/* ===========================================================
   Music Distribution ID & Metadata Guide
   =========================================================== */

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

html {
  -webkit-text-size-adjust: none;
  text-size-adjust: none;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body { min-height: 100dvh; line-height: 1.6; font-family: var(--font-body); font-size: var(--text-base); color: var(--color-text); background: var(--color-bg); }

img, svg { display: block; max-width: 100%; }
ul[role="list"], ol[role="list"] { list-style: none; }
input, button { font: inherit; color: inherit; }

h1, h2, h3, h4 { text-wrap: balance; line-height: 1.2; font-family: var(--font-display); }
p, li { text-wrap: pretty; }

::selection { background: color-mix(in oklab, var(--color-primary) 30%, transparent); color: var(--color-text); }
:focus-visible { outline: 2px solid var(--color-primary); outline-offset: 3px; border-radius: 4px; }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .01ms !important; transition-duration: .01ms !important; scroll-behavior: auto !important; }
}

.skip-link {
  position: absolute; top: -100px; left: 12px; z-index: 200;
  background: var(--color-primary); color: var(--color-bg); padding: 10px 16px;
  border-radius: 6px; font-size: var(--text-sm); font-weight: 600;
  transition: top .2s;
}
.skip-link:focus { top: 12px; }

/* ===================== TOKENS ===================== */
:root, [data-theme="light"] {
  --color-bg: #f5f4ef;
  --color-surface: #fbfaf6;
  --color-surface-2: #ffffff;
  --color-surface-offset: #ecebe4;
  --color-border: #ddd9cf;
  --color-divider: #e6e3da;

  --color-text: #1c1e1c;
  --color-text-muted: #5c5f5a;
  --color-text-faint: #9a9c94;

  --color-primary: #146356;
  --color-primary-hover: #0d4a41;
  --color-primary-highlight: #d7ece6;

  --color-accent-2: #b5541f;

  --color-code-bg: #17201d;
  --color-code-text: #d9f0e6;

  --shadow-sm: 0 1px 2px rgba(20,20,15,0.06);
  --shadow-md: 0 6px 20px rgba(20,20,15,0.08);
  --shadow-lg: 0 16px 40px rgba(20,20,15,0.12);
}

[data-theme="dark"] {
  --color-bg: #12140f;
  --color-surface: #191c16;
  --color-surface-2: #1e221b;
  --color-surface-offset: #21251d;
  --color-border: #33382c;
  --color-divider: #262b21;

  --color-text: #e7e6dd;
  --color-text-muted: #a2a396;
  --color-text-faint: #6c6e60;

  --color-primary: #4fcbb0;
  --color-primary-hover: #71dcc4;
  --color-primary-highlight: #1e3630;

  --color-accent-2: #e8935c;

  --color-code-bg: #0d1210;
  --color-code-text: #b8f0dc;

  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 6px 20px rgba(0,0,0,0.35);
  --shadow-lg: 0 16px 40px rgba(0,0,0,0.5);
}

:root {
  --font-display: 'Cabinet Grotesk', 'General Sans', sans-serif;
  --font-body: 'General Sans', 'Inter', sans-serif;
  --font-mono: 'JetBrains Mono', 'Consolas', monospace;

  --text-xs: clamp(0.75rem, 0.72rem + 0.15vw, 0.8125rem);
  --text-sm: clamp(0.875rem, 0.83rem + 0.2vw, 0.9375rem);
  --text-base: clamp(1rem, 0.96rem + 0.2vw, 1.0625rem);
  --text-lg: clamp(1.125rem, 1.03rem + 0.5vw, 1.375rem);
  --text-xl: clamp(1.5rem, 1.25rem + 1.2vw, 2.1rem);
  --text-2xl: clamp(2rem, 1.4rem + 2.6vw, 3.4rem);

  --space-1: 0.25rem; --space-2: 0.5rem; --space-3: 0.75rem; --space-4: 1rem;
  --space-5: 1.25rem; --space-6: 1.5rem; --space-8: 2rem; --space-10: 2.5rem;
  --space-12: 3rem; --space-16: 4rem; --space-20: 5rem; --space-24: 6rem;

  --radius-sm: 6px; --radius-md: 10px; --radius-lg: 16px;
  --transition: 180ms cubic-bezier(.16,1,.3,1);
  --sidebar-w: 288px;
}

/* ===================== LAYOUT ===================== */
.app { display: flex; min-height: 100dvh; }

.content-col { flex: 1; min-width: 0; margin-left: var(--sidebar-w); display: flex; flex-direction: column; }

