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

:root {
  --bg: #0d1117;
  --surface: #161b22;
  --surface-2: #1c2128;
  --border: #30363d;
  --accent: #7c6af7;
  --accent-dim: rgba(124, 106, 247, 0.12);
  --accent-2: #3fb950;
  --text: #e6edf3;
  --text-muted: #8b949e;
  --text-faint: #484f58;
  --radius: 12px;
  --transition: 0.2s ease;
}

[data-theme="light"] {
  --bg: #f6f8fa;
  --surface: #ffffff;
  --surface-2: #f0f2f5;
  --border: #d0d7de;
  --accent: #6554d4;
  --accent-dim: rgba(101, 84, 212, 0.1);
  --text: #1f2328;
  --text-muted: #57606a;
  --text-faint: #bdc4cc;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: "Lexend", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
  transition: background var(--transition), color var(--transition);
}

/* ─── NAV ─────────────────────────────────────────────── */

nav {
  position: fixed;
  top: 0;
  inset-inline: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 2rem;
  height: 60px;
  background: rgba(13, 17, 23, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: background var(--transition);
}

[data-theme="light"] nav {
  background: rgba(246, 248, 250, 0.85);
}

.nav-brand {
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--text);
  letter-spacing: -0.3px;
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.github-link {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  color: var(--text-muted);
  text-decoration: none;
  font-size: 0.875rem;
  transition: color var(--transition);
}

.github-link:hover {
  color: var(--text);
}

.theme-toggle {
  background: none;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 6px 8px;
  cursor: pointer;
  color: var(--text-muted);
  font-size: 1rem;
  line-height: 1;
  transition: border-color var(--transition), color var(--transition), background var(--transition);
}

.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-dim);
}

/* ─── HERO ────────────────────────────────────────────── */

.hero {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 140px 2rem 80px;
  gap: 1.5rem;
}

.hero-logo {
  width: 120px;
  height: 120px;
  border-radius: 28px;
  box-shadow: 0 8px 32px rgba(124, 106, 247, 0.3);
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%       { transform: translateY(-8px); }
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 4px 12px;
  border-radius: 999px;
  background: var(--accent-dim);
  border: 1px solid rgba(124, 106, 247, 0.3);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.8px;
}

h1 {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  font-weight: 800;
  letter-spacing: -1.5px;
  background: linear-gradient(135deg, var(--text) 40%, var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-sub {
  max-width: 600px;
  color: var(--text-muted);
  font-size: 1.1rem;
  line-height: 1.7;
}

.hero-cta {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 10px 22px;
  border-radius: 8px;
  font-size: 0.9rem;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition);
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
}

.btn-primary:hover {
  background: #6a59e0;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(124, 106, 247, 0.4);
}

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

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

/* ─── SECTIONS ────────────────────────────────────────── */

section {
  max-width: 960px;
  margin: 0 auto;
  padding: 60px 2rem;
}

.section-label {
  font-size: 1.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.2px;
  color: var(--accent);
  margin-bottom: 0.5rem;
}

.section-title {
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
  letter-spacing: -0.5px;
  margin-bottom: 0.75rem;
}

.section-desc {
  color: var(--text-muted);
  margin-bottom: 2.5rem;
}

/* ─── FEATURE GRID ────────────────────────────────────── */

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.25rem;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.75rem;
  transition: border-color var(--transition), transform var(--transition), box-shadow var(--transition);
  position: relative;
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.feature-card::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, var(--accent-dim), transparent);
  opacity: 0;
  transition: opacity var(--transition);
}

.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(124, 106, 247, 0.12);
}

.feature-card:hover::before {
  opacity: 1;
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 1rem;
  align-self: center;
}

.feature-card h3 {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 0.5rem;
  letter-spacing: -0.2px;
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.65;
}

.feature-list {
  list-style: none;
  margin-top: 0.75rem;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}

.feature-list li {
  color: var(--text-muted);
  font-size: 0.875rem;
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
}

.feature-list li::before {
  content: '›';
  color: var(--accent);
  font-weight: 700;
  flex-shrink: 0;
}

/* ─── DEMO ────────────────────────────────────────────── */

#demo {
  padding-top: 0;
  padding-bottom: 40px;
}

.demo-wrapper {
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 16px 48px rgba(0, 0, 0, 0.4);
  max-width: 70%;
  margin: 0 auto;
}

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

/* ─── DIVIDER ─────────────────────────────────────────── */

.divider {
  border: none;
  border-top: 1px solid var(--border);
  max-width: 960px;
  margin: 0 auto;
}

/* ─── TECH STACK ──────────────────────────────────────── */

.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 1rem;
}

.tech-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.25rem 1.5rem;
  display: flex;
  align-items: center;
  gap: 0.9rem;
  transition: border-color var(--transition), transform var(--transition);
}

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

.tech-icon {
  font-size: 1.75rem;
  flex-shrink: 0;
}

.tech-card h4 {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.15rem;
}

.tech-card p {
  font-size: 0.78rem;
  color: var(--text-muted);
}

/* ─── FOOTER ──────────────────────────────────────────── */

footer {
  text-align: center;
  padding: 2.5rem 2rem;
  color: var(--text-faint);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}

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

footer a:hover {
  color: var(--accent);
}

/* ─── SCROLL FADE-IN ──────────────────────────────────── */

.reveal {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.5s ease, transform 0.5s ease;
}

.reveal.visible {
  opacity: 1;
  transform: none;
}

/* ─── RESPONSIVE ──────────────────────────────────────── */

@media (max-width: 600px) {
  nav { padding: 0 1rem; }
  .hero { padding: 120px 1rem 60px; }
  section { padding: 40px 1rem; }
}