@import url('fonts.css');

/* ==========================================================================
   Tokens
   ========================================================================== */

:root {
  --font-ui: 'Inter', ui-sans-serif, system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, 'SF Mono', Menlo, Consolas, monospace;

  --r-xs: 6px;
  --r-sm: 9px;
  --r-md: 12px;
  --r-lg: 18px;
  --r-xl: 26px;

  --ease: cubic-bezier(.2, .7, .2, 1);
  --header-h: 60px;
  --tabbar-h: 64px;
  --code-size: 14px;
  --split: 58%;

  color-scheme: dark;
  --bg: #06090f;
  --bg-elev: #0a0f1a;
  --panel: #0c1220;
  --panel-2: #101829;
  --panel-3: #141d31;
  --glass: rgba(14, 20, 35, .72);
  --line: rgba(148, 170, 210, .11);
  --line-2: rgba(148, 170, 210, .2);
  --text: #e8edf6;
  --text-2: #b5c0d4;
  --muted: #7c889e;
  --faint: #4b566b;

  --accent: #00add8;
  --accent-hi: #4fd6f5;
  --accent-ink: #001a22;
  --accent-soft: rgba(0, 173, 216, .12);
  --accent-glow: rgba(0, 173, 216, .35);
  --violet: #8f83ff;
  --violet-soft: rgba(143, 131, 255, .12);
  --ok: #34d399;
  --ok-soft: rgba(52, 211, 153, .12);
  --err: #ff7a85;
  --err-soft: rgba(255, 122, 133, .1);
  --warn: #fbbf5d;

  --shadow-sm: 0 1px 2px rgba(0, 0, 0, .4);
  --shadow-md: 0 8px 24px -8px rgba(0, 0, 0, .6), 0 2px 6px rgba(0, 0, 0, .3);
  --shadow-lg: 0 30px 80px -20px rgba(0, 0, 0, .75), 0 0 0 1px var(--line);

  /* syntax */
  --s-keyword: #ff7ab2;
  --s-type: #5ce1e6;
  --s-typedef: #7ee7c7;
  --s-func: #82aaff;
  --s-builtin: #c3a6ff;
  --s-string: #a5e075;
  --s-number: #f7b267;
  --s-constant: #f7b267;
  --s-comment: #5d6b84;
  --s-package: #ffcb6b;
  --s-exported: #9cc3ff;
  --s-op: #89ddff;
  --ed-active: rgba(120, 150, 210, .07);
}

:root[data-theme='light'] {
  color-scheme: light;
  --bg: #f5f7fb;
  --bg-elev: #ffffff;
  --panel: #ffffff;
  --panel-2: #f6f8fc;
  --panel-3: #eef2f8;
  --glass: rgba(255, 255, 255, .78);
  --line: rgba(15, 30, 60, .09);
  --line-2: rgba(15, 30, 60, .16);
  --text: #0b1426;
  --text-2: #334058;
  --muted: #5f6b81;
  --faint: #97a1b4;

  --accent: #007d9c;
  --accent-hi: #00add8;
  --accent-ink: #ffffff;
  --accent-soft: rgba(0, 125, 156, .09);
  --accent-glow: rgba(0, 173, 216, .25);
  --violet: #5b4ee0;
  --violet-soft: rgba(91, 78, 224, .08);
  --ok: #0f9d6b;
  --ok-soft: rgba(15, 157, 107, .09);
  --err: #d6334a;
  --err-soft: rgba(214, 51, 74, .07);
  --warn: #b7791f;

  --shadow-sm: 0 1px 2px rgba(15, 30, 60, .06);
  --shadow-md: 0 10px 30px -12px rgba(15, 30, 60, .18), 0 2px 6px rgba(15, 30, 60, .05);
  --shadow-lg: 0 30px 80px -24px rgba(15, 30, 60, .28), 0 0 0 1px var(--line);

  --s-keyword: #c2185b;
  --s-type: #00838f;
  --s-typedef: #00796b;
  --s-func: #2f5bd3;
  --s-builtin: #7b3fe4;
  --s-string: #3a7d0a;
  --s-number: #b45309;
  --s-constant: #b45309;
  --s-comment: #8a94a6;
  --s-package: #9a6700;
  --s-exported: #1d4ed8;
  --s-op: #0e7490;
  --ed-active: rgba(15, 50, 110, .045);
}

@media (prefers-color-scheme: light) {
  :root:not([data-theme]) {
    color-scheme: light;
    --bg: #f5f7fb; --bg-elev: #fff; --panel: #fff; --panel-2: #f6f8fc; --panel-3: #eef2f8;
    --glass: rgba(255, 255, 255, .78); --line: rgba(15, 30, 60, .09); --line-2: rgba(15, 30, 60, .16);
    --text: #0b1426; --text-2: #334058; --muted: #5f6b81; --faint: #97a1b4;
    --accent: #007d9c; --accent-hi: #00add8; --accent-ink: #fff; --accent-soft: rgba(0, 125, 156, .09);
    --accent-glow: rgba(0, 173, 216, .25); --violet: #5b4ee0; --violet-soft: rgba(91, 78, 224, .08);
    --ok: #0f9d6b; --ok-soft: rgba(15, 157, 107, .09); --err: #d6334a; --err-soft: rgba(214, 51, 74, .07); --warn: #b7791f;
    --shadow-sm: 0 1px 2px rgba(15, 30, 60, .06);
    --shadow-md: 0 10px 30px -12px rgba(15, 30, 60, .18), 0 2px 6px rgba(15, 30, 60, .05);
    --shadow-lg: 0 30px 80px -24px rgba(15, 30, 60, .28), 0 0 0 1px var(--line);
    --s-keyword: #c2185b; --s-type: #00838f; --s-typedef: #00796b; --s-func: #2f5bd3; --s-builtin: #7b3fe4;
    --s-string: #3a7d0a; --s-number: #b45309; --s-constant: #b45309; --s-comment: #8a94a6; --s-package: #9a6700;
    --s-exported: #1d4ed8; --s-op: #0e7490; --ed-active: rgba(15, 50, 110, .045);
  }
}

/* ==========================================================================
   Base
   ========================================================================== */

*, *::before, *::after { box-sizing: border-box; }

html, body { height: 100%; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.55 var(--font-ui);
  font-feature-settings: 'cv11', 'ss01', 'ss03';
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  -webkit-tap-highlight-color: transparent;
  overflow: hidden;
}

button, input, select, textarea { font: inherit; color: inherit; }
button { cursor: pointer; }
a { color: var(--accent-hi); text-decoration: none; }
:root[data-theme='light'] a { color: var(--accent); }
code, kbd, pre { font-family: var(--font-mono); font-variant-ligatures: none; }
::selection { background: rgba(0, 173, 216, .3); }

:focus-visible { outline: 2px solid var(--accent-hi); outline-offset: 2px; border-radius: 6px; }

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

.icon { width: 18px; height: 18px; flex: none; stroke: currentColor; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.icon-sm { width: 15px; height: 15px; }

/* ==========================================================================
   App shell
   ========================================================================== */

.app {
  height: 100dvh;
  display: grid;
  grid-template-rows: var(--header-h) 1fr;
  grid-template-columns: minmax(0, 1fr);
  position: relative;
  isolation: isolate;
}

.app::before {
  /* ambient light */
  content: '';
  position: fixed; inset: -20% -10% auto -10%; height: 70vh; z-index: -1; pointer-events: none;
  background:
    radial-gradient(40% 60% at 15% 0%, rgba(0, 173, 216, .14), transparent 70%),
    radial-gradient(35% 50% at 85% 5%, rgba(143, 131, 255, .12), transparent 70%);
}

