:root {
  --primary-color: #2563eb;
  --secondary-color: #64748b;
  --light-bg: #f8fafc;
  --dark-text: #1e293b;
  --border-color: #e2e8f0;
}

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

body {
  min-width: 320px;
  background: var(--light-bg);
  color: var(--dark-text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  line-height: 1.6;
}

.welcome-container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  text-align: center;
}

.welcome-card {
  width: min(100%, 720px);
  padding: 48px;
  border: 1px solid rgba(255, 255, 255, 0.55);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.96);
  box-shadow: 0 25px 50px -12px rgba(15, 23, 42, 0.3);
  color: var(--dark-text);
}

.welcome-title {
  margin-bottom: 12px;
  color: var(--primary-color);
  font-size: clamp(2rem, 6vw, 2.75rem);
  font-weight: 750;
  letter-spacing: -0.03em;
}

.welcome-subtitle {
  margin-bottom: 32px;
  color: var(--secondary-color);
  font-size: 1.125rem;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin: 32px 0;
}

.feature-item {
  min-height: 150px;
  padding: 22px;
  border: 1px solid var(--border-color);
  border-radius: 10px;
  background: #f8fafc;
}

.feature-item h3 {
  margin-bottom: 6px;
}

.feature-item p {
  color: var(--secondary-color);
  font-size: 0.875rem;
}

.feature-icon {
  margin-bottom: 10px;
  color: var(--primary-color);
  font-size: 1rem;
  font-weight: 750;
  letter-spacing: 0.08em;
}

.action-buttons {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
  margin-top: 32px;
}

.btn {
  min-height: 42px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 18px;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  background: #fff;
  color: var(--dark-text);
  font-size: 0.875rem;
  font-weight: 650;
  text-decoration: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease, opacity 0.2s ease;
}

.btn:hover {
  border-color: #94a3b8;
  box-shadow: 0 4px 12px rgba(15, 23, 42, 0.1);
}

.btn:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.25);
  outline-offset: 2px;
}

.btn-primary {
  border-color: var(--primary-color);
  background: var(--primary-color);
  color: #fff;
}

.btn-primary:hover {
  border-color: #1d4ed8;
  background: #1d4ed8;
}

.btn[aria-busy="true"] {
  pointer-events: none;
  opacity: 0.65;
}

.system-info {
  margin-top: 32px;
  padding-top: 32px;
  border-top: 1px solid var(--border-color);
}

.system-info__title {
  margin-bottom: 16px;
  color: var(--dark-text);
}

.system-info__grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 16px;
  font-size: 0.875rem;
}

.system-info__value {
  color: var(--secondary-color);
}

.site-footer {
  margin-top: 32px;
  color: var(--secondary-color);
  font-size: 0.75rem;
}

.site-footer p + p {
  margin-top: 8px;
}

@media (max-width: 640px) {
  .welcome-container {
    align-items: flex-start;
    padding: 16px;
  }

  .welcome-card {
    padding: 28px 20px;
  }

  .feature-grid,
  .system-info__grid {
    grid-template-columns: 1fr;
  }

  .feature-item {
    min-height: 0;
  }

  .action-buttons {
    flex-direction: column;
  }

  .btn {
    width: 100%;
  }
}

@media (prefers-reduced-motion: reduce) {
  .btn {
    transition: none;
  }
}