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

/* CSS变量定义 */
:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --secondary-color: #64748b;
    --success-color: #10b981;
    --error-color: #ef4444;
    --warning-color: #f59e0b;
    --background-color: #f8fafc;
    --card-background: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --border-color: #e2e8f0;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --border-radius: 8px;
    --transition: all 0.3s ease;
}

/* 基础样式 */
body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

/* 加载动画 */
.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.95);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 9999;
    transition: opacity 0.3s ease;
}

.loading-spinner {
    width: 40px;
    height: 40px;
    border: 4px solid var(--border-color);
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin-bottom: 16px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* 容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部 */
.header {
    padding: 20px 0;
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: 8px;
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: white;
}

.nav {
    display: flex;
    gap: 32px;
}

.nav-link {
    color: rgba(255, 255, 255, 0.9);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
    padding: 8px 16px;
    border-radius: var(--border-radius);
}

.nav-link:hover {
    color: white;
    background: rgba(255, 255, 255, 0.1);
}

/* 主要内容 */
.main {
    padding: 60px 0;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 80px;
}

/* 登录卡片 */
.login-card {
    background: var(--card-background);
    border-radius: 16px;
    padding: 40px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 420px;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.login-header {
    text-align: center;
    margin-bottom: 32px;
}

.login-title {
    font-size: 28px;
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 8px;
}

.login-subtitle {
    color: var(--text-secondary);
    font-size: 16px;
}

/* 表单样式 */
.login-form {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.form-label {
    font-weight: 600;
    color: var(--text-primary);
    font-size: 14px;
}

.input-wrapper {
    position: relative;
    display: flex;
    align-items: center;
}

.form-input {
    width: 100%;
    padding: 12px 16px;
    padding-left: 48px;
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    font-size: 16px;
    transition: var(--transition);
    background: white;
}

.form-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.form-input::placeholder {
    color: var(--text-secondary);
}

.input-icon {
    position: absolute;
    left: 16px;
    font-size: 18px;
    color: var(--text-secondary);
    pointer-events: none;
}

.password-toggle {
    position: absolute;
    right: 12px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    border-radius: 4px;
    transition: var(--transition);
}

.password-toggle:hover {
    background: var(--background-color);
}

.toggle-icon {
    font-size: 16px;
}

/* 表单选项 */
.form-options {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 8px 0;
}

.checkbox-wrapper {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
}

.checkbox-wrapper input[type="checkbox"] {
    display: none;
}

.checkmark {
    width: 18px;
    height: 18px;
    border: 2px solid var(--border-color);
    border-radius: 4px;
    position: relative;
    transition: var(--transition);
}

.checkbox-wrapper input[type="checkbox"]:checked + .checkmark {
    background: var(--primary-color);
    border-color: var(--primary-color);
}

.checkbox-wrapper input[type="checkbox"]:checked + .checkmark::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-size: 12px;
    font-weight: bold;
}

.forgot-link {
    color: var(--primary-color);
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: var(--transition);
}

.forgot-link:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* 登录按钮 */
.login-btn {
    width: 100%;
    padding: 14px 24px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

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

.login-btn:active {
    transform: translateY(0);
}

.login-btn:disabled {
    background: var(--secondary-color);
    cursor: not-allowed;
    transform: none;
}

.btn-loading .spinner {
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top: 2px solid white;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: inline-block;
    margin-right: 8px;
}

/* 状态消息 */
.status-message {
    padding: 12px 16px;
    border-radius: var(--border-radius);
    font-size: 14px;
    font-weight: 500;
    text-align: center;
    margin-top: 16px;
}

.status-message.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success-color);
    border: 1px solid rgba(16, 185, 129, 0.2);
}

.status-message.error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error-color);
    border: 1px solid rgba(239, 68, 68, 0.2);
}

.status-message.warning {
    background: rgba(245, 158, 11, 0.1);
    color: var(--warning-color);
    border: 1px solid rgba(245, 158, 11, 0.2);
}

/* 登录页脚 */
.login-footer {
    text-align: center;
    margin-top: 24px;
    padding-top: 24px;
    border-top: 1px solid var(--border-color);
}

.register-text {
    color: var(--text-secondary);
    font-size: 14px;
}

.register-link {
    color: var(--primary-color);
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
}

.register-link:hover {
    color: var(--primary-hover);
    text-decoration: underline;
}

/* 功能特色区域 */
.features-section {
    width: 100%;
    max-width: 1000px;
}

.section-title {
    text-align: center;
    font-size: 32px;
    font-weight: 700;
    color: white;
    margin-bottom: 48px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 32px;
}

.feature-card {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 16px;
    padding: 32px 24px;
    text-align: center;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-4px);
    background: rgba(255, 255, 255, 0.15);
}

.feature-icon {
    font-size: 48px;
    margin-bottom: 16px;
}

.feature-title {
    font-size: 20px;
    font-weight: 600;
    color: white;
    margin-bottom: 12px;
}

.feature-desc {
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

/* 页脚 */
.footer {
    background: rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(10px);
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: 48px 0 24px;
    margin-top: 80px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 32px;
    margin-bottom: 32px;
}

.footer-title {
    color: white;
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: var(--transition);
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    color: rgba(255, 255, 255, 0.6);
}

/* 模态框 */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}

.modal-content {
    background: white;
    border-radius: 16px;
    padding: 32px;
    max-width: 500px;
    width: 90%;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
    box-shadow: var(--shadow-lg);
}

.modal-close {
    position: absolute;
    top: 16px;
    right: 20px;
    font-size: 24px;
    cursor: pointer;
    color: var(--text-secondary);
    transition: var(--transition);
}

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

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }
    
    .header-content {
        flex-direction: column;
        gap: 16px;
    }
    
    .nav {
        gap: 16px;
    }
    
    .login-card {
        padding: 24px;
        margin: 0 16px;
    }
    
    .login-title {
        font-size: 24px;
    }
    
    .section-title {
        font-size: 28px;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 24px;
    }
    
    .form-options {
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }
}

@media (max-width: 480px) {
    .main {
        padding: 40px 0;
        gap: 60px;
    }
    
    .login-card {
        padding: 20px;
    }
    
    .feature-card {
        padding: 24px 20px;
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.login-card {
    animation: fadeIn 0.6s ease-out;
}

.feature-card {
    animation: fadeIn 0.6s ease-out;
}

.feature-card:nth-child(1) { animation-delay: 0.1s; }
.feature-card:nth-child(2) { animation-delay: 0.2s; }
.feature-card:nth-child(3) { animation-delay: 0.3s; }
.feature-card:nth-child(4) { animation-delay: 0.4s; }

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: rgba(255, 255, 255, 0.1);
}

::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.3);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: rgba(255, 255, 255, 0.5);
}