:root {
  --primary: #111111;
  --primary-dark: #000000;
  --accent: #0071e3;
  --bg: #f5f5f7;
  --white: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --border: #d2d2d7;
  --soft-border: #e8e8ed;
  --shadow: 0 24px 60px rgba(0, 0, 0, 0.08);
  --shadow-soft: 0 12px 30px rgba(0, 0, 0, 0.05);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "Segoe UI", Arial, Helvetica, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  width: min(1120px, 92%);
  margin: 0 auto;
}

/* Header */

.site-header {
  background: rgba(255, 255, 255, 0.82);
  border-bottom: 1px solid var(--soft-border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  position: sticky;
  top: 0;
  z-index: 20;
}

.header-content {
  min-height: 86px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 14px;
  color: var(--primary-dark);
}

.logo i {
  width: 52px;
  height: 52px;
  border-radius: 16px;
  background: #f5f5f7;
  border: 1px solid var(--soft-border);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--primary-dark);
  font-size: 1.35rem;
  box-shadow: var(--shadow-soft);
}

.logo strong {
  display: block;
  font-size: 1.35rem;
  text-transform: uppercase;
  letter-spacing: 2px;
  line-height: 1.2;
}

.logo span {
  display: block;
  color: var(--muted);
  font-size: 0.92rem;
}

.header-contact {
  display: flex;
  flex-direction: column;
  gap: 6px;
  color: var(--muted);
  font-size: 0.95rem;
  align-items: flex-start;
}

.header-contact p {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-contact i {
  color: var(--primary-dark);
}

/* Navigation */

.main-nav {
  background: #111111;
  border-top: 1px solid #111111;
}

.nav-content {
  display: flex;
  justify-content: center;
  align-items: center;
}

.main-nav ul {
  list-style: none;
  display: flex;
  justify-content: center;
  gap: 4px;
}

.main-nav a {
  display: block;
  padding: 14px 22px;
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: 999px;
  transition: background 0.25s ease, color 0.25s ease, transform 0.25s ease;
}

.main-nav a:hover {
  background: #ffffff;
  color: #111111;
  transform: translateY(-1px);
}

.main-nav a:focus {
  outline: 3px solid rgba(255, 255, 255, 0.35);
  outline-offset: 3px;
}

/* Menú responsive */

.menu-checkbox {
  position: absolute;
  opacity: 0;
  pointer-events: none;
}

.menu-button {
  display: none;
}

/* Main section */

.form-section {
  padding: 72px 0 88px;
}

.section-title.hero-banner {
  position: relative;
  background:
    linear-gradient(rgba(0, 0, 0, 0.56), rgba(0, 0, 0, 0.56)),
    url("../img/hero-academia.jpg") center/cover no-repeat;
  padding: 96px 28px;
  border-radius: 34px;
  text-align: center;
  margin-bottom: 44px;
  overflow: hidden;
  box-shadow: var(--shadow);
}

.section-title.hero-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.22), transparent 34%),
    radial-gradient(circle at bottom right, rgba(255, 255, 255, 0.12), transparent 36%);
  pointer-events: none;
}

.section-title.hero-banner h1,
.section-title.hero-banner .section-subtitle {
  position: relative;
  z-index: 1;
}

.section-title.hero-banner h1 {
  color: #ffffff;
  font-size: clamp(2.2rem, 5vw, 4.2rem);
  line-height: 1.08;
  margin-bottom: 16px;
  letter-spacing: -1.8px;
  font-weight: 800;
}

.section-title.hero-banner .section-subtitle {
  max-width: 720px;
  margin: 0 auto;
  color: rgba(255, 255, 255, 0.88);
  font-size: clamp(1rem, 2vw, 1.25rem);
  line-height: 1.55;
}

/* Form */

.register-form {
  max-width: 860px;
  margin: 0 auto;
  padding: 42px;
  background: rgba(255, 255, 255, 0.92);
  border-radius: 34px;
  box-shadow: var(--shadow);
  border: 1px solid var(--soft-border);
}

.form-header {
  text-align: center;
  margin-bottom: 34px;
}

.form-header i {
  width: 68px;
  height: 68px;
  margin-bottom: 14px;
  border-radius: 22px;
  background: #f5f5f7;
  border: 1px solid var(--soft-border);
  color: var(--primary-dark);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.8rem;
  box-shadow: var(--shadow-soft);
}

.form-header h2 {
  color: var(--text);
  font-size: clamp(1.45rem, 3vw, 2rem);
  letter-spacing: -0.5px;
}

