:root {
    --primary-color: #4a90e2;
    --secondary-color: #6c63ff;
    --text-color: #333;
    --light-gray: #f5f7fa;
    --medium-gray: #e4e8ef;
    --dark-gray: #666;
    --success-color: #28a745;
    --border-radius: 8px;
    --box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--light-gray);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    text-align: center;
    margin-bottom: 3rem;
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

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

/* Upload Area */
.upload-container {
    background-color: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

.upload-area {
    border: 2px dashed var(--medium-gray);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    transition: all 0.3s ease;
    min-height: 250px;
    display: flex;
    justify-content: center;
    align-items: center;
    margin-bottom: 2rem;
}

.upload-area.dragover {
    border-color: var(--primary-color);
    background-color: rgba(74, 144, 226, 0.05);
}

.upload-instructions {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.upload-instructions img {
    width: 64px;
    height: 64px;
    margin-bottom: 1rem;
}

.upload-instructions p {
    font-size: 1.1rem;
    color: var(--dark-gray);
}

.upload-instructions p span {
    color: var(--primary-color);
    cursor: pointer;
    font-weight: 600;
}

.preview-container {
    width: 100%;
}

.preview-container img {
    max-width: 100%;
    max-height: 300px;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
}

.image-info {
    background-color: var(--light-gray);
    padding: 1rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
}

/* Conversion Options */
.conversion-options {
    margin-top: 2rem;
}

.format-selection h3, 
.quality-options h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.format-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 2rem;
}

.format-btn {
    padding: 0.75rem 1.5rem;
    background-color: var(--light-gray);
    border: 1px solid var(--medium-gray);
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.format-btn:hover {
    background-color: var(--medium-gray);
}

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

.quality-slider {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.quality-slider input {
    flex: 1;
}

.quality-slider span {
    font-weight: 600;
    min-width: 48px;
    text-align: right;
}

.convert-btn {
    width: 100%;
    padding: 1rem;
    background-color: var(--primary-color);
    color: white;
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

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

.convert-btn:disabled {
    background-color: var(--medium-gray);
    cursor: not-allowed;
}

/* Result Container */
.result-container {
    background-color: #fff;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 2rem;
    margin-bottom: 2rem;
}

.result-container h3 {
    color: var(--success-color);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.result-info {
    background-color: var(--light-gray);
    padding: 1rem;
    border-radius: var(--border-radius);
    margin-bottom: 1.5rem;
    font-size: 0.9rem;
}

.result-actions {
    display: flex;
    gap: 1rem;
}

.download-btn, .new-btn {
    flex: 1;
    padding: 0.75rem;
    border-radius: var(--border-radius);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
    text-align: center;
}

.download-btn {
    background-color: var(--success-color);
    color: white;
    border: none;
}

.download-btn:hover {
    background-color: #218838;
}

.new-btn {
    background-color: white;
    color: var(--text-color);
    border: 1px solid var(--medium-gray);
}

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

/* Footer */
footer {
    margin-top: 4rem;
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
    margin-bottom: 3rem;
}

.feature {
    background-color: #fff;
    border-radius: var(--border-radius);
    padding: 1.5rem;
    box-shadow: var(--box-shadow);
}

.feature h3 {
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.copyright {
    text-align: center;
    color: var(--dark-gray);
    margin-top: 2rem;
    font-size: 0.9rem;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 1rem;
    }
    
    .format-buttons {
        justify-content: center;
    }
    
    .result-actions {
        flex-direction: column;
    }
}