/* ==========================================================================
   Laboratorio de Álgebra Lineal — application design system
   IDE-style dark theme (default) and light theme.
   ========================================================================== */

@font-face {
  font-family: "Manrope";
  font-style: normal;
  font-display: swap;
  font-weight: 200 800;
  src: url("../../vendor/fonts/manrope-latin-wght-normal.woff2") format("woff2-variations");
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD;
}
@font-face {
  font-family: "Manrope";
  font-style: normal;
  font-display: swap;
  font-weight: 200 800;
  src: url("../../vendor/fonts/manrope-latin-ext-wght-normal.woff2") format("woff2-variations");
  unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+1D00-1DBF, U+1E00-1E9F, U+1EF2-1EFF, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF;
}
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 400; src: url("../../vendor/fonts/ibm-plex-mono-latin-400-normal.woff2") format("woff2"); unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD; }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 500; src: url("../../vendor/fonts/ibm-plex-mono-latin-500-normal.woff2") format("woff2"); unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD; }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 600; src: url("../../vendor/fonts/ibm-plex-mono-latin-600-normal.woff2") format("woff2"); unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+20AC, U+2122, U+2191, U+2193, U+2212, U+2215, U+FEFF, U+FFFD; }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 400; src: url("../../vendor/fonts/ibm-plex-mono-latin-ext-400-normal.woff2") format("woff2"); unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+1E00-1E9F, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF; }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 500; src: url("../../vendor/fonts/ibm-plex-mono-latin-ext-500-normal.woff2") format("woff2"); unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+1E00-1E9F, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF; }
@font-face { font-family: "IBM Plex Mono"; font-style: normal; font-display: swap; font-weight: 600; src: url("../../vendor/fonts/ibm-plex-mono-latin-ext-600-normal.woff2") format("woff2"); unicode-range: U+0100-02BA, U+02BD-02C5, U+02C7-02CC, U+02CE-02D7, U+02DD-02FF, U+1E00-1E9F, U+2020, U+20A0-20AB, U+20AD-20C0, U+2113, U+2C60-2C7F, U+A720-A7FF; }

/* ---------- Tokens ---------------------------------------------------- */

:root {
  --font-sans: "Manrope", system-ui, -apple-system, "Segoe UI", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
  --font-serif: Georgia, "Times New Roman", serif;
  --radius: 3px;
  --sb-w: 232px;
  --sb-w-collapsed: 52px;
  --insp-w: 384px;
  --tb-h: 38px;
  --status-h: 24px;
  --ease: cubic-bezier(.2, .7, .2, 1);
}
body.wide-inspector { --insp-w: 440px; }

:root,
:root[data-theme="dark"] {
  color-scheme: dark;
  --bg-deep: #141519;
  --ink: #181a1f;
  --surface: #1d1f25;
  --surface-2: #23262d;
  --surface-3: #2c3039;
  --input: #14161a;
  --line: #2c2f37;
  --line-strong: #3c404a;
  --text: #d7dae0;
  --muted: #8f96a3;
  --faint: #646b77;
  --accent: #5aa9ff;
  --accent-bg: #2f6fd6;
  --accent-soft: rgba(90, 169, 255, .14);
  --accent-ink: #ffffff;
  --coral: #f78c6c;
  --ok: #7fd18b;
  --warn: #e5c07b;
  --danger: #f07178;
  --shadow: 0 12px 40px rgba(0, 0, 0, .45);

  /* Canvas palette (3Blue1Brown-inspired semantics) */
  --canvas-bg: #111317;
  --grid: rgba(143, 150, 163, .13);
  --grid-major: rgba(143, 150, 163, .28);
  --tgrid: #1fabc3;
  --axis: #d7dae0;
  --label: #d7dae0;
  --c-i: #8cbe63;
  --c-j: #ff7c5c;
  --c-k: #5ab4ff;
  --c-v: #fdfe00;
  --c-w: #72d9e8;
  --c-eig: #c29bff;
  --c-ker: #ff6fae;
  --c-img: #58c4dd;
  --c-det: #fdfe00;
  --c-det-neg: #ff9f1c;
  --c-row1: #8cbe63;
  --c-row2: #ff7c5c;
  --c-row3: #5ab4ff;
  --c-sol: #fdfe00;
  --c-res: #ff6fae;
}

