:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4cc9f0;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #4bb543;
    --warning-color: #fca311;
    --danger-color: #e63946;
    --gray-color: #6c757d;
    --light-gray: #e9ecef;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Poppins', sans-serif;
}

body {
    background-color: #f5f7ff;
    color: var(--dark-color);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

header {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

header h1 i {
    margin-right: 15px;
}

header p {
    font-size: 1.1rem;
    color: var(--gray-color);
}

.converter-box {
    background-color: white;
    border-radius: 15px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    padding: 30px;
    margin-bottom: 40px;
}

.upload-area {
    border: 2px dashed var(--light-gray);
    border-radius: 10px;
    padding: 40px 20px;
    text-align: center;
    transition: all 0.3s ease;
    margin-bottom: 30px;
    position: relative;
}

.upload-area i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.upload-area h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--dark-color);
}

.upload-area p {
    color: var(--gray-color);
    margin: 10px 0;
}

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

.file-info {
    margin-top: 20px;
    font-size: 0.9rem;
    color: var(--gray-color);
}

.options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.option-group {
    margin-bottom: 15px;
}

.option-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 500;
    color: var(--dark-color);
}

.option-group input,
.option-group select {
    width: 100%;
    padding: 10px 15px;
    border: 1px solid var(--light-gray);
    border-radius: 8px;
    font-size: 0.9rem;
    transition: all 0.3s;
}

.option-group input:focus,
.option-group select:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.preview-section h3 {
    margin-bottom: 15px;
    font-size: 1.2rem;
    color: var(--dark-color);
}

.image-preview {
    display: flex;
    flex-wrap: wrap;
    gap: 15px;
    margin-bottom: 20px;
    max-height: 300px;
    overflow-y: auto;
    padding: 10px;
}

.preview-item {
    position: relative;
    width: 120px;
    height: 120px;
    border-radius: 8px;
    overflow: hidden;
    box-shadow: 0 3px 10px rgba(0, 0, 0, 0.1);
}

.preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.preview-item .remove-btn {
    position: absolute;
    top: 5px;
    right: 5px;
    background-color: var(--danger-color);
    color: white;
    border: none;
    width: 25px;
    height: 25px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.3s;
}

.preview-item:hover .remove-btn {
    opacity: 1;
}

.action-buttons {
    display: flex;
    gap: 15px;
    margin: 25px 0;
}

.btn {
    padding: 12px 25px;
    border: none;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

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

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

.btn-secondary {
    background-color: white;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

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

.btn-convert {
    background-color: var(--success-color);
    color: white;
    flex: 1;
}

.btn-convert:hover {
    background-color: #3a9e3a;
    transform: translateY(-2px);
}

.btn-convert:disabled {
    background-color: #a0a0a0;
    cursor: not-allowed;
    transform: none;
}

.btn-download {
    background-color: var(--warning-color);
    color: white;
    text-decoration: none;
    padding: 15px 30px;
    font-size: 1.1rem;
}

.btn-download:hover {
    background-color: #e69500;
    transform: translateY(-2px);
}

.progress-container {
    margin: 25px 0;
    background-color: var(--light-gray);
    border-radius: 8px;
    height: 30px;
    position: relative;
}

.progress-bar {
    background-color: var(--primary-color);
    height: 100%;
    border-radius: 8px;
    width: 0%;
    transition: width 0.3s;
}

.progress-text {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: white;
    font-weight: 500;
    font-size: 0.9rem;
}

.download-section {
    text-align: center;
    padding: 20px;
    background-color: rgba(75, 181, 67, 0.1);
    border-radius: 10px;
    margin-top: 20px;
}

.download-section h3 {
    color: var(--success-color);
    margin-bottom: 15px;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.feature-card {
    background-color: white;
    border-radius: 10px;
    padding: 30px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.05);
    text-align: center;
    transition: transform 0.3s;
}

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

.feature-card i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-card h4 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    color: var(--dark-color);
}

.feature-card p {
    color: var(--gray-color);
    font-size: 0.95rem;
}

footer {
    text-align: center;
    padding: 20px;
    color: var(--gray-color);
    font-size: 0.9rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    .options {
        grid-template-columns: 1fr;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    header h1 {
        font-size: 2rem;
    }
}

/* Animations */
@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.fade-in {
    animation: fadeIn 0.5s ease-in-out;
}