:root {
  --bg: #f6f7f9;
  --panel: #ffffff;
  --panel-2: #f0f2f5;
  --border: #dde1e7;
  --text: #1c2330;
  --muted: #5f6b7a;
  --accent: #3b6fd1;
  --accent-text: #ffffff;
  --accent-soft: #e6eefb;
  --term-bg: #12161d;
  --term-text: #e3e7ee;
  --term-err: #ff8b8b;
  --term-info: #8fa3bf;
  --term-input: #8ee39a;
  --ok: #2f9e5b;
  --warn: #d48a12;
  --bad: #d64545;

  /* syntax */
  --s-kw: #8a3fbf;
  --s-str: #2f7d32;
  --s-com: #7c8693;
  --s-num: #b5530b;
  --s-fn: #2357b8;
  --s-bi: #00798c;
  --s-dec: #a0522d;

  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "Liberation Mono", monospace;
  --sans: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --radius: 10px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1217;
    --panel: #171b22;
    --panel-2: #1e232c;
    --border: #2b313c;
    --text: #e4e8ee;
    --muted: #97a2b2;
    --accent: #6b9bf0;
    --accent-text: #0b1220;
    --accent-soft: #1d2a42;
    --term-bg: #0a0c10;
    --s-kw: #c792ea;
    --s-str: #a5d68a;
    --s-com: #6f7a89;
    --s-num: #f2a66a;
    --s-fn: #82aaff;
    --s-bi: #5fd3e0;
    --s-dec: #e0a46b;
  }
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 var(--sans);
  display: flex;
  flex-direction: column;
}
button { font: inherit; color: inherit; }
[hidden] { display: none !important; }

/* ---------- top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 16px;
  background: var(--panel);
  border-bottom: 1px solid var(--border);
}
.brand { flex: 1; min-width: 0; }
.brand h1 { margin: 0; font-size: 1.1rem; font-weight: 650; }
.tagline { margin: 0; color: var(--muted); font-size: 0.82rem; }
.icon-btn {
  border: 1px solid var(--border);
  background: var(--panel);
  border-radius: 8px;
  padding: 6px;
  cursor: pointer;
  display: inline-flex;
}
.py-status {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.82rem; color: var(--muted);
  padding: 4px 10px; border: 1px solid var(--border); border-radius: 999px;
  white-space: nowrap;
}
.py-status .dot { width: 8px; height: 8px; border-radius: 50%; background: var(--warn); }
.py-status[data-state="ready"] .dot { background: var(--ok); }
.py-status[data-state="running"] .dot { background: var(--accent); animation: pulse 1s infinite; }
.py-status[data-state="input"] .dot { background: var(--warn); animation: pulse 1s infinite; }
.py-status[data-state="loading"] .dot { animation: pulse 1s infinite; }
.py-status[data-state="error"] .dot { background: var(--bad); }
@keyframes pulse { 50% { opacity: 0.35; } }
.icon-btn.menu-btn { display: none; }

/* ---------- layout ---------- */
.layout { flex: 1; display: flex; min-height: 0; }
.sidebar {
  width: 270px; flex-shrink: 0;
  background: var(--panel);
  border-right: 1px solid var(--border);
  display: flex; flex-direction: column;
  min-height: 0;
}
.search { padding: 12px; border-bottom: 1px solid var(--border); }
.search input {
  width: 100%; padding: 8px 10px;
  border: 1px solid var(--border); border-radius: 8px;
  background: var(--panel-2); color: var(--text); font: inherit;
}
.search input:focus { outline: 2px solid var(--accent); outline-offset: -1px; }
.program-list { flex: 1; overflow-y: auto; padding: 6px 0 12px; }
.group-title {
  margin: 14px 16px 4px; font-size: 0.72rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted);
}
.prog-link {
  display: block; padding: 6px 16px; margin: 1px 8px; border-radius: 7px;
  color: var(--text); text-decoration: none; font-size: 0.92rem;
}
.prog-link small { display: block; color: var(--muted); font-size: 0.78rem; line-height: 1.3;
  white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.prog-link:hover { background: var(--panel-2); }
.prog-link.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.prog-link .dot-edited { color: var(--warn); margin-left: 4px; }
.muted { color: var(--muted); }
.pad { padding: 0 16px; }
.scratch-btn {
  margin: 10px 12px 12px; padding: 8px; border-radius: 8px; cursor: pointer;
  border: 1px dashed var(--border); background: transparent; color: var(--muted);
}
.scratch-btn:hover { color: var(--accent); border-color: var(--accent); }

