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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
}

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

/* 头部样式 */
.header {
    text-align: center;
    margin-bottom: 50px;
    color: white;
}

.logo {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin-bottom: 10px;
}

.logo i {
    font-size: 3rem;
    background: linear-gradient(45deg, #f09433 0%, #e6683c 25%, #dc2743 50%, #cc2366 75%, #bc1888 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.logo h1 {
    font-size: 2.5rem;
    font-weight: 700;
    text-shadow: 2px 2px 4px rgba(0,0,0,0.3);
}

.subtitle {
    font-size: 1.2rem;
    opacity: 0.9;
    font-weight: 300;
}

/* 主要内容区域 */
.main-content {
    background: white;
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 20px 40px rgba(0,0,0,0.1);
    margin-bottom: 30px;
}

/* 下载区域 */
.download-section {
    margin-bottom: 50px;
}

.input-container {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
    flex-wrap: wrap;
}

.url-input {
    flex: 1;
    min-width: 300px;
    padding: 15px 20px;
    border: 2px solid #e1e5e9;
    border-radius: 50px;
    font-size: 16px;
    outline: none;
    transition: all 0.3s ease;
}

.url-input:focus {
    border-color: #667eea;
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.1);
}

.url-input::placeholder {
    color: #aaa;
}

.download-btn {
    padding: 15px 30px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
    border: none;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    gap: 10px;
    white-space: nowrap;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 20px rgba(102, 126, 234, 0.3);
}

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

.download-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* 加载动画 */
.loading-spinner {
    text-align: center;
    padding: 40px;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

/* 结果区域 */
.result-section {
    text-align: center;
    padding: 30px;
    border-radius: 15px;
}

.success-result {
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
}

.success-result i {
    font-size: 3rem;
    margin-bottom: 15px;
    color: #00ff88;
}

.error-result {
    background: linear-gradient(135deg, #ff6b6b 0%, #ee5a24 100%);
    color: white;
}

.error-result i {
    font-size: 3rem;
    margin-bottom: 15px;
    color: #ffd700;
}

.final-download-btn, .retry-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 12px 25px;
    background: rgba(255, 255, 255, 0.2);
    color: white;
    text-decoration: none;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50px;
    font-weight: 600;
    margin-top: 20px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.final-download-btn:hover, .retry-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.retry-btn {
    background: none;
    border: 2px solid white;
}

/* 使用说明 */
.instructions {
    margin-bottom: 50px;
}

.instructions h2 {
    text-align: center;
    margin-bottom: 30px;
    color: #333;
    font-size: 2rem;
}

.steps {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.step {
    display: flex;
    align-items: flex-start;
    gap: 20px;
    padding: 25px;
    background: #f8f9fa;
    border-radius: 15px;
    transition: transform 0.3s ease;
}

.step:hover {
    transform: translateY(-5px);
}

.step-number {
    width: 50px;
    height: 50px;
    background: linear-gradient(45deg, #667eea, #764ba2);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.step-content h3 {
    margin-bottom: 10px;
    color: #333;
}

.step-content p {
    color: #666;
    line-height: 1.5;
}

/* 功能特点 */
.features {
    margin-bottom: 50px;
}

.features h2 {
    text-align: center;
    margin-bottom: 30px;
    color: #333;
    font-size: 2rem;
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.feature {
    text-align: center;
    padding: 30px 20px;
    background: #f8f9fa;
    border-radius: 15px;
    transition: all 0.3s ease;
}

.feature:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.1);
}

.feature i {
    font-size: 2.5rem;
    color: #667eea;
    margin-bottom: 20px;
}

.feature h3 {
    margin-bottom: 15px;
    color: #333;
}

.feature p {
    color: #666;
    line-height: 1.5;
}

/* 页脚 */
.footer {
    text-align: center;
    color: white;
    opacity: 0.8;
    padding: 20px 0;
}

.disclaimer {
    font-size: 0.9rem;
    margin-top: 10px;
    opacity: 0.7;
}

/* 工具类 */
.hidden {
    display: none !important;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .main-content {
        padding: 25px;
    }
    
    .logo h1 {
        font-size: 2rem;
    }
    
    .input-container {
        flex-direction: column;
    }
    
    .url-input {
        min-width: auto;
    }
    
    .steps {
        grid-template-columns: 1fr;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .logo {
        flex-direction: column;
        gap: 10px;
    }
    
    .logo h1 {
        font-size: 1.8rem;
    }
    
    .subtitle {
        font-size: 1rem;
    }
    
    .step {
        flex-direction: column;
        text-align: center;
    }
}