@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

/* Minimalist Core Reset */
* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --bg: #000000;
  --text: #ffffff;
  --text-muted: #8c8c8c;
  --text-dark: #555555;
  --border: #222222;
  --btn-bg: #222222;
  --btn-hover: #333333;
  --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --transition: all 0.2s ease;
}

html {
  scroll-behavior: smooth;
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: 800px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* Header */
header {
  border-bottom: 1px solid var(--border);
  padding: 1.5rem 0;
}

.header-container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  text-decoration: none;
  color: var(--text);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: 0.15em;
}

.nav-menu {
  display: flex;
  align-items: center;
  gap: 1.8rem;
}

.nav-link {
  text-decoration: none;
  color: var(--text-muted);
  font-weight: 500;
  font-size: 0.9rem;
  transition: var(--transition);
  white-space: nowrap;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
}

/* Logo Cross-fade */
.logo-crossfade {
  position: relative;
  display: inline-block;
  max-width: 100%;
  width: 900px;
}

.logo-crossfade .hero-logo {
  display: block;
  max-width: 100%;
  width: 900px;
  height: auto;
}

.logo-crossfade .logo-a {
  position: relative;
  animation: fadeAB 6s ease-in-out infinite;
}

.logo-crossfade .logo-b {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  animation: fadeBA 6s ease-in-out infinite;
}

@keyframes fadeAB {
  0%,  45%  { opacity: 1; }
  55%, 100% { opacity: 0; }
}

@keyframes fadeBA {
  0%,  45%  { opacity: 0; }
  55%, 100% { opacity: 1; }
}

/* Hero Section */
.hero {
  padding: 6rem 0 4rem;
  text-align: center;
  border-bottom: 1px solid var(--border);
}

.header-logo {
  height: 32px;
  width: auto;
  display: block;
}

.hero-container {
  max-width: 1000px;
}

.logo-display {
  margin-bottom: 2rem;
  display: flex;
  justify-content: center;
}

.hero-logo {
  max-width: 100%;
  width: 900px;
  height: auto;
  display: block;
}

.hero-desc {
  font-size: 1.05rem;
  color: var(--text-muted);
  max-width: 540px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}

.btn {
  display: inline-block;
  background-color: var(--btn-bg);
  color: var(--text);
  padding: 0.75rem 2rem;
  border-radius: 4px;
  border: 1px solid var(--border);
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: var(--transition);
}

.btn:hover {
  background-color: var(--btn-hover);
  border-color: #444;
}

/* Technology Specs Section */
.specs {
  padding: 5rem 0;
  border-bottom: 1px solid var(--border);
}

.section-title {
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  margin-bottom: 3rem;
  text-align: center;
}

.specs-list {
  display: flex;
  flex-direction: column;
  gap: 2.5rem;
}

.spec-item {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 2rem;
}

.spec-label {
  font-weight: 700;
  font-size: 0.95rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text);
}

.spec-desc {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* Contact Form Section */
.contact {
  padding: 5rem 0;
}

.contact-container {
  max-width: 500px;
  margin: 0 auto;
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-group label {
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
}

.form-control {
  background-color: transparent;
  border: 1px solid var(--border);
  border-radius: 4px;
  color: var(--text);
  font-family: inherit;
  font-size: 0.95rem;
  padding: 0.75rem 1rem;
  transition: var(--transition);
}

.form-control:focus {
  outline: none;
  border-color: #666;
}

textarea.form-control {
  resize: vertical;
  min-height: 100px;
}

.submit-btn {
  width: 100%;
  text-align: center;
}

/* Product Action Bar */
.product-action-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 1.5rem;
  margin-top: 2.5rem;
  flex-wrap: wrap;
}

.product-price {
  font-size: 1.8rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  color: var(--text);
}

.btn-cart {
  background-color: #ffffff;
  color: #000000;
  border: 1px solid #ffffff;
  font-weight: 700;
  letter-spacing: 0.05em;
  padding: 0.75rem 2rem;
  border-radius: 4px;
  font-size: 0.9rem;
  cursor: pointer;
  transition: var(--transition);
  font-family: var(--font);
}

.btn-cart:hover {
  background-color: #dddddd;
  border-color: #dddddd;
}

/* Toast Success Alert */
.toast {
  position: fixed;
  bottom: 2rem;
  right: 2rem;
  background-color: var(--btn-bg);
  border: 1px solid var(--border);
  color: var(--text);
  padding: 0.75rem 1.5rem;
  border-radius: 4px;
  font-size: 0.85rem;
  font-weight: 600;
  box-shadow: 0 10px 20px rgba(0,0,0,0.5);
  z-index: 10000;
  transform: translateY(100px);
  opacity: 0;
  transition: var(--transition);
}

.toast.show {
  transform: translateY(0);
  opacity: 1;
}

/* Footer Section */
footer {
  border-top: 1px solid var(--border);
  padding: 2.5rem 0;
  text-align: center;
}

.footer-text {
  font-size: 0.8rem;
  color: var(--text-dark);
  letter-spacing: 0.05em;
}

/* Page Section SPA Toggle */
.page-section {
  display: none;
}

.page-section.active {
  display: block;
}

/* Demo Section */
.demo-section {
  padding: 6rem 0 5rem;
}

.demo-title {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-align: center;
  margin-bottom: 1rem;
}

.demo-subtitle {
  font-size: 0.95rem;
  color: var(--text-muted);
  text-align: center;
  max-width: 540px;
  margin: 0 auto 3rem;
  line-height: 1.7;
}

.video-container {
  width: 100%;
  max-width: 860px;
  margin: 0 auto;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  background: #000;
}

.video-container video {
  width: 100%;
  height: auto;
  display: block;
}

/* Responsive adjust */
@media (max-width: 600px) {
  .spec-item {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }
  
  .hero {
    padding: 4rem 0 3rem;
  }

  .demo-section {
    padding: 4rem 0 3rem;
  }

  .nav-menu {
    gap: 1rem;
  }

  .nav-link {
    font-size: 0.75rem;
  }
}