:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --text-color: #333;
    --light-gray: #f5f6fa;
    --border-color: #dcdde1;
    --background-color: #f5f6fa;
    --card-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --hover-shadow: 0 6px 12px rgba(0, 0, 0, 0.15);
    --border-radius: 8px;
    --transition: all 0.3s ease;
    --success-color: #2ecc71;
    --warning-color: #f1c40f;
    --error-color: #e74c3c;
}

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

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

header {
    background-color: var(--primary-color);
    padding: 1rem 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.logo {
    color: white;
    text-decoration: none;
    font-size: 1.5rem;
    font-weight: bold;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.logo i {
    font-size: 1.8rem;
}

.nav-links {
    display: flex;
    gap: 1.5rem;
}

.nav-links a {
    color: white;
    text-decoration: none;
    font-weight: 500;
    transition: color 0.3s;
}

.nav-links a:hover {
    color: var(--secondary-color);
}

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

.hero {
    text-align: center;
    padding: 4rem 0;
    background-color: var(--light-gray);
    border-radius: 10px;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.hero p {
    font-size: 1.2rem;
    color: #666;
}

.tools-section {
    margin-bottom: 4rem;
}

.tools-section h2 {
    color: var(--primary-color);
    margin-bottom: 2rem;
    text-align: center;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.tool-card {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    text-align: center;
    text-decoration: none;
    color: var(--text-color);
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s, box-shadow 0.3s;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.tool-card i {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

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

.tool-card p {
    color: #666;
    margin-bottom: 1rem;
}

.search-count {
    display: block;
    font-size: 0.9rem;
    color: #666;
    margin-bottom: 0.5rem;
}

.feature-tag {
    display: inline-block;
    background-color: var(--light-gray);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    color: var(--primary-color);
    margin: 0.2rem;
}

.converter-box {
    background: white;
    border: 2px dashed var(--primary-color);
    border-radius: var(--border-radius);
    padding: 2rem;
    text-align: center;
    margin: 2rem 0;
    cursor: pointer;
    transition: var(--transition);
}

.converter-box:hover {
    background: #f8f9fa;
}

.converter-box i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.features {
    margin: 3rem 0;
}

.features h2 {
    text-align: center;
    margin-bottom: 2rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.feature-card {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    text-align: center;
}

.feature-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.related-tools {
    margin: 3rem 0;
}

.related-tools h2 {
    text-align: center;
    margin-bottom: 2rem;
}

.related-tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
}

.related-tool-card {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    text-decoration: none;
    color: var(--text-color);
    transition: var(--transition);
}

.related-tool-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--hover-shadow);
}

.faq {
    margin: 3rem 0;
}

.faq h2 {
    text-align: center;
    margin-bottom: 2rem;
}

.faq-item {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 1rem;
    box-shadow: var(--card-shadow);
}

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

footer {
    background-color: var(--primary-color);
    color: white;
    padding: 3rem 2rem 1rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h3 {
    margin-bottom: 1rem;
    font-size: 1.2rem;
}

.footer-section a {
    display: block;
    color: #bdc3c7;
    text-decoration: none;
    margin-bottom: 0.5rem;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
}

@media (max-width: 768px) {
    .mobile-menu-btn {
        display: block;
    }

    .nav-links {
        display: none;
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: white;
        padding: 1rem;
        box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
        flex-direction: column;
        align-items: center;
        gap: 1rem;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-links a {
        width: 100%;
        text-align: center;
        padding: 0.5rem;
        border-radius: var(--border-radius);
    }

    .nav-links a:hover {
        background: var(--background-color);
    }

    .hero h1 {
        font-size: 2rem;
    }
    
    .tools-grid {
        grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    }

    .contact-content {
        grid-template-columns: 1fr;
    }
    
    .contact-info {
        padding-right: 0;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
        padding-bottom: 2rem;
    }
    
    .contact-form {
        padding-left: 0;
        padding-top: 2rem;
    }
}

.progress-container {
    width: 100%;
    background-color: #f0f0f0;
    border-radius: 10px;
    margin: 1rem 0;
    overflow: hidden;
    position: relative;
}

.progress-bar {
    width: 0;
    height: 10px;
    background: linear-gradient(90deg, var(--primary-color), var(--success-color));
    transition: width 0.3s ease;
}

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

.tool-header {
    text-align: center;
    margin-bottom: 2rem;
}

.tool-header h1 {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
}

.tool-header p {
    font-size: 1.2rem;
    color: #666;
}

/* Mobile Navigation */
.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    color: var(--primary-color);
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

/* Preview Section */
.preview-section {
    display: none;
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    margin: 2rem 0;
}

.preview-section.active {
    display: block;
}

.preview-container {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin: 2rem 0;
}

.preview-box {
    background: var(--background-color);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    border: 1px solid #eee;
}

.preview-box h3 {
    margin-bottom: 1rem;
    color: var(--secondary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.preview-box h3 i {
    color: var(--primary-color);
}

.preview-content {
    min-height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: white;
    border-radius: var(--border-radius);
    padding: 1rem;
    border: 1px dashed #ddd;
}

