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

:root {
  --bg: #0b0e1a;
  --bg-card: #141832;
  --bg-card-hover: #1a1f42;
  --primary: #6366f1;
  --primary-light: #818cf8;
  --accent: #f5c542;
  --text: #e2e8f0;
  --text-muted: #8b92b3;
  --text-dim: #4a5178;
  --border: #232849;
  --radius: 16px;
  --glow: rgba(99, 102, 241, 0.15);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  word-break: keep-all;
}

a {
  color: inherit;
  text-decoration: none;
}

/* Stars Background */
.stars-bg {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.stars-bg::before,
.stars-bg::after {
  content: '';
  position: absolute;
  width: 2px;
  height: 2px;
  border-radius: 50%;
  background: white;
  box-shadow:
    80px 120px 0 rgba(255,255,255,0.3),
    200px 80px 0 rgba(255,255,255,0.2),
    400px 200px 0 rgba(255,255,255,0.15),
    600px 50px 0 rgba(255,255,255,0.25),
    150px 350px 0 rgba(255,255,255,0.1),
    750px 300px 0 rgba(255,255,255,0.2),
    320px 500px 0 rgba(255,255,255,0.15),
    900px 150px 0 rgba(255,255,255,0.3),
    50px 600px 0 rgba(255,255,255,0.1),
    500px 400px 0 rgba(255,255,255,0.2),
    1100px 200px 0 rgba(255,255,255,0.15),
    700px 550px 0 rgba(255,255,255,0.25),
    1000px 450px 0 rgba(255,255,255,0.1),
    250px 700px 0 rgba(255,255,255,0.2),
    850px 650px 0 rgba(255,255,255,0.15),
    1200px 100px 0 rgba(255,255,255,0.2),
    450px 150px 0 rgba(255,255,255,0.1),
    1050px 350px 0 rgba(255,255,255,0.25);
  animation: twinkle 4s ease-in-out infinite alternate;
}

.stars-bg::after {
  width: 1px;
  height: 1px;
  box-shadow:
    120px 200px 0 rgba(255,255,255,0.2),
    350px 100px 0 rgba(255,255,255,0.15),
    550px 300px 0 rgba(255,255,255,0.1),
    700px 100px 0 rgba(255,255,255,0.2),
    250px 450px 0 rgba(255,255,255,0.15),
    900px 250px 0 rgba(255,255,255,0.1),
    100px 500px 0 rgba(255,255,255,0.2),
    650px 450px 0 rgba(255,255,255,0.15),
    1100px 300px 0 rgba(255,255,255,0.1),
    400px 600px 0 rgba(255,255,255,0.2),
    800px 500px 0 rgba(255,255,255,0.1);
  animation: twinkle 5s ease-in-out infinite alternate-reverse;
}

@keyframes twinkle {
  0% { opacity: 0.5; }
  100% { opacity: 1; }
}

/* Navigation */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(11, 14, 26, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
  padding: 0 24px;
}

.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.nav-logo {
  font-size: 1.3rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--primary-light);
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-logo-img {
  width: 32px;
  height: 32px;
  border-radius: 8px;
}

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

.nav-links a {
  font-size: 0.95rem;
  color: var(--text-muted);
  transition: color 0.2s;
}

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

/* Hero */
.hero {
  position: relative;
  z-index: 1;
  padding: 180px 24px 120px;
  text-align: center;
  background: radial-gradient(ellipse at 50% 0%, rgba(99, 102, 241, 0.12) 0%, transparent 60%);
}

.hero h1 {
  font-size: 3.2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.25;
  margin-bottom: 20px;
  background: linear-gradient(135deg, #e2e8f0 0%, var(--primary-light) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero p {
  font-size: 1.15rem;
  color: var(--text-muted);
  max-width: 520px;
  margin: 0 auto 44px;
}

.btn {
  display: inline-block;
  padding: 14px 32px;
  border-radius: 50px;
  font-size: 1rem;
  font-weight: 600;
  transition: all 0.25s;
  cursor: pointer;
  border: none;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
  box-shadow: 0 0 24px rgba(99, 102, 241, 0.3);
}

.btn-primary:hover {
  background: var(--primary-light);
  transform: translateY(-2px);
  box-shadow: 0 0 36px rgba(99, 102, 241, 0.45);
}

.btn-outline {
  border: 1.5px solid var(--border);
  background: transparent;
  color: var(--text);
  margin-left: 12px;
}

.btn-outline:hover {
  border-color: var(--primary);
  color: var(--primary-light);
  background: var(--glow);
}