:root[data-theme="light"] {
  color-scheme: light;
  --bg-deep: #e8eaee;
  --ink: #f1f2f5;
  --surface: #f9fafb;
  --surface-2: #eef0f3;
  --surface-3: #e1e4e9;
  --input: #ffffff;
  --line: #d8dbe1;
  --line-strong: #bfc4cd;
  --text: #1f2328;
  --muted: #57606a;
  --faint: #8a929d;
  --accent: #0969da;
  --accent-bg: #0969da;
  --accent-soft: rgba(9, 105, 218, .1);
  --accent-ink: #ffffff;
  --coral: #bc4c00;
  --ok: #1a7f37;
  --warn: #9a6700;
  --danger: #cf222e;
  --shadow: 0 12px 40px rgba(20, 30, 50, .18);

  --canvas-bg: #ffffff;
  --grid: rgba(60, 70, 80, .09);
  --grid-major: rgba(60, 70, 80, .2);
  --tgrid: #1686a0;
  --axis: #1f2328;
  --label: #1f2328;
  --c-i: #3b8a22;
  --c-j: #d4411f;
  --c-k: #1f6fd1;
  --c-v: #b58900;
  --c-w: #0f7e90;
  --c-eig: #7a3fe0;
  --c-ker: #c9246d;
  --c-img: #1686a0;
  --c-det: #d9ad00;
  --c-det-neg: #e36b00;
  --c-row1: #3b8a22;
  --c-row2: #d4411f;
  --c-row3: #1f6fd1;
  --c-sol: #b58900;
  --c-res: #c9246d;
}

/* ---------- Base ------------------------------------------------------- */

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { *, *::before, *::after { transition: none !important; animation: none !important; } }

body {
  margin: 0;
  min-height: 100vh;
  background: var(--ink);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 13px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  /* Manrope turns "(c)" into "©" through a standard ligature; math text needs the literal characters. */
  font-variant-ligatures: none;
}

html[data-loading] body { opacity: 0; animation: reveal 0s 1.2s forwards; }
@keyframes reveal { to { opacity: 1; } }

a { color: inherit; }
img, svg, canvas { display: block; max-width: 100%; }
/* KaTeX draws accents such as \vec with absolutely positioned SVGs; the rule above would give them zero width. */
.katex svg { max-width: none; }
button, input, select, textarea { font: inherit; color: inherit; }
::selection { color: var(--accent-ink); background: var(--accent-bg); }
:focus-visible { outline: 1px solid var(--accent); outline-offset: 1px; }
[hidden] { display: none !important; }
.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; }
.mono { font-family: var(--font-mono); }
.muted { color: var(--muted); }
.skip-link { position: absolute; left: 8px; top: -48px; z-index: 300; padding: 6px 10px; background: var(--accent-bg); color: var(--accent-ink); font-family: var(--font-mono); font-size: 12px; text-decoration: none; }
.skip-link:focus { top: 8px; }
* { scrollbar-width: thin; scrollbar-color: var(--line-strong) transparent; }

/* Semantic colours (also used inside KaTeX via \htmlClass) */
.c-i { color: var(--c-i); } .c-j { color: var(--c-j); } .c-k { color: var(--c-k); }
.c-v { color: var(--c-v); } .c-w { color: var(--c-w); } .c-eig { color: var(--c-eig); }
.c-ker { color: var(--c-ker); } .c-img { color: var(--c-img); } .c-det { color: var(--c-det); }
.c-det-neg { color: var(--c-det-neg); } .c-accent { color: var(--accent); } .c-muted { color: var(--muted); }
.c-row1 { color: var(--c-row1); } .c-row2 { color: var(--c-row2); } .c-row3 { color: var(--c-row3); }
.c-sol { color: var(--c-sol); } .c-res { color: var(--c-res); } .c-grid { color: var(--tgrid); }
.c-ok { color: var(--ok); } .c-warn { color: var(--warn); } .c-danger { color: var(--danger); }

