:root {
  --bg: #f4f6f8;
  --surface: #ffffff;
  --text: #1f2937;
  --muted: #64748b;
  --border: #d8e0ea;
  --border-strong: #b9c6d6;
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --primary-soft: #eff6ff;
  --danger: #b42318;
  --success: #13795b;
  --radius: 8px;
  --shadow: 0 1px 2px rgba(15, 23, 42, 0.06);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }

body {
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Microsoft YaHei", "PingFang SC", "Segoe UI", Arial, sans-serif;
}

button,
input,
select { font: inherit; }

.auth-shell {
  display: grid;
  min-height: 100vh;
  place-items: center;
  padding: 16px;
}

.auth-card {
  width: min(100%, 420px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.eyebrow,
h1,
p { margin: 0; }

.eyebrow {
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
}

h1 {
  margin-top: 6px;
  font-size: 1.55rem;
  line-height: 1.2;
}

h2 {
  margin: 0;
  font-size: 1rem;
}

.intro {
  margin-top: 8px;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.5;
}

form {
  display: grid;
  gap: 16px;
  margin-top: 24px;
}

.field {
  display: grid;
  gap: 7px;
}

label {
  font-size: 0.86rem;
  font-weight: 800;
}

input,
select {
  width: 100%;
  min-height: 42px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius);
  padding: 9px 11px;
  background: #ffffff;
  color: var(--text);
}

input:focus,
select:focus,
button:focus-visible,
a:focus-visible {
  outline: 3px solid #93c5fd;
  outline-offset: 2px;
}

button,
.button-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 42px;
  border: 1px solid var(--primary);
  border-radius: var(--radius);
  padding: 9px 14px;
  background: var(--primary);
  color: #ffffff;
  cursor: pointer;
  font-weight: 800;
  text-decoration: none;
}

button:hover,
.button-link:hover { background: var(--primary-hover); }
button:disabled { cursor: not-allowed; opacity: 0.58; }

.button-link.secondary,
button.secondary {
  border-color: var(--border-strong);
  background: #ffffff;
  color: var(--text);
}

.button-link.secondary:hover,
button.secondary:hover {
  border-color: #93c5fd;
  background: var(--primary-soft);
  color: var(--primary-hover);
}

.form-message {
  min-height: 1.4em;
  color: var(--muted);
  font-size: 0.86rem;
  line-height: 1.45;
}

.form-message.error { color: var(--danger); }
.form-message.success { color: var(--success); }

@media (max-width: 480px) {
  .auth-card { padding: 20px; }
}