/* =========================================================
   VARIABLES Y MODO OSCURO (ANIME NATSUKI THEME)
   ========================================================= */
:root {
  /* Paleta de Colores de Referencia del Icono Natsuki */
  --brand-primary: #1d3949; /* Azul pizarra oscuro (teal) */
  --brand-light: #566b77;   /* Azul pizarra claro */
  --brand-accent: #abb5bb;  /* Gris azulado */
  
  --accent-main: #ffffff; 
  --accent-hover: var(--brand-light);
  
  /* Fondos profundamente oscuros con un ligero matiz del color del icono */
  --bg-main: #020405; 
  --bg-alt: #070b0e;
  --bg-card: #0d151a;
  --bg-footer: #010203;

  --text-main: #f5f5f5;
  --text-secondary: #a0a8ad;
  --text-muted: #5b656b;

  --border-color: rgba(86, 107, 119, 0.2); 
  --hero-grad-start: rgba(29, 57, 73, 0.4);
  --hero-grad-end: transparent;

  --btn-primary-bg: var(--brand-primary);
  --btn-primary-text: #ffffff;

  --shadow-soft: 0 10px 40px -10px rgba(0, 0, 0, 0.8);
  --shadow-glow: 0 0 25px rgba(29, 57, 73, 0.6);
  --border-radius-lg: 24px;
  --border-radius-md: 16px;
}

/* =========================================================
   RESET Y BASE
   ========================================================= */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Open Sans", -apple-system, BlinkMacSystemFont, sans-serif;
  background: var(--bg-main);
  color: var(--text-main);
  line-height: 1.6;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 900px; 
  margin: 0 auto;
  padding: 0 24px;
}

/* =========================================================
   NAV
   ========================================================= */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(2, 4, 5, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-color);
}

.site-header nav {
  height: 80px;
  display: flex;
  align-items: center;
}

.nav-content {
  display: flex;
  justify-content: center;
  align-items: center;
  width: 100%;
}

.logo {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.5rem;
  font-weight: 800;
  text-decoration: none;
  color: var(--text-main);
  letter-spacing: 2px;
  text-transform: uppercase;
}

.logo span {
  font-weight: 400;
  color: var(--text-secondary);
}

.logo img {
  height: 35px;
  border-radius: 8px;
  box-shadow: 0 2px 10px rgba(0,0,0,0.5);
}

/* =========================================================
   HERO SECTION
   ========================================================= */
.hero {
  padding: 120px 0 100px;
  text-align: center;
  position: relative;
  overflow: hidden;
  width: 100vw;
  margin-left: 50%;
  transform: translateX(-50%);
}

.hero::before {
  content: '';
  position: absolute;
  top: -20%;
  left: 50%;
  transform: translateX(-50%);
  width: 150vw;
  height: 150vw;
  min-width: 800px;
  min-height: 800px;
  background: radial-gradient(circle, var(--hero-grad-start) 0%, var(--hero-grad-end) 60%);
  z-index: -1;
  border-radius: 50%;
}

.hero-badge {
  display: inline-block;
  color: var(--brand-accent);
  padding: 6px 16px;
  border-radius: 30px;
  font-size: 0.75rem;
  font-weight: 700;
  margin-bottom: 25px;
  border: 1px solid var(--border-color);
  text-transform: uppercase;
  letter-spacing: 2px;
  background: var(--bg-alt);
}

.hero h1 {
  font-size: 4rem;
  font-weight: 800;
  line-height: 1.1;
  margin-bottom: 25px;
  color: var(--text-main);
  letter-spacing: -1px;
}

.hero h1 span {
  color: var(--brand-light);
}

.hero-description {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin: 0 auto 40px;
  font-weight: 400;
}

/* =========================================================
   DOWNLOAD SECTION
   ========================================================= */
.download-section {
  max-width: 320px;
  margin: 0 auto;
}

.btn-custom-download {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  border-radius: var(--border-radius-md);
  transition: all 0.4s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  cursor: pointer;
  border: 1px solid rgba(255,255,255,0.1);
  background: linear-gradient(145deg, var(--btn-primary-bg), #132733);
  color: var(--btn-primary-text);
  width: 100%;
  padding: 18px 24px;
  box-shadow: var(--shadow-glow);
}

.btn-custom-download:hover {
  background: linear-gradient(145deg, var(--brand-light), var(--brand-primary));
  transform: translateY(-4px);
  box-shadow: 0 15px 30px rgba(29, 57, 73, 0.8);
  border-color: rgba(255,255,255,0.2);
}

.btn-main-row {
  display: flex;
  align-items: center;
  gap: 12px;
  font-size: 1.2rem;
  font-weight: 800;
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 1px;
}

.btn-info-container {
  display: flex;
  gap: 10px;
  font-size: 0.8rem;
  opacity: 0.8;
  font-weight: 600;
}

