:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --bg-light: #f8fafc;
  --text-dark: #000;
  --text-gray: #2f363f;
  --white: #f8f8f8;
  --radius: 12px;
  --shadow:
    0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

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

body {
  font-family: "Inter", sans-serif;
  color: var(--text-dark);
  background-color: var(--bg-light);
  line-height: 1.6;
  font-size: 1.3rem;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 20px;
}

.carousel-track {
  min-height: 650px;
}

/* Hero Section */
.hero {
  background: var(--white);
  padding: 60px 0;
  text-align: center;
  border-bottom: 1px solid #e2e8f0;
}

.problem {
  font-size: 2rem;
  color: var(--text-gray);
  margin-bottom: 10px;
  font-weight: 600;
}

.solution-reveal {
  margin-top: 20px;
  animation: fadeIn 1s ease-out;
}

.solution {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--text-dark);
}

.highlight {
  color: var(--primary);
}

.tagline {
  font-size: 1.1rem;
  color: var(--text-gray);
  margin-top: 10px;
}

.version-badge {
  display: inline-block;
  background: #e0e7ff;
  color: var(--primary);
  padding: 4px 12px;
  border-radius: 20px;
  font-size: 0.8rem;
  font-weight: 600;
  margin-top: 15px;
}

/* Carousel / App Store Style */
.demo-section {
  padding: 60px 0;
  background: var(--white);
}

.demo-section h3 {
  text-align: center;
  margin-bottom: 30px;
  font-size: 1.5rem;
}

.carousel-wrapper {
  position: relative;
  max-width: 400px; /* Mobile width simulation */
  margin: 0 auto;
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  background: #000;
}

.carousel-track {
  display: flex;
  transition: transform 0.4s ease-in-out;
}

.slide {
  min-width: 100%;
  aspect-ratio: 9/16; /* Standard phone ratio */
}

.slide img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.carousel-btn {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  background: rgba(255, 255, 255, 0.8);
  border: none;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  cursor: pointer;
  font-size: 1.2rem;
  color: var(--text-dark);
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}

.carousel-btn:hover {
  background: white;
}

.prev-btn {
  left: 10px;
}
.next-btn {
  right: 10px;
}

.carousel-hint {
  text-align: center;
  margin-top: 15px;
  font-size: 0.9rem;
  color: var(--text-gray);
}

/* Installation Guide */
.guide-section {
  padding: 60px 0;
}

.steps-list {
  counter-reset: step-counter;
  max-width: 750px;
  margin: 0 auto;
  padding: 24px 24px;
}

.security-note {
  margin-top: 15px;
  background: #f0fdf4;
  border: 1px solid #bbf7d0;
  padding: 12px;
  border-radius: 8px;
  display: flex;
  align-items: flex-start;
  gap: 10px;
}

.security-note .icon {
  font-size: 1.2rem;
}

.security-note a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
}

.security-note a:hover {
  text-decoration: underline;
}

/* Download Section */
.download-section {
  background: var(--text-dark);
  color: white;
  text-align: center;
  padding: 80px 0;
}

.download-btn {
  display: inline-block;
  background: var(--primary);
  color: white;
  text-decoration: none;
  padding: 18px 40px;
  border-radius: 50px;
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 20px;
  transition:
    transform 0.2s,
    background 0.2s;
  box-shadow: 0 10px 15px -3px rgba(37, 99, 235, 0.4);
}

.download-btn:hover {
  transform: translateY(-4px) scale(1.02);
  box-shadow: 0 30px 60px -12px rgba(99, 102, 241, 0.8);
}

.file-info {
  display: block;
  font-size: 0.9rem;
  font-weight: 400;
  opacity: 0.9;
  margin-top: 5px;
}

.last-note {
  margin-top: 20px;
  font-size: 0.9rem;
  opacity: 0.7;
}

/* Footer */
footer {
  background: #0f172a;
  color: #94a3b8;
  padding: 40px 0;
  text-align: center;
  font-size: 0.9rem;
}

.links {
  margin-top: 15px;
}

.links a {
  color: #94a3b8;
  text-decoration: none;
  margin: 0 10px;
}

.links a:hover {
  color: white;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Mobile Adjustments */
@media (max-width: 600px) {
  .problem {
    font-size: 1.5rem;
  }
  .solution {
    font-size: 2rem;
  }
  .carousel-wrapper {
    max-width: 100%;
  }
}