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

:root {
  --bg:        #0d0f14;
  --bg2:       #13161e;
  --bg3:       #1a1e28;
  --border:    rgba(255,255,255,0.07);
  --text:      #e8eaf0;
  --text-muted:#8b90a0;
  --blue:      #3b82f6;
  --blue-glow: rgba(59,130,246,0.25);
  --cyan:      #22d3ee;
  --yellow:    #fbbf24;
  --green:     #22c55e;
  --radius:    12px;
  --radius-lg: 20px;
  --nav-h:     68px;
  --max-w:     1200px;
  --font:      'Segoe UI', 'Apple SD Gothic Neo', 'Noto Sans KR', sans-serif;
}

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
code { font-family: 'Courier New', monospace; background: rgba(59,130,246,.15); color: var(--cyan); padding: 2px 6px; border-radius: 4px; font-size: .9em; }
kbd { display: inline-block; padding: 2px 8px; background: var(--bg3); border: 1px solid var(--border); border-radius: 5px; font-size: .85em; color: var(--cyan); }

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

/* ─── Buttons ─── */
.btn-primary {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: 999px;
  background: var(--blue); color: #fff;
  font-size: 1rem; font-weight: 600;
  transition: background .2s, transform .15s, box-shadow .2s;
  border: none; cursor: pointer;
}
.btn-primary:hover { background: #2563eb; transform: translateY(-2px); box-shadow: 0 8px 30px rgba(59,130,246,.4); }

.btn-ghost {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 14px 28px; border-radius: 999px;
  background: transparent; color: var(--text);
  font-size: 1rem; font-weight: 500;
  border: 1px solid var(--border);
  transition: background .2s, border-color .2s;
}
.btn-ghost:hover { background: rgba(255,255,255,.05); border-color: rgba(255,255,255,.2); }

.btn-nav {
  padding: 8px 20px; border-radius: 999px;
  background: var(--blue); color: #fff;
  font-size: .875rem; font-weight: 600;
  transition: background .2s;
}
.btn-nav:hover { background: #2563eb; }

.btn-full { width: 100%; justify-content: center; border-radius: var(--radius); }

/* ─── Nav ─── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  height: var(--nav-h);
  background: rgba(13,15,20,.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  transition: background .3s;
}
.nav.scrolled { background: rgba(13,15,20,.97); }

.nav-inner {
  max-width: var(--max-w); margin: 0 auto; padding: 0 24px;
  height: 100%; display: flex; align-items: center; gap: 8px;
}
.nav-logo { margin-right: auto; }

.nav-logo {
  display: flex; align-items: center; gap: 10px;
  font-size: 1.1rem; font-weight: 700; color: #fff;
  margin-right: auto;
}

/* ─── Lang Switch ─── */
.lang-switch {
  display: flex; align-items: center; gap: 2px;
  flex-shrink: 0;
}
.lang-btn {
  padding: 5px 10px; border-radius: 6px;
  background: none; border: 1px solid transparent;
  color: var(--text-muted); font-size: .78rem; font-weight: 700;
  letter-spacing: .04em; cursor: pointer;
  transition: color .2s, background .2s, border-color .2s;
}
.lang-btn:hover { color: var(--text); background: rgba(255,255,255,.06); }
.lang-btn.active {
  color: #fff; background: rgba(255,255,255,.1);
  border-color: var(--border);
}
.nav-logo img { width: 36px; height: 36px; border-radius: 8px; object-fit: cover; }

.nav-links {
  display: flex; align-items: center; gap: 8px; list-style: none;
}
.nav-links a {
  padding: 8px 14px; border-radius: 8px; font-size: .9rem;
  color: var(--text-muted); transition: color .2s, background .2s;
}
.nav-links a:hover, .nav-links a.active { color: #fff; background: rgba(255,255,255,.07); }
.nav-links a.btn-nav { color: #fff; background: var(--blue); }
.nav-links a.btn-nav:hover { background: #2563eb; }

.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(--text); border-radius: 2px; transition: transform .3s, opacity .3s; }