/* ---------- Sidebar ---------- */
.sidebar {
  position: fixed; top: 0; left: 0; bottom: 0; width: var(--sidebar-w);
  background: var(--color-surface); border-right: 1px solid var(--color-border);
  display: flex; flex-direction: column; z-index: 60;
  transition: transform var(--transition);
}

.sidebar-head { display: flex; align-items: center; justify-content: space-between; gap: var(--space-2); padding: var(--space-5) var(--space-5) var(--space-4); border-bottom: 1px solid var(--color-divider); }

.logo { display: flex; align-items: center; gap: var(--space-2); text-decoration: none; color: var(--color-text); }
.logo-text { font-family: var(--font-display); font-weight: 700; font-size: var(--text-sm); line-height: 1.15; letter-spacing: -0.01em; }

.theme-toggle {
  width: 34px; height: 34px; border-radius: var(--radius-sm); display: flex; align-items: center; justify-content: center;
  color: var(--color-text-muted); border: 1px solid var(--color-border); background: var(--color-surface-2); flex-shrink: 0;
}
.theme-toggle:hover { color: var(--color-primary); border-color: var(--color-primary); }
.theme-toggle svg { width: 16px; height: 16px; }

.sidebar-search { position: relative; margin: var(--space-4) var(--space-5) var(--space-2); display: flex; align-items: center; }
.sidebar-search svg { position: absolute; left: 10px; color: var(--color-text-faint); pointer-events: none; }
.sidebar-search input {
  width: 100%; padding: 8px 10px 8px 32px; border-radius: var(--radius-sm); border: 1px solid var(--color-border);
  background: var(--color-surface-2); color: var(--color-text); font-size: var(--text-xs);
}
.sidebar-search input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }

.toc { flex: 1; overflow-y: auto; padding: var(--space-2) var(--space-3) var(--space-6); }
.toc > ul { display: flex; flex-direction: column; gap: 1px; }
.toc a {
  display: block; padding: 7px 12px; border-radius: var(--radius-sm); color: var(--color-text-muted);
  text-decoration: none; font-size: var(--text-sm); font-weight: 500; transition: background var(--transition), color var(--transition);
}
.toc > ul > li > a { color: var(--color-text); font-weight: 600; margin-top: var(--space-2); }
.toc > ul > li:first-child > a { margin-top: 0; }
.toc ul ul { margin-left: var(--space-3); border-left: 1px solid var(--color-divider); padding-left: var(--space-2); }
.toc ul ul a { font-size: var(--text-xs); font-weight: 400; }
.toc a:hover { background: var(--color-surface-offset); color: var(--color-primary); }
.toc a.active { background: var(--color-primary-highlight); color: var(--color-primary); font-weight: 700; }
.toc li.hidden { display: none; }

.sidebar-foot { padding: var(--space-4) var(--space-5) var(--space-5); border-top: 1px solid var(--color-divider); }
.gh-link {
  display: flex; align-items: center; gap: var(--space-2); padding: 9px 12px; border-radius: var(--radius-sm);
  background: var(--color-text); color: var(--color-bg); text-decoration: none; font-size: var(--text-xs); font-weight: 600;
  justify-content: center; transition: opacity var(--transition);
}
.gh-link:hover { opacity: .85; }
.foot-note { margin-top: var(--space-3); font-size: var(--text-xs); color: var(--color-text-faint); text-align: center; }

.menu-toggle {
  display: none; position: fixed; top: var(--space-4); left: var(--space-4); z-index: 70;
  width: 42px; height: 42px; border-radius: var(--radius-sm); background: var(--color-surface-2);
  border: 1px solid var(--color-border); align-items: center; justify-content: center; color: var(--color-text);
  box-shadow: var(--shadow-sm);
}

/* ---------- Topbar ---------- */
.topbar { position: sticky; top: 0; z-index: 40; background: color-mix(in oklab, var(--color-bg) 88%, transparent); backdrop-filter: blur(10px); border-bottom: 1px solid var(--color-divider); }
.topbar-inner { display: flex; align-items: center; justify-content: space-between; padding: var(--space-4) clamp(var(--space-6), 4vw, var(--space-12)); }
.breadcrumb { font-size: var(--text-xs); color: var(--color-text-faint); font-family: var(--font-mono); text-transform: uppercase; letter-spacing: .06em; }
.topbar-actions { display: flex; align-items: center; gap: var(--space-3); }
.badge { font-family: var(--font-mono); font-size: var(--text-xs); padding: 3px 8px; border-radius: var(--radius-sm); background: var(--color-primary-highlight); color: var(--color-primary); font-weight: 700; }
.btn-ghost {
  display: flex; align-items: center; gap: 6px; font-size: var(--text-xs); font-weight: 600; color: var(--color-text-muted);
  border: 1px solid var(--color-border); padding: 7px 12px; border-radius: var(--radius-sm); background: transparent;
}
.btn-ghost:hover { color: var(--color-primary); border-color: var(--color-primary); }