.topbar {
  position: relative;
  z-index: 20;
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 max(16px, env(safe-area-inset-right)) 0 max(16px, env(safe-area-inset-left));
  border-bottom: 1px solid var(--line);
  background: var(--glass);
  backdrop-filter: saturate(160%) blur(18px);
  -webkit-backdrop-filter: saturate(160%) blur(18px);
}

.brand { display: flex; align-items: center; gap: 10px; color: var(--text) !important; font-weight: 700; letter-spacing: -.01em; }
.brand-mark { width: 30px; height: 30px; flex: none; filter: drop-shadow(0 4px 14px var(--accent-glow)); }
.brand-name { font-size: 16px; }
.brand-name b { color: var(--accent-hi); font-weight: 800; }
:root[data-theme='light'] .brand-name b { color: var(--accent); }

.nav { display: flex; gap: 4px; margin-left: 12px; }
.nav a {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 7px 12px; border-radius: var(--r-sm);
  color: var(--muted); font-weight: 550; font-size: 14px;
  transition: color .15s, background .15s;
}
.nav a:hover { color: var(--text); background: var(--panel-2); }
.nav a[aria-current='page'] { color: var(--text); background: var(--panel-3); box-shadow: inset 0 0 0 1px var(--line); }

.top-actions { margin-left: auto; display: flex; align-items: center; gap: 6px; }

.pill {
  display: inline-flex; align-items: center; gap: 7px;
  height: 28px; padding: 0 10px; border-radius: 99px;
  border: 1px solid var(--line); background: var(--panel-2);
  color: var(--text-2); font-size: 12px; font-weight: 550; white-space: nowrap;
}
.dot { width: 7px; height: 7px; border-radius: 50%; background: var(--faint); flex: none; }
.dot.ok { background: var(--ok); box-shadow: 0 0 0 3px var(--ok-soft); }
.dot.err { background: var(--err); box-shadow: 0 0 0 3px var(--err-soft); }
.dot.busy { background: var(--warn); animation: pulse 1s infinite var(--ease); }

@keyframes pulse { 50% { opacity: .35; } }

.icon-btn {
  display: inline-grid; place-items: center;
  width: 36px; height: 36px; border-radius: var(--r-sm);
  border: 1px solid transparent; background: transparent; color: var(--muted);
  transition: color .15s, background .15s, border-color .15s;
}
.icon-btn:hover { color: var(--text); background: var(--panel-2); border-color: var(--line); }

main#view { min-height: 0; position: relative; }

.view { height: 100%; }
.view[hidden] { display: none !important; }
.view-scroll { overflow-x: hidden; overflow-y: auto; overscroll-behavior: contain; scroll-behavior: smooth; }

/* Mobile tab bar */
.tabbar { display: none; }

@media (max-width: 760px) {
  :root { --header-h: 54px; }
  .app { grid-template-rows: var(--header-h) 1fr calc(var(--tabbar-h) + env(safe-area-inset-bottom)); }
  .nav, .hide-sm { display: none !important; }
  .tabbar {
    display: grid; grid-template-columns: repeat(var(--tabs, 2), 1fr);
    padding: 6px 8px env(safe-area-inset-bottom);
    border-top: 1px solid var(--line);
    background: var(--glass);
    backdrop-filter: saturate(160%) blur(18px);
    -webkit-backdrop-filter: saturate(160%) blur(18px);
    z-index: 20;
  }
  .tabbar a {
    display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px;
    color: var(--muted); font-size: 11px; font-weight: 600; border-radius: var(--r-md);
  }
  .tabbar a .icon { width: 22px; height: 22px; }
  .tabbar a[aria-current='page'] { color: var(--accent-hi); }
  :root[data-theme='light'] .tabbar a[aria-current='page'] { color: var(--accent); }
  .app.kb-open { grid-template-rows: var(--header-h) 1fr; }
  .app.kb-open .tabbar { display: none; }
}

/* ==========================================================================
   Buttons
   ========================================================================== */

.btn {
  --h: 36px;
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  height: var(--h); padding: 0 14px; border-radius: var(--r-sm);
  border: 1px solid var(--line-2); background: var(--panel-2);
  color: var(--text); font-size: 13.5px; font-weight: 600; white-space: nowrap;
  transition: transform .12s var(--ease), background .15s, border-color .15s, box-shadow .2s, color .15s;
  user-select: none;
}
.btn:hover { background: var(--panel-3); border-color: var(--line-2); }
.btn:active { transform: translateY(1px) scale(.99); }
.btn[disabled] { opacity: .5; pointer-events: none; }
.btn-ghost { background: transparent; border-color: transparent; color: var(--text-2); }
.btn-ghost:hover { background: var(--panel-2); border-color: var(--line); color: var(--text); }

.btn-primary {
  border: 0;
  color: var(--accent-ink);
  background: linear-gradient(180deg, #2cc6ec, #00a3cc);
  box-shadow: 0 1px 0 rgba(255, 255, 255, .35) inset, 0 8px 24px -8px var(--accent-glow), 0 0 0 1px rgba(0, 120, 150, .5);
}
:root[data-theme='light'] .btn-primary { color: #fff; background: linear-gradient(180deg, #0a9cc2, #007d9c); }
.btn-primary:hover { background: linear-gradient(180deg, #45d2f4, #09b0da); box-shadow: 0 1px 0 rgba(255, 255, 255, .35) inset, 0 10px 30px -8px var(--accent-glow), 0 0 0 1px rgba(0, 120, 150, .5); }
:root[data-theme='light'] .btn-primary:hover { background: linear-gradient(180deg, #13aad2, #0689aa); }

.btn-danger { border: 0; color: #fff; background: linear-gradient(180deg, #ff7f8a, #e8505e); box-shadow: 0 8px 24px -10px rgba(255, 90, 110, .6); }

.btn-lg { --h: 48px; padding: 0 22px; font-size: 15px; border-radius: var(--r-md); }

kbd {
  display: inline-grid; place-items: center; min-width: 20px; height: 20px; padding: 0 5px;
  border-radius: 5px; font-size: 11px; font-weight: 600;
  background: rgba(0, 0, 0, .14); color: inherit; opacity: .8;
}

/* ==========================================================================
   Playground
   ========================================================================== */

.play {
  display: grid;
  grid-template-rows: auto 1fr;
  min-height: 0;
}

.play-toolbar {
  display: flex; align-items: center; gap: 8px;
  padding: 10px 16px;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 60%, transparent);
}

.file-tab {
  display: inline-flex; align-items: center; gap: 8px;
  height: 34px; padding: 0 12px; border-radius: var(--r-sm);
  background: var(--panel-2); border: 1px solid var(--line);
  font: 600 13px var(--font-mono); color: var(--text);
}
.file-tab .gopher { color: var(--accent-hi); }
.file-tab .dirty { width: 7px; height: 7px; border-radius: 50%; background: var(--warn); opacity: 0; transition: opacity .2s; }
.file-tab.is-dirty .dirty { opacity: 1; }

.toolbar-spacer { flex: 1; }

.menu-wrap { position: relative; }
.menu {
  position: absolute; top: calc(100% + 8px); left: 0; z-index: 50;
  width: min(320px, calc(100vw - 32px)); max-height: min(70vh, 520px); overflow: auto;
  padding: 6px; border-radius: var(--r-md);
  background: var(--panel); box-shadow: var(--shadow-lg);
  transform-origin: top left; animation: pop .16s var(--ease);
}
.menu[hidden] { display: none; }
.menu button {
  display: grid; grid-template-columns: 30px 1fr; align-items: center; gap: 2px 10px;
  width: 100%; padding: 9px 10px; border: 0; border-radius: var(--r-sm);
  background: transparent; text-align: left;
}
.menu button:hover, .menu button:focus-visible { background: var(--panel-3); outline: none; }
.menu .m-ico { grid-row: span 2; width: 30px; height: 30px; display: grid; place-items: center; border-radius: 8px; background: var(--accent-soft); color: var(--accent-hi); font: 700 12px var(--font-mono); }
.menu .m-title { font-weight: 600; font-size: 13.5px; }
.menu .m-note { color: var(--muted); font-size: 12px; }

