:root {
  --bg: #f5f5f7;
  --card: #ffffff;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --border: #d2d2d7;
  --accent: #111111;
  --ok-bg: #e8f5e9;
  --ok-text: #1b5e20;
  --err-bg: #fdecea;
  --err-text: #b71c1c;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #111113;
    --card: #1c1c1e;
    --text: #f5f5f7;
    --muted: #a1a1a6;
    --border: #3a3a3c;
    --accent: #f5f5f7;
    --ok-bg: #1e3a24;
    --ok-text: #a5d6a7;
    --err-bg: #3b1d1d;
    --err-text: #ef9a9a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px 16px;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
}

.card {
  width: 100%;
  max-width: 420px;
  padding: 32px 24px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
}

h1 { margin: 0 0 8px; font-size: 24px; }
.lead { margin: 0 0 24px; color: var(--muted); }

label { display: block; margin: 16px 0 6px; font-size: 14px; font-weight: 600; }

input {
  width: 100%;
  padding: 10px 12px;
  font: inherit;
  color: var(--text);
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 8px;
}

button {
  width: 100%;
  margin-top: 24px;
  padding: 12px;
  font: inherit;
  font-weight: 600;
  color: var(--card);
  background: var(--accent);
  border: 0;
  border-radius: 8px;
  cursor: pointer;
}

button:disabled { opacity: 0.5; cursor: default; }

.alert { margin-bottom: 16px; padding: 12px; border-radius: 8px; }
.alert-success { background: var(--ok-bg); color: var(--ok-text); }
.alert-error { background: var(--err-bg); color: var(--err-text); }