/* ---------- Main / Hero ---------- */
main { flex: 1; }
.hero { padding: clamp(var(--space-16), 8vw, var(--space-24)) clamp(var(--space-6), 4vw, var(--space-12)) clamp(var(--space-12), 6vw, var(--space-16)); max-width: 920px; }
.eyebrow { font-family: var(--font-mono); font-size: var(--text-xs); color: var(--color-primary); text-transform: uppercase; letter-spacing: .1em; font-weight: 700; margin-bottom: var(--space-4); }
.hero h1 { font-size: var(--text-2xl); font-weight: 700; letter-spacing: -0.02em; margin-bottom: var(--space-5); }
.hero-sub { font-size: var(--text-lg); color: var(--color-text-muted); max-width: 62ch; margin-bottom: var(--space-10); }

.hero-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-4); }
.stat { padding: var(--space-4); background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-md); }
.stat-num { display: block; font-family: var(--font-mono); font-size: var(--text-xl); font-weight: 700; color: var(--color-primary); line-height: 1; margin-bottom: var(--space-2); }
.stat-label { display: block; font-size: var(--text-xs); color: var(--color-text-muted); line-height: 1.3; }

/* ---------- Blocks ---------- */
.block { padding: clamp(var(--space-10), 5vw, var(--space-16)) clamp(var(--space-6), 4vw, var(--space-12)); max-width: 920px; border-top: 1px solid var(--color-divider); }
.block-head { display: flex; align-items: baseline; gap: var(--space-4); margin-bottom: var(--space-8); }
.block-num { font-family: var(--font-mono); font-size: var(--text-sm); color: var(--color-text-faint); font-weight: 700; }
.block-head h2 { font-size: var(--text-xl); font-weight: 700; letter-spacing: -0.01em; }
.block-body h3 { font-size: var(--text-lg); font-weight: 600; margin: var(--space-8) 0 var(--space-3); }
.block-body h3:first-child { margin-top: 0; }
.block-body h4 { font-size: var(--text-base); font-weight: 700; margin-bottom: var(--space-3); }
.block-body p { color: var(--color-text); max-width: 68ch; margin-bottom: var(--space-4); }
.block-body p:last-child { margin-bottom: 0; }

.check-list { display: flex; flex-direction: column; gap: var(--space-3); margin-bottom: var(--space-6); }
.check-list.no-margin { margin-bottom: 0; }
.check-list li { position: relative; padding-left: var(--space-6); max-width: 68ch; }
.check-list li::before {
  content: ""; position: absolute; left: 0; top: 8px; width: 8px; height: 8px; border-radius: 2px;
  background: var(--color-primary); transform: rotate(45deg);
}
.check-list li:last-child, .check-list li:only-child {}
code { font-family: var(--font-mono); font-size: 0.92em; background: var(--color-surface-offset); padding: 2px 6px; border-radius: 4px; color: var(--color-primary); }

sup.cite, sup a.cite {
  font-size: 0.68em; font-family: var(--font-mono); font-weight: 600; text-decoration: none;
  color: var(--color-text-faint); vertical-align: super; margin-right: 3px; padding: 0 1px;
}
sup a.cite:hover { color: var(--color-primary); }

/* ---------- Compare cards ---------- */
.compare-cards { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-5); margin-top: var(--space-6); }
.compare-card { padding: var(--space-6); background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg); }
.compare-icon { width: 40px; height: 40px; border-radius: var(--radius-sm); background: var(--color-primary-highlight); color: var(--color-primary); display: flex; align-items: center; justify-content: center; margin-bottom: var(--space-4); }
.compare-card h3 { font-size: var(--text-lg); font-weight: 700; margin-bottom: 4px; }
.compare-tagline { font-size: var(--text-xs); font-family: var(--font-mono); color: var(--color-primary); text-transform: uppercase; letter-spacing: .04em; font-weight: 700; margin-bottom: var(--space-3); }
.compare-card p:last-child { color: var(--color-text-muted); font-size: var(--text-sm); margin-bottom: 0; }

