/* ===== Reset & Base ===== */
*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  --color-bg: #0f1419;
  --color-bg-alt: #161b22;
  --color-surface: #1c2128;
  --color-border: #2d333b;
  --color-text: #e6edf3;
  --color-text-muted: #8b949e;
  --color-primary: #58a6ff;
  --color-primary-hover: #79b8ff;
  --color-accent: #3fb950;
  --color-accent-hover: #56d364;
  --font-body: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --max-width: 1100px;
  --radius: 8px;
  --transition: 0.2s ease;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: var(--font-body);
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition);
}

a:hover {
  color: var(--color-primary-hover);
}

img {
  max-width: 100%;
  display: block;
}

/* ===== Container ===== */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Navbar ===== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: transparent;
  transition: background var(--transition), box-shadow var(--transition);
}

.navbar.scrolled {
  background: rgba(15, 20, 25, 0.95);
  backdrop-filter: blur(12px);
  box-shadow: 0 1px 0 var(--color-border);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--color-text);
  letter-spacing: -0.02em;
}

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

.nav-links {
  display: flex;
  list-style: none;
  gap: 32px;
}

.nav-links a {
  color: var(--color-text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition);
}

.nav-links a:hover {
  color: var(--color-text);
}

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text);
  transition: transform var(--transition), opacity var(--transition);
}

.nav-toggle.active span:nth-child(1) {
  transform: translateY(7px) rotate(45deg);
}

.nav-toggle.active span:nth-child(2) {
  opacity: 0;
}

.nav-toggle.active span:nth-child(3) {
  transform: translateY(-7px) rotate(-45deg);
}

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
  background: linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-alt) 100%);
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 20%;
  left: 50%;
  transform: translateX(-50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(88, 166, 255, 0.06) 0%, transparent 70%);
  pointer-events: none;
}

.hero-content {
  position: relative;
  max-width: 720px;
}

.hero h1 {
  font-size: clamp(3rem, 8vw, 5rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.1;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: clamp(1.1rem, 2.5vw, 1.35rem);
  color: var(--color-primary);
  font-weight: 500;
  margin-bottom: 20px;
}

.hero-tagline {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 560px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.hero-actions {
  display: flex;
  gap: 16px;
  justify-content: center;
  flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
  display: inline-block;
  padding: 12px 28px;
  border-radius: var(--radius);
  font-size: 0.95rem;
  font-weight: 600;
  font-family: var(--font-body);
  transition: all var(--transition);
  cursor: pointer;
  border: none;
  text-align: center;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-bg);
}

.btn-primary:hover {
  background: var(--color-primary-hover);
  color: var(--color-bg);
  transform: translateY(-1px);
}

.btn-secondary {
  background: transparent;
  color: var(--color-text);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover {
  border-color: var(--color-text-muted);
  color: var(--color-text);
  transform: translateY(-1px);
}

/* ===== Sections ===== */
.section {
  padding: 96px 0;
}

.section-alt {
  background: var(--color-bg-alt);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 48px;
  text-align: center;
}

/* ===== Vision ===== */
.vision-content {
  max-width: 780px;
  margin: 0 auto 56px;
}

.vision-content p {
  color: var(--color-text-muted);
  margin-bottom: 20px;
  font-size: 1.05rem;
}

.vision-content a {
  font-weight: 500;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 32px 24px;
  transition: border-color var(--transition), transform var(--transition);
}

.feature-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.feature-card p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
}

/* ===== Architecture ===== */
.architecture-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 32px;
}

.arch-step {
  text-align: center;
}

.arch-number {
  width: 48px;
  height: 48px;
  border-radius: 50%;
  background: var(--color-primary);
  color: var(--color-bg);
  font-weight: 700;
  font-size: 1.2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

.arch-step h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.arch-step p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
}

/* ===== Team ===== */
.team-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 32px;
  max-width: 720px;
  margin: 0 auto;
}

.team-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 36px 28px;
  text-align: center;
  transition: border-color var(--transition);
}

.team-card:hover {
  border-color: var(--color-primary);
}

.team-avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
  color: var(--color-bg);
  font-size: 1.4rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.team-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.team-card p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
}

/* ===== Code ===== */
.code-content {
  max-width: 780px;
  margin: 0 auto;
  text-align: center;
}

.code-content > p {
  color: var(--color-text-muted);
  margin-bottom: 32px;
  font-size: 1.05rem;
}

.code-block {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 24px;
  margin-bottom: 40px;
  overflow-x: auto;
  text-align: left;
}

.code-block pre {
  margin: 0;
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--color-text-muted);
  line-height: 1.8;
}

.tech-stack {
  margin-bottom: 36px;
}

.tech-stack h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 16px;
}

.tech-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  justify-content: center;
}

.tech-tag {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  padding: 6px 16px;
  border-radius: 20px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--color-text-muted);
}

/* ===== Report ===== */
.report-content {
  max-width: 560px;
  margin: 0 auto;
}

.report-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 40px 32px;
  text-align: center;
}

.report-icon {
  font-size: 2.5rem;
  margin-bottom: 16px;
}

.report-card h3 {
  font-size: 1.2rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.report-card p {
  color: var(--color-text-muted);
  margin-bottom: 24px;
  font-size: 0.95rem;
}

/* ===== Materials ===== */
.materials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 32px;
  max-width: 800px;
  margin: 0 auto;
}

.material-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 32px 28px;
  text-align: center;
}

.material-card h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 12px;
}

.material-card p {
  color: var(--color-text-muted);
  font-size: 0.92rem;
  margin-bottom: 20px;
}

.reference-list {
  list-style: none;
  text-align: left;
}

.reference-list li {
  color: var(--color-text-muted);
  font-size: 0.88rem;
  padding: 10px 0;
  border-bottom: 1px solid var(--color-border);
  line-height: 1.6;
}

.reference-list li:last-child {
  border-bottom: none;
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 40px 0;
  text-align: center;
}

.footer p {
  color: var(--color-text-muted);
  font-size: 0.88rem;
  margin-bottom: 8px;
}

.footer a {
  font-weight: 500;
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .nav-toggle {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(15, 20, 25, 0.98);
    backdrop-filter: blur(12px);
    flex-direction: column;
    padding: 16px 24px;
    gap: 0;
    border-bottom: 1px solid var(--color-border);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-links li {
    padding: 12px 0;
  }

  .section {
    padding: 64px 0;
  }

  .section-title {
    font-size: 1.65rem;
    margin-bottom: 36px;
  }

  .hero {
    padding: 100px 24px 64px;
    min-height: auto;
  }

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

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

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

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

@media (max-width: 480px) {
  .features-grid {
    grid-template-columns: 1fr;
  }

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