:root {
      --blue: #1a56db;
      --blue-dark: #1e429f;
      --blue-light: #e8f0fe;
      --blue-mid: #3b82f6;
      --text: #111928;
      --muted: #6b7280;
      --light: #f3f4f8;
      --white: #ffffff;
      --border: #e5e7eb;
      --success: #059669;
      --success-light: #d1fae5;
      --radius: 14px;
    }
* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body { font-family: 'Plus Jakarta Sans', sans-serif; color: var(--text); background: var(--white); overflow-x: hidden; }

/* NAV */
nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  background: rgba(255,255,255,0.93); backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  padding: 0 40px; height: 64px;
  display: flex; align-items: center; justify-content: space-between;
  animation: fadeDown 0.5s ease both;
}
.nav-logo { display: flex; align-items: center; gap: 12px; text-decoration: none; }
.nav-logo-icon {
  width: 40px; height: 40px; background: var(--blue); border-radius: 10px;
  display: flex; align-items: center; justify-content: center; font-size: 20px;
  box-shadow: 0 4px 12px rgba(26,86,219,0.3);
}
.nav-logo-text strong { display: block; font-size: 15px; font-weight: 800; color: var(--text); letter-spacing: -0.02em; }
.nav-logo-text span { font-size: 11px; color: var(--muted); }
.nav-links { display: flex; align-items: center; gap: 8px; }
.nav-links a { text-decoration: none; font-size: 14px; font-weight: 500; color: var(--muted); padding: 6px 16px; border-radius: 8px; transition: all 0.2s; }
.nav-links a:hover { color: var(--blue); }
.nav-links a.active { color: var(--blue); font-weight: 600; }
.nav-links a.btn-admin { border: 1.5px solid var(--border); color: var(--text); font-weight: 600; }
.nav-links a.btn-admin:hover { border-color: var(--blue); color: var(--blue); }

/* HERO */
.hero { min-height: 100vh; position: relative; display: flex; flex-direction: column; justify-content: center; overflow: hidden; }
.hero-img { position: absolute; inset: 0; background-image: url('https://images.unsplash.com/photo-1562774053-701939374585?w=1600&q=80'); background-size: cover; background-position: center; z-index: 0; }
.hero-bg { position: absolute; inset: 0; background: linear-gradient(135deg, rgba(232,240,254,0.97) 0%, rgba(255,255,255,0.78) 55%, transparent 100%); z-index: 1; }
.hero-grid { position: absolute; inset: 0; z-index: 1; background-image: linear-gradient(rgba(26,86,219,0.04) 1px,transparent 1px),linear-gradient(90deg,rgba(26,86,219,0.04) 1px,transparent 1px); background-size: 60px 60px; }
.hero-content { position: relative; z-index: 2; max-width: 680px; padding: 140px 80px 60px; }
.hero-badge { display: inline-flex; align-items: center; gap: 8px; background: rgba(26,86,219,0.1); border: 1px solid rgba(26,86,219,0.2); border-radius: 100px; padding: 6px 14px; font-size: 12px; font-weight: 600; color: var(--blue); letter-spacing: 0.04em; text-transform: uppercase; margin-bottom: 28px; animation: fadeUp 0.6s 0.1s ease both; }
.hero-badge::before { content: ''; width: 6px; height: 6px; background: var(--blue); border-radius: 50%; animation: blink 2s infinite; }
@keyframes blink { 0%,100%{opacity:1;transform:scale(1)} 50%{opacity:0.4;transform:scale(1.4)} }
.hero h1 { font-size: clamp(2.4rem,5vw,3.8rem); font-weight: 800; line-height: 1.08; letter-spacing: -0.03em; color: var(--text); margin-bottom: 24px; animation: fadeUp 0.6s 0.2s ease both; }
.hero h1 em { font-style: normal; color: var(--blue); }
.hero p { font-size: 17px; color: var(--muted); line-height: 1.7; max-width: 480px; margin-bottom: 40px; animation: fadeUp 0.6s 0.3s ease both; }
.hero-btns { display: flex; gap: 14px; flex-wrap: wrap; animation: fadeUp 0.6s 0.4s ease both; }
.btn-primary { display: inline-flex; align-items: center; gap: 8px; background: var(--blue); color: white; font-family: 'Plus Jakarta Sans',sans-serif; font-size: 15px; font-weight: 600; padding: 14px 28px; border-radius: 10px; text-decoration: none; border: none; cursor: pointer; transition: all 0.25s; box-shadow: 0 4px 16px rgba(26,86,219,0.35); }
.btn-primary:hover { background: var(--blue-dark); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(26,86,219,0.4); }
.btn-secondary { display: inline-flex; align-items: center; gap: 8px; background: white; color: var(--text); font-family: 'Plus Jakarta Sans',sans-serif; font-size: 15px; font-weight: 600; padding: 14px 28px; border-radius: 10px; text-decoration: none; border: 1.5px solid var(--border); cursor: pointer; transition: all 0.25s; }
.btn-secondary:hover { border-color: var(--blue); color: var(--blue); transform: translateY(-2px); }
.hero-stats { position: relative; z-index: 2; display: flex; padding: 0 80px 70px; animation: fadeUp 0.6s 0.5s ease both; }
.stat { padding: 20px 36px 20px 0; border-right: 1px solid rgba(0,0,0,0.08); }
.stat:last-child { border-right: none; padding-right: 0; padding-left: 36px; }
.stat:first-child { padding-left: 0; }
.stat-number { font-size: 28px; font-weight: 800; color: var(--blue); letter-spacing: -0.03em; }
.stat-label { font-size: 12px; color: var(--muted); font-weight: 500; margin-top: 2px; }