@keyframes pop { from { opacity: 0; transform: translateY(-4px) scale(.98); } }

.play-split {
  display: grid;
  grid-template-columns: var(--split) 8px 1fr;
  min-height: 0;
  padding: 12px 16px 16px;
  gap: 0;
}

.pane {
  display: flex; flex-direction: column; min-width: 0; min-height: 0;
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--panel);
  box-shadow: var(--shadow-md);
  overflow: hidden;
}

.pane-head {
  display: flex; align-items: center; gap: 8px;
  height: 44px; padding: 0 8px 0 14px; flex: none;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, var(--panel-2), var(--panel));
  font-size: 12.5px; font-weight: 650; color: var(--text-2); letter-spacing: .01em;
}
.pane-head .title { display: inline-flex; align-items: center; gap: 8px; }
.pane-head .title .icon { color: var(--muted); }
.pane-head .sp { flex: 1; }
.pane-head .icon-btn { width: 32px; height: 32px; }

.lights { display: inline-flex; gap: 6px; margin-right: 6px; }
.lights i { width: 10px; height: 10px; border-radius: 50%; background: var(--panel-3); box-shadow: inset 0 0 0 1px var(--line-2); }

.splitter {
  cursor: col-resize; position: relative; touch-action: none;
}
.splitter::after {
  content: ''; position: absolute; top: 50%; left: 50%; width: 3px; height: 40px;
  transform: translate(-50%, -50%); border-radius: 3px; background: var(--line-2);
  transition: background .15s, height .2s var(--ease);
}
.splitter:hover::after, .splitter.drag::after { background: var(--accent); height: 64px; }

.seg { display: none; }

/* Editor --------------------------------------------------------------- */

.editor { position: relative; flex: 1; min-height: 0; display: flex; flex-direction: column; }

.ed-scroll {
  flex: 1; min-height: 0; overflow: auto; display: flex; align-items: flex-start;
  overscroll-behavior: contain;
  font: 400 var(--code-size)/1.7 var(--font-mono);
  font-variant-ligatures: none;
  tab-size: 4; -moz-tab-size: 4;
}

.ed-gutter {
  position: sticky; left: 0; z-index: 2; flex: none;
  min-height: 100%;
  padding: 16px 12px 16px 14px;
  min-width: calc(var(--ed-gutter-ch, 2) * 1ch + 28px);
  text-align: right; color: var(--faint);
  background: var(--panel);
  border-right: 1px solid var(--line);
  user-select: none;
}
.ed-gutter span { display: block; }
.ed-gutter span.cur { color: var(--text-2); }
.ed-gutter span.err { color: var(--err); font-weight: 700; position: relative; }
.ed-gutter span.err::before { content: ''; position: absolute; left: -9px; top: 50%; width: 5px; height: 5px; margin-top: -2.5px; border-radius: 50%; background: var(--err); }

.ed-body { position: relative; display: grid; flex: 1; min-width: max-content; min-height: 100%; }
.ed-hl, .ed-input {
  grid-area: 1 / 1; margin: 0; border: 0;
  padding: 16px 24px 40vh 16px;
  font: inherit; line-height: inherit; letter-spacing: 0;
  white-space: pre; word-wrap: normal; overflow-wrap: normal;
  tab-size: inherit; -moz-tab-size: inherit;
}
.ed-hl { color: var(--text); pointer-events: none; }
.ed-input {
  position: relative; z-index: 1;
  width: 100%; height: 100%; min-height: 100%;
  resize: none; outline: none; overflow: hidden;
  background: transparent; color: transparent;
  caret-color: var(--accent-hi);
  -webkit-text-fill-color: transparent;
}
.ed-input::selection { background: rgba(0, 173, 216, .28); -webkit-text-fill-color: transparent; }
:root[data-theme='light'] .ed-input { caret-color: var(--accent); }
:root[data-theme='light'] .ed-input::selection { background: rgba(0, 125, 156, .2); }

.ed-marks { position: absolute; inset: 0; pointer-events: none; }
.ed-active { position: absolute; left: 0; right: 0; top: 0; background: var(--ed-active); transition: transform .06s linear; }
.editor:not(:focus-within) .ed-active { opacity: 0; }
.ed-err { position: absolute; left: 0; right: 0; background: var(--err-soft); box-shadow: inset 2px 0 0 var(--err); }

.t-keyword { color: var(--s-keyword); }
.t-type { color: var(--s-type); }
.t-typedef { color: var(--s-typedef); font-weight: 600; }
.t-func { color: var(--s-func); }
.t-builtin { color: var(--s-builtin); }
.t-string, .t-rune { color: var(--s-string); }
.t-number, .t-constant { color: var(--s-number); }
.t-comment { color: var(--s-comment); font-style: italic; }
.t-package { color: var(--s-package); }
.t-exported { color: var(--s-exported); }
.t-op { color: var(--s-op); }

/* Mobile key bar */
.keybar {
  display: none; gap: 6px; padding: 8px; overflow-x: auto; flex: none;
  border-top: 1px solid var(--line); background: var(--panel-2);
  scrollbar-width: none;
}
.keybar::-webkit-scrollbar { display: none; }
.keybar button {
  flex: none; min-width: 40px; height: 36px; padding: 0 10px;
  border: 1px solid var(--line); border-radius: 8px;
  background: var(--panel); color: var(--text);
  font: 600 14px var(--font-mono);
  box-shadow: 0 1px 0 var(--line);
}
.keybar button:active { background: var(--accent-soft); border-color: var(--accent); }

/* Terminal ------------------------------------------------------------- */

.term {
  flex: 1; min-height: 0; overflow: auto; overscroll-behavior: contain;
  padding: 14px 16px 24px;
  font-variant-ligatures: none;
  font: 400 calc(var(--code-size) - .5px)/1.65 var(--font-mono);
  white-space: pre-wrap; word-break: break-word;
  background:
    linear-gradient(var(--panel), var(--panel)) padding-box;
  cursor: text;
}
.term-out > span { white-space: pre-wrap; }
.k-out { color: var(--text); }
.k-err { color: var(--err); }
.k-sys { color: var(--muted); }
.k-ok { color: var(--ok); }
.k-warn { color: var(--warn); }
.k-in { color: var(--accent-hi); }
:root[data-theme='light'] .k-in { color: var(--accent); }

.term-input input {
  border: 0; outline: 0; padding: 0; margin: 0;
  background: transparent; color: var(--accent-hi);
  font: inherit; caret-color: var(--accent-hi);
  min-width: 2ch; max-width: 100%;
}
:root[data-theme='light'] .term-input input { color: var(--accent); caret-color: var(--accent); }
.term-input::after {
  content: 'kiriting ↵'; margin-left: 10px; padding: 1px 7px; border-radius: 99px;
  font: 600 10.5px var(--font-ui); letter-spacing: .02em; vertical-align: 2px;
  color: var(--accent-hi); background: var(--accent-soft);
  animation: pulse 1.6s infinite;
}

