/* Enhanced CSS with all new features */
:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --success-color: #48bb78;
    --danger-color: #f56565;
    --warning-color: #ed8936;
    --info-color: #4299e1;
    --dark-color: #2d3748;
    --light-color: #f7fafc;
    --text-color: #4a5568;
    --border-color: #e2e8f0;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] {
    --primary-color: #7c93e0;
    --secondary-color: #8a6bbd;
    --dark-color: #f7fafc;
    --light-color: #2d3748;
    --text-color: #e2e8f0;
    --border-color: #4a5568;
    --shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    transition: background-color 0.3s, color 0.3s;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
    min-height: 100vh;
    color: var(--text-color);
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
}

/* Header Styles */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 15px;
    padding: 20px;
    margin-bottom: 20px;
    box-shadow: var(--shadow);
}

[data-theme="dark"] .header {
    background: rgba(45, 55, 72, 0.95);
}

.header-top {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 20px;
}

.logo-section {
    display: flex;
    align-items: center;
    gap: 15px;
}

.home-btn {
    display: flex;
    align-items: center;
    gap: 15px;
    text-decoration: none;
    color: var(--dark-color);
    font-size: 1.5rem;
    font-weight: bold;
}

.logo {
    width: 50px;
    height: 50px;
    border-radius: 10px;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.user-menu, .auth-buttons {
    display: flex;
    align-items: center;
    gap: 10px;
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 5px;
    border-radius: 50%;
}

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

/* Navigation */
.nav {
    display: flex;
    gap: 10px;
    margin-top: 15px;
    flex-wrap: wrap;
}

.nav-link {
    background: var(--light-color);
    padding: 10px 20px;
    border-radius: 25px;
    text-decoration: none;
    color: var(--text-color);
    font-weight: 600;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.nav-link:hover, .nav-link.active {
    background: var(--primary-color);
    color: white;
    transform: translateY(-2px);
}

/* Stats Banner */
.stats-banner {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 30px;
}

.stat-card {
    background: rgba(255, 255, 255, 0.95);
    padding: 20px;
    border-radius: 10px;
    display: flex;
    align-items: center;
    gap: 15px;
    box-shadow: var(--shadow);
}

[data-theme="dark"] .stat-card {
    background: rgba(45, 55, 72, 0.95);
}

.stat-icon {
    font-size: 2rem;
}

.stat-number {
    font-size: 1.5rem;
    font-weight: bold;
    color: var(--dark-color);
}

.stat-label {
    font-size: 0.9rem;
    color: var(--text-color);
}

.storage-bar {
    width: 100%;
    height: 5px;
    background: var(--border-color);
    border-radius: 3px;
    margin-top: 5px;
    overflow: hidden;
}

.storage-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--success-color), var(--primary-color));
    transition: width 0.3s ease;
}

/* Upload Section */
.upload-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 40px;
    margin-bottom: 30px;
    box-shadow: var(--shadow);
}

[data-theme="dark"] .upload-section {
    background: rgba(45, 55, 72, 0.95);
}

.upload-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    margin-top: 30px;
}

.upload-card {
    background: var(--light-color);
    padding: 30px 20px;
    border-radius: 10px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.upload-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

.upload-card .upload-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

/* Modal Styles */
.modal {
    display: none;
    position: fixed;
    z-index: 1000;
    left: 0;
    top: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0,0,0,0.5);
    backdrop-filter: blur(5px);
}

.modal-content {
    background-color: var(--light-color);
    margin: 5% auto;
    padding: 0;
    border-radius: 15px;
    width: 90%;
    max-width: 600px;
    max-height: 80vh;
    overflow-y: auto;
    box-shadow: var(--shadow-lg);
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px;
    border-bottom: 1px solid var(--border-color);
}

.modal-header h3 {
    margin: 0;
    color: var(--dark-color);
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-color);
}

.close-btn:hover {
    color: var(--danger-color);
}

.modal-body {
    padding: 20px;
}

/* Upload Area */
.upload-area {
    border: 3px dashed var(--border-color);
    border-radius: 12px;
    padding: 60px 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--light-color);
    text-align: center;
}

.upload-area:hover, .upload-area.dragover {
    border-color: var(--primary-color);
    background: rgba(102, 126, 234, 0.05);
}

.upload-content .upload-icon {
    font-size: 3rem;
    margin-bottom: 15px;
}

.upload-content p {
    font-size: 1.2rem;
    margin-bottom: 10px;
    color: var(--text-color);
}

.file-info {
    font-size: 0.9rem;
    color: var(--text-color);
    margin-top: 10px;
}

/* Progress Bar */
.upload-progress {
    margin-top: 20px;
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border-color);
    border-radius: 4px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    width: 0%;
    transition: width 0.3s ease;
}

.progress-text {
    display: block;
    margin-top: 10px;
    font-weight: bold;
    color: var(--text-color);
}

