:root {
    --primary-color: #4361ee;
    --secondary-color: #3a0ca3;
    --accent-color: #4cc9f0;
    --bg-color: #0a0a0a;
    --surface-color: #1a1a1a;
    --text-color: #f8f9fa;
    --text-secondary: #adb5bd;
    --success-color: #4ade80;
    --danger-color: #f87171;
    --border-color: #2d2d2d;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.3);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

[data-theme="light"] {
    --bg-color: #f8f9fa;
    --surface-color: #ffffff;
    --text-color: #212529;
    --text-secondary: #6c757d;
    --border-color: #dee2e6;
    --shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    min-height: 100vh;
    transition: var(--transition);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Header */
header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    margin-bottom: 30px;
}

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

.logo i {
    font-size: 2.5rem;
    color: var(--accent-color);
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

.logo h1 {
    font-size: 2rem;
    background: linear-gradient(135deg, var(--primary-color), var(--accent-color));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
}

.header-controls {
    display: flex;
    gap: 10px;
}

/* Buttons */
.btn-icon {
    background: var(--surface-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    width: 45px;
    height: 45px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: var(--transition);
    font-size: 1.2rem;
}

.btn-icon:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    border: none;
    padding: 15px 30px;
    border-radius: var(--border-radius);
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 10px;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 40px rgba(67, 97, 238, 0.3);
}

.btn-secondary {
    background: var(--surface-color);
    color: var(--text-color);
    border: 1px solid var(--border-color);
    padding: 10px 20px;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
}

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

/* Upload Area */
.upload-area {
    background: var(--surface-color);
    border: 3px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 60px 30px;
    text-align: center;
    margin-bottom: 40px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.upload-area.drag-over {
    border-color: var(--primary-color);
    background: rgba(67, 97, 238, 0.05);
}

.upload-area:hover {
    border-color: var(--primary-color);
    transform: translateY(-5px);
}

.upload-icon {
    font-size: 4rem;
    color: var(--accent-color);
    margin-bottom: 20px;
}

.upload-area h2 {
    margin-bottom: 10px;
    font-size: 1.8rem;
}

.upload-area p {
    color: var(--text-secondary);
    margin-bottom: 30px;
}

/* Progress Bar */
.upload-progress {
    background: var(--border-color);
    border-radius: 20px;
    height: 10px;
    margin: 20px auto;
    max-width: 400px;
    position: relative;
}

.progress-bar {
    background: linear-gradient(90deg, var(--accent-color), var(--primary-color));
    border-radius: 20px;
    height: 100%;
    width: 0%;
    transition: width 0.3s ease;
}

#progressText {
    position: absolute;
    right: -50px;
    top: -5px;
    font-size: 0.9rem;
    font-weight: 600;
}

/* Files Section */
.files-section {
    flex: 1;
}

.section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

.section-header h2 {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
}

.file-count {
    background: var(--surface-color);
    padding: 8px 16px;
    border-radius: 20px;
    font-size: 0.9rem;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

/* Files Grid */
.files-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-bottom: 40px;
}

.file-card {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    padding: 20px;
    border: 1px solid var(--border-color);
    transition: var(--transition);
    animation: slideUp 0.3s ease;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.file-icon {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 15px;
}

.file-name {
    font-weight: 600;
    margin-bottom: 8px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-meta {
    display: flex;
    justify-content: space-between;
    color: var(--text-secondary);
    font-size: 0.85rem;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--border-color);
}

.file-actions {
    display: flex;
    gap: 10px;
}

.action-btn {
    flex: 1;
    padding: 10px;
    border-radius: 8px;
    border: none;
    font-size: 0.9rem;
    cursor: pointer;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

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

.download-btn:hover {
    background: var(--secondary-color);
}

.delete-btn {
    background: var(--surface-color);
    color: var(--danger-color);
    border: 1px solid var(--border-color);
}

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

/* Empty State */
.empty-state {
    grid-column: 1 / -1;
    text-align: center;
    padding: 60px 20px;
    color: var(--text-secondary);
}

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

.empty-state p {
    font-size: 1.2rem;
    margin-bottom: 10px;
}

/* Footer */
footer {
    text-align: center;
    padding: 20px 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
    margin-top: auto;
}

.socket-status {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    margin-top: 10px;
}

.socket-status .connected {
    color: var(--success-color);
}

.socket-status .disconnected {
    color: var(--danger-color);
}

/* Modal */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    z-index: 1000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-content {
    background: var(--surface-color);
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 400px;
    overflow: hidden;
    animation: modalSlide 0.3s ease;
}

@keyframes modalSlide {
    from {
        opacity: 0;
        transform: translateY(-50px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

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

.modal-body {
    padding: 30px;
    text-align: center;
}

.qr-container {
    background: white;
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 20px;
    display: inline-block;
}

.qr-url {
    word-break: break-all;
    background: var(--bg-color);
    padding: 15px;
    border-radius: 8px;
    margin: 20px 0;
    font-size: 0.9rem;
}

.close-btn {
    background: none;
    border: none;
    font-size: 1.8rem;
    color: var(--text-secondary);
    cursor: pointer;
    line-height: 1;
}

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

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 15px;
    }
    
    .logo h1 {
        font-size: 1.5rem;
    }
    
    .files-grid {
        grid-template-columns: 1fr;
    }
    
    .upload-area {
        padding: 40px 20px;
    }
    
    .upload-area h2 {
        font-size: 1.5rem;
    }
}