/*
  Stylesheet for the Aviv Battery Tech landing page (custom version)
  Designed to reflect the blue and silver corporate identity. The layout is
  responsive and modern, with a focus on clear calls a la acción and
  professionalism. Color variables make it easy to tweak the palette.
*/

/* Reset and box model */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* CSS variables for colours and sizing */
:root {
  --primary-color: #0071bc;       /* bright blue – transmite energía y confianza */
  --secondary-color: #005a99;     /* darker blue for hover states */
  --accent-silver: #c0cbd6;       /* silver tint for subtle highlights */
  --light-bg: #ffffff;
  --dark-bg: #041a31;            /* deep navy backdrop */
  --text-light: #1a1a1a;
  --text-dark: #f0f4f8;          /* off‑white for dark backgrounds */
  --radius: 0.5rem;
  --transition-speed: 0.3s;
}

body {
  font-family: 'Inter', sans-serif;
  background-color: var(--dark-bg);
  color: var(--text-dark);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* Sticky navigation bar */
header.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 1rem 2rem;
  position: sticky;
  top: 0;
  z-index: 1000;
  background-color: rgba(4, 26, 49, 0.85);
  backdrop-filter: blur(10px);
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
}

/* Hamburger icon */
.hamburger {
  display: none;
  flex-direction: column;
  justify-content: space-between;
  width: 24px;
  height: 18px;
  cursor: pointer;
  margin-left: 1rem;
  z-index: 1100;
}

.hamburger .bar {
  width: 100%;
  height: 3px;
  background-color: var(--text-dark);
  border-radius: 2px;
  transition: transform var(--transition-speed) ease, opacity var(--transition-speed) ease;
}

/* Rotate bars into a cross when active */
.hamburger.active .bar:nth-child(1) {
  transform: translateY(7.5px) rotate(45deg);
}

.hamburger.active .bar:nth-child(2) {
  opacity: 0;
}

.hamburger.active .bar:nth-child(3) {
  transform: translateY(-7.5px) rotate(-45deg);
}

/* Logo container */
.logo-container {
  display: flex;
  align-items: center;
}

.logo-img {
  height: 50px;
  width: auto;
}

/* Navigation menu */
.navbar nav ul {
  list-style: none;
  display: flex;
  gap: 1.5rem;
}

/* Hide navigation menu on small screens and show hamburger */
@media (max-width: 768px) {
  .navbar nav {
    position: absolute;
    top: 100%;
    right: 0;
    background-color: rgba(4, 26, 49, 0.95);
    backdrop-filter: blur(10px);
    padding: 1rem 2rem;
    border-radius: 0 0 0.5rem 0.5rem;
    display: none;
    flex-direction: column;
    gap: 1rem;
    width: 200px;
  }
  .navbar nav ul {
    flex-direction: column;
    gap: 1rem;
  }
  .navbar nav.active {
    display: flex;
  }
  .hamburger {
    display: flex;
  }
  /* Hide call to action in navbar on mobile to reduce clutter */
  .navbar .cta-btn {
    display: none;
  }
}

.navbar nav ul li a {
  color: var(--text-dark);
  text-decoration: none;
  font-weight: 500;
  transition: color var(--transition-speed) ease;
}

.navbar nav ul li a:hover {
  color: var(--primary-color);
}

/* Primary call‑to‑action button in the navbar */
.navbar .cta-btn {
  padding: 0.6rem 1.4rem;
  background-color: var(--primary-color);
  color: #fff;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  transition: background-color var(--transition-speed) ease;
}

.navbar .cta-btn:hover {
  background-color: var(--secondary-color);
}

/* Hero section */
#hero {
  position: relative;
  overflow: hidden;
  /* Occupy the full viewport height so that the hero always shows first
     when the page loads. This prevents the browser from starting mid‑way
     through the page on some hosts/browsers. */
  min-height: 100vh;
  width: 100%;
}

/* Full‑width hero banner image */
.hero-banner {
  width: 100%;
  height: auto;
  display: block;
}

/* Slideshow container for hero images */
.hero-slider {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  /* place the slideshow underneath the overlay and content */
  z-index: 0;
}

.hero-slide {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-size: cover;
  background-position: center;
  opacity: 0;
  animation: heroFade 15s infinite;
}

