/* ==========================================================================
   1. TOKENS DE DISEÑO
   ========================================================================== */
:root{
  --navy:#0d2440;
  --navy-2:#16375c;
  --navy-3:#1d4470;
  --gold:#b8862a;
  --gold-2:#e8b44a;
  --gold-soft:#fbf4e6;
  --ink:#12202f;
  --body:#4c5f74;
  --muted:#8494a5;
  --line:#e2e8f0;
  --line-2:#eef2f7;
  --surface:#f6f9fc;
  --white:#ffffff;
  --wa:#25d366;

  --sans:'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  --serif:'Source Serif 4', Georgia, 'Times New Roman', serif;

  --r:16px;
  --r-lg:22px;
  --maxw:1140px;

  --sh-1:0 1px 2px rgba(13,36,64,.06), 0 4px 14px rgba(13,36,64,.05);
  --sh-2:0 10px 30px rgba(13,36,64,.10);
  --sh-3:0 18px 50px rgba(13,36,64,.16);
}

/* ==========================================================================
   2. BASE
   ========================================================================== */
*,*::before,*::after{box-sizing:border-box}
html{scroll-behavior:smooth;scroll-padding-top:88px;-webkit-text-size-adjust:100%}
body{
  margin:0;
  font-family:var(--sans);
  font-size:17px;
  line-height:1.65;
  color:var(--body);
  background:var(--white);
  -webkit-font-smoothing:antialiased;
  overflow-x:hidden;
}
img{max-width:100%;display:block}
a{color:inherit;text-decoration:none}
h1,h2,h3,h4{font-family:var(--serif);color:var(--ink);margin:0;line-height:1.2;letter-spacing:-.015em;font-weight:600}
p{margin:0}
ul{margin:0;padding:0;list-style:none}
button{font-family:inherit}
:focus-visible{outline:3px solid var(--gold-2);outline-offset:3px;border-radius:6px}

.wrap{width:100%;max-width:var(--maxw);margin:0 auto;padding:0 24px}
.section{padding:96px 0}
.section--surface{background:var(--surface);border-top:1px solid var(--line-2);border-bottom:1px solid var(--line-2)}
.sr-only{position:absolute;width:1px;height:1px;padding:0;margin:-1px;overflow:hidden;clip:rect(0,0,0,0);white-space:nowrap;border:0}

.kicker{
  display:inline-block;font-size:13px;font-weight:700;letter-spacing:.14em;
  text-transform:uppercase;color:var(--gold);margin-bottom:14px;
}
.h2{font-size:clamp(28px,4vw,42px)}
.lead{font-size:clamp(16.5px,1.6vw,19px);color:var(--body);max-width:66ch}
.section-head{max-width:760px;margin-bottom:52px}

/* ==========================================================================
   3. BOTONES
   ========================================================================== */
.btn{
  display:inline-flex;align-items:center;justify-content:center;gap:10px;
  padding:16px 28px;border-radius:999px;font-weight:600;font-size:16.5px;
  border:1.5px solid transparent;cursor:pointer;
  transition:transform .18s ease, box-shadow .18s ease, background .18s ease, color .18s ease, border-color .18s ease;
  text-align:center;line-height:1.2;
}
.btn svg{flex:none}
.btn:hover{transform:translateY(-2px)}
.btn-wa{background:var(--wa);color:#04321c;box-shadow:0 8px 22px rgba(37,211,102,.35)}
.btn-wa:hover{background:#22c35d;box-shadow:0 12px 30px rgba(37,211,102,.45)}
.btn-mail{background:transparent;color:var(--white);border-color:rgba(255,255,255,.42)}
.btn-mail:hover{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.75)}
.btn-dark{background:var(--navy);color:var(--white);box-shadow:var(--sh-2)}
.btn-dark:hover{background:var(--navy-2)}
.btn-ghost{background:var(--white);color:var(--navy);border-color:var(--line)}
.btn-ghost:hover{border-color:var(--navy)}
.btn-sm{padding:10px 18px;font-size:14.5px}

/* ==========================================================================
   4. CABECERA
   ========================================================================== */
.site-header{
  position:sticky;top:0;z-index:60;
  background:rgba(255,255,255,.9);
  backdrop-filter:saturate(180%) blur(14px);
  -webkit-backdrop-filter:saturate(180%) blur(14px);
  border-bottom:1px solid transparent;
  transition:border-color .25s ease, box-shadow .25s ease;
}
.site-header.scrolled{border-bottom-color:var(--line);box-shadow:0 4px 20px rgba(13,36,64,.06)}
.header-inner{display:flex;align-items:center;justify-content:space-between;gap:18px;height:72px}

