/* ==========================================================================
   afinni.lat — Hoja de estilos principal
   Guía educativa gratuita para afinar instrumentos musicales
   ========================================================================== */

:root {
  --color-bg: #0f1320;
  --color-bg-soft: #171c2e;
  --color-surface: #1d2438;
  --color-surface-2: #252e47;
  --color-border: #2f3a59;
  --color-text: #e8ecf6;
  --color-text-soft: #aab4cf;
  --color-text-dim: #7d88a8;
  --color-primary: #ffb454;
  --color-primary-dark: #e8993a;
  --color-accent: #5ad1c9;
  --color-accent-2: #8b7cff;
  --color-success: #4ade80;
  --color-danger: #f87171;
  --color-warning: #fbbf24;
  --radius: 14px;
  --radius-sm: 9px;
  --shadow: 0 10px 40px rgba(0, 0, 0, 0.35);
  --shadow-sm: 0 4px 18px rgba(0, 0, 0, 0.25);
  --maxw: 1080px;
  --font: "Segoe UI", system-ui, -apple-system, "Helvetica Neue", Arial, sans-serif;
  --font-mono: "SFMono-Regular", "Consolas", "Liberation Mono", Menlo, monospace;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; scroll-padding-top: 80px; }

body {
  margin: 0;
  font-family: var(--font);
  background: radial-gradient(1200px 600px at 15% -10%, #1b2138 0%, transparent 60%),
              radial-gradient(1000px 500px at 100% 0%, #1a2533 0%, transparent 55%),
              var(--color-bg);
  color: var(--color-text);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--color-accent); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; }

h1, h2, h3, h4 { line-height: 1.25; color: #fff; font-weight: 700; }
h2 { font-size: clamp(1.5rem, 3vw, 2.1rem); margin-top: 0; }
h3 { font-size: 1.25rem; }

.container { max-width: var(--maxw); margin: 0 auto; padding: 0 20px; }

/* ---------- Skip link (accesibilidad) ---------- */
.skip-link {
  position: absolute; left: -999px; top: 0;
  background: var(--color-primary); color: #1a1205; padding: 10px 16px;
  border-radius: 0 0 8px 0; z-index: 1000; font-weight: 600;
}
.skip-link:focus { left: 0; }

/* ---------- Header / Nav ---------- */
.site-header {
  position: sticky; top: 0; z-index: 90;
  background: rgba(15, 19, 32, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}
.nav {
  display: flex; align-items: center; justify-content: space-between;
  gap: 16px; padding: 12px 20px; max-width: var(--maxw); margin: 0 auto;
}
.brand { display: flex; align-items: center; gap: 10px; font-weight: 800; font-size: 1.3rem; color: #fff; }
.brand:hover { text-decoration: none; }
.brand .logo {
  width: 38px; height: 38px; border-radius: 10px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent-2));
  display: grid; place-items: center; color: #1a1205; font-size: 1.2rem;
}
.brand span small { display: block; font-size: 0.62rem; font-weight: 500; color: var(--color-text-dim); letter-spacing: 0.5px; }

.nav-links { display: flex; gap: 6px; align-items: center; }
.nav-links a {
  color: var(--color-text-soft); padding: 8px 12px; border-radius: 8px;
  font-size: 0.92rem; font-weight: 500;
}
.nav-links a:hover { background: var(--color-surface); color: #fff; text-decoration: none; }

.nav-toggle {
  display: none; background: var(--color-surface); border: 1px solid var(--color-border);
  color: #fff; font-size: 1.4rem; width: 44px; height: 44px; border-radius: 10px; cursor: pointer;
}

@media (max-width: 860px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 2px;
    background: var(--color-bg-soft); border-bottom: 1px solid var(--color-border);
    padding: 10px 16px;
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px; }
}

/* ---------- Hero ---------- */
.hero {
  text-align: center; padding: 64px 20px 40px;
  max-width: 860px; margin: 0 auto;
}
.hero .eyebrow {
  display: inline-block; background: var(--color-surface); border: 1px solid var(--color-border);
  color: var(--color-accent); padding: 6px 14px; border-radius: 999px; font-size: 0.82rem;
  font-weight: 600; letter-spacing: 0.4px; margin-bottom: 18px;
}
.hero h1 {
  font-size: clamp(2.1rem, 5.5vw, 3.4rem); margin: 0 0 16px;
  background: linear-gradient(120deg, #fff 20%, var(--color-primary) 60%, var(--color-accent) 100%);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.hero p.lead { font-size: 1.15rem; color: var(--color-text-soft); margin: 0 auto 28px; max-width: 640px; }
.hero-cta { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center; gap: 8px; cursor: pointer;
  padding: 12px 22px; border-radius: 999px; font-weight: 600; font-size: 0.98rem;
  border: 1px solid transparent; transition: transform 0.12s ease, box-shadow 0.2s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-2px); }
.btn-primary { background: linear-gradient(120deg, var(--color-primary), var(--color-primary-dark)); color: #1a1205; box-shadow: var(--shadow-sm); }
.btn-ghost { background: var(--color-surface); border-color: var(--color-border); color: var(--color-text); }