.hero-slide:nth-child(1) {
  animation-delay: 0s;
}
.hero-slide:nth-child(2) {
  animation-delay: 5s;
}
.hero-slide:nth-child(3) {
  animation-delay: 10s;
}

@keyframes heroFade {
  0% {
    opacity: 0;
    transform: scale(1);
  }
  5% {
    opacity: 1;
    transform: scale(1.05);
  }
  30% {
    opacity: 1;
    transform: scale(1.1);
  }
  33.33% {
    opacity: 0;
    transform: scale(1.12);
  }
  100% {
    opacity: 0;
    transform: scale(1.12);
  }
}

/* Dark overlay for contrast and readability */
.hero-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  /* Increase opacity of the overlay to further mute details in the background 
     images, ensuring that text remains legible even when the underlying slide 
     contains complex graphics. */
  background: rgba(4, 26, 49, 0.85);
  /* overlay sits above the slideshow but below the text */
  z-index: 1;
}

/* Content overlayed on top of the hero image */
#hero .hero-content {
  position: absolute;
  top: 50%;
  left: 5%;
  transform: translateY(-50%);
  /* content appears above both the slideshow and overlay */
  z-index: 2;
  max-width: 45%;
  color: #fff;
}

.hero-content h1 {
  font-size: 2.8rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 0.6rem;
  color: #fff;
}

.hero-content .tagline {
  font-size: 1.2rem;
  font-weight: 500;
  color: var(--accent-silver);
  margin-bottom: 1.2rem;
}

.hero-content p {
  font-size: 1.05rem;
  margin-bottom: 2rem;
  color: rgba(255, 255, 255, 0.88);
}

.hero-cta {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
}

.btn-primary,
.btn-secondary {
  display: inline-block;
  padding: 0.8rem 1.6rem;
  border-radius: var(--radius);
  text-decoration: none;
  font-weight: 600;
  transition: transform var(--transition-speed) ease,
    box-shadow var(--transition-speed) ease,
    background-color var(--transition-speed) ease,
    color var(--transition-speed) ease;
}

.btn-primary {
  background-color: var(--primary-color);
  color: #fff;
}

.btn-primary:hover {
  background-color: var(--secondary-color);
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

.btn-secondary {
  border: 2px solid var(--primary-color);
  color: var(--primary-color);
  background-color: transparent;
}

.btn-secondary:hover {
  background-color: var(--primary-color);
  color: #fff;
  transform: translateY(-3px);
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.4);
}

/* Services section */
#features {
  padding: 4rem 2rem;
  background-color: #052748;
}

#features h2 {
  text-align: center;
  font-size: 2.3rem;
  margin-bottom: 2rem;
  color: #fff;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 2rem;
}

.feature-item {
  background-color: #041a31;
  padding: 2rem;
  border-radius: var(--radius);
  text-align: center;
  transition: transform var(--transition-speed) ease;
}

.feature-item:hover {
  transform: translateY(-5px);
}

.feature-item i {
  font-size: 2.2rem;
  color: var(--primary-color);
  margin-bottom: 1rem;
}

.feature-item h3 {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: #fff;
}

.feature-item p {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.95rem;
}

/* Technology section */
#technology {
  padding: 4rem 2rem;
  background-color: #041a31;
}

#technology h2 {
  text-align: center;
  font-size: 2.3rem;
  margin-bottom: 1.5rem;
  color: #fff;
}

.tech-content {
  max-width: 900px;
  margin: 0 auto;
  text-align: center;
  color: rgba(255, 255, 255, 0.88);
  font-size: 1.05rem;
}

.tech-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 2.5rem;
}

.tech-item {
  background-color: #052748;
  padding: 1.8rem;
  border-radius: var(--radius);
  transition: transform var(--transition-speed) ease;
}

.tech-item:hover {
  transform: translateY(-5px);
}

.tech-item h3 {
  font-size: 1.4rem;
  margin-bottom: 0.5rem;
  color: var(--primary-color);
}

.tech-item p {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.85);
}

/* Advantages section */
#advantages {
  padding: 4rem 2rem;
  background-color: #052748;
}

#advantages h2 {
  text-align: center;
  font-size: 2.3rem;
  margin-bottom: 2rem;
  color: #fff;
}

