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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 20px;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    background: white;
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
    overflow: hidden;
}

.header {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    padding: 40px 30px;
    text-align: center;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    font-weight: 700;
}

.subtitle {
    font-size: 1.1rem;
    opacity: 0.9;
}

.navigation {
    display: flex;
    justify-content: center;
    background: #f8f9fa;
    border-bottom: 2px solid #e9ecef;
    padding: 0 20px;
}

.nav-item {
    display: flex;
    align-items: center;
    padding: 15px 25px;
    cursor: pointer;
    transition: all 0.3s ease;
    border-bottom: 3px solid transparent;
    margin-bottom: -2px;
}

.nav-item:hover {
    background: #e9ecef;
    transform: translateY(-2px);
}

.nav-item.active {
    background: white;
    border-bottom-color: #667eea;
    color: #667eea;
    font-weight: 600;
}

.nav-icon {
    font-size: 1.3rem;
    margin-right: 8px;
}

.nav-text {
    font-size: 1rem;
}

.main-content {
    padding: 40px 30px;
    position: relative;
}

.notification-container {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
    min-width: 300px;
    max-width: 400px;
    animation: slideIn 0.3s ease;
}

.notification-container.notification-success {
    background: #f0fff4;
    border: 2px solid #48bb78;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(72, 187, 120, 0.3);
}

.notification-container.notification-error {
    background: #fff5f5;
    border: 2px solid #f56565;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(245, 101, 101, 0.3);
}

.notification-container.notification-warning {
    background: #fffaf0;
    border: 2px solid #ed8936;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(237, 137, 54, 0.3);
}

.notification-container.notification-info {
    background: #ebf8ff;
    border: 2px solid #4299e1;
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(66, 153, 225, 0.3);
}

.notification-content {
    display: flex;
    align-items: center;
    padding: 15px;
    gap: 10px;
}

.notification-icon {
    font-size: 1.2rem;
    font-weight: bold;
    min-width: 20px;
    text-align: center;
}

.notification-success .notification-icon {
    color: #48bb78;
}

.notification-error .notification-icon {
    color: #f56565;
}

.notification-warning .notification-icon {
    color: #ed8936;
}

.notification-info .notification-icon {
    color: #4299e1;
}

.notification-text {
    flex: 1;
    font-weight: 500;
    color: #2d3748;
}

.notification-close {
    background: transparent;
    border: none;
    color: #718096;
    font-size: 1.5rem;
    cursor: pointer;
    padding: 0;
    width: 24px;
    height: 24px;
    line-height: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 4px;
    transition: all 0.2s ease;
}

.notification-close:hover {
    background: rgba(0, 0, 0, 0.1);
    color: #2d3748;
}

@keyframes slideIn {
    from {
        transform: translateX(100%);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

.loading-overlay {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 999;
    animation: fadeIn 0.3s ease;
}

.loading-container {
    background: white;
    padding: 40px;
    border-radius: 16px;
    text-align: center;
    min-width: 300px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.3);
    animation: scaleIn 0.3s ease;
}

.loading-spinner {
    width: 60px;
    height: 60px;
    margin: 0 auto 20px;
    border: 4px solid #e2e8f0;
    border-top-color: #667eea;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loading-progress {
    font-size: 2rem;
    font-weight: bold;
    color: #667eea;
    margin-bottom: 10px;
}

.loading-message {
    font-size: 1.1rem;
    color: #4a5568;
    font-weight: 500;
}

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

@keyframes scaleIn {
    from {
        transform: scale(0.9);
        opacity: 0;
    }
    to {
        transform: scale(1);
        opacity: 1;
    }
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

.validation-errors {
    background: #fff5f5;
    border: 2px solid #f56565;
    border-radius: 12px;
    padding: 20px;
    margin-bottom: 30px;
    animation: slideDown 0.3s ease;
}

.error-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 15px;
}

.error-icon {
    font-size: 1.5rem;
    color: #f56565;
}

.error-header h4 {
    color: #c53030;
    margin: 0;
    font-size: 1.1rem;
}

.error-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.error-list li {
    padding: 8px 12px;
    margin: 4px 0;
    background: rgba(245, 101, 101, 0.1);
    border-radius: 6px;
    color: #c53030;
    font-size: 0.95rem;
    display: flex;
    align-items: center;
}

