:root {
  --ink: #17212a;
  --muted: #687682;
  --line: #d9e1e7;
  --paper: #f3f6f8;
  --surface: #ffffff;
  --navy: #1c3f5d;
  --navy-dark: #122d44;
  --danger: #a7453c;
}

* { box-sizing: border-box; }
body { min-height: 100vh; margin: 0; display: grid; place-items: center; padding: 28px 18px; color: var(--ink); background: var(--paper); font-family: "Noto Sans JP", sans-serif; font-size: 14px; line-height: 1.65; }
button, input { font: inherit; }
.auth-shell { width: min(100%, 480px); }
.brand { display: flex; align-items: center; justify-content: center; gap: 10px; margin-bottom: 23px; color: var(--ink); font-weight: 700; letter-spacing: .06em; }
.brand-icon { display: grid; width: 32px; height: 32px; place-items: center; border-radius: 8px; color: #fff; background: var(--navy); }
.auth-card { padding: 32px; border: 1px solid var(--line); border-radius: 13px; background: var(--surface); box-shadow: 0 12px 35px rgba(19, 50, 73, .08); }
.eyebrow { margin: 0 0 8px; color: #52718a; font-family: "Roboto Mono", monospace; font-size: 10px; font-weight: 500; letter-spacing: .11em; }
h1 { margin: 0 0 8px; font-size: 27px; letter-spacing: -.04em; line-height: 1.35; }
.lead { margin: 0; color: var(--muted); font-size: 12px; }
.notice { margin: 21px 0 0; padding: 12px 14px; border-left: 3px solid #78a4bc; border-radius: 4px; color: #3f6176; background: #eef6fa; font-size: 11px; }
.form-fields { display: grid; gap: 16px; margin-top: 25px; }
label { display: block; color: #40505c; font-size: 12px; font-weight: 700; }
label span { display: block; margin-bottom: 6px; }
input { width: 100%; height: 43px; padding: 0 11px; border: 1px solid #cbd7df; border-radius: 6px; outline: none; color: var(--ink); background: #fff; }
input:focus { border-color: #5685a1; box-shadow: 0 0 0 3px rgba(86, 133, 161, .14); }
.field-help { margin: 5px 0 0; color: #7a8790; font-size: 10px; font-weight: 400; }
.primary-button { width: 100%; min-height: 44px; margin-top: 25px; border: 0; border-radius: 6px; color: #fff; background: var(--navy); font-size: 13px; font-weight: 700; cursor: pointer; }
.primary-button:hover { background: var(--navy-dark); }
.primary-button:disabled { cursor: wait; opacity: .65; }
.form-message { min-height: 20px; margin: 12px 0 0; color: var(--muted); font-size: 11px; text-align: center; }
.form-message.error { color: var(--danger); }
.auth-footer { margin: 18px 0 0; color: var(--muted); font-size: 11px; text-align: center; }
.auth-footer a { color: #285b7f; font-weight: 700; }

@media (max-width: 520px) {
  body { padding: 18px 14px; }
  .auth-card { padding: 25px 19px; }
}