/* WHY */
.why-section { background: var(--light); padding: 100px 80px; text-align: center; }
.section-label { font-size: 12px; font-weight: 700; letter-spacing: 0.1em; text-transform: uppercase; color: var(--blue); margin-bottom: 16px; }
.section-title { font-size: clamp(1.8rem,3vw,2.4rem); font-weight: 800; letter-spacing: -0.02em; color: var(--text); margin-bottom: 16px; }
.section-sub { font-size: 16px; color: var(--muted); max-width: 520px; margin: 0 auto 60px; line-height: 1.6; }
.cards-grid { display: grid; grid-template-columns: repeat(3,1fr); gap: 24px; max-width: 1000px; margin: 0 auto; }
.why-card { background: white; border: 1px solid var(--border); border-radius: var(--radius); padding: 32px 28px; text-align: left; transition: all 0.3s; position: relative; overflow: hidden; }
.why-card::before { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px; background: linear-gradient(90deg,var(--blue),var(--blue-mid)); transform: scaleX(0); transform-origin: left; transition: transform 0.3s; }
.why-card:hover { box-shadow: 0 8px 32px rgba(26,86,219,0.1); transform: translateY(-4px); }
.why-card:hover::before { transform: scaleX(1); }
.card-icon-wrap { width: 48px; height: 48px; background: var(--blue-light); border-radius: 12px; display: flex; align-items: center; justify-content: center; font-size: 22px; margin-bottom: 20px; }
.why-card h3 { font-size: 16px; font-weight: 700; margin-bottom: 10px; }
.why-card p { font-size: 14px; color: var(--muted); line-height: 1.6; }

/* SURVEY SECTION */
.survey-section { background: var(--white); padding: 100px 20px 80px; }
.survey-section-header { text-align: center; margin-bottom: 48px; }
.survey-section-header h2 { font-size: clamp(1.8rem,3vw,2.4rem); font-weight: 800; letter-spacing: -0.02em; color: var(--text); margin-bottom: 14px; }
.survey-section-header p { font-size: 15px; color: var(--muted); max-width: 500px; margin: 0 auto; line-height: 1.6; }

/* Progress */
.progress-wrap { max-width: 760px; margin: 0 auto 28px; padding: 0 4px; }
.progress-info { display: flex; justify-content: space-between; font-size: 12px; color: var(--muted); margin-bottom: 8px; font-weight: 600; }
.progress-bar-bg { height: 6px; background: var(--border); border-radius: 100px; }
.progress-bar-fill { height: 100%; background: linear-gradient(90deg,var(--blue),var(--blue-mid)); border-radius: 100px; width: 0%; transition: width 0.5s ease; }

/* Survey card */
.survey-card { max-width: 760px; margin: 0 auto; background: white; border: 1px solid var(--border); border-radius: 20px; padding: 40px 48px; box-shadow: 0 4px 32px rgba(0,0,0,0.06); }
.survey-card-header { margin-bottom: 36px; padding-bottom: 24px; border-bottom: 1px solid var(--border); }
.survey-card-header h3 { font-size: 20px; font-weight: 800; margin-bottom: 6px; }
.survey-card-header p { font-size: 14px; color: var(--muted); }