.brand{display:flex;align-items:center;gap:12px;flex:none}
.brand-mark{
  width:42px;height:42px;border-radius:12px;flex:none;
  background:linear-gradient(150deg,var(--navy-3),var(--navy));
  color:var(--gold-2);font-family:var(--serif);font-weight:700;font-size:17px;
  display:grid;place-items:center;letter-spacing:.02em;
}
.brand-text{display:flex;flex-direction:column;line-height:1.25}
.brand-text strong{font-family:var(--serif);font-size:17.5px;color:var(--ink);font-weight:700}
.brand-text span{font-size:12.5px;color:var(--muted);font-weight:500}

.nav{display:flex;align-items:center;gap:4px}
.nav > a:not(.btn){
  padding:9px 13px;border-radius:9px;font-size:15px;font-weight:500;color:var(--body);
  transition:color .18s ease, background .18s ease;
}
.nav > a:not(.btn):hover{color:var(--navy);background:var(--surface)}
.nav > a.active:not(.btn){color:var(--navy);background:var(--surface);font-weight:600}
.nav-cta{margin-left:8px}

/* Enlace para saltar al contenido (solo visible con el teclado) */
.skip-link{
  position:absolute;left:-9999px;top:0;z-index:100;
  background:var(--navy);color:#fff;padding:13px 22px;border-radius:0 0 12px 0;
  font-weight:600;font-size:15px;
}
.skip-link:focus{left:0}

.header-actions{display:flex;align-items:center;gap:12px;flex:none}
.lang{display:inline-flex;background:var(--surface);border:1px solid var(--line);border-radius:999px;padding:3px}
.lang button{
  border:0;background:transparent;cursor:pointer;padding:6px 13px;border-radius:999px;
  font-size:13px;font-weight:700;letter-spacing:.04em;color:var(--muted);transition:.18s ease;
}
.lang button:hover{color:var(--navy)}
.lang button.active{background:var(--navy);color:#fff;box-shadow:0 2px 8px rgba(13,36,64,.25)}

.nav-toggle{
  display:none;width:44px;height:44px;border-radius:11px;border:1px solid var(--line);
  background:var(--white);cursor:pointer;padding:0;place-items:center;color:var(--navy);
}
.nav-toggle i{display:block;width:19px;height:2px;background:currentColor;border-radius:2px;position:relative;transition:.2s}
.nav-toggle i::before,.nav-toggle i::after{
  content:"";position:absolute;left:0;width:19px;height:2px;background:currentColor;border-radius:2px;transition:.2s;
}
.nav-toggle i::before{top:-6px}
.nav-toggle i::after{top:6px}
.nav-toggle[aria-expanded="true"] i{background:transparent}
.nav-toggle[aria-expanded="true"] i::before{top:0;transform:rotate(45deg)}
.nav-toggle[aria-expanded="true"] i::after{top:0;transform:rotate(-45deg)}

/* ==========================================================================
   5. HERO
   ========================================================================== */
.hero{
  position:relative;overflow:hidden;color:#dce6f2;
  background:
    radial-gradient(1100px 560px at 12% -15%, #23507f 0%, transparent 62%),
    radial-gradient(820px 460px at 92% 4%, #1a3d68 0%, transparent 58%),
    linear-gradient(170deg,#0b1f38 0%,#0d2440 55%,#0a1b31 100%);
}
.hero::after{
  content:"";position:absolute;inset:0;pointer-events:none;opacity:.055;
  background-image:linear-gradient(rgba(255,255,255,.8) 1px,transparent 1px),
                   linear-gradient(90deg,rgba(255,255,255,.8) 1px,transparent 1px);
  background-size:56px 56px;
  -webkit-mask-image:radial-gradient(70% 60% at 50% 30%,#000 0%,transparent 100%);
  mask-image:radial-gradient(70% 60% at 50% 30%,#000 0%,transparent 100%);
}
.hero-inner{position:relative;z-index:2;display:grid;grid-template-columns:1.15fr .85fr;gap:56px;align-items:center;padding:88px 24px 96px}

.badge{
  display:inline-flex;align-items:center;gap:9px;
  background:rgba(232,180,74,.12);border:1px solid rgba(232,180,74,.32);
  color:var(--gold-2);border-radius:999px;padding:8px 16px;
  font-size:13px;font-weight:600;letter-spacing:.03em;margin-bottom:24px;
}
.badge .dot{width:7px;height:7px;border-radius:50%;background:var(--gold-2);box-shadow:0 0 0 4px rgba(232,180,74,.18)}