/* ─── Section base ─── */
.section { padding: 96px 0; }
.section-dark { background: var(--bg2); }

.section-label {
  font-size: .8rem; font-weight: 700; letter-spacing: .12em; text-transform: uppercase;
  color: var(--blue); margin-bottom: 12px;
}
.section-title {
  font-size: clamp(2rem, 4vw, 2.75rem); font-weight: 800; line-height: 1.2;
  margin-bottom: 48px;
}
.section-title.centered { text-align: center; }

.highlight { color: var(--cyan); }

/* ─── Hero ─── */
.hero {
  position: relative; min-height: 100vh;
  display: flex; align-items: center;
  overflow: hidden; padding-top: var(--nav-h);
}

.hero-bg {
  position: absolute; inset: 0; z-index: 0;
}
.hero-bg img { width: 100%; height: 100%; object-fit: cover; object-position: center top; }
.hero-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(105deg, rgba(13,15,20,.92) 40%, rgba(13,15,20,.6) 100%);
}

.hero-content {
  position: relative; z-index: 1;
  max-width: var(--max-w); margin: 0 auto; padding: 80px 24px 100px;
  max-width: 680px; margin-left: max(24px, calc(50vw - 600px + 24px));
}

.hero-badge {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 6px 14px; border-radius: 999px;
  background: rgba(59,130,246,.15); border: 1px solid rgba(59,130,246,.3);
  font-size: .8rem; font-weight: 600; color: var(--blue);
  margin-bottom: 24px;
}
.badge-dot {
  width: 6px; height: 6px; border-radius: 50%;
  background: var(--blue);
  animation: pulse 2s infinite;
}
@keyframes pulse {
  0%,100% { opacity: 1; transform: scale(1); }
  50% { opacity: .5; transform: scale(1.4); }
}

.hero-title {
  font-size: clamp(2.4rem, 5vw, 3.6rem); font-weight: 900; line-height: 1.15;
  color: #fff; margin-bottom: 20px;
  text-shadow: 0 2px 20px rgba(0,0,0,.5);
}

.hero-sub {
  font-size: 1.1rem; color: rgba(232,234,240,.7); margin-bottom: 36px;
  line-height: 1.7;
}
.br-desktop { display: none; }

.hero-actions { display: flex; flex-wrap: wrap; gap: 12px; }

.hero-scroll-hint {
  position: absolute; bottom: 36px; left: 50%; transform: translateX(-50%);
  font-size: .75rem; color: var(--text-muted); letter-spacing: .1em;
  z-index: 1;
  animation: bounceY 2s infinite;
}
.hero-scroll-hint::before { content: '↓'; display: block; text-align: center; font-size: 1rem; }
@keyframes bounceY {
  0%,100% { transform: translateX(-50%) translateY(0); }
  50% { transform: translateX(-50%) translateY(6px); }
}

/* ─── Features ─── */
.features-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 20px;
}

.feature-card {
  padding: 28px; border-radius: var(--radius-lg);
  background: var(--bg2); border: 1px solid var(--border);
  transition: border-color .2s, transform .2s;
}
.feature-card:hover { border-color: rgba(59,130,246,.4); transform: translateY(-4px); }

.feature-card.is-highlight {
  border-color: rgba(34,211,238,.45);
  background: linear-gradient(180deg, rgba(34,211,238,.07), var(--bg2) 70%);
}
.feature-card.is-highlight:hover { border-color: rgba(34,211,238,.7); }
.feature-card.is-highlight .feature-icon { background: rgba(34,211,238,.15); border-color: rgba(34,211,238,.4); color: var(--cyan); }

.feature-icon {
  width: 48px; height: 48px; border-radius: 12px;
  background: var(--blue-glow); border: 1px solid rgba(59,130,246,.3);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 16px; color: var(--blue);
}
.feature-icon svg { width: 24px; height: 24px; }
.feature-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.feature-card p { font-size: .9rem; color: var(--text-muted); line-height: 1.6; }

