/*
 * The look.
 *
 * Modelled on Xcode: its Default (Dark) and Default (Light) syntax themes,
 * its hairline-separated panes, and the macOS chrome around them - SF fonts,
 * translucent toolbar, 6px corners, blue accent.
 *
 * Two rules everything else bends around:
 *
 *   1. Every colour is a token on :root, defined twice - once for dark, once
 *      for light. Nothing below this block names a colour directly, so the
 *      two themes cannot drift apart.
 *   2. The textarea and the highlighted layer under it must agree on every
 *      metric that moves a glyph. Font, size, line height, padding, tab size.
 *      One pixel of disagreement and the caret sits away from its own text.
 */

:root {
  /* ---- Xcode Default (Dark) ---- */
  --bg: #1f1f24;            /* the editor surface */
  --chrome: #2a2a2e;        /* toolbar and pane headers */
  --chrome-2: #252529;      /* gutter, status bar */
  --line: #38383c;          /* hairline */
  --line-soft: #2f2f33;
  --text: #e8e8ea;
  --muted: #8e8e93;         /* macOS secondary label */
  --faint: #5c5c61;         /* line numbers */
  --accent: #0a84ff;        /* macOS blue, dark appearance */
  --accent-quiet: rgba(10, 132, 255, 0.16);
  --on-accent: #ffffff;
  --selection: rgba(63, 99, 139, 0.6);
  --caret-line: rgba(255, 255, 255, 0.045);
  --shadow: rgba(0, 0, 0, 0.42);

  --green: #30d158;
  --red: #ff453a;
  --amber: #ffd60a;
  --violet: #bf5af2;

  /* Xcode Default (Dark) syntax */
  --t-plain: #dfdfe0;
  --t-keyword: #fc5fa3;
  --t-literal: #d0a8ff;
  --t-builtin: #5dd8ff;
  --t-call: #67b7a4;
  --t-string: #fc6a5d;
  --t-number: #d0bf69;
  --t-comment: #6c7986;
  --t-tag: #fc5fa3;
  --t-attr: #bf8555;

  /*
   * San Francisco where it exists, and the closest thing to it elsewhere.
   * ui-monospace resolves to SF Mono on Apple platforms without needing the
   * font to be installed by name.
   */
  --ui-font: -apple-system, BlinkMacSystemFont, "SF Pro Text",
    "Segoe UI Variable Text", "Segoe UI", system-ui, "Helvetica Neue", sans-serif;
  --code-font: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Monaco,
    "Cascadia Mono", "Roboto Mono", Consolas, monospace;
  --code-size: 13.5px;
  --code-line: 1.5;
  --pad: 14px;

  --radius: 6px;
  --radius-lg: 10px;

  color-scheme: dark;
}

/*
 * Light is the system's business unless the user said otherwise, which is how
 * a Mac app behaves. data-theme wins over the system in both directions.
 */
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    color-scheme: light;

    --bg: #ffffff;
    --chrome: #f3f3f5;
    --chrome-2: #fafafc;
    --line: #d9d9de;
    --line-soft: #e7e7ea;
    --text: #1d1d1f;
    --muted: #6e6e73;
    --faint: #a6a6ab;
    --accent: #007aff;
    --accent-quiet: rgba(0, 122, 255, 0.12);
    --on-accent: #ffffff;
    --selection: rgba(179, 215, 255, 0.85);
    --caret-line: rgba(0, 0, 0, 0.035);
    --shadow: rgba(0, 0, 0, 0.14);

    --green: #248a3d;
    --red: #d70015;
    --amber: #a05a00;
    --violet: #8944ab;

    /* Xcode Default (Light) syntax */
    --t-plain: #000000;
    --t-keyword: #ad3da4;
    --t-literal: #703daa;
    --t-builtin: #0b4f79;
    --t-call: #326d74;
    --t-string: #d12f1b;
    --t-number: #272ad8;
    --t-comment: #5d6c79;
    --t-tag: #ad3da4;
    --t-attr: #947100;
  }
}

:root[data-theme="light"] {
  color-scheme: light;

  --bg: #ffffff;
  --chrome: #f3f3f5;
  --chrome-2: #fafafc;
  --line: #d9d9de;
  --line-soft: #e7e7ea;
  --text: #1d1d1f;
  --muted: #6e6e73;
  --faint: #a6a6ab;
  --accent: #007aff;
  --accent-quiet: rgba(0, 122, 255, 0.12);
  --on-accent: #ffffff;
  --selection: rgba(179, 215, 255, 0.85);
  --caret-line: rgba(0, 0, 0, 0.035);
  --shadow: rgba(0, 0, 0, 0.14);