/* ---------- Disclaimer destacado ---------- */
.disclaimer-banner {
  max-width: var(--maxw); margin: 10px auto 0; padding: 16px 20px;
  background: linear-gradient(120deg, rgba(90, 209, 201, 0.08), rgba(139, 124, 255, 0.08));
  border: 1px solid var(--color-border); border-radius: var(--radius);
  display: flex; gap: 14px; align-items: flex-start; font-size: 0.93rem; color: var(--color-text-soft);
}
.disclaimer-banner .ico { font-size: 1.4rem; flex-shrink: 0; }
.disclaimer-banner strong { color: var(--color-text); }

/* ---------- Índice de secciones ---------- */
.toc {
  margin: 40px auto; padding: 26px;
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius);
}
.toc h2 { font-size: 1.3rem; margin-bottom: 16px; }
.toc-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 6px;
  list-style: none; padding: 0; margin: 0; counter-reset: toc;
}
.toc-grid li a {
  display: flex; gap: 10px; align-items: baseline; padding: 9px 12px; border-radius: 8px;
  color: var(--color-text-soft); font-size: 0.92rem;
}
.toc-grid li a:hover { background: var(--color-surface-2); color: #fff; text-decoration: none; }
.toc-grid li a::before {
  counter-increment: toc; content: counter(toc, decimal-leading-zero);
  color: var(--color-primary); font-family: var(--font-mono); font-size: 0.8rem; font-weight: 700;
}

/* ---------- Secciones ---------- */
.section { padding: 42px 0; border-top: 1px solid rgba(47, 58, 89, 0.4); }
.section:first-of-type { border-top: none; }
.section-head { display: flex; gap: 14px; align-items: center; margin-bottom: 6px; }
.section-num {
  font-family: var(--font-mono); font-size: 0.95rem; font-weight: 700; color: #1a1205;
  background: var(--color-primary); width: 40px; height: 40px; border-radius: 12px;
  display: grid; place-items: center; flex-shrink: 0;
}
.section p { color: var(--color-text-soft); }
.section ul, .section ol { color: var(--color-text-soft); }
.section li { margin-bottom: 6px; }

.card {
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 22px; margin: 18px 0; box-shadow: var(--shadow-sm);
}
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 18px; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px; }
@media (max-width: 760px) { .grid-2, .grid-3 { grid-template-columns: 1fr; } }

.callout {
  border-left: 4px solid var(--color-accent); background: var(--color-bg-soft);
  padding: 14px 18px; border-radius: 0 var(--radius-sm) var(--radius-sm) 0; margin: 16px 0;
}
.callout.tip { border-color: var(--color-success); }
.callout.warn { border-color: var(--color-warning); }
.callout strong { color: #fff; }

/* ---------- Tablas ---------- */
.table-wrap { overflow-x: auto; margin: 16px 0; border-radius: var(--radius-sm); border: 1px solid var(--color-border); }
table { width: 100%; border-collapse: collapse; font-size: 0.92rem; min-width: 460px; }
th, td { padding: 11px 14px; text-align: left; border-bottom: 1px solid var(--color-border); }
th { background: var(--color-surface-2); color: #fff; font-weight: 600; }
td { color: var(--color-text-soft); }
tr:last-child td { border-bottom: none; }
td.note-cell { font-family: var(--font-mono); color: var(--color-primary); font-weight: 700; }

/* ==========================================================================
   Herramientas interactivas
   ========================================================================== */
.tool {
  background: linear-gradient(160deg, var(--color-surface), var(--color-bg-soft));
  border: 1px solid var(--color-border); border-radius: var(--radius);
  padding: 24px; margin: 18px 0; box-shadow: var(--shadow);
}
.tool h3 { margin-top: 0; display: flex; align-items: center; gap: 10px; }
.tool-controls { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin: 16px 0; }

button.ctrl {
  background: var(--color-surface-2); color: var(--color-text); border: 1px solid var(--color-border);
  padding: 10px 18px; border-radius: 999px; cursor: pointer; font-weight: 600; font-size: 0.94rem;
  transition: all 0.15s ease;
}
button.ctrl:hover { border-color: var(--color-primary); color: #fff; }
button.ctrl.active { background: var(--color-primary); color: #1a1205; border-color: var(--color-primary); }
button.ctrl:disabled { opacity: 0.45; cursor: not-allowed; }

input[type="range"] { accent-color: var(--color-primary); width: 100%; }
select, input[type="number"], input[type="text"], input[type="email"], textarea {
  background: var(--color-bg); color: var(--color-text); border: 1px solid var(--color-border);
  border-radius: var(--radius-sm); padding: 10px 12px; font-size: 0.95rem; font-family: inherit;
}
select:focus, input:focus, textarea:focus { outline: 2px solid var(--color-accent); outline-offset: 1px; }
label { font-size: 0.9rem; color: var(--color-text-soft); font-weight: 500; }