/* ─── Steps ─── */
.steps-row {
  display: flex; align-items: flex-start; gap: 16px; flex-wrap: wrap;
}

.step {
  flex: 1; min-width: 240px;
  background: var(--bg3); border-radius: var(--radius-lg); overflow: hidden;
  border: 1px solid var(--border);
  transition: border-color .2s;
}
.step:hover { border-color: rgba(34,211,238,.3); }

.step-number {
  padding: 20px 24px 0;
  font-size: 3rem; font-weight: 900; color: rgba(34,211,238,.15);
  line-height: 1;
}

.step-img-wrap { padding: 12px 16px; }
.step-img-wrap img { border-radius: 8px; width: 100%; object-fit: cover; }

.step-body { padding: 8px 24px 24px; }
.step-body h3 { font-size: 1.05rem; font-weight: 700; margin-bottom: 8px; color: var(--cyan); }
.step-body p { font-size: .875rem; color: var(--text-muted); line-height: 1.65; }
.step-code { margin-top: 12px; }
.step-code code { display: inline-block; white-space: normal; line-height: 1.6; }

.step-arrow {
  font-size: 1.5rem; color: var(--border); align-self: center;
  flex-shrink: 0; padding-top: 40px;
}

/* ─── World ─── */
.section-world {
  position: relative; padding: 120px 0; overflow: hidden;
}
.world-img-wrap {
  position: absolute; inset: 0; z-index: 0;
}
.world-img-wrap img { width: 100%; height: 100%; object-fit: cover; }
.world-overlay {
  position: absolute; inset: 0;
  background: linear-gradient(to right, rgba(13,15,20,.9) 40%, rgba(13,15,20,.5));
}
.world-content {
  position: relative; z-index: 1; max-width: 540px;
}
.world-content .section-title { margin-bottom: 16px; }
.world-content p { color: var(--text-muted); margin-bottom: 28px; font-size: 1.05rem; }

/* ─── CTA ─── */
.cta-section { background: linear-gradient(135deg, #0d0f14 0%, #111827 100%); }
.cta-inner { text-align: center; }
.cta-inner h2 { font-size: clamp(1.8rem, 3.5vw, 2.5rem); font-weight: 800; margin-bottom: 12px; }
.cta-inner p { color: var(--text-muted); margin-bottom: 32px; font-size: 1.05rem; }
.cta-actions { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; }

/* ─── Footer ─── */
.footer { border-top: 1px solid var(--border); padding-top: 48px; }
.footer-inner {
  display: flex; flex-wrap: wrap; align-items: center; gap: 24px;
  padding-bottom: 24px; border-bottom: 1px solid var(--border);
}
.footer-brand {
  display: flex; align-items: center; gap: 10px;
  font-size: 1rem; font-weight: 700;
}
.footer-brand img { width: 32px; height: 32px; border-radius: 7px; }
.footer-nav { display: flex; flex-wrap: wrap; gap: 8px; margin-left: auto; }
.footer-nav a { color: var(--text-muted); font-size: .875rem; padding: 4px 8px; border-radius: 6px; transition: color .2s; }
.footer-nav a:hover { color: var(--text); }
.footer-legal { display: flex; gap: 12px; }
.footer-legal a { color: var(--text-muted); font-size: .8rem; transition: color .2s; }
.footer-legal a:hover { color: var(--text); }
.footer-copy { padding: 20px 0; }
.footer-copy .container { font-size: .8rem; color: var(--text-muted); }

/* ─── Page Hero ─── */
.page-hero {
  padding: calc(var(--nav-h) + 72px) 0 80px;
  background: linear-gradient(180deg, var(--bg2) 0%, var(--bg) 100%);
  border-bottom: 1px solid var(--border);
}
.page-hero h1 { font-size: clamp(2.2rem, 5vw, 3.4rem); font-weight: 900; line-height: 1.2; margin-top: 8px; }
.page-hero-sub { color: var(--text-muted); font-size: 1.1rem; margin-top: 16px; }