/* ---------- App frame --------------------------------------------------
   sidebar | workspace (toolbar + stage) | inspector
   status bar across the bottom                                            */

body.app {
  height: 100vh; height: 100dvh; min-height: 0; overflow: hidden;
  display: grid;
  grid-template-columns: var(--sb-w) minmax(0, 1fr) var(--insp-w);
  grid-template-rows: minmax(0, 1fr) var(--status-h);
  grid-template-areas: "sidebar work insp" "status status status";
}
body.app.sidebar-collapsed { --sb-w: var(--sb-w-collapsed); }
body.resizing { cursor: col-resize; user-select: none; }
body.resizing .view { pointer-events: none; }

.brand-mark {
  flex: none; width: 24px; height: 24px; display: grid; place-items: center;
  border: 1px solid var(--accent); border-radius: var(--radius); color: var(--accent);
  font-family: var(--font-serif); font-size: 16px; line-height: 1;
}

/* Sidebar */
.sidebar { grid-area: sidebar; min-width: 0; display: flex; flex-direction: column; background: var(--bg-deep); border-right: 1px solid var(--line); }
.sidebar__head { flex: none; height: var(--tb-h); display: flex; align-items: center; justify-content: space-between; gap: 6px; padding: 0 6px 0 12px; border-bottom: 1px solid var(--line); }
.sidebar__brand { display: flex; align-items: center; gap: 10px; min-width: 0; text-decoration: none; font-weight: 700; font-size: 13px; letter-spacing: -.01em; }
.sidebar__brand-label { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.sidebar__nav { flex: 1; min-height: 0; overflow-y: auto; padding: 4px 0 10px; }
.sidebar__group { padding: 12px 12px 4px; color: var(--faint); font-family: var(--font-mono); font-size: 10px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.navitem { position: relative; display: grid; grid-template-columns: 20px 20px minmax(0, 1fr) auto; align-items: center; gap: 8px; height: 30px; padding: 0 10px 0 12px; color: var(--muted); text-decoration: none; font-size: 12.5px; white-space: nowrap; }
.navitem:hover { background: var(--surface-2); color: var(--text); }
.navitem[aria-current="page"] { background: var(--accent-soft); color: var(--text); }
.navitem[aria-current="page"]::before { content: ""; position: absolute; left: 0; top: 4px; bottom: 4px; width: 2px; background: var(--accent); }
.navitem .app-icon { width: 20px; height: 20px; opacity: .9; }
.navitem__num { color: var(--faint); font-family: var(--font-mono); font-size: 10.5px; }
.navitem__label { overflow: hidden; text-overflow: ellipsis; }
.navitem__done { color: var(--ok); font-family: var(--font-mono); font-size: 11px; }
.sidebar__foot { flex: none; display: grid; gap: 6px; padding: 8px 12px 10px; border-top: 1px solid var(--line); }
.sidebar__link { display: flex; align-items: center; gap: 8px; color: var(--muted); text-decoration: none; font-family: var(--font-mono); font-size: 11px; }
.sidebar__link svg { width: 15px; height: 15px; }
.sidebar__link:hover { color: var(--accent); }
.sidebar__credit { margin: 0; color: var(--faint); font-size: 10.5px; line-height: 1.4; }

body.sidebar-collapsed .sidebar__brand-label,
body.sidebar-collapsed .sidebar__group,
body.sidebar-collapsed .navitem__num,
body.sidebar-collapsed .navitem__label,
body.sidebar-collapsed .navitem__done,
body.sidebar-collapsed .sidebar__link span,
body.sidebar-collapsed .sidebar__credit { display: none; }
body.sidebar-collapsed .sidebar__head { flex-direction: column; justify-content: center; height: auto; padding: 7px 0; gap: 6px; }
body.sidebar-collapsed .navitem { grid-template-columns: 20px; justify-content: center; padding: 0; height: 34px; }
body.sidebar-collapsed .sidebar__nav { padding-top: 6px; }
body.sidebar-collapsed .sidebar__foot { justify-items: center; }
.sidebar-backdrop { display: none; }

