:root {
    --bg: #0f172a;
    --card: #1e293b;
    --border: #334155;
    --text: #f8fafc;
    --muted: #94a3b8;
    --primary: #3b82f6;
    --primary-hover: #2563eb;
    --success: #10b981;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
body { font-family: system-ui, -apple-system, sans-serif; background: var(--bg); color: var(--text); line-height: 1.6; padding: 20px; }
.container { max-width: 760px; margin: 0 auto; }

header { text-align: center; margin-bottom: 24px; }
.badge { background: rgba(16, 185, 129, 0.15); color: #34d399; border: 1px solid rgba(16, 185, 129, 0.3); padding: 5px 14px; border-radius: 99px; font-size: 0.8rem; font-weight: 600; display: inline-block; margin-bottom: 12px; }
h1 { font-size: 2rem; margin-bottom: 8px; }
.subtitle { color: var(--muted); }

.ad-slot { background: rgba(30, 41, 59, 0.5); border: 1px dashed var(--border); border-radius: 10px; min-height: 90px; display: flex; align-items: center; justify-content: center; color: var(--muted); font-size: 0.8rem; margin: 20px 0; }

.converter-box { background: var(--card); border: 1px solid var(--border); border-radius: 16px; padding: 24px; box-shadow: 0 10px 30px rgba(0,0,0,0.3); }

.drop-zone { border: 2px dashed #475569; border-radius: 12px; padding: 40px 20px; text-align: center; cursor: pointer; transition: 0.2s; background: rgba(15, 23, 42, 0.4); }
.drop-zone:hover, .drop-zone.dragover { border-color: var(--primary); background: rgba(59, 130, 246, 0.08); }
.drop-zone .hint { display: block; font-size: 0.85rem; color: var(--muted); margin-top: 6px; }

.controls { display: flex; flex-wrap: wrap; gap: 16px; align-items: flex-end; margin-top: 20px; }
.control-group { flex: 1; min-width: 160px; }
.control-group label { display: block; font-size: 0.85rem; color: var(--muted); margin-bottom: 6px; }
select, input[type="range"] { width: 100%; height: 42px; background: var(--bg); color: var(--text); border: 1px solid var(--border); border-radius: 8px; padding: 0 12px; font-size: 0.95rem; }

button { height: 42px; padding: 0 24px; border: none; border-radius: 8px; font-weight: 600; font-size: 0.95rem; cursor: pointer; transition: 0.2s; }
.btn-primary { background: var(--primary); color: white; }
.btn-primary:hover:not(:disabled) { background: var(--primary-hover); }
.btn-primary:disabled { opacity: 0.4; cursor: not-allowed; }
.btn-success { background: var(--success); color: white; width: 100%; margin-top: 16px; }

.file-list { list-style: none; margin-top: 20px; display: flex; flex-direction: column; gap: 10px; }
.file-item { background: var(--bg); border: 1px solid var(--border); padding: 12px 16px; border-radius: 10px; display: flex; justify-content: space-between; align-items: center; font-size: 0.9rem; }
.file-info { display: flex; flex-direction: column; overflow: hidden; padding-right: 10px; }
.file-name { font-weight: 500; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.file-meta { font-size: 0.8rem; color: var(--muted); }
.download-link { background: #334155; color: white; text-decoration: none; padding: 6px 14px; border-radius: 6px; font-size: 0.85rem; font-weight: 500; white-space: nowrap; }
.download-link:hover { background: var(--primary); }

.hidden { display: none; }
.info-section { margin-top: 32px; color: var(--muted); font-size: 0.95rem; }
.info-section h2 { color: var(--text); font-size: 1.25rem; margin-bottom: 10px; }
.info-section ul { margin-left: 20px; margin-top: 10px; }
.info-section li { margin-bottom: 6px; }
footer { text-align: center; margin-top: 40px; font-size: 0.85rem; color: var(--muted); }