:root {
  --bg: #f8f9fb; --fg: #1a1d23; --muted: #6b7280; --accent: #b8860b;
  --card: #ffffff; --border: #e3e6ec; --hover: #f0f2f6;
  --code-bg: #f3f4f7; --shadow: 0 1px 3px rgba(0,0,0,0.06);
}
[data-theme="dark"] {
  --bg: #0f1419; --fg: #e8eaee; --muted: #8b95a3; --accent: #d4a44a;
  --card: #1a2028; --border: #2a323d; --hover: #232a33;
  --code-bg: #1f252e; --shadow: 0 1px 3px rgba(0,0,0,0.3);
}
* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; height: 100%; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui, sans-serif;
  background: var(--bg); color: var(--fg); font-size: 14px; line-height: 1.5; }
h1, h2, h3 { margin: 0 0 .5em; font-weight: 600; }
h1 { font-size: 18px; }
h2 { font-size: 22px; }
h3 { font-size: 16px; color: var(--accent); }
.muted { color: var(--muted); font-size: 12px; }

.topbar {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 16px; border-bottom: 1px solid var(--border);
  background: var(--card); position: sticky; top: 0; z-index: 10;
}
.topbar h1 { letter-spacing: -0.02em; }
.topbar .tag { color: var(--muted); font-size: 12px; padding: 2px 8px; border: 1px solid var(--border); border-radius: 12px; }
.topbar .spacer { flex: 1; }
.topbar .count { font-size: 12px; color: var(--muted); }

.icon-btn {
  background: transparent; border: 1px solid var(--border); color: var(--fg);
  padding: 4px 10px; border-radius: 6px; cursor: pointer; font-size: 16px;
}
.icon-btn:hover { background: var(--hover); }

.layout { display: flex; min-height: calc(100% - 53px); }
.sidebar {
  width: 280px; border-right: 1px solid var(--border);
  padding: 12px; overflow-y: auto; background: var(--card);
  flex-shrink: 0;
}
.sidebar input[type=search] {
  width: 100%; padding: 8px 10px; border: 1px solid var(--border);
  border-radius: 6px; background: var(--bg); color: var(--fg); font-size: 13px;
  margin-bottom: 12px;
}
.sidebar input[type=search]:focus { outline: 2px solid var(--accent); outline-offset: -1px; }

.sidebar nav h4 {
  margin: 14px 0 6px; font-size: 11px; text-transform: uppercase;
  letter-spacing: 0.05em; color: var(--muted); font-weight: 600;
}
.sidebar nav h4:first-child { margin-top: 0; }
.sidebar nav a {
  display: flex; align-items: center; gap: 8px;
  padding: 6px 8px; border-radius: 6px; color: var(--fg);
  text-decoration: none; font-size: 13px;
}
.sidebar nav a:hover { background: var(--hover); }
.sidebar nav a.active { background: var(--accent); color: #fff; }
.sidebar nav a .ic { width: 20px; text-align: center; }

.main { flex: 1; padding: 24px 32px; overflow-y: auto; }
.welcome { max-width: 600px; margin: 80px auto; text-align: center; }
.welcome p { margin: 8px 0; }

.tool { max-width: 720px; }
.tool > .desc { color: var(--muted); margin-bottom: 20px; font-size: 14px; }
.tool h2 { display: flex; align-items: center; gap: 8px; }
.tool h2 .ic { font-size: 24px; }

.row { display: flex; gap: 12px; flex-wrap: wrap; align-items: end; margin-bottom: 12px; }
.field { display: flex; flex-direction: column; gap: 4px; flex: 1 1 140px; }
.field label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); }
.field input, .field select, .field textarea {
  padding: 8px 10px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg); color: var(--fg); font-size: 13px; font-family: inherit;
}
.field input:focus, .field textarea:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.field textarea { font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: 12px; min-height: 120px; }

.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 8px 14px; border: 1px solid var(--border); border-radius: 6px;
  background: var(--bg); color: var(--fg); cursor: pointer; font-size: 13px;
  font-family: inherit;
}
.btn:hover { background: var(--hover); }
.btn.primary { background: var(--accent); color: #fff; border-color: var(--accent); }
.btn.primary:hover { filter: brightness(1.1); }

.out {
  margin-top: 12px; padding: 12px 14px; border-radius: 6px;
  background: var(--code-bg); border: 1px solid var(--border);
  font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: 12.5px;
  white-space: pre-wrap; word-break: break-word;
}
.out.error { color: #c0392b; border-color: #e9b4af; }
.out.success { color: #2e7d32; }

.actions { display: flex; gap: 8px; margin-top: 10px; }
.kbd {
  font-family: ui-monospace, "SF Mono", Menlo, monospace; font-size: 11px;
  padding: 1px 5px; background: var(--code-bg); border: 1px solid var(--border); border-radius: 4px;
}

@media (max-width: 720px) {
  .layout { flex-direction: column; }
  .sidebar { width: 100%; max-height: 200px; }
  .main { padding: 16px; }
}