.main {
  flex: 1; min-width: 0;
  display: flex; flex-direction: column;
  padding: 16px 20px; gap: 12px; min-height: 0;
}
.program-head h2 { margin: 0; font-size: 1.35rem; }
.crumb { margin: 0; font: 0.78rem var(--mono); color: var(--muted); }
.desc { margin: 2px 0 0; color: var(--muted); max-width: 75ch; white-space: pre-line; }

/* ---------- toolbar ---------- */
.toolbar { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.spacer { flex: 1; }
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 7px 14px; border-radius: 8px; cursor: pointer;
  border: 1px solid var(--border); background: var(--panel);
  font-size: 0.9rem; font-weight: 550;
}
.btn:hover:not(:disabled) { border-color: var(--accent); }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: var(--accent-text); }
.btn.primary:hover:not(:disabled) { filter: brightness(1.08); }
.btn.ghost { background: transparent; }
.btn.tiny { padding: 2px 8px; font-size: 0.78rem; }
.edited-badge {
  font-size: 0.75rem; color: var(--warn); border: 1px solid var(--warn);
  border-radius: 999px; padding: 1px 8px;
}

/* ---------- panes ---------- */
.panes {
  flex: 1; min-height: 0;
  display: grid; grid-template-rows: minmax(180px, 1.3fr) minmax(160px, 1fr); gap: 12px;
}

/* editor: a transparent textarea over a highlighted <pre> */
.editor {
  display: flex; min-height: 0;
  border: 1px solid var(--border); border-radius: var(--radius);
  background: var(--panel); overflow: hidden;
  --ed-font: 13.5px/1.6 var(--mono);
  --ed-pad: 12px;
}
.gutter {
  flex-shrink: 0; padding: var(--ed-pad) 10px var(--ed-pad) 12px;
  font: var(--ed-font); color: var(--muted); text-align: right;
  background: var(--panel-2); border-right: 1px solid var(--border);
  user-select: none; overflow: hidden; white-space: pre; opacity: 0.8;
}
.code-wrap { position: relative; flex: 1; min-width: 0; }
.highlight, #code {
  position: absolute; inset: 0; margin: 0;
  padding: var(--ed-pad);
  font: var(--ed-font);
  tab-size: 4;
  white-space: pre;
  overflow: auto;
  border: 0;
  letter-spacing: normal;
  word-spacing: normal;
}
.highlight { pointer-events: none; color: var(--text); overflow: hidden; }
.highlight code { font: inherit; }
#code {
  resize: none; background: transparent; color: transparent;
  caret-color: var(--text); outline: none; z-index: 1;
}
#code::selection { background: color-mix(in srgb, var(--accent) 30%, transparent); color: transparent; }
.editor:focus-within { border-color: var(--accent); }

.t-kw { color: var(--s-kw); }
.t-str { color: var(--s-str); }
.t-com { color: var(--s-com); font-style: italic; }
.t-num { color: var(--s-num); }
.t-fn { color: var(--s-fn); }
.t-bi { color: var(--s-bi); }
.t-dec { color: var(--s-dec); }

/* terminal */
.terminal-wrap {
  display: flex; flex-direction: column; min-height: 0;
  border-radius: var(--radius); overflow: hidden;
  background: var(--term-bg); border: 1px solid var(--border);
}
.terminal-head {
  display: flex; align-items: center; justify-content: space-between;
  padding: 6px 12px; font-size: 0.78rem; color: var(--term-info);
  border-bottom: 1px solid #ffffff14;
}
.terminal-head .btn { color: var(--term-info); border-color: #ffffff22; }
.terminal {
  flex: 1; overflow: auto; padding: 10px 12px;
  font: 13.5px/1.55 var(--mono); color: var(--term-text);
  white-space: pre-wrap; word-break: break-word; outline: none;
}
.terminal .err { color: var(--term-err); }
.terminal .info { color: var(--term-info); font-style: italic; }
.terminal .echo { color: var(--term-input); }
.term-input {
  background: transparent; border: 0; outline: none; padding: 0; margin: 0;
  color: var(--term-input); font: inherit; caret-color: var(--term-input);
  min-width: 8ch; width: 60%;
  border-bottom: 1px dashed #8ee39a66;
}

/* ---------- small screens ---------- */
@media (max-width: 760px) {
  .icon-btn.menu-btn { display: inline-flex; }
  .tagline { display: none; }
  .py-status .label { display: none; }
  .sidebar {
    position: fixed; top: 0; bottom: 0; left: 0; z-index: 20;
    width: min(85vw, 300px);
    transform: translateX(-100%); transition: transform 0.2s ease;
  }
  body.nav-open .sidebar { transform: none; box-shadow: 0 0 30px #0005; }
  .main { padding: 12px 16px; }
  .panes { grid-template-rows: minmax(260px, auto) minmax(220px, auto); }
  .layout { overflow-y: auto; }
}