.term-empty {
  height: 100%; display: grid; place-content: center; justify-items: center; gap: 10px;
  text-align: center; color: var(--muted); font: 13.5px var(--font-ui); white-space: normal; padding: 20px;
}
.term-empty .big { width: 46px; height: 46px; border-radius: 14px; display: grid; place-items: center; background: var(--accent-soft); color: var(--accent-hi); }
.term-empty strong { color: var(--text-2); font-weight: 650; }

.term-note {
  margin: 10px 0 4px; padding: 12px 14px; border-radius: var(--r-md); white-space: normal;
  font: 13.5px/1.6 var(--font-ui); color: var(--text-2);
  background: rgba(251, 191, 93, .08); border: 1px solid rgba(251, 191, 93, .3);
}
.term-note b { display: block; margin-bottom: 4px; color: var(--warn); }
.term-note p { margin: 0 0 8px; }
.term-note code { padding: 1px 5px; border-radius: 5px; background: var(--panel-3); color: var(--text); font-size: .9em; }
.term-note pre { margin: 0; padding: 10px 12px; border-radius: var(--r-sm); background: var(--panel); border: 1px solid var(--line); font: 12.5px/1.6 var(--font-mono); color: var(--text); white-space: pre; overflow-x: auto; tab-size: 4; font-variant-ligatures: none; }

.run-line {
  display: flex; flex-wrap: wrap; align-items: center; gap: 6px 10px;
  margin: 10px 0 2px; padding-top: 10px; border-top: 1px dashed var(--line-2);
  font: 600 11.5px var(--font-ui); color: var(--muted);
}
.run-line .chip { display: inline-flex; align-items: center; gap: 6px; padding: 2px 8px; border-radius: 99px; background: var(--panel-3); }
.run-line .chip.ok { color: var(--ok); background: var(--ok-soft); }
.run-line .chip.err { color: var(--err); background: var(--err-soft); }
.run-line .chip.warn { color: var(--warn); background: rgba(251, 191, 93, .1); }

.diag { display: grid; gap: 6px; margin: 8px 0; white-space: normal; }
.diag button {
  display: flex; gap: 10px; align-items: baseline; text-align: left;
  padding: 8px 10px; border-radius: var(--r-sm);
  border: 1px solid color-mix(in srgb, var(--err) 30%, transparent);
  background: var(--err-soft); color: var(--text);
  font: 12.5px/1.5 var(--font-mono);
}
.diag button:hover { border-color: var(--err); }
.diag .loc { color: var(--err); font-weight: 700; white-space: nowrap; }

.progress { height: 2px; flex: none; background: transparent; overflow: hidden; position: relative; }
.progress.on::after {
  content: ''; position: absolute; inset: 0; width: 40%;
  background: linear-gradient(90deg, transparent, var(--accent-hi), transparent);
  animation: slide 1.1s infinite var(--ease);
}
@keyframes slide { from { transform: translateX(-100%); } to { transform: translateX(260%); } }

.stdin-box { flex: none; border-top: 1px solid var(--line); background: var(--panel-2); }
.stdin-box summary { cursor: pointer; padding: 10px 14px; font-size: 12.5px; font-weight: 600; color: var(--text-2); list-style: none; display: flex; gap: 8px; align-items: center; }
.stdin-box summary::-webkit-details-marker { display: none; }
.stdin-box textarea {
  display: block; width: calc(100% - 24px); margin: 0 12px 12px; min-height: 70px; resize: vertical;
  padding: 10px 12px; border-radius: var(--r-sm); border: 1px solid var(--line-2);
  background: var(--panel); font: 13px/1.5 var(--font-mono); outline: none;
}
.stdin-box textarea:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.statusbar {
  display: flex; align-items: center; gap: 14px; flex: none;
  height: 30px; padding: 0 14px;
  border-top: 1px solid var(--line);
  font: 500 11.5px var(--font-ui); color: var(--muted);
  white-space: nowrap; overflow: hidden;
}
.statusbar span { display: inline-flex; align-items: center; gap: 6px; }

/* Run FAB (mobile) */
.fab { display: none; }

@media (max-width: 1000px) {
  .play-split { grid-template-columns: 1fr; grid-template-rows: auto 1fr; padding: 10px 12px 12px; gap: 10px; }
  .splitter { display: none; }
  .seg {
    display: grid; grid-template-columns: 1fr 1fr; padding: 3px; gap: 3px;
    border-radius: var(--r-md); background: var(--panel-2); border: 1px solid var(--line);
  }
  .seg button {
    height: 34px; border: 0; border-radius: var(--r-sm); background: transparent;
    color: var(--muted); font-weight: 650; font-size: 13.5px;
    display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  }
  .seg button[aria-selected='true'] { background: var(--panel); color: var(--text); box-shadow: var(--shadow-sm), 0 0 0 1px var(--line); }
  .seg .badge { min-width: 8px; height: 8px; border-radius: 50%; background: var(--accent-hi); display: none; }
  .seg .badge.on { display: inline-block; }
  .play[data-pane='code'] .pane-out, .play[data-pane='out'] .pane-code { display: none; }
}

@media (max-width: 760px) {
  :root { --code-size: 13.5px; }
  .play-toolbar { padding: 8px 12px; gap: 6px; }
  .play-toolbar .btn-label { display: none; }
  .play-toolbar .btn { --h: 34px; padding: 0 10px; }
  .play-toolbar .run-btn { display: none; }
  .keybar { display: flex; }
  .editor:not(:focus-within) + .keybar { display: none; }
  .pane { border-radius: var(--r-md); }
  .ed-gutter { padding-left: 10px; padding-right: 8px; min-width: calc(var(--ed-gutter-ch, 2) * 1ch + 20px); }
  .ed-hl, .ed-input { padding-left: 12px; }
  .fab {
    display: inline-flex; position: fixed; z-index: 30;
    right: max(16px, env(safe-area-inset-right));
    bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom) + 16px);
    --h: 54px; padding: 0 22px 0 18px; border-radius: 99px; font-size: 15px;
  }
  .app.kb-open .fab { bottom: 16px; }
  .play[data-pane='code'] .fab { box-shadow: 0 16px 40px -10px var(--accent-glow), 0 0 0 1px rgba(0, 120, 150, .5); }
  .statusbar .hide-xs { display: none; }
  .statusbar { padding-right: 140px; }
}

/* ==========================================================================
   Home
   ========================================================================== */

.wrap { width: min(1180px, 100%); margin: 0 auto; padding: 0 24px; }

.hero {
  position: relative;
  padding: 72px 0 56px;
  display: grid; grid-template-columns: minmax(0, 1.05fr) minmax(0, .95fr); gap: 56px; align-items: center;
}
.hero::before {
  content: ''; position: absolute; inset: -60px -40vw 0; z-index: -1; pointer-events: none;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 44px 44px;
  mask-image: radial-gradient(60% 70% at 30% 30%, #000 20%, transparent 75%);
  -webkit-mask-image: radial-gradient(60% 70% at 30% 30%, #000 20%, transparent 75%);
  opacity: .55;
}

.eyebrow {
  display: inline-flex; align-items: center; gap: 10px;
  height: 32px; padding: 0 14px 0 6px; border-radius: 99px;
  border: 1px solid var(--line-2); background: var(--glass);
  font-size: 12.5px; font-weight: 600; color: var(--text-2);
  backdrop-filter: blur(10px);
}
.eyebrow b { display: inline-grid; place-items: center; height: 22px; padding: 0 8px; border-radius: 99px; background: var(--accent-soft); color: var(--accent-hi); font-size: 11px; letter-spacing: .04em; }
:root[data-theme='light'] .eyebrow b { color: var(--accent); }