/* ---------- Afinador (tuner) ---------- */
.tuner-display { text-align: center; padding: 10px 0 4px; }
.tuner-note { font-size: 4rem; font-weight: 800; color: #fff; line-height: 1; font-family: var(--font-mono); }
.tuner-freq { color: var(--color-text-dim); font-family: var(--font-mono); font-size: 0.95rem; }
.tuner-status { font-size: 1.1rem; font-weight: 600; margin-top: 6px; min-height: 1.4em; }
.tuner-meter {
  position: relative; height: 56px; margin: 16px auto; max-width: 480px;
  background: var(--color-bg); border: 1px solid var(--color-border); border-radius: 12px; overflow: hidden;
}
.tuner-meter .center-line { position: absolute; left: 50%; top: 0; bottom: 0; width: 2px; background: var(--color-success); transform: translateX(-50%); }
.tuner-meter .needle {
  position: absolute; top: 6px; bottom: 6px; left: 50%; width: 4px; border-radius: 4px;
  background: var(--color-primary); transform: translateX(-50%); transition: left 0.08s linear, background 0.1s;
}
.tuner-scale { display: flex; justify-content: space-between; max-width: 480px; margin: 0 auto; color: var(--color-text-dim); font-size: 0.78rem; font-family: var(--font-mono); }

/* ---------- Generador de tonos / teclado ---------- */
.tone-keys { display: flex; flex-wrap: wrap; gap: 8px; margin: 14px 0; }
.tone-keys button {
  flex: 1 1 64px; min-width: 60px; padding: 16px 8px; border-radius: 10px; cursor: pointer;
  background: var(--color-surface-2); border: 1px solid var(--color-border); color: #fff;
  font-family: var(--font-mono); font-weight: 700; font-size: 1rem; transition: all 0.1s;
}
.tone-keys button:hover { background: var(--color-primary); color: #1a1205; }
.tone-keys button:active, .tone-keys button.playing { background: var(--color-accent); color: #06231f; transform: scale(0.96); }
.tone-keys button small { display: block; font-size: 0.66rem; font-weight: 500; color: inherit; opacity: 0.75; }

/* ---------- Metrónomo ---------- */
.metro-bpm { font-size: 3.2rem; font-weight: 800; font-family: var(--font-mono); color: var(--color-primary); text-align: center; }
.metro-bpm small { font-size: 1rem; color: var(--color-text-dim); font-weight: 500; }
.metro-dots { display: flex; gap: 10px; justify-content: center; margin: 16px 0; }
.metro-dots .dot { width: 18px; height: 18px; border-radius: 50%; background: var(--color-surface-2); border: 1px solid var(--color-border); transition: all 0.05s; }
.metro-dots .dot.on { background: var(--color-accent); box-shadow: 0 0 16px var(--color-accent); transform: scale(1.25); }
.metro-dots .dot.accent.on { background: var(--color-primary); box-shadow: 0 0 16px var(--color-primary); }

/* ---------- Quiz / ear training ---------- */
.quiz-question { font-size: 1.15rem; font-weight: 600; color: #fff; margin: 8px 0 16px; }
.quiz-options { display: grid; grid-template-columns: repeat(auto-fit, minmax(110px, 1fr)); gap: 10px; }
.quiz-options button {
  padding: 14px; border-radius: 10px; background: var(--color-surface-2); border: 1px solid var(--color-border);
  color: var(--color-text); cursor: pointer; font-weight: 600; font-size: 0.98rem; transition: all 0.12s;
}
.quiz-options button:hover:not(:disabled) { border-color: var(--color-primary); }
.quiz-options button.correct { background: var(--color-success); color: #062a13; border-color: var(--color-success); }
.quiz-options button.wrong { background: var(--color-danger); color: #2a0606; border-color: var(--color-danger); }
.quiz-feedback { min-height: 1.5em; margin-top: 14px; font-weight: 600; }
.quiz-score { color: var(--color-text-soft); font-size: 0.92rem; }

