/* reset & basic layout */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
}

body {
  display: flex;
  justify-content: center;
  align-items: center;
  font-family: Arial, sans-serif;
  background-color: var(--bg);
  color: var(--text);
}

/* dark/light adaptive */
@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111;
    --text: #f2f2f2;
    --loader-bg: #444;
    --loader-fg: #eee;
  }
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f9f9f9;
    --text: #222;
    --loader-bg: #ddd;
    --loader-fg: #444;
  }
}

/* centered content */
.container {
  text-align: center;
}

/* spinning loader */
.loader {
  border: 8px solid var(--loader-bg);
  border-top: 8px solid var(--loader-fg);
  border-radius: 50%;
  width: 80px;
  height: 80px;
  margin: 0 auto 20px;
  animation: spin 1s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* headline */
h1 {
  font-size: 1.4rem;
  font-weight: bold;
}