:root {
    --primary-color: #2563eb;
    --primary-hover: #1d4ed8;
    --success-color: #16a34a;
    --error-color: #dc2626;
    --border-color: #e5e7eb;
    --border-radius: 0.5rem;
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --bg-color: #ffffff;
    --text-color: #374151;
    --text-light: #6b7280;
    --bg-light: #f9fafb;
}

[data-theme="dark"] {
    --bg-color: #111827;
    --text-color: #f3f4f6;
    --text-light: #9ca3af;
    --bg-light: #1f2937;
    --border-color: #374151;
}

* {
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
    margin: 0;
    padding: 20px;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

h1 {
    text-align: center;
    color: var(--primary-color);
    margin-bottom: 30px;
    font-size: 2.5rem;
    font-weight: 700;
}

.upload-section {
    background: var(--bg-light);
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    padding: 40px;
    text-align: center;
    margin-bottom: 30px;
    transition: all 0.3s ease;
    cursor: pointer;
}

.upload-section:hover {
    border-color: var(--primary-color);
    background: var(--bg-color);
}

.upload-section.dragover {
    border-color: var(--primary-color);
    background: var(--primary-color);
    background-opacity: 0.1;
    transform: scale(1.02);
}

.upload-icon {
    font-size: 3rem;
    margin-bottom: 15px;
    opacity: 0.6;
}

.upload-text {
    font-size: 1.2rem;
    margin-bottom: 10px;
    font-weight: 500;
}

.upload-subtext {
    color: var(--text-light);
    font-size: 0.9rem;
}

.file-input {
    display: none;
}

.preview-container {
    text-align: center;
    margin: 20px 0;
    padding: 20px;
    background: var(--bg-light);
    border-radius: var(--border-radius);
}

.preview-container.hidden {
    display: none;
}

.preview-img {
    max-width: 200px;
    max-height: 200px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
}

.generate-section {
    text-align: center;
    margin: 30px 0;
}

.generate-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 15px 30px;
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.generate-btn:hover:not(:disabled) {
    background: var(--primary-hover);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.generate-btn:disabled {
    background: #d1d5db;
    cursor: not-allowed;
    transform: none;
}

.error-message {
    background: #fee2e2;
    color: var(--error-color);
    padding: 15px;
    border-radius: var(--border-radius);
    margin: 20px 0;
    border: 1px solid #fecaca;
    text-align: center;
    font-weight: 500;
}

.error-message.hidden {
    display: none;
}

.results-section {
    margin-top: 40px;
}

.results-section.hidden {
    display: none;
}

.download-all-btn {
    background: var(--success-color);
    color: white;
    border: none;
    padding: 12px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: var(--border-radius);
    cursor: pointer;
    margin-bottom: 20px;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.download-all-btn:hover {
    background: #15803d;
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

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

.favicon-item {
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 20px;
    text-align: center;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.favicon-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.favicon-preview {
    width: 64px;
    height: 64px;
    margin: 0 auto 15px;
    display: block;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: white;
    padding: 8px;
}

.favicon-info {
    margin-bottom: 15px;
}

.favicon-name {
    font-weight: 600;
    margin-bottom: 5px;
    font-size: 0.9rem;
}

.favicon-size {
    color: var(--text-light);
    font-size: 0.8rem;
}

.download-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 8px 16px;
    font-size: 0.9rem;
    font-weight: 500;
    border-radius: calc(var(--border-radius) * 0.75);
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.instructions {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 30px;
    margin-top: 40px;
    border: 1px solid var(--border-color);
}

.instructions h2 {
    color: var(--primary-color);
    margin-bottom: 20px;
    font-size: 1.5rem;
}

.instructions ol {
    padding-left: 20px;
}

.instructions li {
    margin-bottom: 10px;
    line-height: 1.6;
}

/* Responsive design */
@media (max-width: 768px) {
    body {
        padding: 10px;
    }
    
    .container {
        padding: 10px;
    }
    
    h1 {
        font-size: 2rem;
    }
    
    .upload-section {
        padding: 20px;
    }
    
    .favicon-grid {
        grid-template-columns: 1fr;
    }
    
    .instructions {
        padding: 20px;
    }
}

/* Animation for loading state */
@keyframes pulse {
    0%, 100% {
        opacity: 1;
    }
    50% {
        opacity: 0.6;
    }
}

.generate-btn:disabled {
    animation: pulse 1.5s ease-in-out infinite;
}

/* Dark mode toggle (if needed) */
.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--bg-light);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    transition: all 0.3s ease;
    box-shadow: var(--shadow-sm);
}

.theme-toggle:hover {
    transform: scale(1.1);
    box-shadow: var(--shadow-md);
}