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

:root {
    --primary-color: #6366f1;
    --primary-dark: #4f46e5;
    --secondary-color: #8b5cf6;
    --success-color: #10b981;
    --error-color: #ef4444;
    --bg-color: #0f172a;
    --bg-light: #1e293b;
    --bg-card: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --border-color: #475569;
    --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: linear-gradient(135deg, var(--bg-color) 0%, #1e293b 100%);
    color: var(--text-primary);
    min-height: 100vh;
    line-height: 1.6;
}

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

/* Header */
.header {
    padding: 20px 0;
    border-bottom: 1px solid var(--border-color);
    background: rgba(15, 23, 42, 0.8);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 100;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.75rem;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.premium-btn {
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    color: #1e293b;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

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

/* Main Content */
.main-content {
    padding: 40px 0;
}

.hero {
    text-align: center;
    margin-bottom: 60px;
}

.hero-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 16px;
    background: linear-gradient(135deg, var(--text-primary), var(--text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
}

/* Converter Card */
.converter-card {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 32px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--border-color);
    max-width: 800px;
    margin: 0 auto 40px;
}

.input-group {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
}

.url-input {
    flex: 1;
    padding: 16px 20px;
    background: var(--bg-light);
    border: 2px solid var(--border-color);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 1rem;
    transition: border-color 0.3s;
}

.url-input:focus {
    outline: none;
    border-color: var(--primary-color);
}

.url-input::placeholder {
    color: var(--text-secondary);
}

.convert-btn {
    padding: 16px 32px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
    white-space: nowrap;
}

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

.convert-btn:disabled {
    opacity: 0.6;
    cursor: not-allowed;
}

.supported-sources {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    gap: 12px;
    justify-content: center;
}

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

.source-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.source-tag {
    background: var(--bg-light);
    padding: 6px 12px;
    border-radius: 20px;
    font-size: 0.875rem;
    color: var(--text-secondary);
    border: 1px solid var(--border-color);
}

/* Progress Section */
.progress-section {
    max-width: 800px;
    margin: 0 auto 40px;
}

.progress-bar-container {
    background: var(--bg-light);
    border-radius: 12px;
    height: 8px;
    overflow: hidden;
    margin-bottom: 12px;
}

.progress-bar {
    background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
    height: 100%;
    width: 0%;
    transition: width 0.3s;
    border-radius: 12px;
}

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

/* Result Section */
.result-section {
    max-width: 800px;
    margin: 0 auto 40px;
}

.result-card {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 32px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--success-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
}

.result-info h3 {
    font-size: 1.5rem;
    margin-bottom: 8px;
    color: var(--success-color);
}

.result-info p {
    color: var(--text-secondary);
}

.download-btn {
    padding: 14px 28px;
    background: linear-gradient(135deg, var(--success-color), #059669);
    color: white;
    border: none;
    border-radius: 12px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    transition: transform 0.2s, box-shadow 0.2s;
    white-space: nowrap;
}

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

/* Error Section */
.error-section {
    max-width: 800px;
    margin: 0 auto 40px;
}

.error-card {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 24px;
    box-shadow: var(--shadow-lg);
    border: 1px solid var(--error-color);
    display: flex;
    align-items: center;
    gap: 16px;
}

.error-icon {
    font-size: 2rem;
}

#errorMessage {
    color: var(--error-color);
    flex: 1;
}

/* Ad Section */
.ad-section {
    margin: 40px 0;
}

.ad-section.ad-inline {
    margin: 30px 0;
}

.ad-container {
    display: flex;
    justify-content: center;
    min-height: 100px;
}

.ad-banner {
    width: 100%;
    max-width: 728px;
    min-height: 90px;
    background: var(--bg-light);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Sticky Sidebar Ad */
.ad-sidebar {
    position: fixed;
    right: 20px;
    top: 50%;
    transform: translateY(-50%);
    width: 160px;
    min-height: 600px;
    z-index: 50;
    display: none;
}

