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

:root {
    --primary: #6366f1;
    --primary-hover: #4f46e5;
    --bg: #0f0f0f;
    --surface: #1a1a1a;
    --surface-hover: #252525;
    --border: #2a2a2a;
    --text: #ffffff;
    --text-muted: #888888;
    --success: #22c55e;
    --error: #ef4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    padding: 2rem 0;
}

.container {
    width: 100%;
    max-width: 600px;
    margin: 0 auto;
    padding: 0 2rem;
}

header {
    text-align: center;
    margin-bottom: 2.5rem;
}

/* Server Badge */
.privacy-badge {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: linear-gradient(135deg, rgba(99, 102, 241, 0.15) 0%, rgba(99, 102, 241, 0.05) 100%);
    border: 1px solid rgba(99, 102, 241, 0.3);
    border-radius: 30px;
    padding: 0.6rem 1.2rem;
    margin-bottom: 1.5rem;
}

.privacy-badge svg {
    width: 18px;
    height: 18px;
    color: #6366f1;
    flex-shrink: 0;
}

.privacy-badge span {
    font-size: 0.85rem;
    color: #6366f1;
    font-weight: 500;
}

header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: -0.02em;
}

header h1 span {
    color: var(--primary);
}

.tagline {
    color: var(--text);
    margin-top: 0.5rem;
    font-size: 1.1rem;
    font-weight: 500;
}

.sub-tagline {
    color: var(--text-muted);
    font-size: 0.9rem;
    margin-top: 0.25rem;
}

.file-limit {
    color: var(--text-muted);
    font-size: 0.75rem;
    margin-top: 1rem;
}

.converter-box {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 2rem;
}

/* Upload Section */
.dropzone {
    border: 2px dashed var(--border);
    border-radius: 12px;
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s ease;
}

.dropzone:hover,
.dropzone.dragover {
    border-color: var(--primary);
    background: rgba(99, 102, 241, 0.05);
}

.upload-icon {
    width: 48px;
    height: 48px;
    color: var(--text-muted);
    margin-bottom: 1rem;
}

.drop-text {
    font-size: 1.1rem;
    margin-bottom: 0.5rem;
}

.or-text {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-bottom: 1rem;
}

.browse-btn {
    background: var(--primary);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: background 0.2s ease;
}

.browse-btn:hover {
    background: var(--primary-hover);
}

/* Convert Section */
.file-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem;
    background: var(--bg);
    border-radius: 10px;
    margin-bottom: 1.5rem;
}

.file-icon {
    width: 40px;
    height: 40px;
    color: var(--primary);
    flex-shrink: 0;
}

.file-icon svg {
    width: 100%;
    height: 100%;
}

.file-details {
    flex: 1;
    min-width: 0;
}

.file-name {
    font-weight: 500;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.file-size {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-top: 0.25rem;
}

.remove-btn {
    width: 32px;
    height: 32px;
    background: transparent;
    border: none;
    color: var(--text-muted);
    cursor: pointer;
    padding: 4px;
    border-radius: 6px;
    transition: all 0.2s ease;
}

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

.conversion-options {
    margin-bottom: 1.5rem;
}

.format-selector {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

.format-selector label {
    font-size: 0.875rem;
    color: var(--text-muted);
}

.format-selector select {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 0.75rem 1rem;
    color: var(--text);
    font-size: 1rem;
    cursor: pointer;
    transition: border-color 0.2s ease;
}

.format-selector select:hover,
.format-selector select:focus {
    border-color: var(--primary);
    outline: none;
}

.convert-btn {
    width: 100%;
    background: var(--primary);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
}

.convert-btn:hover:not(:disabled) {
    background: var(--primary-hover);
}

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

.btn-loader {
    width: 20px;
    height: 20px;
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-top-color: white;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* Download Section */
.download-section {
    text-align: center;
}

.success-icon {
    width: 64px;
    height: 64px;
    color: var(--success);
    margin: 0 auto 1rem;
}

.success-icon svg {
    width: 100%;
    height: 100%;
}

.success-text {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
}

.download-btn {
    width: 100%;
    background: var(--success);
    color: white;
    border: none;
    padding: 1rem;
    border-radius: 10px;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.download-btn:hover {
    filter: brightness(1.1);
}

