:root {
  --bg: #0f172a;
  --card: #1e293b;
  --border: #334155;
  --text: #e2e8f0;
  --muted: #94a3b8;
  --accent: #38bdf8;
  --danger: #f87171;
  --warn: #fbbf24;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 1.5rem;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", Tahoma, system-ui, sans-serif;
}

.card {
  width: min(100%, 26rem);
  padding: 2rem;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
}

h1 {
  margin: 0;
  font-size: 1.5rem;
  color: var(--accent);
}

.subtitle {
  margin: 0.25rem 0 1.75rem;
  color: var(--muted);
  font-size: 0.875rem;
}

label {
  display: block;
  margin-bottom: 0.375rem;
  font-size: 0.875rem;
  color: var(--muted);
}

input {
  width: 100%;
  margin-bottom: 1.125rem;
  padding: 0.625rem 0.75rem;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 0.375rem;
  color: var(--text);
  font-size: 1rem;
  font-family: inherit;
}

input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
  border-color: transparent;
}

button {
  width: 100%;
  padding: 0.688rem;
  background: var(--accent);
  border: none;
  border-radius: 0.375rem;
  color: #0b1120;
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
}

button:hover:not(:disabled) { filter: brightness(1.1); }
button:disabled { opacity: 0.6; cursor: default; }

.error, .notice {
  margin-top: 1rem;
  padding: 0.75rem;
  border-radius: 0.375rem;
  font-size: 0.875rem;
  line-height: 1.6;
}

.error {
  background: rgba(248, 113, 113, 0.12);
  border: 1px solid rgba(248, 113, 113, 0.3);
  color: var(--danger);
}

.notice {
  margin: 0 0 1.25rem;
  background: rgba(251, 191, 36, 0.1);
  border: 1px solid rgba(251, 191, 36, 0.3);
  color: var(--warn);
}

.footnote {
  margin: 1.75rem 0 0;
  padding-top: 1.25rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.75rem;
  line-height: 1.7;
}