/* DarkEye 产品宣传页 — 暗色主题 */
:root {
  --color-bg: #0f0f10;
  --color-bg-elevated: #1a1a1c;
  --color-bg-card: #1e1e21;
  --color-text: #e0e0e0;
  --color-text-muted: #888;
  --color-primary: #00aaff;
  --color-primary-hover: #33bbff;
  --color-border: #2a2a2e;
  --font-serif: "Noto Serif SC", "Source Han Serif SC", serif;
  --font-sans: "Noto Sans SC", "Source Han Sans SC", sans-serif;
  --radius-md: 8px;
  --radius-lg: 12px;
  --space-xs: 0.5rem;
  --space-sm: 1rem;
  --space-md: 1.5rem;
  --space-lg: 2.5rem;
  --space-xl: 4rem;
  --max-width: 960px;
}

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

/* Header */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  padding: var(--space-sm) var(--space-lg);
  background: rgba(15, 15, 16, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  transition: background 0.3s ease;
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--color-text);
  font-family: var(--font-serif);
  font-weight: 600;
  transition: color 0.2s;
}

.nav-logo:hover {
  color: var(--color-primary);
}

.nav-logo-icon {
  width: 28px;
  height: 28px;
  color: var(--color-primary);
}

.nav-cta {
  padding: var(--space-xs) var(--space-md);
  background: transparent;
  border: 1px solid var(--color-primary);
  color: var(--color-primary);
  border-radius: var(--radius-md);
  text-decoration: none;
  font-size: 0.9rem;
  transition: all 0.2s;
}

.nav-cta:hover {
  background: var(--color-primary);
  color: var(--color-bg);
}

/* Hero */
.hero {
  position: relative;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-xl) var(--space-lg);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 80% 50% at 50% 0%, rgba(0, 170, 255, 0.08) 0%, transparent 50%),
    radial-gradient(ellipse 60% 40% at 80% 100%, rgba(0, 170, 255, 0.04) 0%, transparent 50%);
  pointer-events: none;
}

.hero-bg::after {
  content: "";
  position: absolute;
  inset: 0;
  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='0.85' 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");
  opacity: 0.5;
}

.hero-content {
  position: relative;
  text-align: center;
  z-index: 1;
}

.hero-logo {
  width: 72px;
  height: 72px;
  color: var(--color-primary);
  margin-bottom: var(--space-md);
  opacity: 0.9;
}

.hero-title {
  margin: 0 0 var(--space-sm);
  font-family: var(--font-serif);
  font-size: clamp(2.5rem, 6vw, 4rem);
  font-weight: 700;
  letter-spacing: 0.02em;
}

.hero-sub {
  display: block;
  font-size: 0.45em;
  font-weight: 400;
  color: var(--color-text-muted);
  margin-top: 0.2em;
}

.hero-tagline {
  margin: 0 0 var(--space-xs);
  font-size: 1.2rem;
  color: var(--color-primary);
  letter-spacing: 0.05em;
}

.hero-desc {
  margin: 0;
  font-size: 1rem;
  color: var(--color-text-muted);
}

/* Reveal animation (initially hidden, JS will reveal) */
.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.reveal.revealed {
  opacity: 1;
  transform: translateY(0);
}

.reveal.revealed-delay-1 { transition-delay: 0.1s; }
.reveal.revealed-delay-2 { transition-delay: 0.2s; }
.reveal.revealed-delay-3 { transition-delay: 0.3s; }

/* Sections */
.section {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: var(--space-xl) var(--space-lg);
}

.section-title {
  margin: 0 0 var(--space-lg);
  font-family: var(--font-serif);
  font-size: 1.75rem;
  font-weight: 600;
  text-align: center;
  color: var(--color-text);
}

/* Philosophy grid */
.philosophy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: var(--space-md);
}

.philosophy-card {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  transition: border-color 0.2s, transform 0.2s;
}

.philosophy-card:hover {
  border-color: rgba(0, 170, 255, 0.4);
  transform: translateY(-2px);
}

.philosophy-card-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-primary);
}

.philosophy-card-eng {
  margin: 0 0 var(--space-sm);
  font-size: 0.8rem;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.philosophy-card-desc {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text);
  line-height: 1.5;
}

/* Features */
.features-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.feature-item {
  display: flex;
  gap: var(--space-lg);
  align-items: flex-start;
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-border);
}

.feature-item:last-child {
  border-bottom: none;
}

.feature-icon {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(0, 170, 255, 0.2), rgba(0, 170, 255, 0.05));
  border: 1px solid rgba(0, 170, 255, 0.3);
}

.feature-icon--capture::before {
  content: "+";
  font-size: 1.5rem;
  font-weight: 300;
  color: var(--color-primary);
}

.feature-icon--manage::before {
  content: "◇";
  font-size: 1.2rem;
  color: var(--color-primary);
}

.feature-icon--quantify::before {
  content: "◈";
  font-size: 1.1rem;
  color: var(--color-primary);
}

.feature-icon--secure::before {
  content: "◆";
  font-size: 1rem;
  color: var(--color-primary);
}

.feature-content {
  flex: 1;
}

.feature-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text);
}

.feature-desc {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Tech */
.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: var(--space-md);
  margin-bottom: var(--space-md);
}

.tech-item {
  padding: var(--space-md) var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.tech-label {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-text-muted);
}

.tech-value {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-primary);
}

.tech-note {
  margin: 0;
  font-size: 0.9rem;
  color: var(--color-text-muted);
  text-align: center;
}

/* Roadmap */
.roadmap-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.roadmap-item {
  padding: var(--space-lg);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-left: 3px solid var(--color-primary);
  border-radius: var(--radius-md);
  transition: border-color 0.2s;
}

.roadmap-item:hover {
  border-left-color: var(--color-primary-hover);
}

.roadmap-phase {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--color-primary);
  margin-bottom: var(--space-xs);
}

.roadmap-title {
  margin: 0 0 var(--space-xs);
  font-family: var(--font-serif);
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--color-text);
}

.roadmap-desc {
  margin: 0;
  font-size: 0.95rem;
  color: var(--color-text-muted);
}

/* Footer */
.footer {
  margin-top: var(--space-xl);
  padding: var(--space-lg) var(--space-lg);
  border-top: 1px solid var(--color-border);
  background: var(--color-bg-elevated);
}

.footer-content {
  max-width: var(--max-width);
  margin: 0 auto;
  text-align: center;
}

.footer-link {
  display: inline-block;
  margin-bottom: var(--space-sm);
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-link:hover {
  color: var(--color-primary-hover);
}

.footer-copy {
  margin: 0;
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* Responsive */
@media (max-width: 640px) {
  .hero {
    padding: var(--space-xl) var(--space-md);
  }

  .section {
    padding: var(--space-lg) var(--space-md);
  }

  .feature-item {
    flex-direction: column;
    gap: var(--space-sm);
  }

  .philosophy-grid {
    grid-template-columns: 1fr;
  }
}