.download-btn svg {
    width: 20px;
    height: 20px;
}

.convert-another-btn {
    background: transparent;
    border: 1px solid var(--border);
    color: var(--text-muted);
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.2s ease;
}

.convert-another-btn:hover {
    border-color: var(--text-muted);
    color: var(--text);
}

/* Error Section */
.error-section {
    text-align: center;
}

.error-icon {
    width: 64px;
    height: 64px;
    color: var(--error);
    margin: 0 auto 1rem;
}

.error-icon svg {
    width: 100%;
    height: 100%;
}

.error-text {
    color: var(--error);
    margin-bottom: 1.5rem;
}

.try-again-btn {
    background: var(--error);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: 8px;
    font-size: 0.95rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.2s ease;
}

.try-again-btn:hover {
    filter: brightness(1.1);
}

/* Supported Formats Section */
.supported-formats {
    margin-top: 3rem;
    text-align: center;
}

.supported-formats h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
    color: var(--text);
}

.format-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1rem;
}

.format-category {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.25rem 1rem;
    transition: all 0.2s ease;
}

.format-category:hover {
    border-color: var(--primary);
    transform: translateY(-2px);
}

.format-category .format-icon {
    font-size: 1.5rem;
    margin-bottom: 0.5rem;
}

.format-category h3 {
    font-size: 0.95rem;
    font-weight: 600;
    margin-bottom: 0.25rem;
}

.format-category p {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.4;
}

/* Features Section */
.features-section {
    margin-top: 3rem;
    text-align: center;
}

.features-section h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
}

.feature {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem 1rem;
    text-align: center;
    transition: all 0.2s ease;
}

.feature:hover {
    border-color: var(--primary);
}

.feature-icon {
    font-size: 2rem;
    margin-bottom: 0.75rem;
}

.feature h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.feature p {
    font-size: 0.85rem;
    color: var(--text-muted);
    line-height: 1.4;
}

/* Popular Conversions Section */
.popular-conversions {
    margin-top: 3rem;
    text-align: center;
}

.popular-conversions h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.conversion-tags {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.5rem;
}

.conversion-tags span {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.85rem;
    color: var(--text-muted);
    transition: all 0.2s ease;
    cursor: default;
}

.conversion-tags span:hover {
    border-color: var(--primary);
    color: var(--primary);
}

/* How It Works Section */
.how-it-works {
    margin-top: 3rem;
    text-align: center;
}

.how-it-works h2 {
    font-size: 1.5rem;
    margin-bottom: 1.5rem;
}

.steps {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
}

.step {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 1.5rem 1rem;
    flex: 1;
    max-width: 150px;
}

.step-number {
    width: 36px;
    height: 36px;
    background: var(--primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.1rem;
    margin: 0 auto 0.75rem;
}

.step h3 {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 0.5rem;
}

.step p {
    font-size: 0.75rem;
    color: var(--text-muted);
    line-height: 1.4;
}

.step-arrow {
    color: var(--text-muted);
    font-size: 1.5rem;
}

/* Footer */
footer {
    margin-top: 3rem;
    text-align: center;
    padding-bottom: 2rem;
}

footer p {
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 0.25rem;
}

footer .footer-sub {
    font-size: 0.8rem;
}

footer .footer-links {
    margin-top: 0.75rem;
}

footer .footer-links a {
    color: var(--primary);
    text-decoration: none;
    font-size: 0.8rem;
}

footer .footer-links a:hover {
    text-decoration: underline;
}

footer .copyright {
    font-size: 0.75rem;
    margin-top: 1rem;
    opacity: 0.7;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive */
@media (max-width: 640px) {
    .container {
        padding: 0 1rem;
    }

    header h1 {
        font-size: 2rem;
    }

    .tagline {
        font-size: 1rem;
    }

    .converter-box {
        padding: 1.5rem;
    }

    .dropzone {
        padding: 2rem 1rem;
    }

    .format-grid {
        grid-template-columns: repeat(2, 1fr);
    }

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

    .steps {
        flex-direction: column;
        gap: 0.5rem;
    }

    .step-arrow {
        transform: rotate(90deg);
    }

    .step {
        max-width: 100%;
        width: 100%;
    }
}