/* ---------- Checklist interactiva ---------- */
.checklist { list-style: none; padding: 0; margin: 0; }
.checklist li {
  display: flex; gap: 12px; align-items: flex-start; padding: 12px 14px; margin-bottom: 8px;
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-sm);
  cursor: pointer; transition: background 0.12s;
}
.checklist li:hover { background: var(--color-surface-2); }
.checklist li.done { opacity: 0.55; }
.checklist li.done .check-label { text-decoration: line-through; }
.checklist input[type="checkbox"] { width: 20px; height: 20px; accent-color: var(--color-success); margin-top: 2px; flex-shrink: 0; }
.check-label { font-size: 0.96rem; color: var(--color-text); }
.checklist-progress { height: 10px; background: var(--color-bg); border-radius: 999px; overflow: hidden; margin: 8px 0 16px; border: 1px solid var(--color-border); }
.checklist-progress > div { height: 100%; width: 0; background: linear-gradient(90deg, var(--color-accent), var(--color-success)); transition: width 0.3s; }

/* ---------- Glosario ---------- */
.glossary-search { width: 100%; margin-bottom: 16px; }
.glossary dl { margin: 0; }
.glossary dt { font-weight: 700; color: var(--color-primary); margin-top: 14px; font-size: 1.02rem; }
.glossary dd { margin: 4px 0 0; color: var(--color-text-soft); }
.glossary .term.hidden { display: none; }

/* ---------- Acordeón FAQ ---------- */
.accordion details {
  background: var(--color-surface); border: 1px solid var(--color-border); border-radius: var(--radius-sm);
  margin-bottom: 10px; padding: 0 18px;
}
.accordion summary {
  cursor: pointer; padding: 16px 0; font-weight: 600; color: #fff; list-style: none;
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
}
.accordion summary::-webkit-details-marker { display: none; }
.accordion summary::after { content: "+"; font-size: 1.5rem; color: var(--color-primary); transition: transform 0.2s; }
.accordion details[open] summary::after { content: "−"; }
.accordion details > p { margin-top: 0; padding-bottom: 16px; color: var(--color-text-soft); }

/* ---------- Footer ---------- */
.site-footer { border-top: 1px solid var(--color-border); margin-top: 50px; padding: 40px 20px 28px; background: var(--color-bg-soft); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr; gap: 28px; max-width: var(--maxw); margin: 0 auto; }
@media (max-width: 720px) { .footer-grid { grid-template-columns: 1fr; } }
.site-footer h4 { color: #fff; margin: 0 0 12px; font-size: 1rem; }
.site-footer ul { list-style: none; padding: 0; margin: 0; }
.site-footer li { margin-bottom: 7px; }
.site-footer a { color: var(--color-text-soft); font-size: 0.92rem; }
.footer-bottom { text-align: center; color: var(--color-text-dim); font-size: 0.85rem; margin-top: 28px; padding-top: 20px; border-top: 1px solid var(--color-border); max-width: var(--maxw); margin-inline: auto; }

/* ---------- Banner de cookies ---------- */
.cookie-banner {
  position: fixed; left: 16px; right: 16px; bottom: 16px; z-index: 200;
  max-width: 720px; margin: 0 auto;
  background: var(--color-surface); border: 1px solid var(--color-border);
  border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow);
  display: none; gap: 18px; align-items: center; flex-wrap: wrap;
}
.cookie-banner.show { display: flex; }
.cookie-banner p { margin: 0; flex: 1 1 280px; font-size: 0.9rem; color: var(--color-text-soft); }
.cookie-banner .cookie-actions { display: flex; gap: 10px; flex-wrap: wrap; }
.cookie-banner .btn { padding: 10px 18px; font-size: 0.9rem; }

/* ---------- Páginas legales ---------- */
.legal { max-width: 820px; margin: 0 auto; padding: 30px 20px 10px; }
.legal h1 { font-size: clamp(1.8rem, 4vw, 2.6rem); }
.legal h2 { font-size: 1.3rem; margin-top: 32px; }
.legal p, .legal li { color: var(--color-text-soft); }
.legal .updated { color: var(--color-text-dim); font-size: 0.88rem; }

/* ---------- Botón volver arriba ---------- */
.to-top {
  position: fixed; right: 18px; bottom: 18px; z-index: 80;
  width: 48px; height: 48px; border-radius: 50%; border: 1px solid var(--color-border);
  background: var(--color-primary); color: #1a1205; font-size: 1.3rem; cursor: pointer;
  display: none; place-items: center; box-shadow: var(--shadow);
}
.to-top.show { display: grid; }

/* ---------- Utilidades ---------- */
.text-center { text-align: center; }
.muted { color: var(--color-text-dim); font-size: 0.85rem; }
.pill { display: inline-block; background: var(--color-surface-2); border: 1px solid var(--color-border); padding: 3px 10px; border-radius: 999px; font-size: 0.78rem; color: var(--color-text-soft); }
.mt-0 { margin-top: 0; }