:root {
  --bg: #0f1117;
  --surface: #1a1d27;
  --border: #2a2f3d;
  --text: #eef0f4;
  --muted: #9aa3b5;
  --accent: #6c8cff;
  --accent-hover: #5478ff;
}

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

body {
  font-family: "Pretendard", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;
  background: radial-gradient(ellipse 80% 60% at 50% -10%, #1e2640 0%, var(--bg) 55%);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.6;
}

.wrap {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px 20px 64px;
}

header {
  text-align: center;
  margin-bottom: 40px;
}

.logo {
  width: 72px;
  height: 72px;
  border-radius: 18px;
  background: linear-gradient(135deg, #6c8cff, #9b6cff);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 28px;
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
  box-shadow: 0 12px 40px rgba(108, 140, 255, 0.25);
}

h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: 10px;
}

.subtitle {
  color: var(--muted);
  font-size: 1.05rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 28px;
  margin-bottom: 20px;
}

.card h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 16px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.download-row {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 16px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  background: var(--accent);
  color: #fff;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  padding: 14px 24px;
  border-radius: 12px;
  transition: background 0.15s;
}

.btn:hover {
  background: var(--accent-hover);
}

.btn.disabled {
  background: #3a4155;
  pointer-events: none;
  opacity: 0.7;
}

.meta {
  color: var(--muted);
  font-size: 0.9rem;
}

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

.features {
  list-style: none;
  display: grid;
  gap: 10px;
}

.features li {
  padding-left: 1.4em;
  position: relative;
  color: var(--muted);
}

.features li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

.install-notice {
  margin-top: 20px;
  padding: 18px 20px;
  border-radius: 12px;
  border: 1px solid #4a6fa5;
  background: linear-gradient(180deg, rgba(108, 140, 255, 0.14) 0%, rgba(26, 29, 39, 0.9) 100%);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.install-notice__head {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.install-notice__badge {
  display: inline-block;
  padding: 4px 10px;
  border-radius: 999px;
  background: #3d5a9e;
  color: #eef3ff;
  font-size: 0.78rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.install-notice__title {
  font-size: 1rem;
  color: #f0f4ff;
}

.install-notice__safe {
  font-size: 0.92rem;
  color: #d8e2ff;
  margin-bottom: 12px;
  line-height: 1.65;
}

.install-notice__safe strong:last-child {
  color: #a8c4ff;
}

.install-notice__lead {
  font-size: 0.9rem;
  color: var(--text);
  margin-bottom: 10px;
  font-weight: 600;
}

.install-notice__steps {
  margin: 0 0 12px 1.2em;
  padding: 0;
  color: var(--muted);
  font-size: 0.9rem;
  display: grid;
  gap: 8px;
}

.install-notice__steps strong {
  color: #c5d8ff;
}

.install-notice__foot {
  font-size: 0.82rem;
  color: var(--muted);
  padding-top: 12px;
  border-top: 1px solid rgba(108, 140, 255, 0.25);
}

footer {
  text-align: center;
  color: var(--muted);
  font-size: 0.82rem;
  margin-top: 32px;
}

@media (max-width: 480px) {
  h1 {
    font-size: 1.6rem;
  }

  .download-row {
    flex-direction: column;
    align-items: stretch;
  }

  .btn {
    justify-content: center;
  }
}