.hero h1{
  color:#fff;font-size:clamp(34px,5.2vw,58px);line-height:1.08;letter-spacing:-.025em;
  margin-bottom:22px;font-weight:700;
}
.hero h1 .hl{color:var(--gold-2);background:linear-gradient(transparent 66%, rgba(232,180,74,.2) 66%)}
.hero-sub{font-size:clamp(17px,1.7vw,20px);color:#b6c6d8;max-width:60ch;margin-bottom:34px;line-height:1.6}
.hero-cta{display:flex;flex-wrap:wrap;gap:14px;margin-bottom:20px}
.hero-note{font-size:14.5px;color:#8ea3ba;max-width:52ch}
.hero-chips{display:flex;flex-wrap:wrap;gap:10px;margin-top:30px}
.chip{
  display:inline-flex;align-items:center;gap:8px;font-size:13.5px;font-weight:500;color:#c6d4e4;
  background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.12);
  padding:8px 15px;border-radius:999px;
}
.chip svg{color:var(--gold-2)}

.hero-card{
  background:rgba(255,255,255,.06);
  border:1px solid rgba(255,255,255,.14);
  border-radius:var(--r-lg);
  padding:30px 28px;
  backdrop-filter:blur(10px);
  -webkit-backdrop-filter:blur(10px);
  box-shadow:0 28px 60px rgba(3,12,26,.42);
}
.hero-card h2{color:#fff;font-size:20px;margin-bottom:20px;font-weight:600}
.hero-card ul{display:flex;flex-direction:column;gap:14px;margin-bottom:24px}
.hero-card li{display:flex;gap:12px;align-items:flex-start;font-size:15.3px;color:#cfdcea;line-height:1.5}
.tick{
  flex:none;width:22px;height:22px;border-radius:50%;margin-top:1px;
  background:rgba(37,211,102,.16);color:#4ade80;display:grid;place-items:center;
}
.hero-card .divider{height:1px;background:rgba(255,255,255,.14);margin-bottom:22px}
.hero-contact{display:flex;flex-direction:column;gap:14px}
.hero-contact a{display:flex;align-items:center;gap:13px;transition:transform .18s ease}
.hero-contact a:hover{transform:translateX(3px)}
.hero-contact .ic{
  width:40px;height:40px;flex:none;border-radius:11px;display:grid;place-items:center;
  background:rgba(255,255,255,.09);color:var(--gold-2);border:1px solid rgba(255,255,255,.1);
}
.hero-contact .tx{display:flex;flex-direction:column;line-height:1.35;min-width:0}
.hero-contact .tx small{font-size:11.5px;text-transform:uppercase;letter-spacing:.1em;color:#8ea3ba;font-weight:600}
.hero-contact .tx b{font-size:15.5px;color:#fff;font-weight:600;word-break:break-word}

/* ==========================================================================
   6. TARJETAS
   ========================================================================== */
.grid{display:grid;gap:22px}
.grid-3{grid-template-columns:repeat(3,1fr)}
.grid-2{grid-template-columns:repeat(2,1fr)}
.grid-auto{grid-template-columns:repeat(auto-fit,minmax(288px,1fr))}

.card{
  background:var(--white);border:1px solid var(--line);border-radius:var(--r);
  padding:30px 26px;height:100%;
  transition:transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}
.card:hover{transform:translateY(-4px);box-shadow:var(--sh-2);border-color:#d3deea}
.card h3{font-size:20px;margin-bottom:10px}
.card p{font-size:15.5px;line-height:1.6}

.icon-box{
  width:52px;height:52px;border-radius:14px;display:grid;place-items:center;margin-bottom:20px;
  background:linear-gradient(150deg,#f0f5fa,#e4edf6);color:var(--navy-2);border:1px solid #dfe8f2;
}
.icon-box--gold{background:linear-gradient(150deg,#fdf6e8,#f8ecd4);color:var(--gold);border-color:#f0e2c6}

.steps{margin-top:56px;background:var(--white);border:1px solid var(--line);border-radius:var(--r-lg);padding:36px 32px;box-shadow:var(--sh-1)}
.steps h3{font-size:22px;margin-bottom:28px;text-align:center}
.steps-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:26px}
.step{display:flex;gap:16px;align-items:flex-start}
.step-num{
  flex:none;width:38px;height:38px;border-radius:50%;display:grid;place-items:center;
  background:var(--navy);color:var(--gold-2);font-family:var(--serif);font-weight:700;font-size:16px;
}
.step h4{font-size:16.5px;margin-bottom:5px;font-family:var(--sans);font-weight:600;color:var(--ink)}
.step p{font-size:14.8px;line-height:1.55}

