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

:root {
  --primary: #2563eb;
  --primary-dark: #1d4ed8;
  --primary-light: #3b82f6;
  --dark: #0f172a;
  --dark-2: #1e293b;
  --dark-3: #334155;
  --bg: #ffffff;
  --bg-secondary: #f8fafc;
  --bg-tertiary: #f1f5f9;
  --text: #0f172a;
  --text-secondary: #64748b;
  --text-tertiary: #94a3b8;
  --border: #e2e8f0;
  --radius: 16px;
  --radius-sm: 12px;
  --max-width: 1140px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  scroll-behavior: smooth;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans KR', sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.7;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
}

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

/* === Header === */
header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  background: rgba(15, 23, 42, 0.95);
  backdrop-filter: blur(12px);
  z-index: 1000;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

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

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
}

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

.nav-links {
  display: flex;
  gap: 28px;
}

.nav-links a {
  text-decoration: none;
  color: rgba(255, 255, 255, 0.7);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
  color: #fff;
}

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

.mobile-menu-btn span {
  display: block;
  width: 22px;
  height: 2px;
  background: #fff;
  border-radius: 1px;
  transition: var(--transition);
}

/* === Main === */
main {
  flex: 1;
  margin-top: 64px;
}

/* === Hero === */
.hero {
  position: relative;
  background: linear-gradient(135deg, #0f172a 0%, #1e293b 50%, #0f172a 100%);
  overflow: hidden;
  min-height: 560px;
  display: flex;
  align-items: center;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 70% 50%, rgba(37, 99, 235, 0.15) 0%, transparent 60%),
    radial-gradient(ellipse at 30% 80%, rgba(124, 58, 237, 0.1) 0%, transparent 50%);
}

.hero::before {
  content: '';
  position: absolute;
  top: -50%;
  right: -20%;
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(37, 99, 235, 0.08) 0%, transparent 70%);
  border-radius: 50%;
}

.hero-inner {
  position: relative;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 80px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 60px;
  width: 100%;
}

.hero-content {
  flex: 1;
  z-index: 1;
}

.hero-label {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--primary-light);
  letter-spacing: 2px;
  text-transform: uppercase;
  margin-bottom: 20px;
}

.hero h1 {
  font-size: 3.5rem;
  font-weight: 800;
  color: #fff;
  line-height: 1.15;
  margin-bottom: 20px;
  letter-spacing: -1px;
}

.hero-desc {
  font-size: 1.2rem;
  color: rgba(255, 255, 255, 0.7);
  line-height: 1.7;
  margin-bottom: 36px;
  max-width: 480px;
}

.hero-actions {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  padding: 14px 32px;
  background: var(--primary);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 10px;
  transition: background var(--transition), transform var(--transition);
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

.btn-outline {
  display: inline-flex;
  align-items: center;
  padding: 14px 32px;
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  color: #fff;
  font-size: 0.95rem;
  font-weight: 600;
  text-decoration: none;
  border-radius: 10px;
  transition: border-color var(--transition), background var(--transition), transform var(--transition);
}

.btn-outline:hover {
  border-color: rgba(255, 255, 255, 0.6);
  background: rgba(255, 255, 255, 0.05);
  transform: translateY(-2px);
}

.hero-visual {
  flex-shrink: 0;
  z-index: 1;
}

.hero-icon {
  width: 260px;
  height: 260px;
  border-radius: 48px;
  box-shadow: 0 30px 80px rgba(0, 0, 0, 0.4), 0 0 0 1px rgba(255, 255, 255, 0.05);
}

/* === Section Common === */
.section-title {
  font-size: 2.2rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 16px;
  letter-spacing: -0.5px;
  line-height: 1.3;
}

.section-title.white { color: #fff; }

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.05rem;
  margin-bottom: 52px;
  line-height: 1.7;
}

.section-subtitle.white { color: rgba(255, 255, 255, 0.65); }

.section-desc {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.1rem;
  line-height: 1.8;
  margin-bottom: 48px;
}

/* === Intro === */
.intro {
  padding: 100px 0;
  background: var(--bg);
}

.intro-stats {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 40px;
  margin-top: 56px;
  padding: 40px;
  background: var(--bg-secondary);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.stat {
  text-align: center;
}

.stat-number {
  display: block;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 6px;
}

.stat-label {
  display: block;
  font-size: 0.9rem;
  color: var(--text-secondary);
}

.stat-divider {
  width: 1px;
  height: 48px;
  background: var(--border);
}

/* === Features === */
.features {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg);
  padding: 36px 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  transition: transform var(--transition), box-shadow var(--transition);
}

.feature-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 16px 40px rgba(0, 0, 0, 0.08);
}