@media (min-width: 1024px) {
    .ad-sidebar {
        display: block;
    }
}

@media (max-width: 1023px) {
    .ad-sidebar {
        display: none;
    }
}

/* Features Section */
.features {
    margin: 60px 0;
}

.features-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: 40px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 24px;
}

.feature-card {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 32px;
    text-align: center;
    border: 1px solid var(--border-color);
    transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.feature-icon {
    font-size: 3rem;
    margin-bottom: 16px;
}

.feature-card h4 {
    font-size: 1.25rem;
    margin-bottom: 8px;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Premium Section */
.premium-section {
    margin: 60px 0;
}

.premium-card {
    background: linear-gradient(135deg, var(--bg-card), var(--bg-light));
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    border: 2px solid #fbbf24;
    box-shadow: var(--shadow-lg);
    max-width: 600px;
    margin: 0 auto;
}

.premium-header h3 {
    font-size: 2rem;
    margin-bottom: 8px;
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.premium-header p {
    color: var(--text-secondary);
    margin-bottom: 24px;
}

.premium-features {
    list-style: none;
    text-align: left;
    margin: 24px 0;
    display: inline-block;
}

.premium-features li {
    padding: 8px 0;
    color: var(--text-primary);
}

.premium-cta {
    margin-top: 24px;
    padding: 16px 32px;
    background: linear-gradient(135deg, #fbbf24, #f59e0b);
    color: #1e293b;
    border: none;
    border-radius: 12px;
    font-size: 1.125rem;
    font-weight: 700;
    cursor: pointer;
    transition: transform 0.2s, box-shadow 0.2s;
}

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

/* Modal */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
    backdrop-filter: blur(4px);
}

.modal-content {
    background: var(--bg-card);
    border-radius: 16px;
    padding: 40px;
    max-width: 600px;
    width: 90%;
    max-height: 90vh;
    overflow-y: auto;
    position: relative;
    border: 1px solid var(--border-color);
}

.modal-close {
    position: absolute;
    top: 20px;
    right: 20px;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-secondary);
    transition: color 0.2s;
}

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

.modal-content h2 {
    margin-bottom: 32px;
    text-align: center;
}

.pricing-options {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 24px;
    margin-bottom: 24px;
}

.pricing-card {
    background: var(--bg-light);
    border-radius: 12px;
    padding: 24px;
    text-align: center;
    border: 2px solid var(--border-color);
    position: relative;
}

.pricing-card.featured {
    border-color: #fbbf24;
}

.badge {
    position: absolute;
    top: -12px;
    left: 50%;
    transform: translateX(-50%);
    background: #fbbf24;
    color: #1e293b;
    padding: 4px 12px;
    border-radius: 12px;
    font-size: 0.75rem;
    font-weight: 600;
}

.pricing-card h3 {
    margin-bottom: 16px;
}

.price {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}

.price span {
    font-size: 1rem;
    color: var(--text-secondary);
}

.savings {
    color: var(--success-color);
    font-size: 0.875rem;
    margin-bottom: 16px;
}

.purchase-btn {
    width: 100%;
    padding: 12px;
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: white;
    border: none;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: transform 0.2s;
}

.purchase-btn:hover {
    transform: translateY(-2px);
}

.modal-note {
    text-align: center;
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* Footer */
.footer {
    text-align: center;
    padding: 40px 0;
    border-top: 1px solid var(--border-color);
    color: var(--text-secondary);
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 24px;
    margin-top: 16px;
}

.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    transition: color 0.2s;
}

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

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero-title {
        font-size: 2rem;
    }

    .converter-card {
        padding: 24px;
    }

    .input-group {
        flex-direction: column;
    }

    .convert-btn {
        width: 100%;
    }

    .result-card {
        flex-direction: column;
        text-align: center;
    }

    .download-btn {
        width: 100%;
        justify-content: center;
    }

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

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

    .premium-card {
        padding: 24px;
    }

    .modal-content {
        padding: 24px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 1.75rem;
    }

    .logo {
        font-size: 1.5rem;
    }

    .premium-btn {
        padding: 8px 16px;
        font-size: 0.875rem;
    }
}