:root {
    --primary: #4f46e5;
    --primary-dark: #3730a3;
    --primary-light: #a5b4fc;
    --secondary: #06b6d4;
    --accent: #10b981;
    --text: #1f2937;
    --text-light: #6b7280;
    --bg: #ffffff;
    --bg-secondary: #f9fafb;
    --border: #e5e7eb;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    --radius: 0.75rem;
    --radius-sm: 0.5rem;
    --success: #10b981;
    --error: #ef4444;
    --warning: #f59e0b;
    --info: #3b82f6;
}

.dark-mode {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --primary-light: #c7d2fe;
    --secondary: #22d3ee;
    --accent: #34d399;
    --text: #f9fafb;
    --text-light: #d1d5db;
    --bg: #111827;
    --bg-secondary: #1f2937;
    --border: #374151;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.3);
}

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

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    transition: all 0.3s ease;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

/* Header */
header {
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(10px);
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 0;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    text-decoration: none;
    color: var(--text);
    font-weight: 700;
    font-size: 1.25rem;
}

.logo-icon {
    font-size: 1.5rem;
    color: var(--primary);
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.nav-link {
    text-decoration: none;
    color: var(--text-light);
    font-weight: 500;
    padding: 0.5rem 0;
    position: relative;
    transition: color 0.3s ease;
}

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.theme-toggle {
    background: none;
    border: none;
    font-size: 1.25rem;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: var(--radius-sm);
    transition: all 0.3s ease;
}

.theme-toggle:hover {
    background: var(--bg-secondary);
    transform: rotate(15deg);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 0.25rem;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger span {
    width: 1.5rem;
    height: 2px;
    background: var(--text);
    transition: all 0.3s ease;
}

/* Sections */
.section {
    display: none;
    min-height: calc(100vh - 80px);
    padding: 2rem 0;
}

.section.active {
    display: block;
}

/* Hero */
.hero {
    text-align: center;
    margin-bottom: 3rem;
}

.hero h1 {
    font-size: 3rem;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    background-clip: text;
    color: transparent;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-light);
    max-width: 600px;
    margin: 0 auto;
}

/* Converter Card */
.converter-card {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
    margin-bottom: 3rem;
    overflow: hidden;
}

.upload-section {
    padding: 2rem;
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 2rem;
    align-items: center;
}

.upload-area {
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s ease;
    background: var(--bg-secondary);
}

.upload-area:hover,
.upload-area.dragover {
    border-color: var(--primary);
    background: rgba(79, 70, 229, 0.05);
}

.upload-icon {
    font-size: 2rem;
    margin-bottom: 1rem;
    color: var(--primary);
}

.upload-area h3 {
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    color: var(--text);
}

.upload-area p {
    color: var(--text-light);
    margin-bottom: 1rem;
}

.upload-area small {
    color: var(--text-light);
    font-size: 0.875rem;
}

.upload-options {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    min-width: 200px;
}

.quality-control {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.quality-control label {
    font-weight: 500;
    color: var(--text);
}

.quality-control input[type="range"] {
    width: 100%;
    height: 6px;
    border-radius: 3px;
    background: var(--border);
    outline: none;
    -webkit-appearance: none;
}

.quality-control input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary);
    cursor: pointer;
    box-shadow: 0 0 0 4px rgba(79, 70, 229, 0.2);
    transition: all 0.2s ease;
}

.quality-control input[type="range"]::-webkit-slider-thumb:hover {
    transform: scale(1.1);
}

.convert-btn {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    padding: 0.875rem 1.5rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
    font-size: 0.95rem;
}

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

.convert-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.btn-icon {
    font-size: 1rem;
}

/* Progress */
.progress-section {
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border);
    background: var(--bg-secondary);
}

.progress-bar {
    width: 100%;
    height: 8px;
    background: var(--border);
    border-radius: 4px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}

.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    width: 0%;
    transition: width 0.3s ease;
}

.progress-text {
    text-align: center;
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Results */
.results-section {
    padding: 2rem;
    border-top: 1px solid var(--border);
}

.empty-state {
    text-align: center;
    padding: 2rem;
    color: var(--text-light);
}

.empty-icon {
    font-size: 3rem;
    margin-bottom: 1rem;
    opacity: 0.5;
}

.results-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 1.5rem;
}

.result-item {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    overflow: hidden;
    transition: all 0.3s ease;
}