.error-list li::before {
    content: '•';
    margin-right: 8px;
    font-weight: bold;
}

@keyframes slideDown {
    from {
        transform: translateY(-20px);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

.upload-section {
    border: 3px dashed #cbd5e0;
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s ease;
    margin-bottom: 30px;
    background: #f8f9fa;
}

.upload-section.drag-over {
    border-color: #667eea;
    background: #eef2ff;
    transform: scale(1.02);
}

.upload-area {
    margin-bottom: 30px;
}

.upload-icon {
    font-size: 4rem;
    margin-bottom: 20px;
    display: block;
}

.upload-area h2 {
    color: #2d3748;
    margin-bottom: 10px;
    font-size: 1.8rem;
}

.upload-area p {
    color: #718096;
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.upload-button {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    position: relative;
    overflow: hidden;
}

.upload-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
}

.upload-button:active:not(:disabled) {
    transform: translateY(0);
}

.upload-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.upload-button:disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
}

.file-info {
    text-align: left;
    background: white;
    padding: 20px;
    border-radius: 8px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.file-info h3 {
    color: #2d3748;
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.file-list {
    max-height: 300px;
    overflow-y: auto;
}

.file-item {
    display: flex;
    align-items: center;
    padding: 12px 15px;
    border-bottom: 1px solid #e2e8f0;
    transition: background 0.2s ease;
}

.file-item:hover {
    background: #f7fafc;
}

.file-icon {
    font-size: 1.5rem;
    margin-right: 12px;
}

.file-name {
    flex: 1;
    color: #2d3748;
    font-weight: 500;
}

.file-size {
    color: #718096;
    font-size: 0.9rem;
    margin-right: 15px;
}

.remove-file {
    background: #fc8181;
    color: white;
    border: none;
    width: 28px;
    height: 28px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    line-height: 1;
    transition: all 0.2s ease;
}

.remove-file:hover {
    background: #f56565;
    transform: scale(1.1);
}

.conversion-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

.conversion-section h3 {
    color: #2d3748;
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.conversion-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.option-group {
    display: flex;
    flex-direction: column;
}

.option-group label {
    color: #4a5568;
    margin-bottom: 8px;
    font-weight: 600;
    font-size: 0.95rem;
}

.option-group select,
.option-group input[type="text"] {
    padding: 10px 15px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    color: #2d3748;
    background: white;
    transition: border-color 0.2s ease;
    width: 100%;
}

.option-group select:focus,
.option-group input[type="text"]:focus {
    outline: none;
    border-color: #667eea;
}

.page-range-input {
    font-family: inherit;
}

.help-text {
    display: block;
    margin-top: 5px;
    color: #718096;
    font-size: 0.85rem;
}

.convert-button {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    width: 100%;
    position: relative;
    overflow: hidden;
}

.convert-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(72, 187, 120, 0.4);
}

.convert-button:active:not(:disabled) {
    transform: translateY(0);
}

.convert-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.convert-button:disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
}

.long-image-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

.long-image-section h3 {
    color: #2d3748;
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.long-image-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.long-image-button {
    background: linear-gradient(135deg, #ed8936 0%, #dd6b20 100%);
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    width: 100%;
    position: relative;
    overflow: hidden;
}

.long-image-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(237, 137, 54, 0.4);
}

.long-image-button:active:not(:disabled) {
    transform: translateY(0);
}

.long-image-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.long-image-button:disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
}

.page-number-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
}

.page-number-section h3 {
    color: #2d3748;
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.page-number-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin-bottom: 25px;
}

.page-number-button {
    background: linear-gradient(135deg, #9f7aea 0%, #805ad5 100%);
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    width: 100%;
    position: relative;
    overflow: hidden;
}

.page-number-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(159, 122, 234, 0.4);
}

.page-number-button:active:not(:disabled) {
    transform: translateY(0);
}

.page-number-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.page-number-button:disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
}

.number-input {
    padding: 10px 15px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    font-size: 1rem;
    color: #2d3748;
    background: white;
    transition: border-color 0.2s ease;
    width: 100%;
}

.number-input:focus {
    outline: none;
    border-color: #667eea;
}

.color-input {
    width: 100%;
    height: 40px;
    padding: 5px;
    border: 2px solid #e2e8f0;
    border-radius: 8px;
    cursor: pointer;
}