.hero h1 {
  margin: 22px 0 18px;
  font-size: clamp(38px, 5.6vw, 68px); line-height: 1.02; letter-spacing: -.035em; font-weight: 800;
}
.grad {
  background: linear-gradient(100deg, #34d3f7 0%, #00add8 35%, #8f83ff 100%);
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
:root[data-theme='light'] .grad { background-image: linear-gradient(100deg, #0891b2 0%, #007d9c 35%, #5b4ee0 100%); }

.lead { font-size: clamp(16px, 1.6vw, 18.5px); line-height: 1.6; color: var(--text-2); max-width: 540px; margin: 0 0 30px; }
.cta { display: flex; flex-wrap: wrap; gap: 12px; }

.stats { display: grid; grid-template-columns: repeat(4, auto); gap: 28px; margin-top: 44px; justify-content: start; }
.stat b { display: block; font-size: 26px; font-weight: 800; letter-spacing: -.02em; }
.stat span { font-size: 12.5px; color: var(--muted); font-weight: 550; }

/* hero code window */
.window {
  position: relative; border-radius: var(--r-xl); overflow: hidden;
  background: var(--panel); box-shadow: var(--shadow-lg);
  transform: perspective(1400px) rotateY(-6deg) rotateX(2deg);
  transition: transform .6s var(--ease);
}
.window:hover { transform: none; }
.window::before {
  content: ''; position: absolute; inset: -1px; border-radius: inherit; padding: 1px; pointer-events: none;
  background: linear-gradient(140deg, rgba(79, 214, 245, .55), transparent 40%, transparent 60%, rgba(143, 131, 255, .5));
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor; mask-composite: exclude;
}
.window-glow { position: absolute; inset: 10% 5% -10%; z-index: -1; background: radial-gradient(closest-side, var(--accent-glow), transparent); filter: blur(40px); }
.window-bar { display: flex; align-items: center; gap: 10px; height: 42px; padding: 0 16px; border-bottom: 1px solid var(--line); background: var(--panel-2); font: 600 12px var(--font-mono); color: var(--muted); }
.window-bar .lights i:nth-child(1) { background: #ff5f57; box-shadow: none; }
.window-bar .lights i:nth-child(2) { background: #febc2e; box-shadow: none; }
.window-bar .lights i:nth-child(3) { background: #28c840; box-shadow: none; }
.window pre { margin: 0; padding: 18px 20px; font: 13px/1.7 var(--font-mono); font-variant-ligatures: none; overflow: hidden; tab-size: 4; }
.window-term { border-top: 1px solid var(--line); padding: 14px 20px 18px; font: 12.5px/1.7 var(--font-mono); font-variant-ligatures: none; background: var(--panel-2); }
.window-term .prompt { color: var(--accent-hi); }
.caret { display: inline-block; width: 8px; height: 15px; vertical-align: -2px; background: var(--accent-hi); animation: blink 1.1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* sections */
.section { padding: 56px 0; }
.section-head { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.section h2 { margin: 0; font-size: clamp(26px, 3.2vw, 38px); letter-spacing: -.025em; line-height: 1.1; font-weight: 800; }
.kicker { display: block; margin-bottom: 10px; font-size: 12px; font-weight: 700; letter-spacing: .12em; text-transform: uppercase; color: var(--accent-hi); }
:root[data-theme='light'] .kicker { color: var(--accent); }
.section-sub { color: var(--muted); max-width: 440px; margin: 0; }

/* lesson method timeline */
.method { display: grid; grid-template-columns: repeat(7, 1fr); gap: 10px; counter-reset: step; }
.step {
  position: relative; padding: 16px 14px 18px; border-radius: var(--r-md);
  border: 1px solid var(--line); background: var(--panel);
  counter-increment: step; transition: transform .25s var(--ease), border-color .2s;
}
.step:hover { transform: translateY(-3px); border-color: var(--line-2); }
.step::before { content: '0' counter(step); display: block; font: 700 11px var(--font-mono); color: var(--faint); margin-bottom: 14px; }
.step b { display: block; font-size: 14.5px; letter-spacing: -.01em; }
.step span { font-size: 12px; color: var(--muted); }
.step .bar { position: absolute; left: 14px; right: 14px; bottom: 0; height: 2px; border-radius: 2px; background: linear-gradient(90deg, var(--accent), var(--violet)); transform-origin: left; transform: scaleX(var(--w, .3)); opacity: .8; }

/* roadmap tracks */
.tracks { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.track {
  position: relative; padding: 22px; border-radius: var(--r-lg);
  border: 1px solid var(--line); background: var(--panel);
  overflow: hidden; transition: transform .25s var(--ease), border-color .2s, box-shadow .25s;
}
.track:hover { transform: translateY(-3px); border-color: var(--line-2); box-shadow: var(--shadow-md); }
.track::after { content: ''; position: absolute; top: -40%; right: -30%; width: 70%; height: 90%; background: radial-gradient(closest-side, var(--tint, var(--accent-soft)), transparent); pointer-events: none; }
.track-top { display: flex; align-items: center; justify-content: space-between; margin-bottom: 14px; }
.track-no { font: 700 11.5px var(--font-mono); color: var(--muted); }
.track-ico { width: 38px; height: 38px; display: grid; place-items: center; border-radius: 11px; background: var(--tint, var(--accent-soft)); color: var(--tint-fg, var(--accent-hi)); }
.track h3 { margin: 0 0 6px; font-size: 18px; letter-spacing: -.015em; }
.track p { margin: 0 0 14px; color: var(--muted); font-size: 13.5px; }
.track ul { list-style: none; margin: 0; padding: 0; display: flex; flex-wrap: wrap; gap: 6px; }
.track li { padding: 3px 9px; border-radius: 99px; font-size: 12px; font-weight: 550; color: var(--text-2); background: var(--panel-2); border: 1px solid var(--line); }

.band {
  margin: 24px 0 72px; padding: 36px; border-radius: var(--r-xl);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
  background:
    radial-gradient(60% 120% at 0% 0%, rgba(0, 173, 216, .18), transparent 60%),
    radial-gradient(50% 120% at 100% 100%, rgba(143, 131, 255, .16), transparent 60%),
    var(--panel);
  border: 1px solid var(--line-2);
}
.band h3 { margin: 0 0 6px; font-size: 24px; letter-spacing: -.02em; }
.band p { margin: 0; color: var(--text-2); }

.footer { padding: 28px 0 40px; border-top: 1px solid var(--line); color: var(--muted); font-size: 13px; display: flex; justify-content: space-between; gap: 16px; flex-wrap: wrap; }

@media (max-width: 1000px) {
  .hero { grid-template-columns: minmax(0, 1fr); padding-top: 48px; gap: 40px; }
  .window { transform: none; }
  .method { grid-template-columns: repeat(4, 1fr); }
  .tracks { grid-template-columns: 1fr 1fr; }
}

@media (max-width: 760px) {
  .wrap { padding: 0 16px; }
  .hero { padding: 32px 0 24px; gap: 32px; }
  .hero h1 { margin: 18px 0 14px; }
  .lead { margin-bottom: 24px; }
  .cta .btn { flex: 1; }
  .stats { grid-template-columns: repeat(2, 1fr); gap: 18px 24px; margin-top: 32px; }
  .window pre { font-size: 12px; padding: 14px 16px; }
  .section { padding: 36px 0; }
  .section-head { flex-direction: column; align-items: start; gap: 10px; }
  .method { grid-template-columns: repeat(2, 1fr); }
  .method .step:last-child { grid-column: span 2; }
  .tracks { grid-template-columns: 1fr; }
  .band { flex-direction: column; align-items: stretch; padding: 24px; margin-bottom: 40px; }
}

/* ==========================================================================
   Course list
   ========================================================================== */

