:root {
  --bg-color: #0f172a;
  --card-bg: #1e293b;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --primary: #3b82f6;
  --primary-hover: #2563eb;
  --secondary-bg: #334155;
  --secondary-hover: #475569;
  --border-color: #334155;
  --radius: 12px;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-main: #0f172a;
    --text-muted: #64748b;
    --primary: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-bg: #e2e8f0;
    --secondary-hover: #cbd5e1;
    --border-color: #e2e8f0;
  }
}

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

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.5;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.container {
  width: 100%;
  max-width: 480px;
}

.card {
  background-color: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 2.5rem 2rem;
  text-align: center;
  box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
}

.brand {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.025em;
  margin-bottom: 0.75rem;
}

.error-code {
  font-size: 3rem;
  font-weight: 800;
  color: var(--text-muted);
  margin-bottom: 0.5rem;
}

.tagline {
  color: var(--text-muted);
  font-size: 1.05rem;
  margin-bottom: 1.5rem;
}

.error-msg {
  color: var(--text-muted);
  font-size: 1rem;
  margin-bottom: 1.5rem;
}

.btn {
  display: inline-block;
  background-color: var(--primary);
  color: #ffffff;
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  padding: 0.75rem 1.5rem;
  border-radius: 8px;
  transition: background-color 0.2s ease;
  border: none;
  cursor: pointer;
}

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

.btn-secondary {
  background-color: var(--secondary-bg);
  color: var(--text-main);
}

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

[hidden] {
  display: none !important;
}