  --green: #248a3d;
  --red: #d70015;
  --amber: #a05a00;
  --violet: #8944ab;

  --t-plain: #000000;
  --t-keyword: #ad3da4;
  --t-literal: #703daa;
  --t-builtin: #0b4f79;
  --t-call: #326d74;
  --t-string: #d12f1b;
  --t-number: #272ad8;
  --t-comment: #5d6c79;
  --t-tag: #ad3da4;
  --t-attr: #947100;
}

* { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family: var(--ui-font);
  font-size: 13px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow: hidden;
}

.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}

/* A single blue focus ring, the way every control on macOS gets one. */
:where(button, select, textarea, a):focus-visible {
  outline: none;
  box-shadow: 0 0 0 3px var(--accent-quiet), 0 0 0 1px var(--accent);
}

/* ---------- toolbar ---------- */

.bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 9px 12px;
  background: var(--chrome);
  border-bottom: 1px solid var(--line);
  flex-wrap: wrap;
  /* the translucent toolbar every Mac window has, where it is supported */
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
}

.bar-left, .bar-right { display: flex; align-items: center; gap: 8px; }
.bar-left { min-width: 0; }

.bar-left strong {
  font-size: 13.5px;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.logo {
  font-family: var(--code-font);
  color: var(--accent);
  background: var(--accent-quiet);
  border-radius: var(--radius);
  padding: 3px 7px;
  font-size: 11.5px;
  font-weight: 600;
}

/*
 * Xcode's jump bar is a row of flat popups, not boxed dropdowns. The chevron
 * is drawn rather than left to the platform so it matches on every OS.
 */
select {
  appearance: none;
  -webkit-appearance: none;
  background-color: transparent;
  background-image:
    linear-gradient(45deg, transparent 50%, var(--muted) 50%),
    linear-gradient(135deg, var(--muted) 50%, transparent 50%);
  background-position: right 11px center, right 6px center;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  color: var(--text);
  border: 1px solid transparent;
  border-radius: var(--radius);
  padding: 5px 24px 5px 8px;
  font-size: 13px;
  font-family: inherit;
  font-weight: 500;
  cursor: pointer;
  max-width: 190px;
}
select:hover { background-color: var(--line-soft); }

.badge {
  font-size: 11px;
  color: var(--muted);
  background: var(--line-soft);
  border-radius: 999px;
  padding: 3px 9px;
  white-space: nowrap;
  font-weight: 500;
}
.badge.can-run { color: var(--green); background: color-mix(in srgb, var(--green) 14%, transparent); }

/* ---------- buttons ---------- */

.btn {
  background: var(--bg);
  color: var(--text);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 5px 11px;
  font-size: 12.5px;
  font-family: inherit;
  font-weight: 500;
  cursor: pointer;
  box-shadow: 0 1px 1px rgba(0, 0, 0, 0.05);
  transition: background-color 0.12s ease, border-color 0.12s ease;
}
.btn:hover { background: var(--line-soft); }
.btn:active { background: var(--line); }
.btn:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-run {
  background: var(--accent);
  color: var(--on-accent);
  border-color: transparent;
  font-weight: 600;
  min-width: 78px;
}
.btn-run:hover { background: color-mix(in srgb, var(--accent) 88%, #fff); }
.btn-run:active { background: color-mix(in srgb, var(--accent) 82%, #000); }
.btn-run.busy { background: var(--red); }
.btn-run.busy:hover { background: color-mix(in srgb, var(--red) 88%, #fff); }
.play { font-size: 9px; vertical-align: 1px; }

/* the appearance switch, an icon button */
.btn-icon {
  width: 28px;
  padding: 5px 0;
  text-align: center;
  font-size: 13px;
  line-height: 1;
}

/* ---------- layout ---------- */

main {
  flex: 1;
  display: grid;
  grid-template-columns: 1fr 1fr;
  min-height: 0;
}

.pane { display: flex; flex-direction: column; min-width: 0; min-height: 0; }
.pane-editor { border-right: 1px solid var(--line); }

@media (max-width: 860px) {
  main { grid-template-columns: 1fr; grid-template-rows: 1fr 1fr; }
  .pane-editor { border-right: 0; border-bottom: 1px solid var(--line); }
}

/* ---------- editor ---------- */

.editor {
  flex: 1;
  display: flex;
  min-height: 0;
  background: var(--bg);
  position: relative;
}

