ans { border-color: var(--c-green); background: rgba(16,185,129,0.1); color: var(--c-green); }
.et-choice.wrong-ans { border-color: var(--c-red); background: rgba(239,68,68,0.08); color: var(--c-red); }
.et-choice:disabled { cursor: default; }
.et-score-bar {
  display: flex;
  gap: 16px;
  justify-content: center;
  margin-bottom: 24px;
}
.et-score-item {
  text-align: center;
  background: var(--c-white);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  padding: 14px 20px;
}
.et-score-num {
  font-family: var(--font-head);
  font-size: 2rem;
  font-weight: 800;
  color: var(--c-primary);
  line-height: 1;
}
.et-score-label { font-size: 0.75rem; color: var(--c-text-3); font-weight: 600; margin-top: 4px; }

/* === Footer === */
.footer {
  background: var(--c-white);
  border-top: 1px solid var(--c-border);
  padding: 48px 0 32px;
  margin-top: 40px;
}
.footer-grid {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 48px;
  margin-bottom: 40px;
}
.footer-brand .nav-logo { font-size: 1.3rem; margin-bottom: 12px; }
.footer-brand p { font-size: 0.88rem; color: var(--c-text-2); line-height: 1.7; }
.footer-links { display: grid; grid-template-columns: repeat(2, 1fr); gap: 8px 24px; }
.footer-link {
  font-size: 0.88rem;
  color: var(--c-text-2);
  padding: 6px 0;
  transition: color 0.2s;
  display: flex;
  align-items: center;
  gap: 6px;
}
.footer-link:hover { color: var(--c-primary); }
.footer-bottom {
  border-top: 1px solid var(--c-border);
  padding-top: 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 12px;
  font-size: 0.82rem;
  color: var(--c-text-3);
}

/* === Responsive === */
@media (max-width: 900px) {
  .nav-tools { display: none; }
  .nav-burger { display: flex; }
  .footer-grid { grid-template-columns: 1fr; gap: 28px; }
  .drum-row { grid-template-columns: 70px repeat(16, 1fr); gap: 4px; }
  .drum-label { font-size: 0.68rem; }
}
@media (max-width: 640px) {
  :root { --nav-h: 60px; }
  .hero { padding: 48px 0 32px; }
  .tool-card { padding: 24px 18px; }
  .metro-bpm { font-size: 3.5rem; }
  .tuner-note { font-size: 4.5rem; }
  .chord-name { font-size: 2.2rem; }
  .et-choices { grid-template-columns: 1fr 1fr; gap: 8px; }
  .et-score-bar { gap: 8px; }
  .drum-row { grid-template-columns: 55px repeat(16, 1fr); gap: 3px; }
  .drum-step { min-height: 24px; border-radius: 5px; }
  .footer-links { grid-template-columns: 1fr; }
  .tools-grid { grid-template-columns: 1fr; }
  .seo-section { padding: 48px 0; }
}
@media (max-width: 400px) {
  .drum-row { grid-template-columns: 45px repeat(16, 1fr); gap: 2px; }
  .drum-step { min-height: 20px; border-radius: 4px; }
}

/* === Scroll snap for tool cards on mobile === */
@media (max-width: 640px) {
  .tools-grid { display: flex; flex-direction: column; }
}

/* === Loading state === */
.skeleton {
  background: linear-gradient(90deg, var(--c-primary-light) 25%, rgba(255,255,255,0.8) 50%, var(--c-primary-light) 75%);
  background-size: 400% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-sm);
}

/* === Tooltip === */
[data-tip] { position: relative; }
[data-tip]:hover::after {
  content: attr(data-tip);
  position: absolute;
  bottom: 110%;
  left: 50%;
  transform: translateX(-50%);
  background: var(--c-text);
  color: white;
  padding: 5px 10px;
  border-radius: 6px;
  font-size: 0.75rem;
  white-space: nowrap;
  z-index: 10;
  pointer-events: none;
}

/* === Tone Generator specific === */
.freq-display {
  font-family: var(--font-head);
  font-size: 3.5rem;
  font-weight: 800;
  text-align: center;
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 4px;
}
.waveform-selector {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
  margin-bottom: 20px;
}
.wave-btn {
  padding: 10px;
  border-radius: var(--radius-sm);
  border: 2px solid var(--c-border);
  background: var(--c-white);
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
  font-weight: 600;
  font-size: 0.8rem;
  color: var(--c-text-2);
}
.wave-btn.active { border-color: var(--c-primary); background: var(--c-primary-light); color: var(--c-primary); }
.wave-btn:hover:not(.active) { border-color: var(--c-primary-mid); }

/* === Interval Finder specific === */
.interval-result {
  text-align: center;
  font-family: var(--font-head);
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--c-primary);
  padding: 20px;
  border-radius: var(--radius-lg);
  background: var(--c-primary-light);
  margin: 20px 0;
  min-height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
}
.note-selector {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 8px;
}
.note-btn {
  padding: 10px 6px;
  border-radius: var(--radius-sm);
  border: 2px solid var(--c-border);
  background: var(--c-white);
  font-weight: 700;
  font-size: 0.85rem;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font-head);
}
.note-btn:hover { border-color: var(--c-primary-mid); background: var(--c-primary-light); }
.note-btn.selected { border-color: var(--c-primary); background: var(--c-primary); color: white; }

/* === Chord Progression specific === */
.prog-display {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
  margin: 24px 0;
}
.prog-chord {
  padding: 16px 20px;
  border-radius: var(--radius-md);
  background: var(--c-white);
  border: 2px solid var(--c-border);
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.3rem;
  color: var(--c-text);
  min-width: 70px;
  text-align: center;
  transition: var(--transition);
  cursor: default;
}
.prog-chord.active-chord {
  background: linear-gradient(135deg, var(--c-primary), var(--c-accent));
  color: white;
  border-color: transparent;
  transform: scale(1.08);
  box-shadow: 0 8px 24px rgba(124,58,237,0.4);
}
.prog-chord.tonic { border-color: var(--c-primary); color: var(--c-primary); }
.prog-presets {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
  gap: 8px;
  margin-bottom: 20px;
}
.preset-btn {
  padding: 10px 14px;
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--c-border);
  background: var(--c-white);
  font-size: 0.82rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  text-align: left;
  color: var(--c-text-2);
}
.preset-btn:hover { border-color: var(--c-primary); background: var(--c-primary-light); color: var(--c-primary); }
.preset-btn.active { border-color: var(--c-primary); background: var(--c-primary); color: white; }