:root {
  --color-metal: #9CA3AF;
  --color-metal-dark: #374151;
  --color-metal-light: #E5E7EB;
  --color-safety-yellow: #FBBF24;
  --color-industry-blue: #1D4ED8;
  --color-bg: #F3F4F6;
  --color-card: #FFFFFF;
  --color-text-main: #111827;
  
  --shadow-panel: inset 2px 2px 5px rgba(255,255,255,0.7), inset -2px -2px 5px rgba(0,0,0,0.1), 0 10px 15px -3px rgba(0,0,0,0.1);
}

body {
  background-color: var(--color-bg);
  color: var(--color-text-main);
  background-image: 
    linear-gradient(45deg, var(--color-metal-light) 25%, transparent 25%, transparent 75%, var(--color-metal-light) 75%, var(--color-metal-light)), 
    linear-gradient(45deg, var(--color-metal-light) 25%, transparent 25%, transparent 75%, var(--color-metal-light) 75%, var(--color-metal-light));
  background-size: 20px 20px;
  background-position: 0 0, 10px 10px;
}

.hero {
  padding: 6rem 1rem 4rem;
  max-width: 1200px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4rem;
  align-items: center;
}

.hero-content h1 {
  font-size: clamp(2.5rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  text-transform: uppercase;
  letter-spacing: -0.02em;
  margin-bottom: 1.5rem;
}

.hero-content p {
  font-size: 1.125rem;
  color: var(--color-metal-dark);
  line-height: 1.7;
  margin-bottom: 2rem;
  max-width: 500px;
}

/* Folding Mechanism Metaphor */
.hero-visual {
  perspective: 1000px;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 400px;
}

.fold-panel {
  width: 200px;
  height: 250px;
  background: var(--color-metal);
  box-shadow: var(--shadow-panel);
  border-radius: 4px;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s ease-in-out;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: monospace;
  font-size: 1.5rem;
  font-weight: bold;
  color: var(--color-metal-dark);
}

.fold-left {
  transform-origin: right center;
  transform: rotateY(45deg);
  background: var(--color-metal-light);
}

.fold-right {
  transform-origin: left center;
  transform: rotateY(-45deg);
}

.hinge {
  width: 20px;
  height: 200px;
  background: var(--color-metal-dark);
  position: relative;
  border-radius: 10px;
  z-index: 10;
  box-shadow: inset -2px 0 5px rgba(0,0,0,0.5);
}

.hinge::before, .hinge::after {
  content: '';
  position: absolute;
  width: 10px;
  height: 10px;
  background: var(--color-metal-light);
  border-radius: 50%;
  left: 5px;
}

.hinge::before { top: 10px; }
.hinge::after { bottom: 10px; }

.hero-visual:hover .fold-left { transform: rotateY(0deg); }
.hero-visual:hover .fold-right { transform: rotateY(0deg); }

/* Features */
.features {
  max-width: 1200px;
  margin: 0 auto 6rem;
  padding: 0 1rem;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}

.feature-card {
  background: var(--color-card);
  padding: 2.5rem 2rem;
  border-top: 4px solid var(--color-safety-yellow);
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.feature-card h3 {
  font-size: 1.25rem;
  font-weight: 700;
  text-transform: uppercase;
  margin: 1rem 0 0.5rem;
  color: var(--color-metal-dark);
}

.feature-card p {
  color: var(--color-metal-dark);
  line-height: 1.6;
}

.btn-primary {
  background: var(--color-safety-yellow);
  color: var(--color-metal-dark);
  padding: 1rem 2rem;
  border-radius: 4px;
  font-weight: 800;
  text-decoration: none;
  display: inline-block;
  text-transform: uppercase;
  letter-spacing: 1px;
  border: 2px solid var(--color-metal-dark);
  box-shadow: 4px 4px 0 var(--color-metal-dark);
  transition: all 0.2s;
}

.btn-primary:hover {
  transform: translate(2px, 2px);
  box-shadow: 2px 2px 0 var(--color-metal-dark);
}

@media (max-width: 900px) {
  .hero {
    grid-template-columns: 1fr;
    text-align: center;
    padding-top: 4rem;
  }
  .hero-content p {
    margin: 0 auto 2rem;
  }
  .features {
    grid-template-columns: 1fr;
  }
}