:root {
    --primary-color: #4a6fa5;
    --secondary-color: #6b8cae;
    --accent-color: #ff7e5f;
    --light-color: #f8f9fa;
    --dark-color: #343a40;
    --success-color: #28a745;
    --error-color: #dc3545;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f5f7fa;
    padding: 0;
    margin: 0;
}

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

header {
    text-align: center;
    margin-bottom: 30px;
    padding: 20px 0;
}

header h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 10px;
}

header .subtitle {
    font-size: 1.1rem;
    color: var(--secondary-color);
}

.converter-container {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    padding: 25px;
    margin-bottom: 30px;
}

.error-message {
    background-color: #f8d7da;
    color: var(--error-color);
    padding: 10px 15px;
    border-radius: var(--border-radius);
    margin-bottom: 20px;
    border-left: 4px solid var(--error-color);
}

.input-section, .output-section {
    margin-bottom: 20px;
}

.input-header, .output-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
    flex-wrap: wrap;
    gap: 10px;
}

.input-header h2, .output-header h2 {
    color: var(--primary-color);
    font-size: 1.5rem;
}

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

.file-upload-btn, .sample-btn, .convert-btn, .copy-btn, .download-btn, .toggle-btn {
    padding: 8px 15px;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: var(--transition);
}

.file-upload-btn {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 1px solid #ddd;
}

.file-upload-btn:hover {
    background-color: #e9ecef;
}

.sample-btn {
    background-color: #e9ecef;
    color: var(--dark-color);
}

.sample-btn:hover {
    background-color: #dee2e6;
}

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

.convert-btn:hover {
    background-color: #3a5a8f;
    transform: translateY(-2px);
}

.copy-btn, .download-btn {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 1px solid #ddd;
}

.copy-btn:hover, .download-btn:hover {
    background-color: #e9ecef;
}

.toggle-btn {
    background-color: var(--light-color);
    color: var(--dark-color);
    border: 1px solid #ddd;
}

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

textarea {
    width: 100%;
    min-height: 200px;
    padding: 15px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    font-family: 'Courier New', Courier, monospace;
    font-size: 14px;
    resize: vertical;
    transition: var(--transition);
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 2px rgba(74, 111, 165, 0.2);
}

.controls {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 20px 0;
    flex-wrap: wrap;
    gap: 15px;
}

.view-toggle {
    display: flex;
    gap: 5px;
}

.output-content {
    width: 100%;
    min-height: 200px;
    padding: 20px;
    border: 1px solid #ddd;
    border-radius: var(--border-radius);
    background-color: white;
    overflow: auto;
}

.output-content.preview {
    background-color: white;
}

.output-content.html {
    background-color: #f8f9fa;
    font-family: 'Courier New', Courier, monospace;
    white-space: pre-wrap;
}

.placeholder {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: #6c757d;
    text-align: center;
    padding: 40px 0;
}

.placeholder i {
    font-size: 2rem;
    margin-bottom: 15px;
    color: var(--secondary-color);
}

.features {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.feature-card {
    background-color: white;
    padding: 25px;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
    text-align: center;
    transition: var(--transition);
}

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

.feature-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 15px;
}

.feature-card h3 {
    margin-bottom: 10px;
    color: var(--primary-color);
}

footer {
    text-align: center;
    padding: 20px 0;
    color: var(--secondary-color);
    font-size: 0.9rem;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    header h1 {
        font-size: 2rem;
    }
    
    .controls {
        flex-direction: column;
        align-items: stretch;
    }
    
    .view-toggle {
        justify-content: center;
    }
}

/* Syntax highlighting for code blocks */
pre {
    background-color: #f8f8f8;
    padding: 15px;
    border-radius: 4px;
    overflow-x: auto;
}

code {
    font-family: 'Courier New', Courier, monospace;
    font-size: 0.9em;
    color: #333;
}

blockquote {
    border-left: 4px solid var(--primary-color);
    padding-left: 15px;
    margin-left: 0;
    color: #555;
    font-style: italic;
}

img {
    max-width: 100%;
    height: auto;
}