.form-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 22px;
}

.form-group {
  flex: 1 1 calc(50% - 22px);
}

.form-group.full {
  flex-basis: 100%;
}

label {
  display: block;
  margin-bottom: 8px;
  color: var(--text);
  font-weight: 600;
}

.input-icon {
  position: relative;
}

.input-icon i {
  position: absolute;
  left: 17px;
  top: 50%;
  transform: translateY(-50%);
  color: #86868b;
  pointer-events: none;
}

input,
select {
  width: 100%;
  min-height: 52px;
  padding: 13px 15px 13px 46px;
  border: 1px solid var(--border);
  border-radius: 16px;
  font-size: 1rem;
  color: var(--text);
  background: #fbfbfd;
  transition:
    border-color 0.25s ease,
    box-shadow 0.25s ease,
    background 0.25s ease,
    transform 0.25s ease;
}

input:hover,
select:hover {
  border-color: #86868b;
  background: #ffffff;
}

input:focus,
select:focus {
  outline: none;
  border-color: var(--accent);
  background: #ffffff;
  box-shadow: 0 0 0 4px rgba(0, 113, 227, 0.16);
}

input::placeholder {
  color: #a1a1a6;
}

select {
  appearance: none;
  -webkit-appearance: none;
  cursor: pointer;
}

/* Legal */

.legal {
  margin: 28px 0;
  display: flex;
  align-items: flex-start;
  gap: 12px;
  color: var(--muted);
}

.legal input[type="checkbox"] {
  width: 18px;
  height: 18px;
  min-height: auto;
  padding: 0;
  margin-top: 4px;
  accent-color: #111111;
  flex-shrink: 0;
}

.legal label {
  margin: 0;
  font-weight: 400;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

.legal a {
  color: var(--primary-dark);
  font-weight: 700;
  text-decoration: none;
}

.legal a:hover {
  text-decoration: underline;
}

.legal a:focus {
  outline: 3px solid rgba(0, 113, 227, 0.28);
  outline-offset: 3px;
  border-radius: 4px;
}

/* Button */

.submit-btn {
  width: 100%;
  min-height: 54px;
  border: none;
  border-radius: 999px;
  background: #111111;
  color: #ffffff;
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 14px 32px rgba(0, 0, 0, 0.16);
  transition:
    background 0.25s ease,
    transform 0.25s ease,
    box-shadow 0.25s ease;
}

.submit-btn i {
  margin-left: 8px;
}

.submit-btn:hover {
  background: #000000;
  transform: translateY(-2px);
  box-shadow: 0 18px 38px rgba(0, 0, 0, 0.2);
}

/* Footer */

.site-footer {
  background: #111111;
  color: #ffffff;
  padding-top: 46px;
}

.footer-grid {
  display: flex;
  justify-content: space-between;
  gap: 32px;
  flex-wrap: wrap;
}

.footer-grid > div {
  flex: 1 1 210px;
}

.footer-grid h3 {
  margin-bottom: 14px;
  font-size: 1.05rem;
  color: #ffffff;
}

.footer-brand p,
.footer-list li,
.footer-bottom p {
  color: rgba(255, 255, 255, 0.72);
  font-size: 0.95rem;
}

.footer-list {
  list-style: none;
}

.footer-list li {
  margin-bottom: 8px;
}

.footer-list a {
  color: rgba(255, 255, 255, 0.72);
  text-decoration: none;
}

.footer-list a:hover {
  color: #ffffff;
}

.social-links {
  display: flex;
  gap: 10px;
  margin-top: 18px;
}

.social-links a {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.1);
  color: #ffffff;
  border: 1px solid rgba(255, 255, 255, 0.14);
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
}

.social-links a:hover {
  background: #ffffff;
  color: #111111;
}

.footer-bottom {
  margin-top: 38px;
  padding: 18px;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.14);
}

/* Responsive */

@media (max-width: 768px) {
  .header-content {
    min-height: auto;
    padding: 22px 0;
    flex-direction: column;
    text-align: center;
  }

  .header-contact {
    align-items: center;
  }

  .nav-content {
    justify-content: flex-end;
    flex-wrap: wrap;
  }

  .menu-button {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 0;
    color: #ffffff;
    font-weight: 700;
    cursor: pointer;
  }

  .main-nav ul {
    display: none;
    width: 100%;
    flex-direction: column;
    gap: 8px;
    padding-bottom: 14px;
  }

