:root {
  --bg: #f5f6f8;
  --card: #ffffff;
  --text: #1f2430;
  --muted: #5c6370;
  --primary: #228be6;
  --primary-text: #ffffff;
  --border: #d9dde3;
  --error-bg: #fff0f0;
  --error-text: #c92a2a;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #1a1b1e;
    --card: #25262b;
    --text: #e9ecef;
    --muted: #a6a7ab;
    --border: #373a40;
    --error-bg: #3b1f1f;
    --error-text: #ffa8a8;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

.shell { max-width: 420px; margin: 0 auto; padding: 32px 16px; }
.brand { margin: 0 0 16px; font-weight: 700; color: var(--muted); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 12px; padding: 24px; }
h1 { margin: 0 0 16px; font-size: 1.5rem; }
form { display: flex; flex-direction: column; gap: 8px; }
label { font-weight: 600; }

input[type="text"], input[type="password"], input:not([type]) {
  width: 100%;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font: inherit;
}

.check { display: flex; align-items: center; gap: 8px; font-weight: 400; }
.actions { display: flex; gap: 8px; margin-top: 8px; }

button {
  flex: 1;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card);
  color: var(--text);
  font: inherit;
  cursor: pointer;
}

button.primary { background: var(--primary); border-color: var(--primary); color: var(--primary-text); }
.alert { background: var(--error-bg); color: var(--error-text); border-radius: 8px; padding: 12px; margin-bottom: 16px; }
.alert ul { margin: 0; padding-left: 20px; }