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

html, body {
  height: 100%;
  font-family: 'Inter', sans-serif;
  background: #0f0f0f;
  color: #e0e0e0;
  overflow: hidden;
}

.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(15, 15, 15, 0.92);
  backdrop-filter: blur(8px);
  padding: 0.6rem 1.5rem;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 0.8rem;
  flex-wrap: wrap;
  border-bottom: 1px solid #2a2a2a;
}

.header a {
  color: #94a3b8;
  text-decoration: none;
  font-weight: 500;
  font-size: 0.85rem;
  padding: 0.3rem 0.8rem;
  border-radius: 30px;
  transition: background 0.2s, color 0.2s;
}

.header a:hover,
.header a.active {
  background: #2a2a2a;
  color: #f0f0f0;
}

.header .slide-indicator {
  color: #7DC89A;
  font-weight: 600;
  margin-left: 0.5rem;
  font-size: 0.85rem;
}

.slides-wrapper {
  position: relative;
  width: 100%;
  height: 100vh;
  overflow: hidden;
  margin-top: 54px;
}

.slides-container {
  display: flex;
  width: 100%;
  height: 100%;
  transition: transform 0.5s cubic-bezier(0.25, 0.46, 0.45, 0.94);
  will-change: transform;
}

.slide {
  flex: 0 0 100%;
  height: 100%;
  overflow-y: auto;
  overflow-x: hidden;
  padding: 2rem 3rem 3rem;
  background: #0f0f0f;
  scrollbar-width: thin;
  scrollbar-color: #2a2a2a #1a1a1a;
}

.slide::-webkit-scrollbar { width: 6px; }
.slide::-webkit-scrollbar-track { background: #1a1a1a; }
.slide::-webkit-scrollbar-thumb { background: #2a2a2a; border-radius: 8px; }

.slide h2 {
  font-size: 2rem;
  color: #7DC89A;
  border-left: 5px solid #214E34;
  padding-left: 1rem;
  margin: 0 0 1.2rem 0;
}

.slide h3 {
  color: #5A9E73;
  margin: 1.5rem 0 0.6rem 0;
  font-size: 1.2rem;
}

.slide p {
  color: #d1d9e6;
  line-height: 1.7;
  margin-bottom: 1.2rem;
}

.slide ul,
.slide ol {
  margin-left: 1.5rem;
  margin-bottom: 1rem;
  color: #d1d9e6;
}

.slide li { margin-bottom: 0.4rem; }

.slide .card {
  background: #1a1a1a;
  border: 1px solid #2a2a2a;
  border-radius: 1.2rem;
  padding: 1.2rem 1.5rem;
  margin: 1rem 0 1.5rem 0;
}

.slide .highlight {
  background: #123324;
  color: #8BC3A0;
  padding: 0.1rem 0.5rem;
  border-radius: 6px;
  font-weight: 500;
}

.slide .grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

.slide-footer {
  margin-top: 2rem;
  padding-top: 0.8rem;
  border-top: 1px solid #2a2a2a;
  font-size: 0.8rem;
  color: #94a3b8;
  text-align: center;
}

.slides-wrapper {
  scrollbar-width: none;
}

.slides-wrapper::-webkit-scrollbar {
  display: none;
}

.eq-box {
  background: #0D2419;
  padding: 0.6rem 1rem;
  border-radius: 10px;
  display: block;
  margin: 0.5rem auto;
  font-family: 'Courier New', monospace;
  color: #7DC89A;
  border-left: 4px solid #214E34;
  text-align: center;
  width: fit-content;
  max-width: 90%;
}

@media (max-width: 700px) {
  .slide { padding: 1.5rem; }
  .slide .grid-2 { grid-template-columns: 1fr; }
  .header a { font-size: 0.7rem; padding: 0.2rem 0.5rem; }
}

.slide {
  opacity: 0;
  transition: opacity 0.4s ease;
}

.slide.visible {
  opacity: 1;
}

.slide.visible h2,
.slide.visible h3,
.slide.visible p,
.slide.visible ul,
.slide.visible ol,
.slide.visible .card,
.slide.visible .diagram-box,
.slide.visible .eq-box,
.slide.visible .slide-footer,
.slide.visible .sim-wrapper {
  animation: slideFadeIn 0.5s ease forwards;
  opacity: 0;
}

.slide.visible h2 { animation-delay: 0.05s; }
.slide.visible h3 { animation-delay: 0.10s; }
.slide.visible p  { animation-delay: 0.15s; }
.slide.visible ul,
.slide.visible ol { animation-delay: 0.20s; }
.slide.visible .card { animation-delay: 0.25s; }
.slide.visible .diagram-box { animation-delay: 0.30s; }
.slide.visible .eq-box { animation-delay: 0.35s; }
.slide.visible .slide-footer { animation-delay: 0.40s; }
.slide.visible .sim-wrapper { animation-delay: 0.20s; }

@keyframes slideFadeIn {
  0% {
    opacity: 0;
    transform: translateY(15px);
  }
  100% {
    opacity: 1;
    transform: translateY(0);
  }
}