/* ==========================================================================
   7. IDIOMAS
   ========================================================================== */
.lang-card{
  position:relative;background:var(--white);border:1px solid var(--line);
  border-radius:var(--r);padding:34px 30px;overflow:hidden;height:100%;
  transition:transform .22s ease, box-shadow .22s ease;
}
.lang-card:hover{transform:translateY(-4px);box-shadow:var(--sh-2)}
.lang-card::before{content:"";position:absolute;top:0;left:0;right:0;height:4px}
.lang-card.is-es::before{background:linear-gradient(90deg,#c60b1e,#ffc400,#c60b1e)}
.lang-card.is-en::before{background:linear-gradient(90deg,#00247d,#cf142b,#00247d)}
.lang-flag{font-size:34px;line-height:1;margin-bottom:16px}
.lang-card h3{font-size:22px;margin-bottom:12px}
.lang-card p{font-size:15.6px}
.lang-list{margin-top:18px;display:flex;flex-direction:column;gap:9px}
.lang-list li{display:flex;gap:10px;font-size:14.8px;align-items:flex-start;line-height:1.5}
.lang-list svg{flex:none;margin-top:4px;color:var(--gold)}
.lang-note{
  margin-top:28px;background:var(--gold-soft);border:1px solid #f1e3c7;border-radius:var(--r);
  padding:18px 22px;font-size:15.5px;color:#6d5720;display:flex;gap:12px;align-items:flex-start;
}
.lang-note svg{flex:none;margin-top:3px;color:var(--gold)}

/* Bloque destacado: estudios en Estados Unidos */
.us-panel{
  margin-top:28px;color:#c6d4e4;border-radius:var(--r-lg);padding:40px 38px;
  display:grid;grid-template-columns:1.05fr .95fr;gap:44px;align-items:center;
  box-shadow:var(--sh-3);
  background:
    radial-gradient(700px 380px at 88% -10%, #23507f 0%, transparent 62%),
    linear-gradient(160deg,#0b1f38,#0d2440 60%,#0a1b31);
}
.us-eyebrow{
  display:inline-flex;align-items:center;gap:10px;margin-bottom:14px;
  font-size:12.5px;font-weight:700;letter-spacing:.14em;text-transform:uppercase;color:var(--gold-2);
}
.us-eyebrow .flag{font-size:19px;letter-spacing:0}
.us-panel h3{color:#fff;font-size:clamp(23px,2.6vw,31px);margin-bottom:14px;line-height:1.18}
.us-panel p{font-size:16.2px;line-height:1.65;color:#b6c6d8}
.us-stats{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}
.us-stat{
  background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.14);
  border-radius:14px;padding:22px 14px;text-align:center;
}
.us-stat b{
  display:block;font-family:var(--serif);font-weight:700;line-height:1.05;margin-bottom:9px;
  font-size:clamp(23px,2.9vw,31px);color:var(--gold-2);
}
.us-stat span{display:block;font-size:13px;line-height:1.4;color:#a9bdd3}

/* ==========================================================================
   8. ASIGNATURAS
   ========================================================================== */
.subject{
  background:var(--white);border:1px solid var(--line);border-radius:var(--r);
  padding:26px 24px;height:100%;display:flex;flex-direction:column;
  transition:transform .22s ease, box-shadow .22s ease, border-color .22s ease;
}
.subject:hover{transform:translateY(-4px);box-shadow:var(--sh-2);border-color:#d3deea}
.subject .icon-box{width:46px;height:46px;border-radius:12px;margin-bottom:16px}
.subject h3{font-size:18px;margin-bottom:8px;line-height:1.3}
.subject p{font-size:14.8px;line-height:1.58}

.subjects-more{
  margin-top:34px;background:var(--navy);color:#dbe6f3;border-radius:var(--r-lg);
  padding:32px 34px;display:flex;align-items:center;justify-content:space-between;gap:26px;flex-wrap:wrap;
  box-shadow:var(--sh-2);
}
.subjects-more h3{color:#fff;font-size:22px;margin-bottom:6px}
.subjects-more p{font-size:15.5px;color:#a9bdd3}

/* ==========================================================================
   9. SOBRE MÍ
   ========================================================================== */
.about{display:grid;grid-template-columns:.85fr 1.15fr;gap:56px;align-items:center}
.about-visual{position:relative}
.quote-panel{
  position:relative;overflow:hidden;margin:0;
  border-radius:var(--r-lg);box-shadow:var(--sh-3);
  padding:52px 42px 44px;
  background:radial-gradient(600px 400px at 30% 10%,#23507f 0%,transparent 60%),linear-gradient(160deg,#123055,#0a1b31);
}
.quote-panel .mark{
  position:absolute;top:-26px;left:26px;
  font-family:var(--serif);font-size:150px;line-height:1;font-weight:700;
  color:var(--gold-2);opacity:.17;pointer-events:none;user-select:none;
}
.quote-panel blockquote{
  position:relative;margin:0;
  font-family:var(--serif);font-weight:400;font-style:italic;
  font-size:clamp(21px,2.5vw,27px);line-height:1.42;color:#fff;
  text-wrap:balance;
}
.quote-panel figcaption{
  position:relative;margin-top:26px;padding-top:20px;
  border-top:1px solid rgba(255,255,255,.16);
  font-size:14px;line-height:1.45;color:#a9bdd3;
}
.quote-panel figcaption b{display:block;color:var(--gold-2);font-weight:600;font-size:15px;margin-bottom:2px}
.about-text p{margin-bottom:18px;font-size:16.6px;line-height:1.72}
.about-stats{display:flex;flex-wrap:wrap;gap:10px;margin-top:26px}
.stat{
  background:var(--white);border:1px solid var(--line);border-radius:999px;
  padding:9px 17px;font-size:14px;font-weight:600;color:var(--navy);display:inline-flex;gap:8px;align-items:center;
}
.stat svg{color:var(--gold)}

