:root {
  --color-bg: #fafbfc;
  --color-bg-card: #ffffff;
  --color-text: #24292f;
  --color-text-secondary: #57606a;
  --color-border: #d0d7de;
  --color-border-focus: #0969da;
  --color-error: #cf222e;
  --color-btn: #0969da;
  --color-btn-hover: #0860ca;
  --color-btn-text: #ffffff;
  --spacing-xs: 4px;
  --spacing-sm: 8px;
  --spacing-md: 16px;
  --spacing-lg: 24px;
  --spacing-xl: 32px;
  --spacing-2xl: 40px;
  --radius: 6px;
  --transition: 80ms cubic-bezier(0.33, 1, 0.68, 1);
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0d1117;
    --color-bg-card: #161b22;
    --color-text: #c9d1d9;
    --color-text-secondary: #8b949e;
    --color-border: #30363d;
    --color-border-focus: #58a6ff;
    --color-error: #f85149;
    --color-btn: #1f6feb;
    --color-btn-hover: #1a5cd8;
    --color-btn-text: #ffffff;
  }
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans', Helvetica, Arial, sans-serif, 'Apple Color Emoji', 'Segoe UI Emoji';
  line-height: 1.5;
  color: var(--color-text);
  background: var(--color-bg);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-md);
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

.auth-container {
  width: 100%;
  max-width: 340px;
}

.auth-card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: var(--spacing-xl) var(--spacing-2xl);
  transition: transform var(--transition);
}

.auth-card.shake {
  animation: shake 0.4s cubic-bezier(0.36, 0.07, 0.19, 0.97) both;
}

@keyframes shake {
  10%, 90% {
    transform: translateX(-2px);
  }
  20%, 80% {
    transform: translateX(3px);
  }
  30%, 50%, 70% {
    transform: translateX(-4px);
  }
  40%, 60% {
    transform: translateX(4px);
  }
}

.auth-header {
  margin-bottom: var(--spacing-xl);
}

.auth-title {
  font-size: 24px;
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
  letter-spacing: 0;
}

.auth-subtitle {
  font-size: 14px;
  color: var(--color-text-secondary);
  font-weight: 400;
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-lg);
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-xs);
}

.form-label {
  font-size: 14px;
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--spacing-xs);
}

.form-input {
  width: 100%;
  padding: 8px 12px;
  font-size: 14px;
  font-family: inherit;
  color: var(--color-text);
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  transition: border-color var(--transition);
  outline: none;
}

.form-input:hover:not(:disabled):not([aria-invalid="true"]) {
  border-color: var(--color-text-secondary);
}

.form-input:focus {
  border-color: var(--color-border-focus);
  outline: 2px solid transparent;
  outline-offset: 2px;
  box-shadow: 0 0 0 3px rgba(9, 105, 218, 0.1);
}

@media (prefers-color-scheme: dark) {
  .form-input:focus {
    box-shadow: 0 0 0 3px rgba(88, 166, 255, 0.1);
  }
}

.form-input:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  background: var(--color-bg);
}

.form-input[aria-invalid="true"] {
  border-color: var(--color-error);
}

.form-input[aria-invalid="true"]:focus {
  box-shadow: 0 0 0 3px rgba(207, 34, 46, 0.1);
}

@media (prefers-color-scheme: dark) {
  .form-input[aria-invalid="true"]:focus {
    box-shadow: 0 0 0 3px rgba(248, 81, 73, 0.1);
  }
}

.form-hint {
  font-size: 12px;
  color: var(--color-text-secondary);
  min-height: 16px;
}

.form-error {
  font-size: 12px;
  color: var(--color-error);
  min-height: 16px;
  display: block;
}

.form-error:empty {
  display: none;
}

.form-error-global {
  font-size: 14px;
  color: var(--color-error);
  margin-top: var(--spacing-sm);
  display: none;
  outline: none;
}

.form-error-global:not(:empty) {
  display: block;
}

.form-error-global:focus {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

.form-actions {
  margin-top: var(--spacing-xl);
}

.form-demo-hint {
  font-size: 11px;
  color: var(--color-text-secondary);
  margin-top: var(--spacing-md);
  text-align: center;
  line-height: 1.6;
  opacity: 0.8;
}

.form-demo-hint div {
  margin-bottom: 2px;
}

.form-demo-hint div:last-child {
  margin-bottom: 0;
}

.btn {
  width: 100%;
  padding: 7px 16px;
  font-size: 14px;
  font-weight: 500;
  font-family: inherit;
  color: var(--color-btn-text);
  background: var(--color-btn);
  border: 1px solid transparent;
  border-radius: var(--radius);
  cursor: pointer;
  transition: background-color var(--transition), opacity var(--transition);
  outline: none;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 29px;
}

.btn:focus-visible {
  outline: 2px solid var(--color-border-focus);
  outline-offset: 2px;
}

.btn:hover:not(:disabled) {
  background: var(--color-btn-hover);
}

.btn:active:not(:disabled) {
  background: var(--color-btn-hover);
}

.btn:disabled {
  opacity: 0.6;
  cursor: wait;
}

.btn-loader {
  display: none;
}

.btn.loading .btn-text {
  opacity: 0;
  transition: opacity var(--transition);
}

.btn.loading .btn-loader {
  display: block;
}

.success-panel {
  text-align: center;
  padding: var(--spacing-xl) 0;
}

.success-icon {
  width: 48px;
  height: 48px;
  margin: 0 auto var(--spacing-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-border-focus);
}

.success-title {
  font-size: 20px;
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: var(--spacing-sm);
}

.success-message {
  font-size: 14px;
  color: var(--color-text-secondary);
}

@media (max-width: 480px) {
  body {
    padding: var(--spacing-sm);
  }

  .auth-card {
    padding: var(--spacing-xl);
  }

  .auth-title {
    font-size: 20px;
  }
}