/* Badge */
.badge {
  display: inline-block;
  padding: 6px 16px;
  border-radius: 50px;
  font-size: 0.8rem;
  font-weight: 600;
  background: rgba(99, 102, 241, 0.15);
  color: var(--primary-light);
  border: 1px solid rgba(99, 102, 241, 0.25);
  margin-bottom: 20px;
}

/* Sections */
.section {
  position: relative;
  z-index: 1;
  padding: 100px 24px;
  max-width: 1080px;
  margin: 0 auto;
}

.section-alt {
  background: rgba(20, 24, 50, 0.5);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.section-title {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 16px;
}

.section-desc {
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 48px;
  max-width: 600px;
}

/* Feature Cards */
.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  transition: all 0.25s;
}

.feature-card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(99, 102, 241, 0.3);
  box-shadow: 0 4px 24px rgba(99, 102, 241, 0.08);
  transform: translateY(-2px);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: rgba(99, 102, 241, 0.12);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.5rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text);
}

.feature-card p {
  color: var(--text-muted);
  font-size: 0.95rem;
}

/* Screenshots */
.screenshots {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-top: 48px;
  flex-wrap: wrap;
}

.screenshot-frame {
  width: 220px;
  height: 440px;
  border-radius: 28px;
  border: 2px solid var(--border);
  background: var(--bg-card);
  overflow: hidden;
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
  transition: transform 0.3s;
}

.screenshot-frame:hover {
  transform: translateY(-4px);
}

.screenshot-frame img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* CTA */
.cta {
  position: relative;
  z-index: 1;
  text-align: center;
  padding: 100px 24px;
  background: radial-gradient(ellipse at 50% 100%, rgba(99, 102, 241, 0.08) 0%, transparent 60%);
}

.cta h2 {
  font-size: 2rem;
  font-weight: 700;
  margin-bottom: 16px;
}

.cta p {
  color: var(--text-muted);
  margin-bottom: 32px;
}

/* Footer */
.footer {
  position: relative;
  z-index: 1;
  border-top: 1px solid var(--border);
  padding: 40px 24px;
  text-align: center;
  color: var(--text-dim);
  font-size: 0.875rem;
}

.footer-links {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 16px;
  list-style: none;
}

.footer-links a {
  color: var(--text-muted);
  font-size: 0.875rem;
  transition: color 0.2s;
}

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

/* Page Header */
.page-header {
  position: relative;
  z-index: 1;
  padding: 140px 24px 60px;
  text-align: center;
  background: radial-gradient(ellipse at 50% 0%, rgba(99, 102, 241, 0.1) 0%, transparent 50%);
}

.page-header h1 {
  font-size: 2.5rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.page-header p {
  color: var(--text-muted);
  font-size: 1.1rem;
}

/* Content (for about, privacy pages) */
.content {
  position: relative;
  z-index: 1;
  max-width: 800px;
  margin: 0 auto;
  padding: 60px 24px 100px;
}

.content h2 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-top: 56px;
  margin-bottom: 16px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  color: var(--text);
}

.content h2:first-child {
  margin-top: 0;
  padding-top: 0;
  border-top: none;
}

.content h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-top: 32px;
  margin-bottom: 12px;
  color: var(--text);
}

.content p,
.content li {
  color: var(--text-muted);
  margin-bottom: 12px;
}

.content ul {
  padding-left: 20px;
  margin-bottom: 16px;
}

.content strong {
  color: var(--text);
}

.content table {
  width: 100%;
  border-collapse: collapse;
  margin: 24px 0;
}

.content th,
.content td {
  text-align: left;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  font-size: 0.95rem;
}

.content th {
  font-weight: 600;
  color: var(--text);
  background: var(--bg-card);
}

.content td {
  color: var(--text-muted);
}

/* Info Box */
.info-box {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-left: 3px solid var(--primary);
  border-radius: 8px;
  padding: 20px 24px;
  margin: 24px 0;
}

.info-box p {
  color: var(--text-muted);
  margin-bottom: 0;
}

/* Responsive */
@media (max-width: 768px) {
  .hero h1 {
    font-size: 2.2rem;
  }

  .hero p {
    font-size: 1rem;
  }

  .nav-links {
    gap: 20px;
  }

  .nav-links a {
    font-size: 0.85rem;
  }

  .section-title {
    font-size: 1.5rem;
  }

  .btn-outline {
    margin-left: 0;
    margin-top: 12px;
  }

  .hero .btn {
    display: block;
    width: 100%;
    max-width: 280px;
    margin: 0 auto;
  }

  .hero .btn + .btn {
    margin-top: 12px;
  }

  .screenshot-frame {
    width: 160px;
    height: 320px;
  }

  .page-header h1 {
    font-size: 1.8rem;
  }
}