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

:root {
  --bg: #0a0a0f;
  --surface: #13131a;
  --surface-hover: #1a1a24;
  --border: #23232f;
  --text: #e8e8ed;
  --text-muted: #8a8a9a;
  --accent: #6c5ce7;
  --accent-light: #a29bfe;
  --gradient-start: #6c5ce7;
  --gradient-end: #00cec9;
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent-light);
  text-decoration: none;
}

/* ===== Layout ===== */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Nav ===== */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

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

.nav-links {
  display: flex;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  color: var(--text-muted);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

/* ===== Hero ===== */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: 120px 24px 80px;
}

.hero-content {
  max-width: 700px;
}

.hero-badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 100px;
  background: var(--surface);
  border: 1px solid var(--border);
  font-size: 0.8rem;
  color: var(--text-muted);
  margin-bottom: 28px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.hero h1 {
  font-size: clamp(2.8rem, 6vw, 4.5rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}

.hero h1 .gradient {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto 36px;
  line-height: 1.7;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 14px 32px;
  border-radius: 12px;
  font-size: 1rem;
  font-weight: 600;
  border: none;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
}

.btn:hover {
  transform: translateY(-2px);
}

.btn-primary {
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  color: #fff;
  box-shadow: 0 4px 24px rgba(108, 92, 231, 0.3);
}

.btn-primary:hover {
  box-shadow: 0 8px 32px rgba(108, 92, 231, 0.45);
  color: #fff;
}

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

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

/* ===== Section shared ===== */
section {
  padding: 100px 0;
}

.section-label {
  font-size: 0.8rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--accent-light);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.8rem, 4vw, 2.5rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-subtitle {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 560px;
  line-height: 1.7;
}

.section-header {
  text-align: center;
  margin-bottom: 64px;
}

.section-header .section-subtitle {
  margin: 0 auto;
}

/* ===== Demo Video ===== */
.demo-video {
  max-width: 900px;
  margin: 0 auto;
  border-radius: 16px;
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 8px 40px rgba(0, 0, 0, 0.4);
}

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

/* ===== Features Grid ===== */
.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 32px 28px;
  transition: border-color 0.2s, transform 0.2s;
}

.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-3px);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--gradient-start), var(--gradient-end));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin-bottom: 20px;
}

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

.feature-card p {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.6;
}

/* ===== How It Works ===== */
.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
  position: relative;
}

.steps::before {
  content: "";
  position: absolute;
  top: 36px;
  left: calc(16.66% + 36px);
  right: calc(16.66% + 36px);
  height: 2px;
  background: var(--border);
}

.step {
  text-align: center;
}

.step-number {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: var(--surface);
  border: 2px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--accent-light);
  margin: 0 auto 24px;
  position: relative;
  z-index: 1;
}

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

.step p {
  color: var(--text-muted);
  font-size: 0.92rem;
  line-height: 1.6;
  max-width: 280px;
  margin: 0 auto;
}

/* ===== Developer's Notes ===== */
.dev-notes-content {
  max-width: 720px;
  margin: 0 auto;
  color: var(--text-muted);
  font-size: 1.05rem;
  line-height: 1.8;
}

.dev-notes-content p {
  margin-bottom: 16px;
}

.dev-notes-content h3 {
  color: var(--text);
  font-size: 1.1rem;
  margin-top: 32px;
  margin-bottom: 12px;
}

.dev-notes-content ul {
  list-style: none;
  padding: 0;
}

.dev-notes-content li {
  padding: 8px 0;
  padding-left: 20px;
  position: relative;
}

.dev-notes-content li::before {
  content: "→";
  position: absolute;
  left: 0;
  color: var(--accent-light);
}

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

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

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

.footer-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.85rem;
  transition: color 0.2s;
}

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

/* ===== Responsive ===== */
@media (max-width: 768px) {
  .features-grid {
    grid-template-columns: 1fr;
  }

  .steps {
    grid-template-columns: 1fr;
    gap: 48px;
  }

  .steps::before {
    display: none;
  }

  .nav-links {
    display: none;
  }

  footer .container {
    flex-direction: column;
    gap: 16px;
    text-align: center;
  }

  .hero {
    min-height: auto;
    padding: 140px 24px 60px;
  }
}

@media (max-width: 1024px) and (min-width: 769px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}