/* ---------- Code breakdown (ISRC / UPC visualizer) ---------- */
.code-breakdown { margin: var(--space-6) 0; padding: var(--space-6); background: var(--color-code-bg); border-radius: var(--radius-lg); }
.code-string {
  font-family: var(--font-mono); font-size: clamp(1.1rem, 1rem + 1.4vw, 1.9rem); font-weight: 600;
  display: flex; justify-content: center; flex-wrap: wrap; margin-bottom: var(--space-6); letter-spacing: 0.02em;
}
.code-string .sep { color: var(--color-code-text); opacity: .35; padding: 0 2px; }
.code-string .seg { padding: 4px 6px; border-radius: 4px; transition: transform var(--transition), box-shadow var(--transition); cursor: default; }
.code-string .seg.hi { transform: translateY(-3px); box-shadow: 0 4px 14px rgba(0,0,0,.35); }

.seg-cc, .swatch-cc { background: #4fcbb0; color: #0a1512; }
.seg-reg, .swatch-reg { background: #e8935c; color: #26140a; }
.seg-yr, .swatch-yr { background: #7fb2e8; color: #0b1a26; }
.seg-des, .swatch-des { background: #e0c15e; color: #241d05; }
.seg-comp, .swatch-comp { background: #4fcbb0; color: #0a1512; }
.seg-item, .swatch-item { background: #e8935c; color: #26140a; }
.seg-chk, .swatch-chk { background: #d97b93; color: #260a12; }

.code-legend { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-3); }
.legend-item {
  display: flex; align-items: flex-start; gap: var(--space-3); text-align: left; background: transparent; border: 1px solid transparent;
  border-radius: var(--radius-sm); padding: var(--space-2); transition: background var(--transition), border-color var(--transition);
}
.legend-item:hover, .legend-item.active { background: rgba(255,255,255,0.06); border-color: rgba(255,255,255,0.15); }
.legend-item span:last-child { font-size: var(--text-xs); color: var(--color-code-text); opacity: .85; line-height: 1.5; }
.legend-item strong { color: #fff; opacity: 1; }
.swatch { width: 10px; height: 10px; border-radius: 3px; flex-shrink: 0; margin-top: 4px; }
.fine-print { font-size: var(--text-xs); color: var(--color-code-text); opacity: .55; margin-top: var(--space-5); max-width: 68ch; }

/* ---------- Callouts ---------- */
.callout { border-radius: var(--radius-md); padding: var(--space-5) var(--space-6); margin: var(--space-4) 0; border-left: 3px solid var(--color-primary); background: var(--color-primary-highlight); }
.callout-info li::before { background: var(--color-primary); }

/* ---------- Provider chips ---------- */
.provider-chip-row { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-6); }
.chip { font-family: var(--font-mono); font-size: var(--text-xs); font-weight: 600; padding: 6px 12px; border-radius: 999px; background: var(--color-surface); border: 1px solid var(--color-border); color: var(--color-text-muted); }

/* ---------- Pricing cards ---------- */
.pricing-cards { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-5); margin: var(--space-6) 0; }
.pricing-card { padding: var(--space-6); border-radius: var(--radius-lg); background: var(--color-surface); border: 1px solid var(--color-border); }
.pricing-card-accent { border-color: var(--color-primary); background: var(--color-primary-highlight); }
.pricing-label { font-size: var(--text-xs); font-family: var(--font-mono); text-transform: uppercase; letter-spacing: .05em; color: var(--color-text-muted); font-weight: 700; margin-bottom: var(--space-2); }
.pricing-value { font-family: var(--font-mono); font-size: var(--text-xl); font-weight: 700; color: var(--color-primary); margin-bottom: var(--space-3); }
.pricing-value span { display: block; font-size: var(--text-xs); font-weight: 500; color: var(--color-text-muted); font-family: var(--font-body); margin-top: 2px; }
.pricing-card p:last-child { font-size: var(--text-sm); color: var(--color-text-muted); margin: 0; }

/* ---------- Metadata grid ---------- */
.metadata-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-5); margin-top: var(--space-6); }
.metadata-card { padding: var(--space-6); background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-lg); }
.tag-list { display: flex; flex-wrap: wrap; gap: var(--space-2); margin-bottom: var(--space-4); }
.tag-list li { font-size: var(--text-xs); font-family: var(--font-mono); padding: 4px 9px; border-radius: 5px; background: var(--color-surface-offset); color: var(--color-text-muted); }

