/* 全局样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* 根变量定义 */
:root {
    --primary-color: #007AFF;
    --primary-hover: #0056CC;
    --secondary-color: #5856D6;
    --success-color: #34C759;
    --warning-color: #FF9500;
    --error-color: #FF3B30;
    --background-color: #F2F2F7;
    --surface-color: #FFFFFF;
    --text-primary: #1C1C1E;
    --text-secondary: #8E8E93;
    --border-color: #D1D1D6;
    --shadow-light: 0 2px 10px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 4px 20px rgba(0, 0, 0, 0.15);
    --border-radius: 12px;
    --border-radius-small: 8px;
    --transition: all 0.3s ease;
    --max-width: 800px;
}

/* 基础样式 */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background-color: var(--background-color);
    font-size: 16px;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

/* 头部样式 */
.header {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 30px;
    margin-bottom: 30px;
    box-shadow: var(--shadow-light);
}

.app-info {
    display: flex;
    align-items: center;
    gap: 20px;
}

.app-icon {
    flex-shrink: 0;
}

.app-icon img {
    border-radius: 18px;
    box-shadow: var(--shadow-medium);
}

.app-name {
    font-size: 2rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.app-subtitle {
    font-size: 1.1rem;
    color: var(--text-secondary);
    font-weight: 400;
}

/* 主要内容区域 */
.main-content {
    display: flex;
    flex-direction: column;
    gap: 30px;
}

/* 应用描述区域 */
.app-description {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow-light);
}

.app-description h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.app-description p {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 25px;
    line-height: 1.7;
}

/* 功能特性 */
.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
}

.feature {
    text-align: center;
    padding: 20px;
    border-radius: var(--border-radius-small);
    background: var(--background-color);
    transition: var(--transition);
}

.feature:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.feature h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--text-primary);
}

.feature p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* 反馈区域 */
.feedback-section {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow-light);
}

.feedback-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.feedback-intro {
    font-size: 1rem;
    color: var(--text-secondary);
    margin-bottom: 25px;
    line-height: 1.6;
}

/* 表单样式 */
.feedback-form {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.form-group {
    display: flex;
    flex-direction: column;
}

.form-group label {
    font-weight: 500;
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 0.95rem;
}

.required {
    color: var(--error-color);
}

.optional {
    color: var(--text-secondary);
    font-weight: 400;
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 12px 16px;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-small);
    font-size: 1rem;
    transition: var(--transition);
    font-family: inherit;
    background: var(--surface-color);
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(0, 122, 255, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.help-text {
    margin-top: 5px;
    font-size: 0.85rem;
    color: var(--text-secondary);
}

/* 文件上传区域 */
.file-upload-area {
    position: relative;
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius-small);
    padding: 30px;
    text-align: center;
    transition: var(--transition);
    background: var(--background-color);
}

.file-upload-area:hover {
    border-color: var(--primary-color);
    background: rgba(0, 122, 255, 0.05);
}

.file-upload-area input[type="file"] {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    opacity: 0;
    cursor: pointer;
}

.upload-placeholder {
    pointer-events: none;
}

.upload-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.upload-placeholder p {
    font-weight: 500;
    margin-bottom: 5px;
    color: var(--text-primary);
}

.upload-placeholder small {
    color: var(--text-secondary);
}

/* 文件列表 */
.file-list {
    margin-top: 15px;
    text-align: left;
}

.file-item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 12px;
    background: var(--surface-color);
    border-radius: var(--border-radius-small);
    margin-bottom: 8px;
    border: 1px solid var(--border-color);
}

.file-info {
    display: flex;
    align-items: center;
    gap: 8px;
}

.file-name {
    font-size: 0.9rem;
    color: var(--text-primary);
}

.file-size {
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.remove-file {
    background: none;
    border: none;
    color: var(--error-color);
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: var(--transition);
}

.remove-file:hover {
    background: rgba(255, 59, 48, 0.1);
}

/* 隐私政策复选框 */
.form-group label input[type="checkbox"] {
    margin-right: 8px;
    margin-bottom: 0;
}

.privacy-link {
    color: var(--primary-color);
    text-decoration: none;
}

.privacy-link:hover {
    text-decoration: underline;
}

/* 提交按钮 */
.form-actions {
    margin-top: 10px;
}

.submit-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 14px 30px;
    border-radius: var(--border-radius-small);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    min-width: 150px;
}