/* Workspace */
.workspace { grid-area: work; min-width: 0; min-height: 0; display: flex; flex-direction: column; background: var(--ink); }
.toolbar { flex: none; height: var(--tb-h); display: flex; align-items: center; gap: 4px; padding: 0 6px 0 12px; border-bottom: 1px solid var(--line); background: var(--surface); }
.icon-btn.toolbar__menu { display: none; }
.toolbar__title { display: flex; align-items: baseline; gap: 10px; min-width: 0; margin: 0; font-size: 13px; font-weight: 650; white-space: nowrap; overflow: hidden; }
.toolbar__title > span:nth-child(2) { overflow: hidden; text-overflow: ellipsis; }
.toolbar__num { color: var(--coral); font-family: var(--font-mono); font-size: 11px; font-weight: 500; }
.toolbar__chapter { color: var(--faint); font-family: var(--font-mono); font-size: 10.5px; font-weight: 400; overflow: hidden; text-overflow: ellipsis; }
.toolbar__spacer { flex: 1; }
.toolbar__group { display: flex; align-items: center; gap: 2px; }
.toolbar__sep { width: 1px; height: 18px; margin: 0 6px; background: var(--line); }

/* Stage */
.stage { position: relative; flex: 1; min-height: 0; display: flex; flex-direction: column; background: var(--canvas-bg); }
.stage__views { position: relative; flex: 1; min-height: 0; display: grid; gap: 1px; background: var(--line); }
.stage__views--2 { grid-template-columns: 1fr 1fr; }
.view { position: relative; min-width: 0; min-height: 0; height: 100%; background: var(--canvas-bg); overflow: hidden; touch-action: none; }
.view canvas { width: 100%; height: 100%; }
.view:focus-visible { outline-offset: -2px; }
.view__title {
  position: absolute; top: 8px; left: 8px; z-index: 5; padding: 2px 7px;
  border: 1px solid var(--line); border-radius: var(--radius); background: color-mix(in srgb, var(--canvas-bg) 85%, transparent);
  color: var(--muted); font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .06em; text-transform: uppercase; pointer-events: none;
}
.view__tools { position: absolute; right: 8px; bottom: 8px; z-index: 6; display: flex; gap: 2px; padding: 2px; border: 1px solid var(--line); border-radius: var(--radius); background: color-mix(in srgb, var(--surface) 88%, transparent); }
.view__tools .icon-btn { width: 26px; min-height: 26px; border-color: transparent; background: transparent; }
.view__corner { position: absolute; left: 8px; bottom: 8px; z-index: 6; display: flex; gap: 4px; flex-wrap: wrap; }
.view__hint { position: absolute; left: 50%; top: 10px; transform: translateX(-50%); z-index: 5; padding: 4px 9px; background: color-mix(in srgb, var(--surface) 92%, transparent); border: 1px solid var(--line); border-radius: var(--radius); font-family: var(--font-mono); font-size: 11px; color: var(--muted); pointer-events: none; transition: opacity .4s; white-space: nowrap; }
.view--3d .label3d { font-family: var(--font-mono); font-size: 12px; font-weight: 600; pointer-events: none; text-shadow: 0 0 3px var(--canvas-bg), 0 0 6px var(--canvas-bg); }
.view--3d canvas { cursor: grab; }
.view--3d canvas:active { cursor: grabbing; }

.stage__bar { flex: none; display: flex; flex-wrap: wrap; align-items: center; gap: 6px 14px; padding: 6px 10px; border-top: 1px solid var(--line); background: var(--surface); }
.stage__bar:empty { display: none; }
.legend { flex: none; display: flex; flex-wrap: wrap; gap: 4px 14px; padding: 5px 10px; border-top: 1px solid var(--line); background: var(--surface); font-size: 11.5px; color: var(--muted); }
.legend:empty { display: none; }
.legend__item { display: inline-flex; align-items: center; gap: 6px; }
.legend__swatch { width: 14px; height: 3px; background: currentColor; border-radius: 2px; }
.legend__swatch--area { height: 10px; opacity: .6; }
.legend__swatch--dash { background: repeating-linear-gradient(90deg, currentColor 0 4px, transparent 4px 7px); }