/* ==========================================================================
   10. PREGUNTAS FRECUENTES
   ========================================================================== */
.faq{display:grid;gap:12px;max-width:880px}
.faq details{
  background:var(--white);border:1px solid var(--line);border-radius:var(--r);
  transition:border-color .2s ease, box-shadow .2s ease;
}
.faq details[open]{border-color:#d3deea;box-shadow:var(--sh-1)}
.faq summary{
  list-style:none;cursor:pointer;padding:22px 26px;display:flex;align-items:center;gap:18px;
  font-family:var(--serif);font-size:18.5px;font-weight:600;color:var(--ink);line-height:1.35;
  transition:color .18s ease;
}
.faq summary::-webkit-details-marker{display:none}
.faq summary:hover{color:var(--navy-2)}
.faq .q-mark{
  margin-left:auto;flex:none;width:28px;height:28px;border-radius:50%;
  border:1px solid var(--line);display:grid;place-items:center;color:var(--gold);
  transition:transform .22s ease, background .22s ease, border-color .22s ease;
}
.faq details[open] .q-mark{transform:rotate(45deg);background:var(--gold-soft);border-color:#f0e2c6}
.faq .answer{padding:0 26px 24px;font-size:15.8px;line-height:1.68;max-width:70ch}

/* ==========================================================================
   11. CONTACTO
   ========================================================================== */
.contact{
  position:relative;overflow:hidden;color:#dce6f2;
  background:
    radial-gradient(900px 480px at 85% 0%, #23507f 0%, transparent 60%),
    linear-gradient(160deg,#0b1f38,#0d2440 60%,#0a1b31);
}
.contact .kicker{color:var(--gold-2)}
.contact h2{color:#fff}
.contact .lead{color:#b6c6d8}
.contact-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:20px;margin:48px 0 40px}
.contact-card{
  background:rgba(255,255,255,.06);border:1px solid rgba(255,255,255,.14);
  border-radius:var(--r);padding:28px 24px;display:block;
  transition:transform .22s ease, background .22s ease, border-color .22s ease;
}
.contact-card:hover{transform:translateY(-4px);background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.3)}
.contact-card .ic{
  width:50px;height:50px;border-radius:14px;display:grid;place-items:center;margin-bottom:18px;
  background:rgba(232,180,74,.14);color:var(--gold-2);border:1px solid rgba(232,180,74,.24);
}
.contact-card.is-wa .ic{background:rgba(37,211,102,.16);color:#4ade80;border-color:rgba(37,211,102,.26)}
.contact-card small{display:block;font-size:11.5px;letter-spacing:.11em;text-transform:uppercase;color:#8ea3ba;font-weight:700;margin-bottom:7px}
.contact-card b{display:block;font-size:19px;color:#fff;font-weight:600;margin-bottom:8px;word-break:break-word;font-family:var(--serif)}
.contact-card p{font-size:14.4px;color:#a9bdd3;line-height:1.5}
.contact-cta{display:flex;flex-wrap:wrap;gap:14px}

/* ==========================================================================
   12. PIE
   ========================================================================== */
.site-footer{background:#081729;color:#7f93aa;padding:44px 0;font-size:14.5px}
.footer-inner{display:flex;flex-wrap:wrap;gap:22px;align-items:center;justify-content:space-between}
.footer-brand{display:flex;align-items:center;gap:12px}
.footer-brand .brand-mark{width:38px;height:38px;border-radius:11px;font-size:15px}
.footer-brand strong{font-family:var(--serif);font-size:16.5px;color:#fff;display:block;line-height:1.3}
.footer-brand span{font-size:13px;color:#7f93aa}
.footer-links{display:flex;flex-wrap:wrap;gap:20px}
.footer-links a{transition:color .18s}
.footer-links a:hover{color:#fff}
.footer-bottom{margin-top:26px;padding-top:22px;border-top:1px solid rgba(255,255,255,.08);font-size:13.4px;color:#65788e;text-align:center;line-height:1.7}