/* ─── About ─── */
.about-grid {
  display: grid; grid-template-columns: 1fr 1fr; gap: 64px; align-items: center;
}
.about-text .section-title { margin-bottom: 20px; }
.about-text p { color: var(--text-muted); margin-bottom: 16px; line-height: 1.75; }
.about-visual img { border-radius: var(--radius-lg); border: 1px solid var(--border); }

.stats-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 20px;
  margin-bottom: 32px;
}
.stat-card {
  padding: 28px; border-radius: var(--radius-lg);
  background: var(--bg3); border: 1px solid var(--border);
  text-align: center;
}
.stat-number { font-size: 2rem; font-weight: 900; color: var(--cyan); margin-bottom: 6px; }
.stat-label { font-size: .85rem; color: var(--text-muted); }
.stats-note { color: var(--text-muted); font-size: .95rem; line-height: 1.75; text-align: center; max-width: 640px; margin: 0 auto; }

.team-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 20px; }
.team-card {
  padding: 32px; border-radius: var(--radius-lg);
  background: var(--bg2); border: 1px solid var(--border);
}
.team-avatar {
  width: 56px; height: 56px; border-radius: 16px;
  background: var(--blue-glow); border: 1px solid rgba(59,130,246,.4);
  display: flex; align-items: center; justify-content: center;
  font-size: .75rem; font-weight: 800; color: var(--blue);
  margin-bottom: 16px;
}
.team-card h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 4px; }
.team-role { font-size: .8rem; color: var(--blue); font-weight: 600; margin-bottom: 10px; }
.team-card p { font-size: .875rem; color: var(--text-muted); }

.pilot-inner { max-width: 800px; margin: 0 auto; text-align: center; }
.pilot-inner .section-title { margin-bottom: 32px; }
.pilot-card {
  display: flex; align-items: center; gap: 32px;
  padding: 32px; border-radius: var(--radius-lg);
  background: var(--bg3); border: 1px solid var(--border);
  text-align: left;
}
.pilot-logo {
  flex-shrink: 0; width: 96px; height: 96px;
  border-radius: 20px; background: var(--blue-glow);
  border: 1px solid rgba(59,130,246,.3);
  display: flex; align-items: center; justify-content: center;
  font-size: .9rem; font-weight: 800; color: var(--blue); text-align: center;
  line-height: 1.2;
}
.pilot-text h3 { font-size: 1.1rem; font-weight: 700; margin-bottom: 8px; }
.pilot-text p { font-size: .875rem; color: var(--text-muted); margin-bottom: 16px; }

/* ─── Guide: Onboarding List ─── */
.onboard-list { display: flex; flex-direction: column; gap: 14px; }
.onboard-item {
  display: flex; gap: 18px; align-items: flex-start;
  padding: 20px 24px; border-radius: var(--radius-lg);
  background: var(--bg3); border: 1px solid var(--border);
}
.onboard-num {
  flex-shrink: 0; width: 36px; height: 36px; border-radius: 50%;
  background: var(--blue-glow); border: 1px solid rgba(59,130,246,.3);
  display: flex; align-items: center; justify-content: center;
  font-weight: 800; color: var(--blue); font-size: .9rem;
}
.onboard-item h3 { font-size: .95rem; font-weight: 700; margin-bottom: 4px; }
.onboard-item p { font-size: .85rem; color: var(--text-muted); line-height: 1.6; }

/* ─── Guide: Lesson Cards ─── */
.lesson-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 18px; }
.lesson-card { padding: 24px; border-radius: var(--radius-lg); background: var(--bg2); border: 1px solid var(--border); }
.lesson-card-head { display: flex; align-items: baseline; gap: 10px; margin-bottom: 10px; }
.lesson-num { font-size: 1.3rem; font-weight: 900; color: var(--cyan); }
.lesson-card h3 { font-size: 1rem; font-weight: 700; }
.lesson-goal { font-size: .85rem; color: var(--text-muted); line-height: 1.6; margin-bottom: 14px; }
.lesson-tags { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 14px; }
.lesson-tag {
  font-size: .72rem; font-weight: 600; padding: 3px 10px; border-radius: 999px;
  background: rgba(59,130,246,.12); border: 1px solid rgba(59,130,246,.28); color: var(--blue);
}
.lesson-tag.concept { background: rgba(34,211,238,.1); border-color: rgba(34,211,238,.28); color: var(--cyan); }
.lesson-condition { font-size: .8rem; color: var(--text-muted); border-top: 1px solid var(--border); padding-top: 12px; }
.lesson-condition strong { color: var(--text); font-weight: 600; }