/* ---------- Tools section ---------- */
.block-tools { background: var(--color-surface); }
.tools-intro { color: var(--color-text-muted); margin-bottom: var(--space-6) !important; font-size: var(--text-sm); }
.tool-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--space-5); margin-bottom: var(--space-5); }
.tool-card { padding: var(--space-6); background: var(--color-surface-2); border: 1px solid var(--color-border); border-radius: var(--radius-lg); }
.tool-card h3 { font-size: var(--text-base); font-weight: 700; margin-bottom: var(--space-2); }
.tool-help { font-size: var(--text-xs); color: var(--color-text-muted); margin-bottom: var(--space-4) !important; }
.tool-help code { font-size: var(--text-xs); }
.tool-row { display: flex; gap: var(--space-2); }
.tool-row input[type="text"] {
  flex: 1; padding: 10px 12px; border-radius: var(--radius-sm); border: 1px solid var(--color-border);
  background: var(--color-bg); color: var(--color-text); font-family: var(--font-mono); font-size: var(--text-sm);
}
.tool-row input:focus { outline: none; border-color: var(--color-primary); box-shadow: 0 0 0 3px var(--color-primary-highlight); }
.tool-row button:not(.btn-primary) {
  padding: 10px 16px; border-radius: var(--radius-sm); background: var(--color-text); color: var(--color-bg);
  font-weight: 600; font-size: var(--text-sm); flex-shrink: 0;
}
.tool-row button:not(.btn-primary):hover { opacity: .85; }
.tool-result { margin-top: var(--space-4); font-size: var(--text-sm); font-family: var(--font-mono); min-height: 1.2em; }
.tool-result.valid { color: #2e8b57; }
[data-theme="dark"] .tool-result.valid { color: #6dd49a; }
.tool-result.invalid { color: var(--color-accent-2); }
.tool-card-wide { grid-column: 1 / -1; }
.btn-primary {
  display: flex; align-items: center; gap: var(--space-2); padding: 10px 18px; border-radius: var(--radius-sm);
  background: var(--color-primary); color: #fff; font-weight: 600; font-size: var(--text-sm);
}
.btn-primary:hover { background: var(--color-primary-hover); }

/* ---------- Next step CTA ---------- */
.next-step { padding: clamp(var(--space-12), 6vw, var(--space-20)) clamp(var(--space-6), 4vw, var(--space-12)); max-width: 920px; border-top: 1px solid var(--color-divider); }
.next-step p { font-family: var(--font-mono); font-size: var(--text-xs); text-transform: uppercase; letter-spacing: .08em; color: var(--color-primary); font-weight: 700; margin-bottom: var(--space-3); }
.next-step h2 { font-size: var(--text-lg); font-weight: 500; color: var(--color-text-muted); max-width: 60ch; }

/* ---------- Sources ---------- */
.block-sources { background: var(--color-surface); }
.sources-list { columns: 2; column-gap: var(--space-8); counter-reset: src; }
.sources-list li { break-inside: avoid; margin-bottom: var(--space-3); font-size: var(--text-xs); }
.sources-list a { color: var(--color-text-muted); text-decoration: none; word-break: break-all; }
.sources-list a:hover { color: var(--color-primary); text-decoration: underline; }
.sources-list .src-num { font-family: var(--font-mono); color: var(--color-text-faint); margin-right: 6px; }

/* ---------- Footer ---------- */
.site-footer { padding: var(--space-8) clamp(var(--space-6), 4vw, var(--space-12)) var(--space-12); max-width: 920px; }
.site-footer p { font-size: var(--text-xs); color: var(--color-text-faint); }

/* ---------- Toast ---------- */
.toast {
  position: fixed; bottom: var(--space-6); left: 50%; transform: translate(-50%, 20px); z-index: 300;
  background: var(--color-text); color: var(--color-bg); padding: 10px 18px; border-radius: var(--radius-sm);
  font-size: var(--text-sm); font-weight: 600; opacity: 0; pointer-events: none; transition: opacity var(--transition), transform var(--transition);
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

/* ===================== RESPONSIVE ===================== */
@media (max-width: 1024px) {
  .sidebar { transform: translateX(-100%); box-shadow: var(--shadow-lg); }
  .sidebar.open { transform: translateX(0); }
  .content-col { margin-left: 0; }
  .menu-toggle { display: flex; }
  .topbar-inner { padding-left: calc(var(--space-4) + 50px); }
}

@media (max-width: 720px) {
  .compare-cards, .pricing-cards, .metadata-grid, .tool-grid { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: 1fr 1fr; }
  .code-legend { grid-template-columns: 1fr; }
  .sources-list { columns: 1; }
  .code-string { font-size: clamp(0.85rem, 3.5vw, 1.3rem); }
}

@media print {
  .sidebar, .menu-toggle, .topbar, .theme-toggle, .tool-row button, .toast { display: none !important; }
  .content-col { margin-left: 0; }
  .block, .hero { max-width: 100%; break-inside: avoid; }
  body { background: #fff; color: #000; }
}