.feature-icon-wrap {
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: linear-gradient(135deg, #eff6ff, #e0e7ff);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  color: var(--primary);
}

.feature-card h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.feature-card p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* === Detection === */
.detection {
  padding: 100px 0;
  background: linear-gradient(135deg, var(--dark) 0%, var(--dark-2) 100%);
}

.detection-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.detection-card {
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid rgba(255, 255, 255, 0.08);
  border-radius: var(--radius);
  padding: 36px 24px;
  text-align: center;
  transition: background var(--transition), transform var(--transition);
}

.detection-card:hover {
  background: rgba(255, 255, 255, 0.08);
  transform: translateY(-4px);
}

.detection-icon {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: rgba(37, 99, 235, 0.15);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
  color: var(--primary-light);
}

.detection-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  color: #fff;
  margin-bottom: 10px;
}

.detection-card p {
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.55);
  line-height: 1.6;
}

/* === How It Works === */
.how-it-works {
  padding: 100px 0;
  background: var(--bg);
}

.steps {
  display: flex;
  align-items: flex-start;
  justify-content: center;
  gap: 0;
}

.step {
  text-align: center;
  flex: 1;
  max-width: 300px;
  padding: 0 24px;
}

.step-number {
  font-size: 2.5rem;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 16px;
  letter-spacing: -1px;
}

.step h3 {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 10px;
}

.step p {
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.7;
}

.step-line {
  width: 60px;
  height: 2px;
  background: var(--border);
  margin-top: 32px;
  flex-shrink: 0;
}

/* === Use Cases === */
.usecases {
  padding: 100px 0;
  background: var(--bg-secondary);
}

.usecase-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.usecase-card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px 24px;
  transition: transform var(--transition), box-shadow var(--transition), border-color var(--transition);
}

.usecase-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.06);
  border-color: var(--primary);
}

.usecase-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text);
}

.usecase-card p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* === Download === */
.download {
  padding: 100px 0;
  background: linear-gradient(135deg, var(--dark) 0%, #1a2744 50%, var(--dark) 100%);
  text-align: center;
}

.download-buttons {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.download-btn {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 32px;
  border-radius: 14px;
  text-decoration: none;
  font-weight: 600;
  transition: transform var(--transition), box-shadow var(--transition);
  min-width: 240px;
}

.download-btn:hover {
  transform: translateY(-3px);
  box-shadow: 0 12px 32px rgba(0, 0, 0, 0.3);
}

.download-btn.android {
  background: #fff;
  color: var(--dark);
}

.download-btn.tester {
  background: rgba(255, 255, 255, 0.1);
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  color: #fff;
}

.download-btn.tester:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.5);
}

.download-btn-sub {
  display: block;
  font-size: 0.75rem;
  font-weight: 500;
  opacity: 0.6;
  margin-bottom: 2px;
}

.download-btn-main {
  display: block;
  font-size: 1.05rem;
  font-weight: 700;
}

.download-btn.tester-primary {
  background: #fff;
  color: var(--dark);
}

.download-btn.android-outline {
  background: rgba(255, 255, 255, 0.1);
  border: 1.5px solid rgba(255, 255, 255, 0.3);
  color: #fff;
}

.download-btn.android-outline:hover {
  background: rgba(255, 255, 255, 0.15);
  border-color: rgba(255, 255, 255, 0.5);
}

/* === Viewer === */
.viewer {
  padding: 100px 0;
  background: var(--bg);
}

.viewer-content {
  display: flex;
  gap: 48px;
  align-items: center;
}

.viewer-screenshot-wrap {
  flex: 1.4;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
  box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
}

.viewer-screenshot {
  width: 100%;
  display: block;
}

.viewer-info {
  flex: 1;
}

.viewer-info h3 {
  font-size: 1.6rem;
  font-weight: 800;
  margin-bottom: 12px;
}

.viewer-desc {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.7;
  margin-bottom: 24px;
}

.viewer-features {
  list-style: none;
  padding: 0;
  margin-bottom: 32px;
}

.viewer-features li {
  position: relative;
  padding-left: 24px;
  margin-bottom: 12px;
  color: var(--text-secondary);
  font-size: 0.95rem;
  line-height: 1.6;
}

.viewer-features li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 8px;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
}

.btn-viewer-download {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 28px;
  background: var(--dark);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  border-radius: 10px;
  transition: background var(--transition), transform var(--transition);
}

.btn-viewer-download:hover {
  background: var(--dark-2);
  transform: translateY(-2px);
}

/* === Contact Section === */
.contact-section {
  padding: 80px 0;
  background: var(--bg);
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
  max-width: 640px;
  margin: 0 auto;
}

