/* Main Application Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    line-height: 1.6;
    color: #2c3e50;
    background-color: #f8f9fa;
}

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

/* Header Styles */
header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border-radius: 12px;
    box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
}

header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* Navigation Tabs */
.tabs {
    display: flex;
    background: white;
    border-radius: 12px;
    padding: 8px;
    margin-bottom: 30px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    overflow-x: auto;
}

.tab-button {
    flex: 1;
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: #6c757d;
    cursor: pointer;
    border-radius: 8px;
    font-weight: 500;
    transition: all 0.3s ease;
    white-space: nowrap;
    min-width: 120px;
}

.tab-button:hover {
    background: #f8f9fa;
    color: #495057;
}

.tab-button.active {
    background: #667eea;
    color: white;
    box-shadow: 0 2px 4px rgba(102, 126, 234, 0.3);
}

/* Tab Content */
.tab-content {
    display: none;
    background: white;
    border-radius: 12px;
    padding: 30px;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

.tab-content.active {
    display: block;
}

.tab-content h2 {
    color: #2c3e50;
    margin-bottom: 20px;
    font-size: 1.8rem;
}

/* Button Styles */
.btn-primary, .btn-secondary {
    padding: 12px 24px;
    border: none;
    border-radius: 8px;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 14px;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: #667eea;
    color: white;
}

.btn-primary:hover {
    background: #5a6fd8;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(102, 126, 234, 0.3);
}

.btn-secondary {
    background: #6c757d;
    color: white;
}

.btn-secondary:hover {
    background: #5a6268;
    transform: translateY(-1px);
    box-shadow: 0 4px 8px rgba(108, 117, 125, 0.3);
}

.btn-primary:disabled, .btn-secondary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

/* Utility Classes */
.placeholder {
    text-align: center;
    color: #6c757d;
    font-style: italic;
    padding: 40px 20px;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    header h1 {
        font-size: 2rem;
    }
    
    .tabs {
        flex-direction: column;
        gap: 4px;
    }
    
    .tab-button {
        min-width: auto;
    }
    
    .tab-content {
        padding: 20px;
    }
}