.advantages-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 2rem;
}

.advantage-item {
  text-align: center;
}

.advantage-item i {
  font-size: 2.3rem;
  color: var(--primary-color);
  margin-bottom: 0.5rem;
}

.advantage-item h3 {
  font-size: 1.6rem;
  margin-bottom: 0.3rem;
  color: #fff;
}

.advantage-item p {
  font-size: 0.95rem;
  color: rgba(255, 255, 255, 0.85);
}

/* About section */
#about {
  padding: 4rem 2rem;
  background-color: #041a31;
  display: flex;
  flex-wrap: wrap;
  gap: 2rem;
  align-items: center;
}

.about-text {
  flex: 1 1 50%;
  min-width: 280px;
}

.about-text h2 {
  font-size: 2.3rem;
  margin-bottom: 1rem;
  color: #fff;
}

.about-text p {
  color: rgba(255, 255, 255, 0.88);
  margin-bottom: 1rem;
  font-size: 1.05rem;
}

.about-image {
  flex: 1 1 45%;
  display: flex;
  justify-content: center;
}

.about-image img {
  max-width: 100%;
  border-radius: var(--radius);
  box-shadow: 0 12px 24px rgba(0, 0, 0, 0.5);
}

/* Call to action strip */
#cta {
  padding: 3rem 2rem;
  text-align: center;
  background-color: var(--primary-color);
  color: #fff;
}

#cta h2 {
  font-size: 2.3rem;
  margin-bottom: 0.8rem;
}

#cta p {
  margin-bottom: 2rem;
  font-size: 1.1rem;
}

#cta .btn-primary {
  background-color: #fff;
  color: var(--primary-color);
  font-weight: 700;
}

#cta .btn-primary:hover {
  background-color: #f4f4f4;
  color: var(--secondary-color);
}

/* Footer */
footer {
  background-color: #03192e;
  padding: 2.5rem 2rem;
  color: rgba(255, 255, 255, 0.8);
  font-size: 0.95rem;
}

.footer-content {
  display: flex;
  flex-wrap: wrap;
  gap: 3rem;
  justify-content: space-between;
}

.footer-column {
  flex: 1 1 200px;
  min-width: 150px;
}

.footer-column h3 {
  color: #fff;
  margin-bottom: 1rem;
  font-size: 1.2rem;
}

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

.footer-column ul li a {
  color: rgba(255, 255, 255, 0.75);
  text-decoration: none;
  display: block;
  margin-bottom: 0.6rem;
  transition: color var(--transition-speed) ease;
}

.footer-column ul li a:hover {
  color: var(--primary-color);
}

.social-icons {
  display: flex;
  gap: 1rem;
  margin-top: 1rem;
}

.social-icons a {
  color: rgba(255, 255, 255, 0.75);
  font-size: 1.3rem;
  transition: color var(--transition-speed) ease;
}

.social-icons a:hover {
  color: var(--primary-color);
}

.footer-bottom {
  text-align: center;
  margin-top: 2rem;
  font-size: 0.85rem;
  border-top: 1px solid rgba(255, 255, 255, 0.1);
  padding-top: 1rem;
  color: rgba(255, 255, 255, 0.7);
}

/* Responsive adjustments */
@media (max-width: 768px) {
  /* Adjust hero positioning on small screens */
  #hero .hero-content {
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    max-width: 90%;
    text-align: center;
  }
  #hero .hero-content h1 {
    font-size: 2.3rem;
  }
  .features-grid,
  .tech-list,
  .advantages-grid {
    grid-template-columns: 1fr;
  }
  #about {
    flex-direction: column;
    text-align: center;
  }
  .about-image {
    order: -1;
    margin-bottom: 2rem;
  }
}

/* ------------------------------------------------------------------ */
/* Animation helpers
   Elements with the `.animate` class start hidden (translated down and transparent).
   When they enter the viewport, JavaScript adds the `visible` class which triggers
   a fade-up animation. This subtle movement llama la atención y aporta dinamismo
   sin distraer al usuario. */

.animate {
  opacity: 0;
  transform: translateY(30px);
  transition: opacity 0.8s ease-out, transform 0.8s ease-out;
}

.animate.visible {
  opacity: 1;
  transform: translateY(0);
}