:root { font-family: "Microsoft YaHei", system-ui, sans-serif; color: #182846; background: #f2f5fa; }
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 24px; }
.login-card { width: 100%; max-width: 440px; padding: 40px; background: white; border-radius: 20px; box-shadow: 0 16px 50px #16294712; }
.brand { color: #245fe5; font-size: 13px; font-weight: 700; letter-spacing: 2px; }
h1 { font-size: 26px; margin: 20px 0 12px; }
.intro, .help { color: #64748b; font-size: 14px; line-height: 1.7; }
label { display: block; margin: 22px 0 8px; font-size: 14px; font-weight: 600; }
input { width: 100%; padding: 12px; border: 1px solid #bac6d8; border-radius: 8px; font: inherit; }
input:focus { outline: 3px solid #245fe530; border-color: #245fe5; }
button { width: 100%; margin-top: 28px; padding: 13px; border: 0; border-radius: 8px; color: white; background: #245fe5; font: inherit; cursor: pointer; }
button:hover { background: #184bc4; }
button:focus-visible { outline: 3px solid #142544; outline-offset: 3px; }
.error { padding: 12px; background: #fff1f0; color: #a32020; border-radius: 8px; font-size: 14px; }
.help { margin-bottom: 0; }
@media (max-width: 480px) { .login-card { padding: 28px 22px; } }