/* Questions */
.question-block { margin-bottom: 40px; padding-bottom: 40px; border-bottom: 1px solid var(--border); }
.question-block:last-of-type { border-bottom: none; margin-bottom: 0; }
.question-num { display: inline-flex; align-items: center; justify-content: center; width: 24px; height: 24px; background: var(--blue-light); color: var(--blue); border-radius: 6px; font-size: 11px; font-weight: 800; margin-bottom: 12px; }
.question-text { font-size: 16px; font-weight: 700; color: var(--text); margin-bottom: 20px; line-height: 1.4; }
.required-dot { color: #ef4444; margin-left: 4px; }

/* Radio options */
.options-list { display: flex; flex-direction: column; gap: 10px; }
.option-item { position: relative; }
.option-input { position: absolute; opacity: 0; width: 0; height: 0; }
.option-label { display: flex; align-items: center; gap: 14px; padding: 14px 18px; border: 1.5px solid var(--border); border-radius: 10px; cursor: pointer; transition: all 0.2s; background: white; user-select: none; }
.option-label:hover { border-color: rgba(26,86,219,0.4); background: rgba(26,86,219,0.02); transform: translateX(3px); }
.option-input:checked + .option-label { border-color: var(--blue); background: var(--blue-light); box-shadow: 0 0 0 3px rgba(26,86,219,0.1); }
.option-radio { width: 20px; height: 20px; border: 2px solid var(--border); border-radius: 50%; display: flex; align-items: center; justify-content: center; flex-shrink: 0; transition: all 0.2s; background: white; position: relative; }
.option-input:checked + .option-label .option-radio { border-color: var(--blue); background: var(--blue); }
.option-radio::after { content: ''; width: 7px; height: 7px; background: white; border-radius: 50%; opacity: 0; transform: scale(0); transition: all 0.2s; position: absolute; }
.option-input:checked + .option-label .option-radio::after { opacity: 1; transform: scale(1); }
.option-text { font-size: 14px; font-weight: 500; flex: 1; }
.option-badge { font-size: 11px; font-weight: 700; padding: 3px 10px; border-radius: 100px; opacity: 0.55; transition: opacity 0.2s; }
.option-input:checked + .option-label .option-badge { opacity: 1; }
.badge-ex { background: #d1fae5; color: #059669; }
.badge-bu { background: #dbeafe; color: #1d4ed8; }
.badge-re { background: #fef3c7; color: #d97706; }
.badge-ma { background: #fee2e2; color: #dc2626; }

/* Textarea */
textarea { width: 100%; min-height: 120px; padding: 16px; border: 1.5px solid var(--border); border-radius: 10px; font-family: 'Plus Jakarta Sans',sans-serif; font-size: 14px; color: var(--text); background: white; resize: vertical; outline: none; transition: border-color 0.2s, box-shadow 0.2s; line-height: 1.6; }
textarea::placeholder { color: #c1c5cf; }
textarea:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(26,86,219,0.1); }
.char-count { text-align: right; font-size: 11px; color: var(--muted); margin-top: 6px; }

/* Registro de alumno */
.registro-block { background: var(--blue-light); border: 1.5px solid rgba(26,86,219,0.15); border-radius: 14px; padding: 28px 32px; margin-bottom: 36px; }
.registro-block-title { display: flex; align-items: center; gap: 10px; font-size: 15px; font-weight: 700; color: var(--blue-dark); margin-bottom: 6px; }
.registro-block-sub { font-size: 13px; color: var(--muted); margin-bottom: 22px; }
.registro-fields { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 600px) { .registro-fields { grid-template-columns: 1fr; } }
.field-group { display: flex; flex-direction: column; gap: 6px; }
.field-label { font-size: 13px; font-weight: 600; color: var(--text); }
.field-input { width: 100%; padding: 13px 16px; border: 1.5px solid rgba(26,86,219,0.2); border-radius: 10px; font-family: 'Plus Jakarta Sans',sans-serif; font-size: 14px; color: var(--text); background: white; outline: none; transition: border-color 0.2s, box-shadow 0.2s; }
.field-input::placeholder { color: #c1c5cf; }
.field-input:focus { border-color: var(--blue); box-shadow: 0 0 0 3px rgba(26,86,219,0.1); }

/* Submit */
.submit-area { display: flex; justify-content: flex-end; align-items: center; gap: 16px; margin-top: 32px; }
.privacy-note { font-size: 12px; color: var(--muted); }
.btn-submit { display: inline-flex; align-items: center; gap: 10px; background: var(--blue); color: white; font-family: 'Plus Jakarta Sans',sans-serif; font-size: 15px; font-weight: 700; padding: 15px 36px; border-radius: 10px; border: none; cursor: pointer; transition: all 0.25s; box-shadow: 0 4px 16px rgba(26,86,219,0.3); }
.btn-submit:hover { background: var(--blue-dark); transform: translateY(-2px); box-shadow: 0 8px 24px rgba(26,86,219,0.4); }
.btn-submit:active { transform: translateY(0); }