.gutter {
  flex: 0 0 auto;
  padding: var(--pad) 8px var(--pad) 12px;
  text-align: right;
  color: var(--faint);
  background: var(--chrome-2);
  border-right: 1px solid var(--line-soft);
  font-family: var(--code-font);
  font-size: var(--code-size);
  line-height: var(--code-line);
  font-variant-numeric: tabular-nums;
  white-space: pre;
  overflow: hidden;
  user-select: none;
  min-width: 44px;
}

/* the line the caret is on, brighter - as Xcode does it */
.gutter .on { color: var(--text); font-weight: 400; }

.code { position: relative; flex: 1; min-width: 0; }

/*
 * Behind the text, moved by the editor as the caret changes line. It is a
 * child of .code so it scrolls with nothing and is positioned by script.
 */
.caret-line {
  position: absolute;
  left: 0;
  right: 0;
  height: calc(var(--code-size) * var(--code-line));
  background: var(--caret-line);
  pointer-events: none;
  z-index: 0;
}

/*
 * The textarea and the highlighted layer must agree on every metric that moves
 * a glyph, or the caret drifts away from the text under it.
 */
.layer, .code textarea {
  margin: 0;
  padding: var(--pad) 16px;
  border: 0;
  font-family: var(--code-font);
  font-size: var(--code-size);
  line-height: var(--code-line);
  tab-size: 2;
  white-space: pre;
  word-wrap: normal;
  overflow: auto;
  position: absolute;
  inset: 0;
}

.layer {
  pointer-events: none;
  color: var(--t-plain);
  z-index: 1;
}

.code textarea {
  z-index: 2;
  background: transparent;
  color: transparent;
  caret-color: var(--accent);
  resize: none;
  outline: none;
}
.code textarea::selection { background: var(--selection); }
.code textarea:focus-visible { box-shadow: none; }

.status {
  padding: 5px var(--pad);
  border-top: 1px solid var(--line-soft);
  background: var(--chrome-2);
  color: var(--muted);
  font-size: 11.5px;
  min-height: 27px;
  font-family: var(--code-font);
  font-variant-numeric: tabular-nums;
  display: flex;
  align-items: center;
}

/* ---------- syntax colours ---------- */

.t-keyword { color: var(--t-keyword); }
.t-literal { color: var(--t-literal); }
.t-builtin { color: var(--t-builtin); }
.t-call    { color: var(--t-call); }
.t-string  { color: var(--t-string); }
.t-number  { color: var(--t-number); }
.t-comment { color: var(--t-comment); }
.t-tag     { color: var(--t-tag); }
.t-attr    { color: var(--t-attr); }

/* ---------- output ---------- */

.pane-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px var(--pad);
  border-bottom: 1px solid var(--line-soft);
  background: var(--chrome);
  font-size: 12px;
  font-weight: 600;
  color: var(--muted);
  min-height: 32px;
}

.link-btn {
  background: none;
  border: 0;
  color: var(--accent);
  font-size: 12px;
  font-family: inherit;
  font-weight: 500;
  cursor: pointer;
  padding: 2px 4px;
  border-radius: 4px;
}
.link-btn:hover { background: var(--accent-quiet); }

.output {
  flex: 1;
  overflow: auto;
  padding: 10px var(--pad);
  background: var(--bg);
  font-family: var(--code-font);
  font-size: 12.5px;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

.out-line { padding: 1px 0; }
.out-log { color: var(--t-plain); }
.out-warn { color: var(--amber); }
.out-error { color: var(--red); }
.out-result { color: var(--violet); }
.out-note { color: var(--muted); }
.out-meta {
  color: var(--muted);
  border-top: 1px solid var(--line-soft);
  margin-top: 8px;
  padding-top: 8px;
}
.out-empty { color: var(--muted); }

.preview {
  flex: 1;
  border: 0;
  background: #ffffff;
  width: 100%;
}

/* ---------- footer ---------- */

footer {
  padding: 6px var(--pad);
  border-top: 1px solid var(--line);
  background: var(--chrome);
  color: var(--muted);
  font-size: 11px;
  text-align: center;
}
footer a { color: var(--accent); margin-left: 6px; text-decoration: none; }
footer a:hover { text-decoration: underline; }

@media (max-width: 620px) {
  .bar { padding: 8px 10px; }
  .bar-left strong, footer { display: none; }
}

@media (prefers-reduced-motion: reduce) {
  .btn { transition: none; }
}