.track-link, .track-soon { display: inline-flex; align-items: center; gap: 6px; margin-top: 16px; font-size: 13px; font-weight: 650; }
.track-soon { color: var(--faint); }

.learn-head { display: flex; align-items: end; justify-content: space-between; gap: 32px; padding: 48px 0 28px; }
.learn-head h1 { margin: 0 0 10px; font-size: clamp(28px, 3.6vw, 42px); letter-spacing: -.03em; line-height: 1.1; }
.course-progress { display: flex; align-items: center; gap: 16px; flex: none; }
.course-progress strong { display: block; margin-bottom: 8px; font-size: 14px; }
.cp-ring {
  --p: 0; width: 68px; height: 68px; border-radius: 50%; display: grid; place-items: center; flex: none;
  background: conic-gradient(var(--accent) calc(var(--p) * 1turn), var(--panel-3) 0);
}
.cp-ring b { width: 54px; height: 54px; border-radius: 50%; display: grid; place-items: center; background: var(--bg); font: 700 14px var(--font-mono); }

.lessons { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; padding-bottom: 40px; }
.lesson-card {
  position: relative; display: flex; flex-direction: column; padding: 20px 22px 18px;
  border: 1px solid var(--line); border-radius: var(--r-lg); background: var(--panel);
  color: var(--text) !important; box-shadow: var(--shadow-sm);
  transition: transform .2s var(--ease), border-color .2s, box-shadow .2s;
}
.lesson-card:hover { transform: translateY(-3px); border-color: var(--line-2); box-shadow: var(--shadow-md); }
.lesson-card.done { border-color: color-mix(in srgb, var(--ok) 35%, var(--line)); }
.lc-top { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.lc-no { width: 34px; height: 34px; display: grid; place-items: center; border-radius: 10px; background: var(--accent-soft); color: var(--accent-hi); font: 700 13px var(--font-mono); }
:root[data-theme='light'] .lc-no { color: var(--accent); }
.lesson-card.done .lc-no { background: var(--ok-soft); color: var(--ok); }
.lc-state { margin-left: auto; display: inline-flex; align-items: center; gap: 5px; font-size: 12px; font-weight: 650; color: var(--muted); }
.lesson-card.done .lc-state { color: var(--ok); }
.lesson-card.started .lc-state { color: var(--warn); }
.lesson-card h3 { margin: 0 0 6px; font-size: 18px; letter-spacing: -.015em; }
.lesson-card p { margin: 0 0 14px; color: var(--muted); font-size: 13.5px; }
.lesson-card ul { list-style: none; margin: 0 0 16px; padding: 0; display: flex; flex-wrap: wrap; gap: 6px; }
.lesson-card li { padding: 3px 9px; border-radius: 99px; font: 550 12px var(--font-mono); color: var(--text-2); background: var(--panel-2); border: 1px solid var(--line); }
.lc-foot { margin-top: auto; display: flex; align-items: center; gap: 12px; }
.lc-bar { flex: 1; height: 5px; border-radius: 5px; background: var(--panel-3); overflow: hidden; }
.lc-bar i { display: block; height: 100%; border-radius: inherit; background: linear-gradient(90deg, var(--accent), var(--accent-hi)); transition: width .4s var(--ease); }
.lesson-card.done .lc-bar i { background: var(--ok); }
.lc-tasks { display: inline-flex; gap: 5px; }
.lc-tasks i { width: 9px; height: 9px; border-radius: 50%; background: var(--panel-3); box-shadow: inset 0 0 0 1px var(--line-2); }
.lc-tasks i.on { background: var(--ok); box-shadow: 0 0 0 3px var(--ok-soft); }

.lesson-card.project { border-color: color-mix(in srgb, var(--violet) 35%, var(--line)); background: linear-gradient(160deg, var(--violet-soft), transparent 55%), var(--panel); }
.lesson-card.project .lc-no { background: var(--violet-soft); color: var(--violet); }
.lesson-card.project.done .lc-no { background: var(--ok-soft); color: var(--ok); }
.lesson-card.project .track-no { color: var(--violet); }

.notice { display: flex; gap: 12px; align-items: flex-start; padding: 14px 16px; border-radius: var(--r-md); border: 1px solid var(--line); background: var(--panel-2); margin: 0 0 18px; }
.notice > div { display: grid; gap: 2px; }
.notice span { color: var(--text-2); font-size: 13.5px; }
.notice.ok { border-color: color-mix(in srgb, var(--ok) 35%, transparent); background: var(--ok-soft); }
.notice.ok > .icon { color: var(--ok); }
.notice.err { border-color: color-mix(in srgb, var(--err) 35%, transparent); background: var(--err-soft); }
.notice.err > .icon { color: var(--err); }

/* ==========================================================================
   Lesson
   ========================================================================== */

.lesson { display: grid; grid-template-rows: auto 1fr; min-height: 0; }

.lesson-bar {
  display: flex; align-items: center; gap: 12px; padding: 8px 16px; min-width: 0;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 60%, transparent);
}
.lesson-title { display: grid; min-width: 0; gap: 1px; }
.lesson-title b { font-size: 14.5px; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.lesson-title .track-no { font-size: 10.5px; }
.ls-meter { display: block; height: 3px; width: 100%; max-width: 220px; border-radius: 3px; background: var(--panel-3); overflow: hidden; margin-top: 4px; }
.ls-meter i { display: block; height: 100%; background: linear-gradient(90deg, var(--accent), var(--ok)); transition: width .4s var(--ease); }

.lesson-steps { margin-left: auto; display: flex; gap: 4px; flex: none; }
.lesson-steps button {
  display: inline-flex; align-items: center; gap: 7px; height: 34px; padding: 0 10px 0 6px;
  border: 1px solid transparent; border-radius: 99px; background: transparent;
  color: var(--muted); font-size: 12.5px; font-weight: 650;
  transition: background .15s, color .15s, border-color .15s;
}
.lesson-steps button i {
  width: 22px; height: 22px; display: grid; place-items: center; border-radius: 50%; font: 700 11px var(--font-mono); font-style: normal;
  background: var(--panel-2); box-shadow: inset 0 0 0 1px var(--line-2);
}
.lesson-steps button:hover { color: var(--text); background: var(--panel-2); }
.lesson-steps button.seen { color: var(--text-2); }
.lesson-steps button.done i { background: var(--ok-soft); color: var(--ok); box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--ok) 45%, transparent); }
.lesson-steps button.cur { color: var(--text); background: var(--panel-3); border-color: var(--line-2); }
.lesson-steps button.cur i { background: var(--accent); color: var(--accent-ink); box-shadow: none; }
:root[data-theme='light'] .lesson-steps button.cur i { color: #fff; }

.lesson-split {
  display: grid; min-height: 0; gap: 12px; padding: 12px 16px 16px;
  grid-template-columns: minmax(340px, 42%) minmax(0, 1fr);
  grid-template-rows: minmax(0, 1.3fr) minmax(0, 1fr);
  grid-template-areas: 'doc code' 'doc out';
}
.pane-doc { grid-area: doc; }
.lesson .pane-code { grid-area: code; }
.lesson .pane-out { grid-area: out; }
.seg-3 { grid-template-columns: repeat(3, 1fr) !important; }

.doc-scroll { flex: 1; min-height: 0; overflow: auto; overscroll-behavior: contain; padding: 22px 26px 28px; }
.doc-nav { display: flex; justify-content: space-between; gap: 8px; padding: 10px 12px; border-top: 1px solid var(--line); flex: none; }