/* ==========================================================================
   13. BOTÓN FLOTANTE DE WHATSAPP
   ========================================================================== */
.wa-float{
  position:fixed;right:22px;bottom:22px;z-index:80;
  display:inline-flex;align-items:center;gap:11px;
  background:var(--wa);color:#04321c;font-weight:700;font-size:15.5px;
  padding:15px 22px;border-radius:999px;
  box-shadow:0 10px 30px rgba(18,140,126,.42);
  transition:transform .2s ease, box-shadow .2s ease, background .2s ease;
}
.wa-float:hover{transform:translateY(-3px) scale(1.02);background:#22c35d;box-shadow:0 16px 38px rgba(18,140,126,.5)}
.wa-float::before{
  content:"";position:absolute;inset:0;border-radius:999px;border:2px solid var(--wa);
  animation:pulse 2.6s ease-out infinite;pointer-events:none;
}
@keyframes pulse{
  0%{opacity:.55;transform:scale(1)}
  70%{opacity:0;transform:scale(1.3)}
  100%{opacity:0;transform:scale(1.3)}
}

/* ==========================================================================
   14. ANIMACIÓN DE ENTRADA
   Solo se oculta el contenido si JavaScript está activo (clase .js en el elemento raiz),
   para que la web se vea completa aunque el script no llegue a ejecutarse.
   ========================================================================== */
.js .reveal{opacity:0;transform:translateY(20px);transition:opacity .65s ease, transform .65s ease}
.js .reveal.in{opacity:1;transform:none}

/* ==========================================================================
   15. RESPONSIVE
   ========================================================================== */
@media (max-width:1024px){
  .hero-inner{grid-template-columns:1fr;gap:44px;padding:72px 24px 80px}
  .hero-sub{max-width:none}
  .about{grid-template-columns:1fr;gap:44px}
  .quote-panel{max-width:560px;padding:46px 38px 40px}
  .grid-3,.steps-grid{grid-template-columns:1fr 1fr}
  .contact-grid{grid-template-columns:1fr 1fr}
  .us-panel{grid-template-columns:1fr;gap:32px;padding:34px 30px}
}

/* El menú pasa a desplegable antes que el resto del diseño: con seis enlaces
   (y las etiquetas en español, que son más largas) deja de caber en una línea */
@media (max-width:1100px){
  .nav{
    position:absolute;top:72px;left:0;right:0;
    flex-direction:column;align-items:stretch;gap:2px;
    background:var(--white);border-bottom:1px solid var(--line);
    padding:14px 20px 20px;box-shadow:0 16px 30px rgba(13,36,64,.1);
    display:none;
  }
  .nav.open{display:flex}
  .nav > a:not(.btn){padding:13px 12px;font-size:16px;border-radius:10px}
  .nav > a.active:not(.btn){background:var(--surface)}
  .nav-cta{margin:10px 0 0}
  .nav-toggle{display:grid}
}
@media (max-width:900px){
  .brand-text span{display:none}
}
@media (max-width:720px){
  body{font-size:16.5px}
  .section{padding:68px 0}
  .wrap{padding:0 20px}
  .section-head{margin-bottom:38px}
  .grid-3,.grid-2,.steps-grid,.contact-grid{grid-template-columns:1fr}
  .hero-inner{padding:52px 20px 64px}
  .hero-cta{flex-direction:column;align-items:stretch}
  .hero-cta .btn{width:100%}
  .hero-card{padding:26px 22px}
  .steps{padding:28px 22px;margin-top:34px}
  .subjects-more{padding:26px 24px;flex-direction:column;align-items:flex-start}
  .subjects-more .btn{width:100%}
  .contact-grid{margin:34px 0 32px}
  .contact-cta{flex-direction:column;align-items:stretch}
  .contact-cta .btn{width:100%}
  .quote-panel{padding:40px 26px 30px}
  .quote-panel .mark{font-size:110px;top:-18px;left:18px}
  .us-panel{padding:30px 24px;gap:28px}
  .us-stats{grid-template-columns:1fr;gap:10px}
  .us-stat{display:flex;align-items:center;gap:16px;text-align:left;padding:16px 18px}
  .us-stat b{margin-bottom:0;flex:none;min-width:96px}
  .faq summary{padding:19px 20px;font-size:17px;gap:14px}
  .faq .answer{padding:0 20px 21px}
  .footer-inner{flex-direction:column;align-items:flex-start}
  .wa-float{right:16px;bottom:16px;padding:15px;gap:0}
  .wa-float .wa-label{display:none}
}
@media (prefers-reduced-motion:reduce){
  html{scroll-behavior:auto}
  *,*::before,*::after{animation-duration:.001ms !important;animation-iteration-count:1 !important;transition-duration:.001ms !important}
  .js .reveal{opacity:1;transform:none}
}

/* ==========================================================================
   16. SELECTOR DE IDIOMA (ahora son enlaces reales, no botones)
   ========================================================================== */
.lang span,
.lang a{
  display:inline-block;padding:6px 13px;border-radius:999px;
  font-size:13px;font-weight:700;letter-spacing:.04em;color:var(--muted);
  transition:color .18s ease, background .18s ease;
}
.lang a:hover{color:var(--navy);background:var(--white)}
.lang .active{background:var(--navy);color:#fff;box-shadow:0 2px 8px rgba(13,36,64,.25)}