.anim { display: grid; grid-template-columns: auto minmax(120px, 1fr) minmax(110px, .6fr); gap: 4px 14px; align-items: center; width: 100%; }
.anim__buttons { display: flex; gap: 2px; }
.anim__stages { grid-column: 1 / -1; display: flex; gap: 6px; flex-wrap: wrap; font-family: var(--font-mono); font-size: 11px; color: var(--faint); }
.anim__stage[data-active="true"] { color: var(--accent); }

.present-tools { display: none; position: absolute; top: 8px; right: 8px; z-index: 8; gap: 4px; }

/* Inspector */
.inspector { grid-area: insp; position: relative; min-width: 0; min-height: 0; display: flex; flex-direction: column; background: var(--surface); border-left: 1px solid var(--line); }
.inspector__resizer { position: absolute; left: -3px; top: 0; bottom: 0; width: 6px; z-index: 20; cursor: col-resize; }
.inspector__resizer:hover, body.resizing .inspector__resizer { background: var(--accent-bg); opacity: .6; }
.inspector__panes { flex: 1; min-height: 0; overflow-y: auto; }
.tabs { flex: none; display: flex; height: var(--tb-h); border-bottom: 1px solid var(--line); overflow-x: auto; background: var(--surface); }
.tabs button { position: relative; flex: none; padding: 0 14px; border: 0; background: none; color: var(--muted); font-family: var(--font-mono); font-size: 11px; letter-spacing: .04em; text-transform: uppercase; cursor: pointer; white-space: nowrap; }
.tabs button[aria-selected="true"] { color: var(--text); background: var(--ink); box-shadow: inset 0 2px 0 var(--accent); }
.tabs button:hover { color: var(--text); }
.tabs__count { margin-left: 7px; padding: 0 5px; border-radius: 8px; background: var(--surface-3); color: var(--muted); font-size: 10px; }
.tabpanel { padding: 0; }
.panel { display: grid; align-content: start; }

/* Status bar */
.statusbar { grid-area: status; display: flex; align-items: center; gap: 0; min-width: 0; height: var(--status-h); background: var(--bg-deep); border-top: 1px solid var(--line); color: var(--faint); font-family: var(--font-mono); font-size: 10.5px; white-space: nowrap; overflow: hidden; }
.statusbar__mode { align-self: stretch; display: grid; place-items: center; padding: 0 10px; background: var(--accent-bg); color: var(--accent-ink); font-family: var(--font-serif); font-size: 13px; }
.statusbar__item { padding: 0 10px; overflow: hidden; text-overflow: ellipsis; }
.statusbar__item + .statusbar__item { border-left: 1px solid var(--line); }

/* ---------- Buttons & controls ---------------------------------------- */

.btn, .icon-btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 6px;
  min-height: 28px; padding: 0 10px;
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--surface-2); color: var(--text);
  font-family: var(--font-mono); font-size: 11.5px;
  cursor: pointer; text-decoration: none; white-space: nowrap;
  transition: background-color .12s var(--ease), border-color .12s var(--ease), color .12s var(--ease);
}
.btn:hover, .icon-btn:hover { background: var(--surface-3); }
.btn:disabled, .icon-btn:disabled { opacity: .45; cursor: not-allowed; }
.btn--primary { background: var(--accent-bg); border-color: var(--accent-bg); color: var(--accent-ink); }
.btn--primary:hover { background: var(--accent-bg); filter: brightness(1.1); }
.btn--ghost, .icon-btn--ghost { background: transparent; border-color: transparent; color: var(--muted); }
.btn--ghost:hover, .icon-btn--ghost:hover { background: var(--surface-3); color: var(--text); }
.btn--sm { min-height: 24px; padding: 0 8px; font-size: 11px; }
.icon-btn { width: 28px; padding: 0; }
.icon-btn svg, .btn svg { width: 16px; height: 16px; flex: none; }
.icon-btn[aria-pressed="true"], .btn[aria-pressed="true"] { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); }

