:root { --red: #dc2626; --red-dark: #b91c1c; --ink: #111827; --muted: #6b7280; --line: #e5e7eb; }
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; color: var(--ink); background: #f3f4f6; font-family: Arial, "Noto Sans JP", sans-serif; }
button, input { font: inherit; }
.login-shell { min-height: 100vh; display: grid; place-items: center; padding: 24px; }
.login-card { width: min(100%, 420px); padding: 36px; border: 1px solid var(--line); border-radius: 10px; background: #fff; box-shadow: 0 10px 30px rgba(17, 24, 39, .08); }
.eyebrow { margin: 0 0 8px; color: var(--red); font-size: 11px; font-weight: 800; letter-spacing: .12em; }
h1 { margin: 0; font-size: 24px; letter-spacing: -.02em; }
.login-description { margin: 12px 0 26px; color: var(--muted); font-size: 13px; line-height: 1.7; }
label { display: block; margin-bottom: 8px; font-size: 12px; font-weight: 700; }
input { width: 100%; height: 44px; padding: 0 12px; border: 1px solid #d1d5db; border-radius: 7px; outline: none; }
input:focus { border-color: var(--red); box-shadow: 0 0 0 3px rgba(220, 38, 38, .12); }
.login-error { min-height: 20px; margin: 8px 0; color: var(--red); font-size: 12px; }
button { width: 100%; height: 44px; border: 0; border-radius: 7px; color: #fff; background: var(--red); font-weight: 700; cursor: pointer; }
button:hover { background: var(--red-dark); }
button:disabled { opacity: .6; cursor: wait; }
@media (max-width: 480px) { .login-card { padding: 28px 22px; } }