/* ==========================================================================
   17. MIGAS DE PAN
   ========================================================================== */
.breadcrumb{
  font-size:13.5px;color:var(--muted);padding:26px 0 0;
  display:flex;flex-wrap:wrap;gap:8px;align-items:center;
}
.breadcrumb a{color:var(--body);text-decoration:underline;text-decoration-color:var(--line);text-underline-offset:3px}
.breadcrumb a:hover{color:var(--navy);text-decoration-color:var(--navy)}
.breadcrumb .sep{color:var(--line);font-size:15px}
.breadcrumb [aria-current]{color:var(--muted)}

/* ==========================================================================
   18. PÁGINA DE ASIGNATURA
   ========================================================================== */
.article-head{padding:34px 0 8px;max-width:800px}
.article-head h1{font-size:clamp(30px,4.4vw,46px);line-height:1.12;margin-bottom:20px}
.article-head .lead{font-size:clamp(17px,1.8vw,20px);line-height:1.6}
.article-head .lead + .lead{margin-top:14px}

.article-cta{display:flex;flex-wrap:wrap;gap:14px;margin-top:30px;align-items:center}
.article-cta .note{font-size:14.5px;color:var(--muted);max-width:34ch}

.prose{max-width:760px}
.prose h2{font-size:clamp(23px,2.9vw,31px);margin:52px 0 16px;line-height:1.2}
.prose h2:first-child{margin-top:0}
.prose p{font-size:17px;line-height:1.72;margin-bottom:16px}
.prose p:last-child{margin-bottom:0}

/* Errores típicos */
.pitfalls{display:grid;gap:16px;margin-top:24px}
.pitfall{
  background:var(--white);border:1px solid var(--line);border-left:3px solid var(--gold);
  border-radius:0 var(--r) var(--r) 0;padding:22px 24px;
}
.pitfall h3{font-size:17.5px;margin-bottom:8px;font-family:var(--sans);font-weight:600}
.pitfall p{font-size:15.6px;line-height:1.62;margin:0}

/* Ejercicio resuelto */
.worked{
  margin-top:28px;border:1px solid var(--line);border-radius:var(--r-lg);
  overflow:hidden;background:var(--white);box-shadow:var(--sh-1);
}
.worked-head{
  background:var(--navy);color:#fff;padding:22px 26px;
  display:flex;align-items:center;gap:13px;
}
.worked-head .badge-x{
  font-family:var(--sans);font-size:11px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;
  background:rgba(232,180,74,.16);color:var(--gold-2);border:1px solid rgba(232,180,74,.3);
  padding:4px 10px;border-radius:999px;flex:none;
}
.worked-head h3{color:#fff;font-size:19px;margin:0;line-height:1.3}
.worked-body{padding:26px}
.worked-statement{
  background:var(--surface);border:1px solid var(--line-2);border-radius:var(--r-sm,10px);
  padding:18px 20px;font-size:16px;line-height:1.65;margin-bottom:24px;
}
.worked-steps{counter-reset:paso;display:grid;gap:16px}
.worked-steps li{
  counter-increment:paso;list-style:none;display:grid;grid-template-columns:32px 1fr;gap:15px;
  font-size:15.8px;line-height:1.62;
}
.worked-steps li::before{
  content:counter(paso);
  width:28px;height:28px;border-radius:50%;display:grid;place-items:center;
  background:var(--surface);border:1px solid var(--line);color:var(--navy);
  font-weight:700;font-size:13.5px;font-variant-numeric:tabular-nums;
}
.worked-solution{
  margin-top:24px;padding:18px 20px;border-radius:var(--r-sm,10px);
  background:var(--gold-soft);border:1px solid #f1e3c7;color:#6d5720;
  font-size:16.2px;line-height:1.6;
}
.worked-solution b{
  display:block;font-family:var(--sans);font-size:11px;font-weight:700;letter-spacing:.12em;
  text-transform:uppercase;color:var(--gold);margin-bottom:6px;
}

/* Otras asignaturas */
.related{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:14px;margin-top:26px}
.related a{
  background:var(--white);border:1px solid var(--line);border-radius:var(--r);
  padding:18px 20px;display:flex;align-items:center;justify-content:space-between;gap:12px;
  font-size:15.6px;font-weight:600;color:var(--ink);line-height:1.35;
  transition:transform .2s ease, box-shadow .2s ease, border-color .2s ease;
}
.related a:hover{transform:translateY(-3px);box-shadow:var(--sh-2);border-color:#d3deea}
.related a svg{flex:none;color:var(--gold)}