.submit-btn:hover {
    background: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: var(--shadow-medium);
}

.submit-btn:disabled {
    background: var(--text-secondary);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
}

/* 成功消息 */
.success-message {
    text-align: center;
    padding: 30px;
    background: rgba(52, 199, 89, 0.1);
    border: 1px solid rgba(52, 199, 89, 0.3);
    border-radius: var(--border-radius);
    margin-top: 20px;
}

.success-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.success-message h3 {
    color: var(--success-color);
    margin-bottom: 10px;
    font-weight: 600;
}

.success-message p {
    color: var(--text-secondary);
}

/* 联系信息 */
.contact-info {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow-light);
}

.contact-info h2 {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 20px;
    color: var(--text-primary);
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.contact-item {
    font-size: 1rem;
    color: var(--text-secondary);
}

.contact-item strong {
    color: var(--text-primary);
    margin-right: 10px;
}

.contact-item a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-item a:hover {
    text-decoration: underline;
}

/* 页脚 */
.footer {
    text-align: center;
    padding: 30px 0;
    margin-top: 30px;
    border-top: 1px solid var(--border-color);
}

.footer p {
    color: var(--text-secondary);
    font-size: 0.9rem;
    margin-bottom: 5px;
}

/* 模态框样式 */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-content {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-medium);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 25px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    font-size: 1.3rem;
    font-weight: 600;
    color: var(--text-primary);
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-secondary);
    padding: 5px;
    border-radius: 4px;
    transition: var(--transition);
}

.close-btn:hover {
    background: var(--background-color);
    color: var(--text-primary);
}

.modal-body {
    padding: 25px;
}

.modal-body h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 10px;
    margin-top: 15px;
}

.modal-body h4:first-child {
    margin-top: 0;
}

.modal-body p {
    color: var(--text-secondary);
    line-height: 1.6;
    margin-bottom: 15px;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .header {
        padding: 20px;
    }
    
    .app-info {
        flex-direction: column;
        text-align: center;
        gap: 15px;
    }
    
    .app-name {
        font-size: 1.6rem;
    }
    
    .features {
        grid-template-columns: 1fr;
    }
    
    .feedback-section,
    .app-description,
    .contact-info {
        padding: 20px;
    }
    
    .file-upload-area {
        padding: 20px;
    }
    
    .modal-content {
        width: 95%;
    }
    
    .contact-methods {
        gap: 12px;
    }
    
    .contact-item {
        font-size: 0.9rem;
    }
}

@media (max-width: 480px) {
    .app-name {
        font-size: 1.4rem;
    }
    
    .app-subtitle {
        font-size: 1rem;
    }
    
    .feedback-section h2,
    .app-description h2,
    .contact-info h2 {
        font-size: 1.3rem;
    }
    
    .submit-btn {
        width: 100%;
        padding: 16px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.success-message {
    animation: fadeIn 0.5s ease-out;
}

/* 隐私政策页面专用样式 */
.back-button {
    margin-top: 15px;
}

.btn-back {
    display: inline-flex;
    align-items: center;
    padding: 8px 16px;
    background: var(--background-color);
    color: var(--primary-color);
    text-decoration: none;
    border-radius: var(--border-radius-small);
    border: 1px solid var(--border-color);
    font-size: 0.9rem;
    transition: var(--transition);
}

.btn-back:hover {
    background: var(--primary-color);
    color: white;
    transform: translateX(-2px);
}

.privacy-policy-content {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 30px;
    box-shadow: var(--shadow-light);
}

.policy-header {
    text-align: center;
    margin-bottom: 40px;
    padding-bottom: 20px;
    border-bottom: 1px solid var(--border-color);
}

.policy-title {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 10px;
}

.last-updated {
    font-size: 1rem;
    color: var(--text-secondary);
    font-style: italic;
}

.policy-section {
    margin-bottom: 40px;
}

.policy-section h2 {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--primary-color);
}

.policy-section h3 {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
    margin-top: 20px;
}

.policy-section p {
    font-size: 1rem;
    color: var(--text-primary);
    line-height: 1.7;
    margin-bottom: 15px;
}

.policy-section ul {
    list-style: none;
    padding: 0;
    margin-bottom: 20px;
}

