:root {
  color-scheme: light;
  --bg: #f3f6fb;
  --panel: #fff;
  --text: #182033;
  --muted: #667085;
  --line: #d7deea;
  --primary: #155eef;
  --primary-hover: #0f4ac1;
  --danger: #b42318;
  --success: #067647;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

* { box-sizing: border-box; }
html, body { min-height: 100%; margin: 0; }
body { background: var(--bg); color: var(--text); }
button, input { font: inherit; }
button { cursor: pointer; }
.hidden { display: none !important; }
.muted { color: var(--muted); }
.error { color: var(--danger); }
.success { color: var(--success); }
.auth-tab-radio { position: absolute; width: 1px; height: 1px; opacity: 0; pointer-events: none; }

.auth-page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px 16px;
}

.auth-card {
  width: min(440px, 100%);
  padding: 30px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel);
  box-shadow: 0 18px 48px rgba(16, 24, 40, .10);
}

.auth-boot { display: flex; justify-content: center; align-items: center; gap: 12px; color: var(--muted); }
.auth-spinner { width: 20px; height: 20px; border: 3px solid #dbe5f5; border-top-color: var(--primary); border-radius: 50%; animation: spin .8s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.auth-header { text-align: center; margin-bottom: 24px; }
.auth-brand { margin: 0 0 5px; color: var(--primary); font-size: 14px; font-weight: 800; letter-spacing: .12em; }
.auth-header h1 { margin: 0; font-size: 26px; }
.auth-header > p:last-child { margin: 8px 0 0; color: var(--muted); }

.auth-primary-tabs, .auth-method-tabs { display: grid; grid-template-columns: 1fr 1fr; }
.auth-primary-tabs { padding: 4px; margin-bottom: 20px; border-radius: 10px; background: #eef2f8; }
.auth-primary-tabs > label { display: block; border: 0; border-radius: 7px; padding: 10px; background: transparent; color: var(--muted); font-size: 16px; font-weight: 700; text-align: center; cursor: pointer; }
#primaryLoginMode:checked ~ .auth-primary-tabs label[for="primaryLoginMode"],
#primaryRegisterMode:checked ~ .auth-primary-tabs label[for="primaryRegisterMode"] { background: #fff; color: var(--text); box-shadow: 0 1px 4px rgba(16, 24, 40, .12); }
.auth-method-tabs { margin-bottom: 22px; border-bottom: 1px solid var(--line); }
.auth-method-tabs > label { display: block; border: 0; border-bottom: 3px solid transparent; padding: 11px 6px; background: transparent; color: var(--muted); font-size: 16px; font-weight: 700; text-align: center; cursor: pointer; }
#codeLoginMode:checked ~ .auth-method-tabs label[for="codeLoginMode"],
#passwordLoginMode:checked ~ .auth-method-tabs label[for="passwordLoginMode"] { border-bottom-color: var(--primary); color: var(--primary); }

#primaryLoginMode:checked ~ #registerPanel,
#primaryRegisterMode:checked ~ #loginPanel,
#codeLoginMode:checked ~ #passwordLoginForm,
#passwordLoginMode:checked ~ #codeLoginForm { display: none !important; }
#primaryLoginMode:focus-visible ~ .auth-primary-tabs label[for="primaryLoginMode"],
#primaryRegisterMode:focus-visible ~ .auth-primary-tabs label[for="primaryRegisterMode"],
#codeLoginMode:focus-visible ~ .auth-method-tabs label[for="codeLoginMode"],
#passwordLoginMode:focus-visible ~ .auth-method-tabs label[for="passwordLoginMode"] { outline: 3px solid #8bb3ff; outline-offset: 2px; }

.auth-form { display: grid; gap: 16px; }
label { display: grid; gap: 6px; color: #475467; font-size: 14px; }
input { width: 100%; min-height: 44px; padding: 10px 12px; border: 1px solid var(--line); border-radius: 8px; background: #fff; color: var(--text); }
button { min-height: 42px; padding: 9px 13px; border: 1px solid var(--line); border-radius: 8px; background: #fff; color: var(--text); }
button:hover { border-color: #9db4dc; }
button:disabled { cursor: wait; opacity: .65; }
button.primary { border-color: var(--primary); background: var(--primary); color: #fff; }
button.primary:hover { border-color: var(--primary-hover); background: var(--primary-hover); }
button:focus-visible, input:focus-visible { outline: 3px solid #8bb3ff; outline-offset: 2px; }

.auth-code-row { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 10px; align-items: end; }
.auth-code-row button { min-width: 108px; }
.submit { width: 100%; font-weight: 800; }
.form-message { display: block; min-height: 20px; margin-top: -8px; font-size: 14px; }
.form-help { margin: -4px 0 0; color: var(--muted); font-size: 13px; text-align: center; }
.auth-notice { margin-top: 20px; padding: 13px 14px; border-radius: 8px; background: #f5f8fe; color: #475467; font-size: 13px; line-height: 1.6; }
.auth-notice p { margin: 5px 0 0; }

@media (max-width: 480px) {
  .auth-card { padding: 24px 18px; }
  .auth-code-row { grid-template-columns: minmax(0, 1fr) auto; }
  .auth-code-row button { min-width: 96px; padding-inline: 10px; }
}

@media (prefers-reduced-motion: reduce) {
  .auth-spinner { animation: none; }
}