.tasks { display: inline-flex; padding: 3px; gap: 2px; border-radius: var(--r-sm); background: var(--panel-3); }
.tasks[hidden] { display: none; }
.ftabs { display: flex; gap: 2px; min-width: 0; overflow-x: auto; scrollbar-width: none; }
.ftabs::-webkit-scrollbar { display: none; }
.ftabs[hidden] { display: none; }
.ftab {
  flex: none; height: 28px; padding: 0 10px; border: 1px solid transparent; border-radius: 7px;
  background: transparent; color: var(--muted); font: 600 12px var(--font-mono); white-space: nowrap;
}
.ftab:hover { color: var(--text); background: var(--panel-3); }
.ftab[aria-selected='true'] { color: var(--text); background: var(--panel); border-color: var(--line-2); box-shadow: var(--shadow-sm); }
.ftab.has-err { color: var(--err); }
.ftab.has-err::after { content: ''; display: inline-block; width: 6px; height: 6px; margin-left: 6px; border-radius: 50%; background: var(--err); vertical-align: 1px; }
#ls-file[hidden] { display: none; }
.tasks button { height: 28px; padding: 0 10px; border: 0; border-radius: 7px; background: transparent; color: var(--muted); font-size: 12.5px; font-weight: 650; }
.tasks button:hover { color: var(--text); }
.tasks button[aria-selected='true'] { background: var(--panel); color: var(--text); box-shadow: var(--shadow-sm), 0 0 0 1px var(--line); }
.lesson .file-tab { height: 28px; font-size: 12px; }

.code-actions { display: flex; justify-content: flex-end; gap: 8px; padding: 8px 10px; border-top: 1px solid var(--line); flex: none; background: var(--panel-2); }
.code-actions .btn-ghost { border-color: var(--line-2); }

/* Lesson text */
.prose { max-width: 70ch; color: var(--text-2); font-size: 15px; line-height: 1.7; }
.prose .kicker { margin-bottom: 6px; }
.prose h2 { margin: 0 0 16px; font-size: 26px; letter-spacing: -.02em; color: var(--text); line-height: 1.2; }
.prose h4 { margin: 24px 0 10px; font-size: 14px; color: var(--text); letter-spacing: .01em; }
.prose p { margin: 0 0 14px; }
.prose b { color: var(--text); font-weight: 650; }
.prose ul, .prose ol { margin: 0 0 14px; padding-left: 22px; }
.prose li { margin: 4px 0; }
.prose li::marker { color: var(--muted); }
.prose code { padding: 1px 6px; border-radius: 6px; background: var(--panel-3); color: var(--text); font-size: .88em; }
.prose pre.code, .test-cases pre {
  margin: 0 0 16px; padding: 14px 16px; overflow-x: auto;
  border-radius: var(--r-md); background: var(--panel-2); border: 1px solid var(--line);
  font: 13px/1.65 var(--font-mono); color: var(--text); tab-size: 4;
}
.prose .muted { color: var(--muted); font-size: 13.5px; }
.callout { margin: 0 0 16px; padding: 12px 16px; border-radius: var(--r-md); background: var(--violet-soft); border: 1px solid color-mix(in srgb, var(--violet) 30%, transparent); }
.callout p:last-child { margin: 0; }
details.reveal { margin: 4px 0 16px; border-radius: var(--r-md); border: 1px dashed var(--line-2); background: var(--panel-2); }
details.reveal summary { cursor: pointer; padding: 12px 16px; font-weight: 650; color: var(--accent-hi); list-style: none; }
:root[data-theme='light'] details.reveal summary { color: var(--accent); }
details.reveal summary::-webkit-details-marker { display: none; }
details.reveal summary::before { content: '▸ '; }
details.reveal[open] summary::before { content: '▾ '; }
details.reveal > :not(summary) { margin-left: 16px; margin-right: 16px; }
details.reveal[open] { padding-bottom: 2px; }
.doc-code { margin-bottom: 16px; }
.code-file { margin: 0 0 -1px; display: inline-block; padding: 4px 12px; border: 1px solid var(--line); border-bottom: 0; border-radius: var(--r-sm) var(--r-sm) 0 0; background: var(--panel-3); font: 600 12px var(--font-mono); color: var(--text-2); }
.code-file + pre.code { border-top-left-radius: 0; }
.doc-code pre.code { margin-bottom: 10px; }
.doc-actions { margin: 6px 0 18px; }

.test-cases { display: grid; gap: 10px; margin-bottom: 10px; }
.case { padding: 10px 12px; border-radius: var(--r-md); border: 1px solid var(--line); background: var(--panel); display: grid; gap: 6px; }
.case-h { font-size: 12.5px; font-weight: 700; color: var(--text); }
.case small { display: block; margin-bottom: 3px; font-size: 11px; font-weight: 650; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.test-cases pre { margin: 0; padding: 8px 12px; font-size: 12.5px; }

.hints { display: grid; gap: 8px; justify-items: start; }
.hint { width: 100%; display: grid; gap: 2px; padding: 10px 14px; border-radius: var(--r-md); background: rgba(251, 191, 93, .08); border: 1px solid rgba(251, 191, 93, .28); animation: pop .2s var(--ease); }
.hint b { font-size: 12px; color: var(--warn); }

.reflect { padding-left: 22px; }
.reflect li { margin-bottom: 14px; }
.reflect p { margin: 0 0 6px; color: var(--text); }
.reflect textarea {
  width: 100%; resize: vertical; padding: 8px 12px; border-radius: var(--r-sm);
  border: 1px solid var(--line-2); background: var(--panel-2); color: var(--text); font-size: 14px; line-height: 1.5;
}
.reflect textarea:focus { outline: none; border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.plan { padding-left: 22px; }
.plan li { margin: 6px 0; }
.plan li.done { color: var(--ok); }
.plan li.done::marker { color: var(--ok); }

/* Test results in the terminal */
.tests { display: grid; gap: 6px; margin: 4px 0 10px; white-space: normal; font-family: var(--font-ui); font-size: 13px; }
.test { padding: 7px 12px; border-radius: var(--r-sm); border: 1px solid var(--line); background: var(--panel-2); animation: pop .18s var(--ease); }
.t-head { display: flex; align-items: center; gap: 8px; }
.t-ico { width: 18px; height: 18px; display: grid; place-items: center; border-radius: 50%; font-size: 11px; font-weight: 800; }
.test.ok .t-ico { background: var(--ok-soft); color: var(--ok); }
.test.fail { border-color: color-mix(in srgb, var(--err) 40%, transparent); background: var(--err-soft); }
.test.fail .t-ico { background: var(--err); color: #fff; }
.t-name { color: var(--muted); }
.t-tag { margin-left: auto; padding: 1px 7px; border-radius: 99px; font-size: 11px; color: var(--muted); border: 1px solid var(--line-2); }
.t-why { margin: 6px 0 8px; color: var(--err); }
.t-diff { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 8px; }
.t-box small { display: block; margin-bottom: 3px; font-size: 10.5px; font-weight: 700; color: var(--muted); text-transform: uppercase; letter-spacing: .06em; }
.t-box pre { margin: 0; padding: 7px 10px; border-radius: 7px; background: var(--panel); border: 1px solid var(--line); font: 12px/1.55 var(--font-mono); white-space: pre-wrap; word-break: break-word; max-height: 220px; overflow: auto; }
.t-box.want pre { border-color: color-mix(in srgb, var(--ok) 35%, transparent); }
.t-box.got pre { border-color: color-mix(in srgb, var(--err) 35%, transparent); }
.next-card {
  display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap;
  margin: 12px 0 4px; padding: 12px 14px; border-radius: var(--r-md); white-space: normal; font-family: var(--font-ui);
  background: var(--ok-soft); border: 1px solid color-mix(in srgb, var(--ok) 35%, transparent);
}
.next-card > span { display: inline-flex; align-items: center; gap: 8px; color: var(--ok); }
.next-card b { color: var(--text); }