.color-input:focus {
    outline: none;
    border-color: #667eea;
}

.long-image-preview-container {
    margin-top: 15px;
    max-height: 400px;
    overflow-y: auto;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    background: #f7fafc;
    padding: 10px;
}

.long-image-preview {
    width: 100%;
    height: auto;
    display: block;
    border-radius: 4px;
}

.result-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.result-section h3 {
    color: #2d3748;
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.result-list {
    max-height: 400px;
    overflow-y: auto;
}

.result-item {
    padding: 15px;
    border: 1px solid #e2e8f0;
    border-radius: 8px;
    margin-bottom: 12px;
    transition: all 0.2s ease;
}

.result-item:hover {
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.result-info {
    display: flex;
    align-items: center;
    margin-bottom: 10px;
}

.result-status {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-right: 12px;
    font-weight: bold;
}

.result-status.success {
    background: #48bb78;
    color: white;
}

.result-status.error {
    background: #f56565;
    color: white;
}

.result-filename {
    color: #2d3748;
    font-weight: 500;
    flex: 1;
}

.result-actions {
    text-align: right;
}

.download-button {
    background: #4299e1;
    color: white;
    border: none;
    padding: 8px 20px;
    font-size: 0.9rem;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-weight: 500;
}

.download-button:hover {
    background: #3182ce;
    transform: translateY(-1px);
}

.result-error {
    color: #f56565;
    font-size: 0.9rem;
    padding: 8px 12px;
    background: #fff5f5;
    border-radius: 6px;
}

.result-details {
    margin: 10px 0;
    padding: 10px;
    background: #f7fafc;
    border-radius: 6px;
}

.result-summary {
    color: #4a5568;
    font-size: 0.9rem;
    margin-bottom: 10px;
    font-weight: 500;
}

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

.preview-item {
    position: relative;
    width: 80px;
    height: 100px;
    border-radius: 4px;
    overflow: hidden;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
}

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

.preview-label {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    font-size: 0.7rem;
    padding: 2px 4px;
    text-align: center;
}

.more-images {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 80px;
    height: 100px;
    background: #e2e8f0;
    border-radius: 4px;
    color: #4a5568;
    font-size: 0.8rem;
    font-weight: 600;
}

.download-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
}

.image2pdf-section {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.image-upload-section {
    border: 3px dashed #cbd5e0;
    border-radius: 12px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s ease;
    background: #f8f9fa;
}

.image-upload-section.drag-over {
    border-color: #667eea;
    background: #eef2ff;
    transform: scale(1.02);
}

.support-formats {
    color: #718096;
    font-size: 0.9rem;
    margin-top: 15px;
}

.image-list-section {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
}

.image-list-section h3 {
    color: #2d3748;
    margin-bottom: 20px;
    font-size: 1.3rem;
}

.image-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 20px;
    margin-bottom: 30px;
}

.image-item {
    background: white;
    border: 2px solid #e2e8f0;
    border-radius: 12px;
    padding: 15px;
    transition: all 0.3s ease;
    cursor: move;
    position: relative;
}

.image-item:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    border-color: #667eea;
    transform: translateY(-2px);
}

.image-item.dragging {
    opacity: 0.5;
    border-style: dashed;
}

.image-preview {
    width: 100%;
    height: 180px;
    border-radius: 8px;
    overflow: hidden;
    background: #f7fafc;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 12px;
}

.image-preview img {
    max-width: 100%;
    max-height: 100%;
    object-fit: contain;
    transition: transform 0.3s ease;
}

.image-info {
    display: flex;
    flex-direction: column;
    gap: 4px;
    margin-bottom: 12px;
}

.image-name {
    color: #2d3748;
    font-weight: 600;
    font-size: 0.95rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.image-dimensions {
    color: #718096;
    font-size: 0.85rem;
}

.image-actions {
    display: flex;
    gap: 8px;
    justify-content: flex-end;
}

.rotate-button {
    background: #4299e1;
    color: white;
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1rem;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.rotate-button:hover {
    background: #3182ce;
    transform: scale(1.1);
}

