* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 40px 20px;
    color: #2c3e50;
}
.back-button {
            position: fixed;
            top: 20px;
            left: 20px;
            background: rgba(255, 255, 255, 0.95);
            color: #2c3e50;
            padding: 12px 20px;
            border-radius: 50px;
            text-decoration: none;
            font-weight: 600;
            box-shadow: 0 4px 15px rgba(0,0,0,0.1);
            transition: all 0.3s ease;
            backdrop-filter: blur(10px);
            border: 1px solid rgba(255,255,255,0.2);
            z-index: 1000;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .back-button:hover {
            background: white;
            transform: translateY(-2px);
            box-shadow: 0 6px 20px rgba(0,0,0,0.15);
        }

.container {
    max-width: 900px;
    margin: 0 auto;
    background: white;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.1);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #16a085 0%, #2980b9 100%);
    color: white;
    padding: 60px 40px;
    text-align: center;
}

.header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 20px;
    letter-spacing: -1px;
}

.header p {
    font-size: 1.2rem;
    opacity: 0.9;
    line-height: 1.6;
    max-width: 600px;
    margin: 0 auto;
}

.content {
    padding: 50px 40px;
}

.benefits-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 50px;
}

.benefit-card {
    background: #f8f9fa;
    padding: 30px;
    border-radius: 15px;
    border-left: 5px solid #16a085;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

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

.benefit-icon {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: #16a085;
}

.benefit-card h3 {
    font-size: 1.3rem;
    color: #2c3e50;
    margin-bottom: 15px;
    font-weight: 600;
}

.benefit-card p {
    color: #666;
    line-height: 1.6;
    font-size: 0.95rem;
}

.target-users {
    background: linear-gradient(135deg, #16a085 0%, #2980b9 100%);
    color: white;
    padding: 40px;
    border-radius: 15px;
    margin-bottom: 40px;
    text-align: center;
}

.target-users h2 {
    font-size: 1.8rem;
    margin-bottom: 20px;
    font-weight: 600;
}

.users-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
}

.user-tag {
    background: rgba(255,255,255,0.2);
    padding: 10px 20px;
    border-radius: 25px;
    font-weight: 500;
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
}

.upload-section {
    background: #f8f9fa;
    padding: 40px;
    border-radius: 15px;
    text-align: center;
    margin-bottom: 30px;
}

.upload-section h2 {
    color: #2c3e50;
    font-size: 1.8rem;
    margin-bottom: 30px;
    font-weight: 600;
}

.form-container {
    max-width: 500px;
    margin: 0 auto;
}

.form-group {
    margin-bottom: 25px;
    text-align: left;
}

.form-group label {
    display: block;
    color: #2c3e50;
    font-weight: 600;
    margin-bottom: 8px;
    font-size: 1rem;
}

.form-input {
    width: 100%;
    padding: 15px 20px;
    font-size: 1rem;
    border: 2px solid #e9ecef;
    border-radius: 10px;
    outline: none;
    transition: all 0.3s ease;
    background: white;
}

.form-input:focus {
    border-color: #16a085;
    box-shadow: 0 0 0 4px rgba(22, 160, 133, 0.1);
}

.form-input::placeholder {
    color: #666;
}

.required {
    color: #e74c3c;
    font-size: 0.9rem;
    margin-top: 5px;
}

.file-upload-area {
    border: 3px dashed #16a085;
    border-radius: 15px;
    padding: 40px 20px;
    text-align: center;
    background: rgba(22, 160, 133, 0.05);
    transition: all 0.3s ease;
    cursor: pointer;
    margin-bottom: 20px;
}

.file-upload-area:hover {
    background: rgba(22, 160, 133, 0.1);
    border-color: #138d75;
}

.file-upload-area .upload-icon {
    font-size: 3rem;
    color: #16a085;
    margin-bottom: 15px;
}

.file-upload-area p {
    color: #2c3e50;
    font-size: 1.1rem;
    margin-bottom: 10px;
}

.file-upload-area .supported-formats {
    color: #666;
    font-size: 0.9rem;
}

.file-name {
    display: block;
    margin-top: 5px;
    font-size: 0.9rem;
    color: #2c3e50;
}