.result-item:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.result-preview {
    position: relative;
    aspect-ratio: 16/9;
    overflow: hidden;
}

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

.result-info {
    padding: 1rem;
}

.result-name {
    font-weight: 600;
    margin-bottom: 0.5rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.result-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.875rem;
    color: var(--text-light);
    margin-bottom: 1rem;
}

.result-actions {
    display: flex;
    gap: 0.5rem;
}

.result-btn {
    flex: 1;
    padding: 0.5rem;
    border: none;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
    text-decoration: none;
    text-align: center;
}

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

.result-btn-secondary {
    background: var(--border);
    color: var(--text);
}

.result-btn:hover {
    transform: translateY(-1px);
}

/* Features Grid */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
    margin-top: 3rem;
}

.feature-item {
    text-align: center;
    padding: 2rem 1rem;
    background: var(--bg-secondary);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: all 0.3s ease;
}

.feature-item:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-lg);
}

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

.feature-item h3 {
    font-size: 1.25rem;
    margin-bottom: 0.75rem;
    color: var(--text);
}

.feature-item p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* About Page */
.content-wrapper {
    max-width: 800px;
    margin: 0 auto;
}

.section-subtitle {
    font-size: 1.25rem;
    color: var(--text-light);
    text-align: center;
    margin-bottom: 3rem;
}

.about-content {
    display: grid;
    grid-template-columns: 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.about-text h2 {
    color: var(--primary);
    margin-bottom: 1rem;
    font-size: 1.5rem;
}

.about-text p {
    margin-bottom: 1.5rem;
    color: var(--text-light);
    line-height: 1.7;
}

.benefits-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin-top: 2rem;
}

.benefit-item {
    display: flex;
    gap: 1rem;
    align-items: flex-start;
}

.benefit-icon {
    font-size: 1.25rem;
    color: var(--accent);
    margin-top: 0.25rem;
}

.benefit-item h4 {
    color: var(--text);
    margin-bottom: 0.25rem;
}

.benefit-item p {
    color: var(--text-light);
    margin: 0;
}

.about-stats {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

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

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
    gap: 2rem;
    text-align: center;
}

.stat-item {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 800;
    color: var(--primary);
    line-height: 1;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-light);
}

.cta-section {
    text-align: center;
    padding: 3rem 2rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: var(--radius);
    color: white;
}

.cta-section h2 {
    margin-bottom: 1rem;
    color: white;
}

.cta-section p {
    margin-bottom: 2rem;
    opacity: 0.9;
}

.cta-btn {
    background: white;
    color: var(--primary);
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    cursor: pointer;
    transition: all 0.3s ease;
}

.cta-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

/* Contact Page */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 3rem;
    margin-top: 2rem;
}

.contact-form-wrapper {
    background: var(--bg-secondary);
    padding: 2rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.contact-form {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.form-group label {
    font-weight: 500;
    color: var(--text);
}

.form-group input,
.form-group select,
.form-group textarea {
    padding: 0.75rem;
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    background: var(--bg);
    color: var(--text);
    font-family: inherit;
    transition: all 0.3s ease;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.1);
}

.form-group textarea {
    resize: vertical;
    min-height: 120px;
}

.submit-btn {
    background: linear-gradient(135deg, var(--primary), var(--primary-dark));
    color: white;
    border: none;
    padding: 1rem 1.5rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    transition: all 0.3s ease;
}

.submit-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

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

.contact-info p {
    color: var(--text-light);
    margin-bottom: 2rem;
}

.contact-methods {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.contact-method {
    display: flex;
    gap: 1rem;
    align-items: center;
}

.method-icon {
    font-size: 1.5rem;
    color: var(--primary);
    width: 40px;
    text-align: center;
}

.contact-method h4 {
    color: var(--text);
    margin-bottom: 0.25rem;
}

.contact-method p {
    color: var(--text-light);
    margin: 0;
}

.faq-link {
    background: var(--bg-secondary);
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
}

.faq-link h3 {
    color: var(--primary);
    margin-bottom: 1rem;
}

.faq-item {
    margin-bottom: 1.5rem;
}

.faq-item:last-child {
    margin-bottom: 0;
}

.faq-item h4 {
    color: var(--text);
    margin-bottom: 0.5rem;
    font-size: 0.95rem;
}

