* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "微软雅黑", sans-serif; background: #f0f2f5; display: flex; justify-content: center; align-items: center; min-height: 100vh; padding: 20px; }
.login-box { width: 400px; max-width: 100%; background: #fff; padding: 40px; border-radius: 8px; box-shadow: 0 2px 12px rgba(0,0,0,0.1); }
h2 { text-align: center; margin-bottom: 30px; color: #333; }
.form-item { margin-bottom: 20px; }
label { display: block; margin-bottom: 8px; color: #666; }
input { width: 100%; padding: 10px; border: 1px solid #ddd; border-radius: 4px; font-size: 16px; }
@media (max-width: 768px) {
    body { padding: 16px; align-items: flex-start; padding-top: max(24px, env(safe-area-inset-top)); }
    .login-box { padding: 24px 16px; }
}
button { width: 100%; padding: 12px; background: #409eff; color: #fff; border: none; border-radius: 4px; font-size: 16px; cursor: pointer; }
/* 验证码题目按钮是行内元素，不能被上面的 button{width:100%} 撑满整行挤扁输入框 */
#captcha-box { width: auto; flex-shrink: 0; }
button:hover { background: #66b1ff; }
button:disabled { opacity: .7; cursor: not-allowed; }
.register-link { text-align: center; margin-top: 20px; color: #666; }
.register-link a { color: #409eff; text-decoration: none; }
.msg { color: #f56c6c; text-align: center; margin-bottom: 15px; min-height: 20px; }