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

:root {
    --bg: #f5f5f7;
    --text: #1d1d1f;
    --text-secondary: #86868b;
    --border: #d2d2d7;
    --accent: #3b82f6;
    --success: #10b981;
    --error: #ef4444;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', sans-serif;
    -webkit-font-smoothing: antialiased;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 600px;
    margin: 0 auto;
    padding: 60px 24px;
}

.header {
    text-align: center;
    margin-bottom: 40px;
}

.header h1 {
    font-size: 32px;
    font-weight: 700;
    margin-bottom: 8px;
}

.subtitle {
    font-size: 16px;
    color: var(--text-secondary);
}

.subtext {
    font-size: 13px;
    color: var(--text-secondary);
    margin-top: 8px;
    opacity: 0.7;
}

.card {
    background: white;
    border-radius: 12px;
    padding: 28px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.06);
}

.input-section,
.format-section {
    margin-bottom: 20px;
}

.label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 8px;
}

.input {
    width: 100%;
    padding: 12px;
    font-size: 15px;
    border: 1px solid var(--border);
    border-radius: 8px;
    font-family: monospace;
    transition: border-color 0.2s;
}

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

.input::placeholder {
    color: var(--text-secondary);
    opacity: 0.6;
}

.format-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 10px;
}

.format-card {
    position: relative;
    display: block;
    padding: 12px;
    border: 2px solid var(--border);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
}

.format-card:hover {
    border-color: var(--accent);
}

.format-card input[type="radio"] {
    position: absolute;
    opacity: 0;
}

.format-card:has(input:checked) {
    border-color: var(--accent);
    background: rgba(59, 130, 246, 0.04);
}

.format-content {
    display: flex;
    align-items: center;
    gap: 8px;
}

.format-icon {
    font-size: 20px;
}

.format-text {
    display: flex;
    flex-direction: column;
}

.format-name {
    font-size: 13px;
    font-weight: 600;
}

.format-ext {
    font-size: 11px;
    color: var(--text-secondary);
}

.format-check {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 18px;
    height: 18px;
    background: var(--accent);
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 12px;
    font-weight: bold;
    opacity: 0;
    transition: opacity 0.2s;
}

.format-card:has(input:checked) .format-check {
    opacity: 1;
}

.btn {
    width: 100%;
    padding: 12px;
    font-size: 15px;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s;
    font-family: inherit;
}

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

.btn-primary:hover:not(:disabled) {
    background: #2563eb;
    transform: translateY(-1px);
}

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

.btn-success:hover:not(:disabled) {
    background: #059669;
    transform: translateY(-1px);
}

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

.status {
    margin-top: 16px;
    padding: 10px;
    border-radius: 8px;
    font-size: 14px;
    text-align: center;
}

.status:empty {
    display: none;
}

.status.loading {
    background: rgba(59, 130, 246, 0.1);
    color: var(--accent);
}

.status.success {
    background: rgba(16, 185, 129, 0.1);
    color: var(--success);
}

.status.error {
    background: rgba(239, 68, 68, 0.1);
    color: var(--error);
}

.result-card {
    margin-top: 24px;
    text-align: center;
}

.result-card.hidden {
    display: none;
}

.result-title {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 16px;
}

.result-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 16px;
    padding: 16px;
    background: var(--bg);
    border-radius: 8px;
}

.stat {
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.stat-value {
    font-size: 20px;
    font-weight: 700;
}

.stat-label {
    font-size: 12px;
    color: var(--text-secondary);
}

.footer {
    margin-top: 48px;
    padding-top: 24px;
    border-top: 1px solid var(--border);
    text-align: center;
    font-size: 13px;
    color: var(--text-secondary);
}

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

.btn.loading::before {
    content: '⏳';
    margin-right: 8px;
    display: inline-block;
    animation: spin 1s linear infinite;
}

@media (max-width: 640px) {
    .container {
        padding: 40px 20px;
    }
    
    .header h1 {
        font-size: 28px;
    }
    
    .card {
        padding: 20px;
    }
    
    .format-grid {
        grid-template-columns: 1fr;
    }
}