.contact-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 32px;
  text-align: center;
  transition: transform var(--transition);
}

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

.contact-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: linear-gradient(135deg, #eff6ff, #e0e7ff);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
  color: var(--primary);
}

.contact-card h3 {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 6px;
}

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

.contact-card a {
  color: var(--primary);
  text-decoration: none;
}

.contact-card a:hover {
  text-decoration: underline;
}

/* === Footer === */
footer {
  background: var(--dark);
  color: rgba(255, 255, 255, 0.6);
  padding: 0;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

.footer-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 32px 0;
  border-bottom: 1px solid rgba(255, 255, 255, 0.08);
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1rem;
  color: #fff;
}

.footer-logo {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  color: rgba(255, 255, 255, 0.5);
  text-decoration: none;
  font-size: 0.88rem;
  transition: color var(--transition);
}

.footer-links a:hover {
  color: #fff;
}

.footer-bottom {
  padding: 20px 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
}

.footer-bottom a {
  color: rgba(255, 255, 255, 0.5);
  text-decoration: none;
}

.footer-bottom a:hover {
  color: #fff;
}

/* === Legal Pages (Privacy, Terms, Delete) === */
.legal-content {
  max-width: 800px;
  margin: 0 auto;
  padding: 60px 24px 80px;
}

.legal-content h1 {
  font-size: 2rem;
  font-weight: 800;
  margin-bottom: 8px;
}

.effective-date {
  color: var(--text-secondary);
  font-size: 0.95rem;
  margin-bottom: 40px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.legal-content h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-top: 40px;
  margin-bottom: 12px;
  color: var(--text);
}

.legal-content h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin-top: 20px;
  margin-bottom: 8px;
}

.legal-content p {
  margin-bottom: 12px;
  color: var(--text-secondary);
}

.legal-content ul,
.legal-content ol {
  margin-bottom: 16px;
  padding-left: 24px;
}

.legal-content li {
  margin-bottom: 6px;
  color: var(--text-secondary);
}

.legal-content table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0 24px;
}

.legal-content th,
.legal-content td {
  padding: 12px 16px;
  border: 1px solid var(--border);
  text-align: left;
  font-size: 0.95rem;
}

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

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

.appendix {
  margin-top: 40px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  font-weight: 600;
  color: var(--text);
}

/* === Delete Account Page === */
.delete-methods {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin: 20px 0 32px;
}

.delete-method {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 24px;
}

.delete-method h3 {
  margin-top: 0;
  margin-bottom: 12px;
  color: var(--text);
}

.delete-method ul {
  margin-bottom: 16px;
}

.delete-email-btn {
  display: inline-block;
  background: var(--primary);
  color: white;
  text-decoration: none;
  padding: 12px 24px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 0.95rem;
  transition: background var(--transition), transform var(--transition);
}

.delete-email-btn:hover {
  background: var(--primary-dark);
  transform: translateY(-2px);
}

/* === Responsive === */
@media (max-width: 1024px) {
  .feature-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .detection-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .usecase-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .mobile-menu-btn {
    display: flex;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: rgba(15, 23, 42, 0.98);
    flex-direction: column;
    padding: 16px 24px 24px;
    gap: 16px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.08);
  }

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

  .hero-inner {
    flex-direction: column-reverse;
    text-align: center;
    padding: 48px 24px 64px;
    gap: 32px;
  }

  .hero {
    min-height: auto;
  }

  .hero h1 {
    font-size: 2.4rem;
  }

  .hero-desc {
    font-size: 1.05rem;
    margin: 0 auto 28px;
  }

  .hero-actions {
    justify-content: center;
  }

  .hero-icon {
    width: 160px;
    height: 160px;
    border-radius: 32px;
  }

  .section-title {
    font-size: 1.7rem;
  }

  .intro-stats {
    flex-direction: column;
    gap: 24px;
    padding: 28px;
  }

  .stat-divider {
    width: 60px;
    height: 1px;
  }

  .feature-grid,
  .detection-grid,
  .usecase-grid {
    grid-template-columns: 1fr;
  }

  .steps {
    flex-direction: column;
    align-items: center;
    gap: 8px;
  }

  .step-line {
    width: 2px;
    height: 32px;
    margin: 0;
  }

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

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

  .footer-bottom {
    flex-direction: column;
    gap: 4px;
    text-align: center;
  }

  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
    gap: 16px;
  }

  .viewer-content {
    flex-direction: column;
    gap: 32px;
  }

  .intro, .features, .detection, .how-it-works, .usecases, .download, .contact-section, .viewer {
    padding: 64px 0;
  }
}