/* Franja final de contacto */
.cta-band{
  margin-top:56px;border-radius:var(--r-lg);padding:38px 36px;color:#c6d4e4;
  box-shadow:var(--sh-2);
  background:
    radial-gradient(700px 380px at 88% -10%, #23507f 0%, transparent 62%),
    linear-gradient(160deg,#0b1f38,#0d2440 60%,#0a1b31);
  display:grid;grid-template-columns:1.1fr auto;gap:32px;align-items:center;
}
.cta-band h2{color:#fff;font-size:clamp(22px,2.6vw,28px);margin-bottom:10px}
.cta-band p{font-size:16px;color:#b6c6d8;max-width:52ch}
.cta-band .buttons{display:flex;flex-wrap:wrap;gap:12px}

@media (max-width:860px){
  .cta-band{grid-template-columns:1fr;padding:30px 26px;gap:24px}
  .cta-band .buttons{width:100%}
  .cta-band .buttons .btn{flex:1 1 200px}
}
@media (max-width:720px){
  .article-head{padding:24px 0 4px}
  .article-cta{flex-direction:column;align-items:stretch}
  .article-cta .btn{width:100%}
  .article-cta .note{max-width:none;text-align:center}
  .prose h2{margin:38px 0 14px}
  .worked-head{padding:18px 20px;flex-wrap:wrap;gap:10px}
  .worked-body{padding:20px 18px}
  .worked-statement{padding:15px 16px}
  .pitfall{padding:18px 20px}
  .cta-band{padding:26px 22px}
}

/* ==========================================================================
   19. ENLACES DENTRO DE TARJETAS
   ========================================================================== */
.subject-more{
  margin-top:auto;padding-top:18px;display:inline-flex;align-items:center;gap:8px;
  font-size:14.5px;font-weight:600;color:var(--gold);
  transition:gap .2s ease;
}
.subject:hover .subject-more{gap:12px}
.subject-more svg{flex:none}

.card-link{margin-top:20px}
.card-link a{
  display:inline-flex;align-items:center;gap:9px;
  font-size:15.3px;font-weight:600;color:var(--navy-2);
  border-bottom:1px solid var(--line);padding-bottom:3px;
  transition:gap .2s ease, border-color .2s ease, color .2s ease;
}
.card-link a:hover{gap:13px;color:var(--navy);border-bottom-color:var(--gold)}
.card-link svg{flex:none;color:var(--gold)}


/* ==========================================================================
   20. PIE: ENLACES A LAS ASIGNATURAS
   ========================================================================== */
.footer-subjects{
  margin-top:28px;padding-top:22px;border-top:1px solid rgba(255,255,255,.08);
  display:grid;grid-template-columns:auto 1fr;gap:10px 26px;align-items:start;
}
.footer-subjects-title{
  font-size:12px;font-weight:700;letter-spacing:.12em;text-transform:uppercase;color:#a9bdd3;padding-top:2px;
}
.footer-subjects div{display:flex;flex-wrap:wrap;gap:8px 20px}
.footer-subjects a{font-size:14px;color:#7f93aa;transition:color .18s}
.footer-subjects a:hover{color:#fff}
@media (max-width:720px){
  .footer-subjects{grid-template-columns:1fr}
}


/* ==========================================================================
   21. GUÍAS
   ========================================================================== */
.guide-meta{margin-top:18px;font-size:14.5px;color:var(--muted)}
.guide{max-width:820px}
.guide h2{scroll-margin-top:96px}
.formula{
  font-family:var(--serif);font-size:18px;line-height:1.6;color:var(--ink);
  background:var(--surface);border:1px solid var(--line);border-radius:var(--r-sm,10px);
  padding:14px 18px;margin:14px 0;overflow-x:auto;
}
.formula sup,.formula sub{font-size:.72em}
.guide-list{margin:14px 0 18px;padding-left:22px;display:grid;gap:8px}
.guide-list li{font-size:16.4px;line-height:1.65}
.guide-table-wrap{overflow-x:auto;margin:14px 0 8px;border:1px solid var(--line);border-radius:var(--r-sm,10px)}
.guide-table{border-collapse:collapse;width:100%;min-width:560px;font-size:15px}
.guide-table th,.guide-table td{text-align:left;padding:11px 14px;border-bottom:1px solid var(--line-2);vertical-align:top}
.guide-table thead th{background:var(--surface);font-size:12.5px;font-weight:700;letter-spacing:.08em;text-transform:uppercase;color:var(--muted)}
.guide-table tbody tr:last-child td{border-bottom:0}
.guide-table td:first-child{font-weight:600;color:var(--ink)}
.guide-table td:last-child{color:var(--muted);font-size:14px;white-space:nowrap}
.guide a{color:var(--navy-2);text-decoration:underline;text-decoration-color:var(--gold);text-underline-offset:3px}
@media (max-width:720px){
  .formula{font-size:16px;padding:12px 14px}
}