/* File Cards */
.files-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.file-card {
    background: var(--light-color);
    border-radius: 10px;
    padding: 20px;
    box-shadow: var(--shadow);
    transition: all 0.3s ease;
    border-left: 4px solid var(--primary-color);
}

.file-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
}

.file-header {
    display: flex;
    align-items: center;
    gap: 15px;
    margin-bottom: 15px;
}

.file-icon {
    font-size: 2rem;
}

.file-info {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-weight: bold;
    color: var(--dark-color);
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.file-size {
    font-size: 0.8rem;
    color: var(--text-color);
    margin-top: 5px;
}

.file-meta {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin: 15px 0;
}

.meta-item {
    display: flex;
    justify-content: space-between;
    font-size: 0.85rem;
}

.expiry-soon {
    color: var(--danger-color);
    font-weight: bold;
}

.expiry-normal {
    color: var(--success-color);
}

.file-description {
    background: rgba(0,0,0,0.05);
    padding: 10px;
    border-radius: 5px;
    margin: 10px 0;
    font-size: 0.9rem;
}

.file-actions {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    margin-top: 15px;
}

/* Button Styles */
.btn-primary, .btn-secondary, .btn-success, .btn-danger, .btn-warning {
    padding: 10px 20px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-weight: 600;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-block;
    text-align: center;
}

.btn-primary {
    background: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background: #5a6fd8;
    transform: translateY(-2px);
}

.btn-secondary {
    background: var(--border-color);
    color: var(--text-color);
}

.btn-secondary:hover {
    background: #cbd5e0;
}

.btn-success {
    background: var(--success-color);
    color: white;
}

.btn-danger {
    background: var(--danger-color);
    color: white;
}

.btn-warning {
    background: var(--warning-color);
    color: white;
}

/* Small action buttons */
.btn-copy, .btn-qr, .btn-share, .btn-delete {
    padding: 8px 12px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
    font-size: 0.8rem;
    transition: all 0.3s ease;
}

.btn-copy {
    background: var(--info-color);
    color: white;
}

.btn-qr {
    background: var(--warning-color);
    color: white;
}

.btn-share {
    background: var(--success-color);
    color: white;
}

.btn-delete {
    background: var(--danger-color);
    color: white;
}

/* Features Section */
.features-section, .api-section {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 15px;
    padding: 40px;
    margin: 30px 0;
}

[data-theme="dark"] .features-section,
[data-theme="dark"] .api-section {
    background: rgba(45, 55, 72, 0.95);
}

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

.feature-item {
    background: var(--light-color);
    padding: 25px;
    border-radius: 10px;
    text-align: center;
    transition: transform 0.3s ease;
}

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

.feature-item h3 {
    margin: 15px 0 10px;
    color: var(--dark-color);
}

/* Auth Pages */
.auth-container {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
}

.auth-card {
    background: rgba(255, 255, 255, 0.95);
    padding: 40px;
    border-radius: 15px;
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 400px;
}

[data-theme="dark"] .auth-card {
    background: rgba(45, 55, 72, 0.95);
}

.auth-card h2 {
    text-align: center;
    margin-bottom: 30px;
    color: var(--dark-color);
}

.auth-card input {
    width: 100%;
    padding: 12px 15px;
    margin-bottom: 15px;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    background: var(--light-color);
    color: var(--text-color);
}

.auth-card input:focus {
    outline: none;
    border-color: var(--primary-color);
}

/* Alert Styles */
.alert {
    padding: 12px 15px;
    border-radius: 5px;
    margin-bottom: 20px;
    font-weight: 500;
}

.alert.success {
    background: #c6f6d5;
    color: #22543d;
    border: 1px solid #9ae6b4;
}

.alert.error {
    background: #fed7d7;
    color: #742a2a;
    border: 1px solid #feb2b2;
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 60px 20px;
    color: var(--text-color);
}

.empty-icon {
    font-size: 4rem;
    margin-bottom: 20px;
    opacity: 0.5;
}

/* API Examples */
.api-examples {
    background: var(--dark-color);
    color: var(--light-color);
    padding: 20px;
    border-radius: 5px;
    margin: 20px 0;
    overflow-x: auto;
}

.api-examples code {
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

/* Responsive Design */
@media (max-width: 768px) {
    .container {
        padding: 10px;
    }
    
    .header-top {
        flex-direction: column;
        text-align: center;
    }
    
    .upload-options {
        grid-template-columns: 1fr;
    }
    
    .files-grid {
        grid-template-columns: 1fr;
    }
    
    .file-actions {
        grid-template-columns: 1fr;
    }
    
    .stats-banner {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .modal-content {
        width: 95%;
        margin: 10% auto;
    }
    
    .nav {
        justify-content: center;
    }
}

@media (max-width: 480px) {
    .stats-banner {
        grid-template-columns: 1fr;
    }
    
    .upload-section {
        padding: 20px;
    }
    
    .file-header {
        flex-direction: column;
        text-align: center;
    }
}