.file-preview, .pdf-preview, .excel-preview, .csv-preview {
    text-align: center;
    padding: 1rem;
}

.file-preview i, .pdf-preview i, .excel-preview i, .csv-preview i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.file-preview p, .pdf-preview p, .excel-preview p, .csv-preview p {
    margin-bottom: 0.5rem;
    word-break: break-all;
}

.file-meta {
    font-size: 0.9rem;
    color: #666;
}

.download-section {
    text-align: center;
    margin-top: 2rem;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    font-weight: 500;
    transition: var(--transition);
    text-decoration: none;
    border: none;
    cursor: pointer;
    background: var(--success-color);
    color: white;
}

.download-btn:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.download-btn:not(:disabled):hover {
    transform: translateY(-2px);
    box-shadow: var(--hover-shadow);
}

.download-btn i {
    font-size: 1.2rem;
}

@media (max-width: 768px) {
    .preview-container {
        grid-template-columns: 1fr;
    }
}

/* Status Messages */
.status-message {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 1rem;
    border-radius: var(--border-radius);
    margin: 1rem 0;
    font-weight: 500;
}

.status-message.success {
    background: rgba(46, 204, 113, 0.1);
    color: var(--success-color);
}

.status-message.error {
    background: rgba(231, 76, 60, 0.1);
    color: var(--error-color);
}

.status-message i {
    font-size: 1.2rem;
}

/* File Info */
.file-info {
    display: none;
    margin: 1rem 0;
    padding: 1rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
}

.file-info.active {
    display: block;
}

.file-info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1rem;
}

.file-info-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.file-info-item i {
    color: var(--primary-color);
}

/* Loading Animation */
.loading-spinner {
    display: none;
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 1rem auto;
}

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

/* Conversion Options */
.conversion-options {
    background: white;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    margin: 2rem 0;
}

.conversion-options h3 {
    margin-bottom: 1rem;
    color: var(--secondary-color);
}

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

.option-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.option-item label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
}

.option-item input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

/* Batch Files */
.batch-files {
    background: white;
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: var(--card-shadow);
    margin: 2rem 0;
}

.batch-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    padding-bottom: 1rem;
    border-bottom: 1px solid #eee;
}

.batch-header h3 {
    font-size: 1.2rem;
    color: var(--secondary-color);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.clear-all-btn {
    background: none;
    border: none;
    color: var(--error-color);
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1rem;
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-weight: 500;
}

.clear-all-btn:hover {
    background: rgba(231, 76, 60, 0.1);
}

.files-list {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.file-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem;
    background: var(--background-color);
    border-radius: var(--border-radius);
    transition: var(--transition);
    border: 1px solid #eee;
}

.file-item:hover {
    background: #f8f9fa;
    border-color: var(--primary-color);
}

.file-item-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.file-item-info i {
    color: var(--primary-color);
    font-size: 1.2rem;
}

.file-item-details {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
}

.file-name {
    font-weight: 500;
    color: var(--secondary-color);
}

.file-meta {
    font-size: 0.9rem;
    color: #666;
}

.remove-file {
    background: none;
    border: none;
    color: var(--error-color);
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    transition: var(--transition);
    display: flex;
    align-items: center;
    justify-content: center;
}

.remove-file:hover {
    background: rgba(231, 76, 60, 0.1);
}

/* Preview Thumbnails */
.preview-thumbnails {
    display: flex;
    gap: 0.5rem;
    margin-top: 1rem;
    overflow-x: auto;
    padding: 0.5rem;
    scrollbar-width: thin;
    scrollbar-color: var(--primary-color) transparent;
}

.preview-thumbnails::-webkit-scrollbar {
    height: 6px;
}

.preview-thumbnails::-webkit-scrollbar-track {
    background: transparent;
}

.preview-thumbnails::-webkit-scrollbar-thumb {
    background-color: var(--primary-color);
    border-radius: 3px;
}

.thumbnail {
    flex: 0 0 auto;
    width: 100px;
    height: 140px;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--card-shadow);
    cursor: pointer;
    transition: var(--transition);
}

.thumbnail:hover {
    transform: scale(1.05);
}

.thumbnail canvas {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

/* Mobile Enhancements */
@media (max-width: 768px) {
    .conversion-options {
        padding: 1rem;
    }

    .options-grid {
        grid-template-columns: 1fr;
    }

    .preview-container {
        flex-direction: column;
    }

    .preview-box {
        width: 100%;
    }

    .preview-thumbnails {
        justify-content: flex-start;
    }

    .thumbnail {
        width: 80px;
        height: 112px;
    }

    .download-section {
        display: flex;
        flex-direction: column;
        gap: 1rem;
    }

    .download-all-btn {
        margin-left: 0;
    }

    .file-item {
        flex-direction: column;
        align-items: flex-start;
        gap: 0.5rem;
    }

    .file-item-actions {
        align-self: flex-end;
    }
}

/* Touch Interactions */
@media (hover: none) {
    .tool-card:hover {
        transform: none;
    }

    .tool-card:active {
        transform: scale(0.98);
    }

    .download-btn:active,
    .download-all-btn:active {
        transform: scale(0.98);
    }
}