/* Error */
.error-banner { display: none; background: #fef2f2; border: 1px solid #fecaca; border-radius: 10px; padding: 14px 18px; font-size: 14px; color: #dc2626; margin-bottom: 24px; font-weight: 500; }
.error-banner.show { display: flex; align-items: center; gap: 10px; }

/* Success */
.success-screen { text-align: center; padding: 60px 20px; }
.success-icon { width: 80px; height: 80px; background: var(--success-light); border-radius: 50%; display: flex; align-items: center; justify-content: center; font-size: 36px; margin: 0 auto 24px; animation: popIn 0.4s ease both; }
@keyframes popIn { from{transform:scale(0.5);opacity:0} to{transform:scale(1);opacity:1} }
.success-screen h2 { font-size: 24px; font-weight: 800; margin-bottom: 12px; }
.success-screen p { font-size: 15px; color: var(--muted); margin-bottom: 32px; line-height: 1.6; }

/* CTA */
.cta-section { padding: 100px 80px; text-align: center; background: var(--light); }
.cta-box { background: linear-gradient(135deg,var(--blue) 0%,#3b5ef5 100%); border-radius: 24px; padding: 70px 60px; max-width: 800px; margin: 0 auto; position: relative; overflow: hidden; }
.cta-box::before { content: ''; position: absolute; top: -60px; right: -60px; width: 240px; height: 240px; background: rgba(255,255,255,0.06); border-radius: 50%; }
.cta-box h2 { font-size: clamp(1.6rem,3vw,2.2rem); font-weight: 800; color: white; letter-spacing: -0.02em; margin-bottom: 16px; position: relative; z-index: 1; }
.cta-box p { color: rgba(255,255,255,0.8); font-size: 16px; line-height: 1.6; margin-bottom: 36px; position: relative; z-index: 1; }
.btn-white { display: inline-flex; align-items: center; gap: 8px; background: white; color: var(--blue); font-family: 'Plus Jakarta Sans',sans-serif; font-size: 15px; font-weight: 700; padding: 14px 32px; border-radius: 10px; text-decoration: none; border: none; cursor: pointer; transition: all 0.25s; position: relative; z-index: 1; box-shadow: 0 4px 20px rgba(0,0,0,0.15); }
.btn-white:hover { transform: translateY(-2px); box-shadow: 0 8px 28px rgba(0,0,0,0.2); }

/* FOOTER */
footer { background: var(--text); color: rgba(255,255,255,0.5); padding: 48px 80px; display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 40px; }
.footer-brand { display: flex; align-items: flex-start; gap: 14px; }
.footer-logo-icon { width: 40px; height: 40px; background: var(--blue); border-radius: 10px; display: flex; align-items: center; justify-content: center; font-size: 18px; flex-shrink: 0; }
.footer-logo-text strong { display: block; color: white; font-size: 14px; font-weight: 700; }
.footer-logo-text span { font-size: 12px; }
footer h4 { color: white; font-size: 13px; font-weight: 700; margin-bottom: 16px; letter-spacing: 0.05em; text-transform: uppercase; }
footer ul { list-style: none; }
footer ul li { margin-bottom: 10px; }
footer ul li a { color: rgba(255,255,255,0.5); text-decoration: none; font-size: 13px; transition: color 0.2s; }
footer ul li a:hover { color: white; }

/* Animations */
@keyframes fadeDown { from{opacity:0;transform:translateY(-10px)} to{opacity:1;transform:translateY(0)} }
@keyframes fadeUp   { from{opacity:0;transform:translateY(24px)}  to{opacity:1;transform:translateY(0)} }
.reveal { opacity:0; transform:translateY(30px); transition: opacity 0.6s ease, transform 0.6s ease; }
.reveal.visible { opacity:1; transform:translateY(0); }

@media (max-width: 768px) {
  nav { padding: 0 20px; }
  .hero-content { padding: 100px 24px 40px; }
  .hero-stats { padding: 0 24px 40px; flex-wrap: wrap; }
  .why-section, .cta-section { padding: 60px 24px; }
  .cards-grid { grid-template-columns: 1fr; }
  footer { grid-template-columns: 1fr; padding: 40px 24px; }
  .survey-card { padding: 28px 20px; }
  .submit-area { flex-direction: column; align-items: stretch; }
  .btn-submit { justify-content: center; }
}