:root {
  --color-bg: #f0f4f8;
  --color-surface: #fff;
  --color-text: #1e293b;
  --color-muted: #64748b;
  --color-border: #e2e8f0;
  --color-accent: #003b83;
  --color-accent-hover: #002a5c;
  --color-danger: #dc2626;
  --font-sans: "Hiragino Sans", "Hiragino Kaku Gothic ProN", "Yu Gothic", Meiryo, sans-serif;
  --radius: 6px;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

a {
  color: var(--color-accent);
}

a:hover {
  color: var(--color-accent-hover);
}

.auth-logo {
  display: block;
  margin: 0 auto 2rem;
  text-align: center;
  line-height: 0;
}

.auth-logo img {
  width: 12rem;
  height: auto;
  max-width: 100%;
}

.auth-container {
  max-width: 420px;
  margin: 3rem auto;
  padding: 1rem 1.75rem 2rem;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.08);
}

.auth-container h1 {
  margin: 0 0 1.25rem;
  font-size: 1.375rem;
  text-align: center;
  color: var(--color-accent);
}

.auth-container p {
  margin: 0 0 1rem;
}

.auth-container label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: 1rem;
  cursor: pointer;
}

.auth-container input[type="text"],
.auth-container input[type="email"],
.auth-container input[type="password"] {
  display: block;
  width: 100%;
  margin-top: 0.35rem;
  padding: 0.55rem 0.65rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  font: inherit;
  box-sizing: border-box;
}

.auth-container input:focus {
  outline: 2px solid rgba(0, 59, 131, 0.25);
  border-color: var(--color-accent);
}

.auth-container input[type="checkbox"] {
  width: auto;
  margin-right: 0.35rem;
  vertical-align: middle;
}

.terms-agreement {
  display: flex;
  align-items: flex-start;
  gap: 0.5rem;
  margin: 1rem 0;
  font-size: 0.9375rem;
  line-height: 1.5;
}

.terms-agreement input {
  margin-top: 0.2rem;
  flex-shrink: 0;
}

.auth-container .btn {
  display: block;
  width: 100%;
  margin-top: 0.5rem;
  padding: 0.65rem 1rem;
  border: none;
  border-radius: var(--radius);
  background: var(--color-accent);
  color: #fff;
  font: inherit;
  font-size: 1rem;
  cursor: pointer;
}

.auth-container .btn:hover {
  background: var(--color-accent-hover);
}

.auth-footer {
  margin-top: 1.5rem;
  text-align: center;
  font-size: 0.875rem;
}

.auth-footer p {
  margin: 0.5rem 0;
}

.auth-back {
  display: block;
  text-align: center;
  margin-top: 1.5rem;
  font-size: 0.875rem;
}

.alert {
  padding: 0.75rem 1rem;
  border-radius: var(--radius);
  margin-bottom: 1rem;
  font-size: 0.9375rem;
}

.alert--success {
  background: #ecfdf5;
  border: 1px solid #a7f3d0;
  color: #065f46;
}

.alert--error {
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: var(--color-danger);
}

.alert--warning {
  background: #eef3f8;
  border: 1px solid #c5d4e8;
  color: var(--color-text);
}

.alert p {
  margin: 0 0 0.5rem;
}

.alert p:last-child {
  margin-bottom: 0;
}

.input-error {
  margin: 0.25rem 0 0;
  padding: 0;
  list-style: none;
  font-size: 0.875rem;
  color: var(--color-danger);
}