docs(website): 添加简记memo产品原型和UI设计规范文档

- 新增「简记memo」一体化小程序产品原型设计文档
- 新增简记memo完整版UI视觉设计规范和界面细节
- 添加IDEA项目配置文件.gitignore
- 创建404页面HTML文件，包含响应式布局和错误提示
- 添加关于页面HTML文件，展示品牌介绍和团队信息
- 实现AES加解密工具函数，支持请求体加密
- 添加用户协议页面基础框架

static/css/login.css

@@ -0,0 +1,174 @@
+/* ===================================
+   简记memo - 登录页样式
+   =================================== */
+
+.login-page {
+    display: flex;
+    min-height: calc(100vh - 70px);
+}
+
+/* 左侧品牌区 */
+.login-left {
+    flex: 1;
+    background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    padding: 60px;
+    color: #fff;
+}
+
+.login-logo {
+    width: 120px;
+    height: 120px;
+    border-radius: 28px;
+    background: rgba(255, 255, 255, 0.2);
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    margin-bottom: 32px;
+    overflow: hidden;
+}
+
+.login-logo img {
+    width: 100%;
+    height: 100%;
+    object-fit: cover;
+}
+
+.login-brand {
+    font-size: 2.5rem;
+    font-weight: 800;
+    margin-bottom: 12px;
+    letter-spacing: 3px;
+}
+
+.login-slogan {
+    font-size: 1rem;
+    opacity: 0.9;
+    text-align: center;
+    line-height: 1.8;
+    max-width: 300px;
+}
+
+.login-features {
+    margin-top: 48px;
+    display: flex;
+    gap: 32px;
+}
+
+.feature-item {
+    text-align: center;
+}
+
+.feature-icon {
+    font-size: 2rem;
+    margin-bottom: 8px;
+}
+
+.feature-text {
+    font-size: 0.875rem;
+    opacity: 0.85;
+}
+
+/* 右侧表单区 */
+.login-right {
+    flex: 1;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    background: #f8fafc;
+    padding: 40px;
+}
+
+/* 响应式 */
+@media (max-width: 768px) {
+    .login-page {
+        flex-direction: column;
+    }
+
+    .login-left {
+        padding: 40px 24px;
+    }
+
+    .login-logo {
+        width: 80px;
+        height: 80px;
+    }
+
+    .login-brand {
+        font-size: 1.75rem;
+    }
+
+    .login-features {
+        margin-top: 24px;
+        gap: 20px;
+    }
+
+    .login-right {
+        padding: 24px;
+    }
+}
+
+/* 页面底部版权信息 */
+.page-footer {
+    padding: 24px;
+    text-align: center;
+    font-size: 0.75rem;
+    color: #94a3b8;
+    background: #fff;
+    border-top: 1px solid #e2e8f0;
+}
+
+.page-footer a {
+    color: #6366f1;
+    text-decoration: none;
+}
+
+.page-footer a:hover {
+    text-decoration: underline;
+}
+
+.footer-divider {
+    margin: 0 8px;
+    color: #cbd5e1;
+}
+
+/* 协议勾选框样式 */
+.checkbox-group {
+    padding: 0;
+    margin-bottom: 16px;
+}
+
+.checkbox-label {
+    display: flex;
+    align-items: flex-start;
+    gap: 6px;
+    cursor: pointer;
+    font-size: 13px;
+    color: #64748b;
+    flex-wrap: wrap;
+}
+
+.form-checkbox {
+    width: 14px;
+    height: 14px;
+    cursor: pointer;
+    margin-top: 3px;
+    flex-shrink: 0;
+}
+
+.checkbox-text {
+    line-height: 1.6;
+}
+
+.link-text {
+    color: #4F9EDE;
+    text-decoration: none;
+    line-height: 1.6;
+}
+
+.link-text:hover {
+    text-decoration: underline;
+}