  .menu-checkbox:checked ~ .nav-menu {
    display: flex;
  }

  .main-nav a {
    text-align: center;
    border-radius: 14px;
    background: #111111;
    color: #ffffff;
  }

  .main-nav a:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #ffffff;
  }

  .form-section {
    padding: 44px 0 64px;
  }

  .section-title.hero-banner {
    padding: 66px 20px;
    border-radius: 26px;
    margin-bottom: 30px;
  }

  .section-title.hero-banner h1 {
    margin-bottom: 10px;
    letter-spacing: -1px;
  }

  .section-title.hero-banner .section-subtitle {
    font-size: 1rem;
  }

  .register-form {
    padding: 28px;
    border-radius: 28px;
  }

  .form-grid {
    gap: 18px;
  }

  .form-group {
    flex-basis: 100%;
  }

  .footer-grid {
    flex-direction: column;
    text-align: center;
  }

  .social-links {
    justify-content: center;
  }
}

@media (max-width: 480px) {
  .container {
    width: min(100% - 28px, 1120px);
  }

  .logo {
    flex-direction: column;
    text-align: center;
  }

  .logo strong {
    font-size: 1.12rem;
  }

  .section-title.hero-banner {
    padding: 54px 18px;
  }

  .register-form {
    padding: 22px;
  }

  input,
  select {
    min-height: 50px;
    font-size: 0.95rem;
  }

  .legal {
    gap: 10px;
  }
}

/* Modo oscuro automático */

@media (prefers-color-scheme: dark) {
  :root {
    --primary: #ffffff;
    --primary-dark: #ffffff;
    --accent: #2997ff;
    --bg: #000000;
    --white: #1d1d1f;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --border: #3a3a3c;
    --soft-border: #2c2c2e;
    --shadow: 0 24px 60px rgba(0, 0, 0, 0.45);
    --shadow-soft: 0 12px 30px rgba(0, 0, 0, 0.35);
  }

  body {
    background: #000000;
    color: var(--text);
  }

  .site-header {
    background: rgba(29, 29, 31, 0.82);
    border-bottom: 1px solid var(--soft-border);
  }

  .logo {
    color: var(--text);
  }

  .logo i,
  .form-header i {
    background: #2c2c2e;
    border-color: #3a3a3c;
    color: #ffffff;
  }

  .logo span,
  .header-contact {
    color: var(--muted);
  }

  .header-contact i {
    color: #ffffff;
  }

  .main-nav,
  .nav-content {
    background: #000000;
  }

  .main-nav {
    border-top: 1px solid #2c2c2e;
  }

  .menu-button {
    color: #ffffff;
  }

  .menu-button:hover {
    color: var(--accent);
  }

  .main-nav a {
    color: #ffffff;
    background: transparent;
  }

  .main-nav a:hover {
    background: rgba(255, 255, 255, 0.12);
    color: #ffffff;
  }

  .register-form {
    background: rgba(29, 29, 31, 0.94);
    border-color: var(--soft-border);
  }

  .form-header h2,
  label {
    color: var(--text);
  }

  input,
  select {
    background: #2c2c2e;
    border-color: #3a3a3c;
    color: var(--text);
  }

  input:hover,
  select:hover {
    background: #1d1d1f;
    border-color: #6e6e73;
  }

  input:focus,
  select:focus {
    background: #1d1d1f;
    border-color: var(--accent);
    box-shadow: 0 0 0 4px rgba(41, 151, 255, 0.2);
  }

  input::placeholder {
    color: #86868b;
  }

  .input-icon i {
    color: #a1a1a6;
  }

  .legal input[type="checkbox"] {
    accent-color: #ffffff;
  }

  .legal label {
    color: #a1a1a6;
  }

  .legal a {
    color: #ffffff;
  }

  .legal a:hover {
    color: var(--accent);
  }

  .submit-btn {
    background: #ffffff;
    color: #000000;
  }

  .submit-btn:hover {
    background: #d2d2d7;
  }

  .site-footer {
    background: #000000;
    border-top: 1px solid #2c2c2e;
  }

  .footer-brand p,
  .footer-list li,
  .footer-bottom p,
  .footer-list a {
    color: rgba(255, 255, 255, 0.72);
  }

  .footer-list a:hover {
    color: #ffffff;
  }

  .social-links a {
    background: rgba(255, 255, 255, 0.1);
    color: #ffffff;
  }

  .social-links a:hover {
    background: #ffffff;
    color: #000000;
  }
}