/* Base */
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Inter', system-ui, -apple-system, sans-serif; }

/* Slide transitions */
.slide {
  position: absolute;
  top: 0;
  left: 0;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.5s ease, transform 0.5s ease;
  pointer-events: none;
}

.slide.active {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

/* Non-active slides are invisible but in DOM */

/* Subtle background grain */
body::before {
  content: '';
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)' opacity='0.03'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 0;
}

#deck { z-index: 1; }

/* Gradient glow behind hero text */
.slide[data-slide="1"]::after,
.slide[data-slide="8"]::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(99, 102, 241, 0.08) 0%, transparent 70%);
  pointer-events: none;
  z-index: -1;
}

/* Nav styling */
#nav {
  transition: opacity 0.3s ease;
}

/* Active language button */
.lang-btn.active-lang {
  background: rgba(255, 255, 255, 0.1);
  color: white;
  border-color: rgba(255, 255, 255, 0.2);
}

/* Scrollbar hide */
::-webkit-scrollbar { display: none; }
html { scrollbar-width: none; }

/* Responsive adjustments */
@media (max-width: 768px) {
  .slide { padding-left: 1.5rem; padding-right: 1.5rem; }
  h1 { font-size: 2.5rem !important; }
  h2 { font-size: 2rem !important; }

  /* Allow vertical scroll inside slide if content is taller than viewport */
  .slide.active { overflow-y: auto; -webkit-overflow-scrolling: touch; }

  /* Minimum 44px tap targets for nav and language buttons */
  #nav button {
    min-width: 44px;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0.5rem;
  }
  .lang-btn {
    min-height: 40px;
    padding-top: 0.5rem;
    padding-bottom: 0.5rem;
  }
}

@media (max-width: 480px) {
  h1 { font-size: 2rem !important; }
  h2 { font-size: 1.75rem !important; }
}