/* ─── Contact ─── */
.contact-layout {
  display: grid; grid-template-columns: 1fr 360px; gap: 48px; align-items: start;
}

.contact-form { display: flex; flex-direction: column; gap: 20px; }

.form-group { display: flex; flex-direction: column; gap: 6px; }
.form-group label { font-size: .875rem; font-weight: 600; color: var(--text-muted); }
.required { color: #f87171; }
.form-group input,
.form-group select,
.form-group textarea {
  padding: 12px 16px; border-radius: 10px;
  background: var(--bg2); border: 1px solid var(--border);
  color: var(--text); font-size: 1rem; font-family: var(--font);
  transition: border-color .2s, box-shadow .2s;
  outline: none;
}
.form-group input::placeholder,
.form-group textarea::placeholder { color: var(--text-muted); }
.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
  border-color: var(--blue); box-shadow: 0 0 0 3px rgba(59,130,246,.2);
}
.form-group select { cursor: pointer; }
.form-group select option { background: var(--bg2); }

.form-status {
  padding: 12px 16px; border-radius: 10px;
  font-size: .9rem; font-weight: 600;
}
.form-status.success { background: rgba(34,197,94,.15); color: var(--green); border: 1px solid rgba(34,197,94,.3); }
.form-status.error { background: rgba(248,113,113,.15); color: #f87171; border: 1px solid rgba(248,113,113,.3); }

.contact-info { display: flex; flex-direction: column; gap: 16px; }
.contact-info-card {
  padding: 24px; border-radius: var(--radius-lg);
  background: var(--bg2); border: 1px solid var(--border);
}
.contact-info-card h3 { font-size: 1rem; font-weight: 700; margin-bottom: 8px; }
.contact-info-card p { font-size: .875rem; color: var(--text-muted); margin-bottom: 12px; }
.contact-email {
  display: block; color: var(--cyan); font-size: .9rem; font-weight: 600;
  word-break: break-all;
}
.contact-email:hover { text-decoration: underline; }

/* ─── Responsive ─── */
@media (min-width: 900px) { .br-desktop { display: inline; } }

@media (max-width: 900px) {
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
  .about-visual { order: -1; }
  .contact-layout { grid-template-columns: 1fr; }
  .step-arrow { display: none; }
  .steps-row { flex-direction: column; }
  .step { min-width: 0; }
  .pilot-card { flex-direction: column; text-align: center; }
}

@media (max-width: 640px) {
  .nav-toggle { display: flex; }
  /* lang-switch is always visible — sits between logo and hamburger */
  .nav-links {
    display: none; position: fixed; inset: var(--nav-h) 0 0 0;
    background: rgba(13,15,20,.98); backdrop-filter: blur(20px);
    flex-direction: column; align-items: stretch; gap: 0;
    padding: 16px;
    z-index: 99;
  }
  .nav-links.open { display: flex; }
  .nav-links li { width: 100%; }
  .nav-links a { display: block; padding: 14px 16px; font-size: 1rem; border-radius: 10px; }
  .nav-links a.btn-nav { text-align: center; margin-top: 8px; }

  .hero-content { margin-left: 0; padding: 60px 24px 80px; }
  .section { padding: 64px 0; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .footer-nav { margin-left: 0; }
  .world-overlay { background: rgba(13,15,20,.85); }
  .world-content { max-width: 100%; }
  .feature-card, .team-card, .stat-card { padding: 20px; }
}