.policy-section li {
    position: relative;
    padding-left: 20px;
    margin-bottom: 8px;
    color: var(--text-primary);
    line-height: 1.6;
}

.policy-section li::before {
    content: "•";
    color: var(--primary-color);
    font-weight: bold;
    position: absolute;
    left: 0;
}

.subsection {
    margin-bottom: 25px;
    padding: 20px;
    background: var(--background-color);
    border-radius: var(--border-radius-small);
    border-left: 4px solid var(--primary-color);
}

.service-list {
    margin: 20px 0;
}

.service-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 16px;
    background: var(--background-color);
    border-radius: var(--border-radius-small);
    margin-bottom: 10px;
    border: 1px solid var(--border-color);
}

.service-item strong {
    color: var(--text-primary);
}

.service-item span {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.rights-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 25px 0;
}

.right-item {
    text-align: center;
    padding: 20px;
    background: var(--background-color);
    border-radius: var(--border-radius);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.right-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
}

.right-icon {
    font-size: 2rem;
    margin-bottom: 10px;
}

.right-item h4 {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.right-item p {
    font-size: 0.9rem;
    color: var(--text-secondary);
    line-height: 1.5;
    margin: 0;
}

.contact-box {
    background: var(--background-color);
    border-radius: var(--border-radius);
    padding: 20px;
    margin: 20px 0;
    border: 1px solid var(--border-color);
}

.contact-method {
    margin-bottom: 15px;
    font-size: 1rem;
}

.contact-method:last-child {
    margin-bottom: 0;
}

.contact-method strong {
    color: var(--text-primary);
    margin-right: 10px;
}

.contact-method a {
    color: var(--primary-color);
    text-decoration: none;
}

.contact-method a:hover {
    text-decoration: underline;
}

.update-notice {
    display: flex;
    align-items: flex-start;
    gap: 15px;
    background: rgba(0, 122, 255, 0.1);
    border: 1px solid rgba(0, 122, 255, 0.3);
    border-radius: var(--border-radius);
    padding: 20px;
    margin-top: 20px;
}

.notice-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
}

.notice-content strong {
    color: var(--primary-color);
    display: block;
    margin-bottom: 5px;
}

.notice-content p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.footer-links {
    margin-top: 10px;
    font-size: 0.9rem;
}

.footer-links a {
    color: var(--primary-color);
    text-decoration: none;
    margin: 0 5px;
}

.footer-links a:hover {
    text-decoration: underline;
}

.footer-links span {
    color: var(--text-secondary);
    margin: 0 5px;
}

/* 阅读进度条样式 */
.reading-progress {
    position: fixed;
    top: 0;
    left: 0;
    width: 0%;
    height: 3px;
    background: var(--primary-color);
    z-index: 1000;
    transition: width 0.3s ease;
}

/* 隐私政策页面响应式设计 */
@media (max-width: 768px) {
    .policy-title {
        font-size: 2rem;
    }
    
    .privacy-policy-content {
        padding: 20px;
    }
    
    .rights-grid {
        grid-template-columns: 1fr;
    }
    
    .service-item {
        flex-direction: column;
        text-align: center;
        gap: 5px;
    }
    
    .back-button {
        text-align: center;
    }
}

@media (max-width: 480px) {
    .policy-title {
        font-size: 1.6rem;
    }
    
    .policy-section h2 {
        font-size: 1.3rem;
    }
    
    .policy-section h3 {
        font-size: 1.1rem;
    }
    
    .contact-box {
        padding: 15px;
    }
    
    .update-notice {
        flex-direction: column;
        text-align: center;
    }
}

/* 深色模式支持 */
@media (prefers-color-scheme: dark) {
    :root {
        --background-color: #000000;
        --surface-color: #1C1C1E;
        --text-primary: #FFFFFF;
        --text-secondary: #8E8E93;
        --border-color: #38383A;
    }
    
    .file-upload-area {
        background: #2C2C2E;
    }
    
    .feature {
        background: #2C2C2E;
    }
    
    .subsection {
        background: #2C2C2E;
    }
    
    .service-item {
        background: #2C2C2E;
    }
    
    .right-item {
        background: #2C2C2E;
    }
    
    .contact-box {
        background: #2C2C2E;
    }
}