.remove-image-button {
    background: #f56565;
    color: white;
    border: none;
    width: 32px;
    height: 32px;
    border-radius: 6px;
    cursor: pointer;
    font-size: 1.2rem;
    line-height: 1;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.remove-image-button:hover {
    background: #e53e3e;
    transform: scale(1.1);
}

.pdf-settings {
    background: #f8f9fa;
    padding: 20px;
    border-radius: 12px;
    margin-bottom: 20px;
}

.pdf-settings h3 {
    color: #2d3748;
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.pdf-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
    gap: 20px;
    margin-bottom: 20px;
}

.generate-pdf-button {
    background: linear-gradient(135deg, #48bb78 0%, #38a169 100%);
    color: white;
    border: none;
    padding: 14px 40px;
    font-size: 1.1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    width: 100%;
    position: relative;
    overflow: hidden;
}

.generate-pdf-button:hover:not(:disabled) {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(72, 187, 120, 0.4);
}

.generate-pdf-button:active:not(:disabled) {
    transform: translateY(0);
}

.generate-pdf-button:disabled {
    background: #cbd5e0;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.generate-pdf-button:disabled::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(255, 255, 255, 0.3);
    border-radius: 8px;
}

.pdf-result-section {
    background: #f0fff4;
    border: 2px solid #48bb78;
    border-radius: 12px;
    padding: 20px;
}

.pdf-result-section h3 {
    color: #276749;
    margin-bottom: 15px;
    font-size: 1.2rem;
}

.pdf-result-info {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.pdf-result-info p {
    color: #2f855a;
    font-size: 1rem;
    font-weight: 500;
}

.download-pdf-button {
    background: linear-gradient(135deg, #4299e1 0%, #3182ce 100%);
    color: white;
    border: none;
    padding: 12px 30px;
    font-size: 1rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    align-self: flex-start;
}

.download-pdf-button:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(66, 153, 225, 0.4);
}

.features-section {
    padding: 30px;
    background: #f8f9fa;
    border-radius: 12px;
    margin-bottom: 20px;
}

.features-section h2 {
    color: #2d3748;
    text-align: center;
    font-size: 2rem;
    margin-bottom: 30px;
    font-weight: 700;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 25px;
    margin-bottom: 40px;
}

.feature-card {
    background: white;
    border-radius: 12px;
    padding: 25px;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.15);
    border-color: #667eea;
}

.feature-icon {
    font-size: 2.5rem;
    margin-bottom: 15px;
    text-align: center;
}

.feature-card h3 {
    color: #2d3748;
    font-size: 1.4rem;
    margin-bottom: 12px;
    text-align: center;
    font-weight: 600;
}

.feature-card p {
    color: #4a5568;
    font-size: 0.95rem;
    margin-bottom: 15px;
    line-height: 1.6;
}

.feature-card ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.feature-card li {
    color: #4a5568;
    font-size: 0.9rem;
    padding: 8px 0;
    padding-left: 20px;
    position: relative;
    line-height: 1.5;
}

.feature-card li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: #48bb78;
    font-weight: bold;
}

.feature-card strong {
    color: #2d3748;
    font-weight: 600;
}

.features-advantages {
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    border-radius: 12px;
    padding: 30px;
    color: white;
}

.features-advantages h3 {
    text-align: center;
    font-size: 1.8rem;
    margin-bottom: 25px;
    font-weight: 600;
}

.advantages-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.advantage-item {
    display: flex;
    align-items: flex-start;
    gap: 15px;
}

.advantage-icon {
    font-size: 2rem;
    flex-shrink: 0;
}

.advantage-content h4 {
    font-size: 1.2rem;
    margin-bottom: 8px;
    font-weight: 600;
}

.advantage-content p {
    font-size: 0.95rem;
    opacity: 0.9;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .navigation {
        flex-wrap: wrap;
    }
    
    .nav-item {
        flex: 1;
        min-width: 50%;
        justify-content: center;
        padding: 12px 15px;
    }
    
    .main-content {
        padding: 20px 15px;
    }
    
    .upload-section {
        padding: 25px 20px;
    }
    
    .conversion-options {
        grid-template-columns: 1fr;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .features-section {
        padding: 20px 15px;
    }
    
    .features-section h2 {
        font-size: 1.5rem;
    }
    
    .advantages-list {
        grid-template-columns: 1fr;
    }
}