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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    backdrop-filter: blur(10px);
}

.header {
    background: linear-gradient(135deg, #4f46e5, #7c3aed);
    color: white;
    padding: 30px;
    text-align: center;
    position: relative;
}

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

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

.breadcrumb {
    background: #f8fafc;
    padding: 15px 30px;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    align-items: center;
    gap: 10px;
}

.breadcrumb-item {
    color: #64748b;
    text-decoration: none;
    padding: 5px 10px;
    border-radius: 6px;
    transition: all 0.2s;
}

.breadcrumb-item:hover {
    background: #e2e8f0;
    color: #475569;
}

.breadcrumb-item.active {
    color: #4f46e5;
    font-weight: 600;
}

.breadcrumb-separator {
    color: #cbd5e1;
}

.navigation {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
    padding: 30px;
}

.folder-card {
    background: white;
    border-radius: 15px;
    padding: 25px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.folder-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #4f46e5, #7c3aed);
    transform: scaleX(0);
    transition: transform 0.3s ease;
}

.folder-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.15);
    border-color: #e0e7ff;
}

.folder-card:hover::before {
    transform: scaleX(1);
}

.folder-icon {
    font-size: 3rem;
    margin-bottom: 15px;
    display: block;
}

.folder-card h3 {
    color: #1e293b;
    font-size: 1.5rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.folder-card p {
    color: #64748b;
    line-height: 1.5;
}

.content {
    min-height: 70vh;
}

.iframe-container {
    position: relative;
    width: 100%;
    height: 80vh;
    min-height: 600px;
    display: none;
}

#driveFrame {
    width: 100%;
    height: 100%;
    border: none;
    background: white;
}

.loading {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
    z-index: 10;
}

.spinner {
    width: 50px;
    height: 50px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid #4f46e5;
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 0 auto 20px;
}

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

.back-button {
    position: absolute;
    left: 30px;
    top: 50%;
    transform: translateY(-50%);
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    color: white;
    padding: 10px 20px;
    border-radius: 25px;
    cursor: pointer;
    transition: all 0.3s;
    backdrop-filter: blur(10px);
}

.back-button:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-50%) translateX(-2px);
}

.error-message {
    background: #fee2e2;
    border: 1px solid #fecaca;
    color: #dc2626;
    padding: 20px;
    margin: 20px;
    border-radius: 10px;
    text-align: center;
}

@media (max-width: 768px) {
    .navigation {
        grid-template-columns: 1fr;
        padding: 20px;
    }
    
    .header h1 {
        font-size: 2rem;
    }
    
    .back-button {
        position: static;
        transform: none;
        margin-bottom: 15px;
        display: inline-block;
    }
}