@media (max-width: 1280px) {
  .lesson-steps button:not(.cur) span { display: none; }
  .lesson-steps button:not(.cur) { padding: 0 6px; }
}

@media (max-width: 1000px) {
  .lessons { grid-template-columns: 1fr; }
  .lesson-bar { flex-wrap: wrap; row-gap: 6px; }
  .lesson-title { flex: 1; }
  .lesson-steps { order: 3; width: 100%; margin: 0; overflow-x: auto; scrollbar-width: none; }
  .lesson-steps::-webkit-scrollbar { display: none; }
  .lesson-split { grid-template-columns: 1fr; grid-template-rows: auto minmax(0, 1fr); grid-template-areas: none; padding: 10px 12px 12px; gap: 10px; }
  .pane-doc, .lesson .pane-code, .lesson .pane-out { grid-area: auto; }
  .lesson[data-pane='doc'] .pane-code, .lesson[data-pane='doc'] .pane-out,
  .lesson[data-pane='code'] .pane-doc, .lesson[data-pane='code'] .pane-out,
  .lesson[data-pane='out'] .pane-doc, .lesson[data-pane='out'] .pane-code { display: none; }
}

@media (max-width: 760px) {
  .learn-head { flex-direction: column; align-items: stretch; padding: 28px 0 20px; gap: 20px; }
  .lesson-bar { padding: 6px 12px; gap: 8px; }
  .lesson-bar .back { padding: 0 8px; }
  .lesson-bar .btn-label { display: none; }
  .doc-scroll { padding: 18px 16px 24px; }
  .prose h2 { font-size: 22px; }
  .lesson .pane-head { padding-left: 8px; }
  .code-actions { padding: 8px; }
  .code-actions .btn { flex: 1; }
  .code-actions kbd { display: none; }
  .lesson .statusbar { padding-right: 14px; }
  .lesson .pane-code .pane-head { height: auto; min-height: 44px; flex-wrap: wrap; row-gap: 6px; padding-top: 6px; padding-bottom: 6px; }
  .lesson .pane-code .ftabs { order: 10; flex-basis: 100%; }
}

/* ==========================================================================
   Overlays
   ========================================================================== */

.toast-host { position: fixed; left: 50%; width: max-content; max-width: calc(100vw - 32px); bottom: calc(var(--tabbar-h) + 28px + env(safe-area-inset-bottom)); transform: translateX(-50%); z-index: 100; display: grid; gap: 8px; pointer-events: none; }
@media (min-width: 761px) { .toast-host { bottom: 28px; } }
@media (max-width: 760px) { .toast-host { bottom: auto; top: calc(var(--header-h) + 12px + env(safe-area-inset-top)); } }
.toast {
  display: flex; align-items: center; gap: 10px;
  padding: 10px 16px; border-radius: 99px;
  background: var(--text); color: var(--bg);
  font-size: 13.5px; font-weight: 600; box-shadow: var(--shadow-lg);
  animation: toast-in .25s var(--ease);
}
.toast.ok { background: var(--ok); color: #03140d; }
.toast.err { background: var(--err); color: #fff; }
.toast.out { animation: toast-out .2s var(--ease) forwards; }
@keyframes toast-in { from { opacity: 0; transform: translateY(8px) scale(.97); } }
@keyframes toast-out { to { opacity: 0; transform: translateY(6px); } }

dialog {
  width: min(460px, calc(100vw - 32px)); padding: 0; border: 0; border-radius: var(--r-lg);
  background: var(--panel); color: var(--text); box-shadow: var(--shadow-lg);
}
dialog::backdrop { background: rgba(3, 6, 12, .55); backdrop-filter: blur(4px); }
dialog[open] { animation: pop .2s var(--ease); }
.dlg-head { display: flex; align-items: center; justify-content: space-between; padding: 18px 20px 6px; }
.dlg-head h2 { margin: 0; font-size: 18px; letter-spacing: -.01em; }
.dlg-body { display: grid; gap: 18px; padding: 12px 20px 20px; }
.field { display: grid; gap: 8px; }
.field > span { font-size: 12.5px; font-weight: 650; color: var(--text-2); }
.field small { color: var(--muted); font-size: 12px; }
.field input[type='text'], .field input[type='url'], .field select {
  height: 40px; padding: 0 12px; border-radius: var(--r-sm);
  border: 1px solid var(--line-2); background: var(--panel-2); outline: none;
}
.field input:focus, .field select:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.field input[type='range'] { accent-color: var(--accent); }
.choice { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; padding: 3px; border-radius: var(--r-md); background: var(--panel-2); border: 1px solid var(--line); }
.choice label { position: relative; }
.choice input { position: absolute; opacity: 0; }
.choice span { display: flex; align-items: center; justify-content: center; gap: 6px; height: 34px; border-radius: var(--r-sm); font-size: 13px; font-weight: 600; color: var(--muted); cursor: pointer; }
.choice input:checked + span { background: var(--panel); color: var(--text); box-shadow: var(--shadow-sm), 0 0 0 1px var(--line); }
.choice input:focus-visible + span { outline: 2px solid var(--accent-hi); }
.switch { display: flex; align-items: center; justify-content: space-between; gap: 16px; }
.switch input { appearance: none; width: 42px; height: 24px; border-radius: 99px; background: var(--panel-3); border: 1px solid var(--line-2); position: relative; cursor: pointer; transition: background .2s; flex: none; }
.switch input::after { content: ''; position: absolute; top: 2px; left: 2px; width: 18px; height: 18px; border-radius: 50%; background: #fff; box-shadow: var(--shadow-sm); transition: transform .2s var(--ease); }
.switch input:checked { background: var(--accent); border-color: var(--accent); }
.switch input:checked::after { transform: translateX(18px); }

/* startup loading modal */
.boot {
  position: fixed; inset: 0; z-index: 1000; display: grid; place-items: center; padding: 16px;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  -webkit-backdrop-filter: blur(10px); backdrop-filter: blur(10px);
  transition: opacity .3s var(--ease), visibility .3s;
}
.boot.out { opacity: 0; visibility: hidden; pointer-events: none; }
.boot-card {
  display: grid; justify-items: center; gap: 14px; width: min(320px, 100%); padding: 32px 28px; text-align: center;
  background: var(--panel); border: 1px solid var(--line); border-radius: var(--r-lg); box-shadow: 0 24px 60px -20px rgba(0, 0, 0, .55);
}
.boot-logo { width: 52px; height: 52px; filter: drop-shadow(0 6px 20px var(--accent-glow)); }
.boot-spinner {
  width: 28px; height: 28px; border-radius: 50%;
  border: 3px solid var(--accent-soft); border-top-color: var(--accent-hi);
  animation: boot-spin .8s linear infinite;
}
.boot-card h2 { margin: 0; font-size: 16px; font-weight: 700; letter-spacing: -.01em; }
.boot-note { margin: 0; color: var(--muted); font-size: 13px; }
@keyframes boot-spin { to { transform: rotate(360deg); } }

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation-duration: .001ms !important; transition-duration: .001ms !important; scroll-behavior: auto !important; }
}

/* scrollbars */
* { scrollbar-width: thin; scrollbar-color: var(--line-2) transparent; }
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-thumb { background: var(--line-2); border-radius: 10px; border: 3px solid transparent; background-clip: content-box; }
::-webkit-scrollbar-corner { background: transparent; }

/* JetBrains Mono ligatures turn Go's <- and <= into arrows; keep code literal. */
.keybar button, .diag button, .stdin-box textarea, .file-tab { font-variant-ligatures: none; }