:root {
    --primary-color: #0d6efd;
    --secondary-color: #6c757d;
    --success-color: #198754;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #0dcaf0;
    --light-color: #f8f9fa;
    --dark-color: #212529;
}

/* Dark theme variables */
[data-bs-theme="dark"] {
    --bs-body-bg: #1a1a1a;
    --bs-body-color: #e9ecef;
    --bs-border-color: #495057;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    transition: all 0.3s ease;
}

/* Custom navbar styling */
.navbar-brand {
    font-size: 1.5rem;
    font-weight: bold;
}

/* Drop zone styling */
.drop-zone {
    transition: all 0.3s ease;
    cursor: pointer;
    background: linear-gradient(45deg, #f8f9fa, #e9ecef);
}

.drop-zone:hover {
    border-color: var(--primary-color) !important;
    background: linear-gradient(45deg, #e3f2fd, #bbdefb);
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(13, 110, 253, 0.2);
}

.drop-zone.dragover {
    border-color: var(--success-color) !important;
    background: linear-gradient(45deg, #e8f5e8, #c8e6c9);
    transform: scale(1.02);
}

[data-bs-theme="dark"] .drop-zone {
    background: linear-gradient(45deg, #2d3238, #343a40);
    border-color: #495057 !important;
}

[data-bs-theme="dark"] .drop-zone:hover {
    background: linear-gradient(45deg, #1e3a5f, #2c5aa0);
    border-color: var(--primary-color) !important;
}

/* File item styling */
.file-item {
    border: 1px solid #dee2e6;
    border-radius: 8px;
    transition: all 0.3s ease;
    background: white;
}

[data-bs-theme="dark"] .file-item {
    border-color: #495057;
    background: #2d3238;
}

.file-item:hover {
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
    transform: translateY(-1px);
}

/* Preview image styling */
.preview-image {
    max-width: 60px;
    max-height: 60px;
    object-fit: cover;
    border-radius: 4px;
    border: 1px solid #dee2e6;
}

/* Progress bar animations */
.progress-bar {
    transition: width 0.6s ease;
}

/* Status badges */
.status-badge {
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
}

/* Conversion type selector */
.conversion-selector {
    background: #f8f9fa;
    border: 1px solid #dee2e6;
    border-radius: 6px;
    padding: 0.5rem;
}

[data-bs-theme="dark"] .conversion-selector {
    background: #2d3238;
    border-color: #495057;
}

/* Download button animations */
.download-btn {
    transition: all 0.3s ease;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(25, 135, 84, 0.3);
}

/* File type icons */
.file-type-icon {
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 6px;
    font-size: 1.2rem;
}

.file-type-doc {
    background: linear-gradient(135deg, #2b579a, #1e4a8c);
    color: white;
}

.file-type-pdf {
    background: linear-gradient(135deg, #d32f2f, #b71c1c);
    color: white;
}

.file-type-image {
    background: linear-gradient(135deg, #388e3c, #2e7d32);
    color: white;
}

/* Theme toggle button */
#themeToggle {
    transition: all 0.3s ease;
}

#themeToggle:hover {
    transform: scale(1.1);
}

/* Card hover effects */
.card {
    transition: all 0.3s ease;
    border: none;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

.card:hover {
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.15);
    transform: translateY(-2px);
}

/* Alert styling */
.alert {
    border: none;
    border-radius: 8px;
}

/* Loading animation */
.loading-spinner {
    width: 20px;
    height: 20px;
    border: 2px solid #f3f3f3;
    border-top: 2px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

/* Responsive design */
@media (max-width: 768px) {
    .display-4 {
        font-size: 2rem;
    }
    
    .drop-zone {
        padding: 2rem 1rem !important;
    }
    
    .file-item {
        margin-bottom: 1rem;
    }
}

/* Smooth transitions for theme switching */
* {
    transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease;
}

/* Custom scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}

[data-bs-theme="dark"] ::-webkit-scrollbar-track {
    background: #2d3238;
}

[data-bs-theme="dark"] ::-webkit-scrollbar-thumb {
    background: #495057;
}

[data-bs-theme="dark"] ::-webkit-scrollbar-thumb:hover {
    background: #6c757d;
}