/* =========================================================
   SECTIONS & TYPOGRAPHY
   ========================================================= */
.section-header {
  text-align: center;
  margin-bottom: 50px;
}

.section-header h2 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.5px;
}

.section-header h2 span {
  color: var(--brand-light);
}

/* Features */
.features {
  margin: 100px 0;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 20px;
}

.card {
  background: var(--bg-card);
  padding: 40px 30px;
  border-radius: var(--border-radius-lg);
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-soft);
  transition: transform 0.4s ease, background 0.4s ease;
  text-align: left;
}

.card:hover {
  transform: translateY(-5px);
  background: #15222b;
  border-color: var(--brand-light);
}

.card .icon {
  font-size: 2rem;
  margin-bottom: 20px;
  color: var(--brand-light);
  opacity: 0.9;
}

.card h3 {
  font-size: 1.3rem;
  margin-bottom: 12px;
  font-weight: 700;
}

.card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* Install Guide */
.install-guide {
  margin: 100px 0;
}

.guide-container {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.guide-step {
  display: flex;
  align-items: center;
  gap: 25px;
  background: var(--bg-card);
  padding: 25px 30px;
  border-radius: var(--border-radius-md);
  border: 1px solid var(--border-color);
}

.step-number {
  color: white;
  background: var(--brand-primary);
  width: 45px;
  height: 45px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 50%;
  font-weight: 800;
  font-size: 1.1rem;
  flex-shrink: 0;
  box-shadow: 0 4px 15px rgba(29, 57, 73, 0.5);
}

.step-text strong {
  display: block;
  font-size: 1.1rem;
  margin-bottom: 5px;
  font-weight: 700;
}

.step-text p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* FAQ */
.faq {
  margin: 100px 0;
}

.faq-container {
  display: flex;
  flex-direction: column;
  gap: 15px;
}

.faq-item {
  background: var(--bg-card);
  border-radius: var(--border-radius-md);
  border: 1px solid var(--border-color);
}

.faq-item summary {
  padding: 25px;
  font-weight: 600;
  font-size: 1.05rem;
  cursor: pointer;
  list-style: none;
  position: relative;
  outline: none;
}

.faq-item summary::-webkit-details-marker {
  display: none;
}

.faq-item summary::after {
  content: "+";
  position: absolute;
  right: 25px;
  top: 50%;
  transform: translateY(-50%);
  font-size: 1.5rem;
  color: var(--brand-light);
}

.faq-item[open] summary::after {
  content: "−";
}

.faq-content {
  padding: 0 25px 25px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* Footer */
footer {
  background: var(--bg-footer);
  padding: 60px 0 calc(110px + env(safe-area-inset-bottom, 0px));
  text-align: center;
  border-top: 1px solid var(--border-color);
}

.footer-logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 15px;
  letter-spacing: 2px;
  text-transform: uppercase;
}

.footer-logo span {
  font-weight: 400;
  color: var(--text-secondary);
}

.footer-logo img {
  height: 25px;
  border-radius: 6px;
  opacity: 0.8;
}

.copyright {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* =========================================================
   STICKY MOBILE BAR (Bottom Bar)
   ========================================================= */
.mobile-sticky-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  background: rgba(2, 4, 5, 0.95);
  backdrop-filter: blur(15px);
  -webkit-backdrop-filter: blur(15px);
  border-top: 1px solid var(--border-color);
  padding: 15px 24px calc(15px + env(safe-area-inset-bottom, 0px));
  display: flex;
  justify-content: space-between;
  align-items: center;
  transform: translateY(100%);
  transition: transform 0.4s cubic-bezier(0.16, 1, 0.3, 1);
  z-index: 1000;
  box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.8);
}

.mobile-sticky-bar.visible {
  transform: translateY(0);
}

.sticky-info {
  display: flex;
  align-items: center;
  gap: 15px;
}

.sticky-icon {
  width: 42px;
  height: 42px;
  border-radius: 10px;
  object-fit: cover;
  box-shadow: 0 2px 8px rgba(0,0,0,0.5);
  border: 1px solid var(--border-color);
}

.sticky-text span {
  display: block;
  font-weight: 800;
  font-size: 1rem;
  letter-spacing: 0.5px;
}

.sticky-text p {
  font-size: 0.75rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.sticky-btn {
  background: linear-gradient(145deg, var(--btn-primary-bg), #132733);
  color: var(--btn-primary-text);
  border: 1px solid rgba(255,255,255,0.1);
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 800;
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  cursor: pointer;
  text-decoration: none;
  transition: all 0.3s ease;
}

.sticky-btn:hover {
  background: linear-gradient(145deg, var(--brand-light), var(--brand-primary));
  transform: translateY(-2px);
  box-shadow: 0 5px 15px rgba(29, 57, 73, 0.6);
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.8rem;
  }
  .section-header h2 {
    font-size: 2rem;
  }
  .card {
    padding: 30px 20px;
  }
  .guide-step {
    padding: 20px;
    gap: 15px;
  }
}