:root {
  --bg: #0f172a;        /* slate-900 */
  --panel: #111827;     /* gray-900 */
  --muted: #9ca3af;     /* gray-400 */
  --text: #e5e7eb;      /* gray-200 */
  --accent: #22d3ee;    /* cyan-400 */
  --red: #f87171;       /* red-400 */
  --green: #34d399;     /* emerald-400 */
  --yellow: #fbbf24;    /* amber-400 */
  --border: #1f2937;    /* gray-800 */
  --link: #60a5fa;      /* blue-400 */
  --code-bg: #0b1220;
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Ubuntu, Cantarell, Noto Sans, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  color: var(--text);
  background: linear-gradient(180deg, #0b1022 0%, var(--bg) 30% 100%);
}
header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 16px 20px; border-bottom: 1px solid var(--border);
  background: rgba(17, 24, 39, 0.7); backdrop-filter: blur(8px);
  position: sticky; top: 0; z-index: 10;
}
header h1 { margin: 0; font-size: 16px; font-weight: 600; letter-spacing: 0.2px; }
header .badge { color: var(--muted); font-size: 12px; margin-left: 8px; }
.container { padding: 16px; max-width: 1300px; margin: 0 auto; }

.toolbar { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0 14px; }
button, .btn {
  background: #0b1324; color: var(--text); border: 1px solid var(--border);
  padding: 8px 12px; border-radius: 8px; cursor: pointer; font-size: 14px;
  display: inline-flex; align-items: center; gap: 8px; text-decoration: none;
}
button:hover, .btn:hover { border-color: #2b3a56; }
button.primary { background: #112143; border-color: #1d3a6d; color: #cfe3ff; }
button.success { background: #0f2a22; border-color: #1d5e4a; color: #c7ffee; }
button.warn { background: #2a210f; border-color: #5e4d1d; color: #fff2c7; }

.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; }
@media (max-width: 900px){ .grid { grid-template-columns: 1fr; } }
@media (min-width: 1200px){ .grid { grid-template-columns: 3fr 2fr; } }

.panel { background: var(--panel); border: 1px solid var(--border); border-radius: 12px; overflow: hidden; }
.panel header { position: static; background: #0e162a; border-bottom: 1px solid var(--border); display: flex; align-items: center; justify-content: space-between; padding: 10px 12px; }
.panel header h2 { font-size: 14px; margin: 0; }
.panel header .actions { display: inline-flex; gap: 8px; }

.area { position: relative; }
textarea {
  width: 100%; height: clamp(260px, 45vh, 620px); resize: vertical; background: var(--code-bg);
  color: var(--text); border: none; outline: none; padding: 12px 14px; font-size: 14px;
  font-family: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;
}
@media (max-width: 900px){
  textarea { height: 38vh; }
}
@media (min-width: 1400px){
  textarea { height: 50vh; }
}

.drop { border: 2px dashed #1f2b49; padding: 10px; text-align: center; color: var(--muted); }
.drop.dragover { border-color: var(--accent); color: var(--accent); }

.status { font-size: 13px; color: var(--muted); padding: 8px 12px; border-top: 1px solid var(--border); display: flex; gap: 12px; align-items: center; }
.status .ok { color: var(--green); }
.status .err { color: var(--red); }

/* Output */
.output-wrap { display: grid; grid-template-rows: auto auto 1fr; min-height: clamp(260px, 45vh, 620px); }
@media (max-width: 900px){
  .output-wrap { min-height: 42vh; }
}
@media (min-width: 1400px){
  .output-wrap { min-height: 55vh; }
}
pre.code { margin: 0; padding: 12px 14px; overflow: auto; background: var(--code-bg); }
pre.code .k { color: #93c5fd; }
pre.code .s { color: #86efac; }
pre.code .n { color: #fca5a5; }
pre.code .b { color: #facc15; }
pre.code .p { color: #94a3b8; }

.view-toggle { display: flex; gap: 6px; padding: 10px 12px; border-bottom: 1px solid var(--border); }
.view-toggle button { padding: 6px 10px; font-size: 13px; }
.view-toggle button.active { outline: 2px solid var(--accent); }
button.active { outline: 2px solid var(--accent); }

.tree { padding: 12px 14px; background: var(--code-bg); overflow: auto; }
.tree details { margin-left: 14px; }
.tree summary { cursor: pointer; }
.tree .k { color: #93c5fd; }
.tree .s { color: #86efac; }
.tree .n { color: #fca5a5; }
.tree .b { color: #facc15; }
.tree .p { color: #94a3b8; }

.footer { text-align: center; color: var(--muted); font-size: 12px; padding: 20px 10px; }
.footer a { color: var(--link); }

/* SEO content sections */
.info { margin-top: 16px; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; padding: 16px; margin-bottom: 12px; }
.info h2 { font-size: 18px; margin: 0 0 8px 0; }
.info h3 { font-size: 15px; margin: 16px 0 6px 0; }
.info p, .info li { color: var(--muted); line-height: 1.6; }
.info ul { padding-left: 18px; }