/* Dragover State */
.converter-box.dragover {
    background: rgba(74, 144, 226, 0.1);
    border-color: var(--primary-color);
    transform: scale(1.02);
}

/* Loading States */
.loading-spinner {
    display: none;
    width: 40px;
    height: 40px;
    border: 4px solid #f3f3f3;
    border-top: 4px solid var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
    margin: 1rem auto;
}

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

/* Sub-text */
.sub-text {
    font-size: 0.9rem;
    color: #666;
    margin-top: 0.5rem;
}

/* Feature Tags */
.tool-features {
    display: flex;
    gap: 0.5rem;
    margin-top: 0.5rem;
    flex-wrap: wrap;
}

.feature-tag {
    background: rgba(74, 144, 226, 0.1);
    color: var(--primary-color);
    padding: 0.25rem 0.5rem;
    border-radius: 12px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Active Navigation */
.nav-links a.active {
    color: var(--primary-color);
    font-weight: 600;
}

/* About Page */
.about-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.about-content {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.about-section {
    margin-bottom: 2rem;
}

.about-section h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.about-section ul {
    list-style-position: inside;
    margin-left: 1rem;
}

/* Contact Page */
.contact-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 2fr;
    gap: 2rem;
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.contact-info {
    padding-right: 2rem;
    border-right: 1px solid var(--border-color);
}

.contact-details {
    margin-top: 2rem;
}

.contact-item {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.contact-item i {
    color: var(--secondary-color);
}

.contact-form {
    padding-left: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    margin-bottom: 0.5rem;
    color: var(--primary-color);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid var(--border-color);
    border-radius: 5px;
    font-size: 1rem;
}

.submit-btn {
    background-color: var(--secondary-color);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: 5px;
    cursor: pointer;
    font-size: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: background-color 0.3s;
}

.submit-btn:hover {
    background-color: #2980b9;
}

/* Privacy Policy Page */
.privacy-container {
    max-width: 800px;
    margin: 0 auto;
    padding: 2rem;
}

.privacy-content {
    background: white;
    border-radius: 10px;
    padding: 2rem;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

.privacy-section {
    margin-bottom: 2rem;
}

.privacy-section h2 {
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.privacy-section ul {
    list-style-position: inside;
    margin-left: 1rem;
}

/* Tool Sections */
.tool-section {
    margin-bottom: 4rem;
    padding: 2rem;
    border-radius: 12px;
    background-color: white;
    box-shadow: var(--card-shadow);
    max-width: 1200px;
    margin-left: auto;
    margin-right: auto;
}

.tool-section h2 {
    font-size: 1.8rem;
    margin-bottom: 2rem;
    color: var(--secondary-color);
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 1rem;
    text-align: center;
}

.tool-section h2 i {
    margin-right: 0.5rem;
    color: var(--primary-color);
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
    padding: 1rem;
}

.tool-card {
    background: white;
    padding: 1.5rem;
    border-radius: 8px;
    box-shadow: var(--card-shadow);
    transition: transform 0.3s, box-shadow 0.3s;
    border: 1px solid #eee;
    text-decoration: none;
    color: var(--text-color);
    display: block;
}

.tool-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.1);
}

.tool-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
    display: block;
    text-align: center;
}

.tool-card h3 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: var(--secondary-color);
    text-align: center;
}

.tool-card p {
    color: #666;
    margin-bottom: 1rem;
    font-size: 0.9rem;
    text-align: center;
}

.tool-features {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    flex-wrap: wrap;
}

.tool-features span {
    background-color: #f0f4f8;
    color: var(--primary-color);
    padding: 0.3rem 0.8rem;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 500;
}

/* Tool Container */
.tool-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

.tool-container h1 {
    font-size: 2.5rem;
    color: var(--secondary-color);
    margin-bottom: 1rem;
    text-align: center;
}

.tool-container h1 i {
    margin-right: 0.5rem;
    color: var(--primary-color);
}

.tool-description {
    text-align: center;
    color: #666;
    font-size: 1.2rem;
    margin-bottom: 2rem;
}

/* Conversion Box */
.conversion-box {
    background: white;
    border-radius: 12px;
    padding: 2rem;
    box-shadow: var(--card-shadow);
    margin-bottom: 2rem;
}

.upload-section {
    margin-bottom: 2rem;
}

.drop-zone {
    border: 2px dashed var(--primary-color);
    border-radius: 8px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: background-color 0.3s;
}

.drop-zone:hover {
    background-color: #f8f9fa;
}

.drop-zone i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}

.drop-zone p {
    color: #666;
    margin: 0.5rem 0;
}

.upload-btn {
    background-color: var(--primary-color);
    color: white;
    border: none;
    padding: 0.8rem 1.5rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s;
}

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

.file-info {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: #f8f9fa;
    padding: 1rem;
    border-radius: 8px;
    margin-top: 1rem;
}

.file-details {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.file-details i {
    font-size: 2rem;
    color: var(--primary-color);
}

.remove-btn {
    background: none;
    border: none;
    color: #666;
    cursor: pointer;
    font-size: 1.2rem;
    transition: color 0.3s;
}

.remove-btn:hover {
    color: var(--error-color);
}