.faq-item p {
    color: var(--text-light);
    font-size: 0.875rem;
    margin: 0;
}

/* Footer */
footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    margin-top: 4rem;
    padding: 3rem 0 1rem;
}

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

.footer-section h4 {
    color: var(--text);
    margin-bottom: 1rem;
}

.footer-section ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.footer-section a {
    color: var(--text-light);
    text-decoration: none;
    transition: color 0.3s ease;
}

.footer-section a:hover {
    color: var(--primary);
}

.footer-logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text);
    margin-bottom: 1rem;
}

.footer-section p {
    color: var(--text-light);
    line-height: 1.6;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
    color: var(--text-light);
    font-size: 0.875rem;
}

/* Toast */
.toast {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow-lg);
    padding: 1rem 1.5rem;
    transform: translateY(100px);
    opacity: 0;
    transition: all 0.3s ease;
    z-index: 1000;
    max-width: 300px;
}

.toast.show {
    transform: translateY(0);
    opacity: 1;
}

.toast.success {
    border-left: 4px solid var(--success);
}

.toast.error {
    border-left: 4px solid var(--error);
}

.toast.warning {
    border-left: 4px solid var(--warning);
}

.toast.info {
    border-left: 4px solid var(--info);
}

.toast-content {
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.toast-icon {
    font-size: 1.25rem;
    color: var(--success);
}

.toast.error .toast-icon {
    color: var(--error);
}

.toast.warning .toast-icon {
    color: var(--warning);
}

.toast.info .toast-icon {
    color: var(--info);
}

.toast-message {
    color: var(--text);
    font-weight: 500;
}

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.modal.show {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background: var(--bg);
    border-radius: var(--radius);
    padding: 2rem;
    max-width: 90%;
    max-height: 90%;
    overflow: auto;
    position: relative;
    box-shadow: var(--shadow-lg);
}

.modal-close {
    position: absolute;
    top: 1rem;
    right: 1rem;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-light);
    transition: color 0.3s ease;
}

.modal-close:hover {
    color: var(--text);
}

.modal-image {
    max-width: 100%;
    max-height: 70vh;
    display: block;
    margin: 0 auto 1rem;
    border-radius: var(--radius-sm);
}

.modal-info {
    text-align: center;
    color: var(--text-light);
}

/* Responsive Design */
@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background: var(--bg);
        border-top: 1px solid var(--border);
        flex-direction: column;
        gap: 0;
        padding: 1rem;
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: all 0.3s ease;
    }
    
    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }
    
    .nav-link {
        padding: 0.75rem 0;
        width: 100%;
        text-align: center;
    }
    
    .hero h1 {
        font-size: 2rem;
    }
    
    .hero p {
        font-size: 1rem;
    }
    
    .upload-section {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .upload-options {
        min-width: auto;
    }
    
    .contact-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
    
    .about-content {
        gap: 2rem;
    }
    
    .stats-grid {
        grid-template-columns: repeat(auto-fit, minmax(100px, 1fr));
        gap: 1rem;
    }
    
    .stat-number {
        font-size: 2rem;
    }
    
    .features-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 1.5rem;
        text-align: center;
    }
    
    .toast {
        bottom: 1rem;
        right: 1rem;
        left: 1rem;
        max-width: none;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 0.75rem;
    }
    
    .converter-card {
        margin: 0 -0.75rem 2rem;
        border-radius: 0;
        border-left: none;
        border-right: none;
    }
    
    .upload-section {
        padding: 1.5rem;
    }
    
    .upload-area {
        padding: 1.5rem;
    }
    
    .hero h1 {
        font-size: 1.75rem;
    }
    
    .cta-section {
        padding: 2rem 1rem;
        margin: 0 -0.75rem;
        border-radius: 0;
    }
}

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

.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: 50%;
    border-top-color: white;
    animation: spin 1s ease-in-out infinite;
}

/* Smooth scrolling */
html {
    scroll-behavior: smooth;
}

/* Focus styles for accessibility */
button:focus,
input:focus,
select:focus,
textarea:focus {
    outline: 2px solid var(--primary);
    outline-offset: 2px;
}

/* Print styles */
@media print {
    .hamburger,
    .theme-toggle,
    .toast,
    .modal {
        display: none !important;
    }
}