.analyze-btn {
    background: linear-gradient(135deg, #16a085, #138d75);
    color: white;
    border: none;
    padding: 18px 40px;
    border-radius: 50px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1.1rem;
    width: 100%;
    margin-top: 20px;
}

.analyze-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 25px rgba(22, 160, 133, 0.3);
}

.analysis-features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-top: 40px;
}

.feature-item {
    text-align: center;
    padding: 25px 20px;
    background: white;
    border-radius: 10px;
    border: 2px solid #e9ecef;
    transition: all 0.3s ease;
}

.feature-item:hover {
    border-color: #16a085;
    transform: translateY(-3px);
}

.feature-icon {
    font-size: 2rem;
    color: #16a085;
    margin-bottom: 15px;
}

.feature-item h4 {
    color: #2c3e50;
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.feature-item p {
    color: #666;
    font-size: 0.85rem;
    line-height: 1.4;
}

.sync-score-highlight {
    background: linear-gradient(135deg, #f39c12, #e67e22);
    color: white;
    padding: 30px;
    border-radius: 15px;
    text-align: center;
    margin-bottom: 30px;
}

.sync-score-highlight h3 {
    font-size: 1.6rem;
    margin-bottom: 10px;
    font-weight: 600;
}

.sync-score-highlight p {
    font-size: 1rem;
    opacity: 0.9;
}

.cta-section {
    text-align: center;
    padding: 30px;
    background: linear-gradient(135deg, #27ae60, #2ecc71);
    color: white;
    border-radius: 15px;
}

.cta-section h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.cta-section p {
    opacity: 0.9;
    font-size: 1rem;
}

#error {
    text-align: center;
    margin-top: 15px;
    color: #e74c3c;
    font-size: 0.9rem;
}

.analyzing-container {
    background: #f8f9fa;
    padding: 15px;
    border-radius: 10px;
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
    margin: 10px auto;
    max-width: 600px;
    height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
}

#loading-text {
    font-weight: bold;
    color: #2c3e50;
    display: inline;
}

.spinner {
    width: 18px;
    height: 18px;
    border: 2px solid #2c3e50;
    border-top: 2px solid transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    display: inline-block;
    vertical-align: middle;
    margin-left: 5px;
}

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

.loading-bar {
    width: 200px;
    height: 20px;
    background-color: #d1e0f0;
    border-radius: 10px;
    overflow: hidden;
    margin-top: 10px;
}

.loading-progress {
    width: 0;
    height: 100%;
    background: linear-gradient(to right, #4a90e2, #50c878);
    border-radius: 10px;
    animation: progress 3s linear infinite;
}

@keyframes progress {
    0% { width: 0; }
    100% { width: 100%; }
}

@media (max-width: 768px) {
.back-button {
                position: relative;
                top: 0;
                left: 0;
                margin-bottom: 20px;
                display: inline-flex;
            }
    body {
        padding: 20px 10px;
    }
    
    .header {
        padding: 40px 20px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .content {
        padding: 30px 20px;
    }
    
    .benefits-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .target-users {
        padding: 30px 20px;
    }
    
    .upload-section {
        padding: 30px 20px;
    }
    
    .form-input {
        padding: 12px 15px;
        font-size: 0.9rem;
    }
    
    .analyze-btn {
        padding: 15px 30px;
        font-size: 1rem;
    }
    
    .spinner {
        width: 14px;
        height: 14px;
    }
    
    .loading-bar {
        width: 150px;
        height: 15px;
    }
}

@media (max-width: 400px) {
    .header h1 {
        font-size: 1.8rem;
    }
    
    .header p {
        font-size: 1rem;
    }
    
    .target-users h2 {
        font-size: 1.5rem;
    }
    
    .upload-section h2 {
        font-size: 1.5rem;
    }
    
    .form-input {
        padding: 10px 12px;
        font-size: 0.85rem;
    }
    
    .analyze-btn {
        padding: 12px 25px;
        font-size: 0.9rem;
    }
    
    .spinner {
        width: 12px;
        height: 12px;
    }
    
    .loading-bar {
        width: 120px;
        height: 12px;
    }
}