.chip-row { display: flex; flex-wrap: wrap; gap: 4px; }
.chip {
  display: inline-flex; align-items: center; gap: 7px; min-height: 24px; padding: 0 8px;
  border: 1px solid var(--line); border-radius: var(--radius); background: transparent; color: var(--muted);
  font-size: 12px; cursor: pointer; user-select: none;
}
.chip::before { content: ""; width: 8px; height: 8px; border-radius: 2px; border: 1.5px solid currentColor; background: transparent; }
.chip[aria-pressed="true"] { color: var(--text); border-color: var(--line-strong); background: var(--surface-2); }
.chip[aria-pressed="true"]::before { background: var(--chip-color, var(--accent)); border-color: var(--chip-color, var(--accent)); }
.chip:hover { border-color: var(--line-strong); color: var(--text); }

.seg { display: inline-flex; flex-wrap: wrap; border: 1px solid var(--line-strong); border-radius: var(--radius); overflow: hidden; background: var(--input); }
.seg button { min-height: 26px; padding: 0 10px; border: 0; border-right: 1px solid var(--line); background: transparent; color: var(--muted); font-family: var(--font-mono); font-size: 11.5px; cursor: pointer; }
.seg button:last-child { border-right: 0; }
.seg button[aria-pressed="true"] { background: var(--accent-bg); color: var(--accent-ink); }
.seg button:not([aria-pressed="true"]):hover { color: var(--text); background: var(--surface-2); }

.field { display: grid; gap: 4px; }
.field > label, .label { color: var(--muted); font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .05em; text-transform: uppercase; }
select, .input {
  min-height: 28px; width: 100%; padding: 0 8px;
  border: 1px solid var(--line-strong); border-radius: var(--radius);
  background: var(--input); color: var(--text); font-family: var(--font-mono); font-size: 12px;
}
select { appearance: none; background-image: linear-gradient(45deg, transparent 50%, var(--muted) 50%), linear-gradient(135deg, var(--muted) 50%, transparent 50%); background-position: calc(100% - 14px) 50%, calc(100% - 9px) 50%; background-size: 5px 5px; background-repeat: no-repeat; padding-right: 26px; }
select:focus, .input:focus { border-color: var(--accent); outline: none; }
.input[aria-invalid="true"] { border-color: var(--danger); }

input[type="range"] { width: 100%; accent-color: var(--accent-bg); min-height: 22px; }
input[type="checkbox"] { accent-color: var(--accent-bg); }

.slider { display: grid; grid-template-columns: auto 1fr 4.6em; align-items: center; gap: 8px; }
.slider__label { color: var(--muted); font-family: var(--font-mono); font-size: 11.5px; white-space: nowrap; }
.slider__value { color: var(--text); font-family: var(--font-mono); font-size: 11.5px; text-align: right; font-variant-numeric: tabular-nums; }

.lang-switch { display: inline-flex; align-items: center; gap: 0; color: var(--faint); font-family: var(--font-mono); font-size: 11px; }
.lang-switch button { min-width: 26px; min-height: 26px; padding: 0 3px; border: 0; border-radius: var(--radius); background: none; color: var(--muted); cursor: pointer; font-family: var(--font-mono); font-size: 11px; }
.lang-switch button[aria-pressed="true"] { color: var(--accent); }
.lang-switch button:hover { background: var(--surface-3); color: var(--text); }

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

.matrix-editor { display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
.matrix { position: relative; display: inline-grid; gap: 3px; padding: 4px 9px; }
.matrix::before, .matrix::after { content: ""; position: absolute; top: 0; bottom: 0; width: 6px; border: 1.5px solid var(--line-strong); }
.matrix::before { left: 0; border-right: 0; }
.matrix::after { right: 0; border-left: 0; }
.matrix input {
  width: 4.4em; min-height: 26px; padding: 0 5px; text-align: center;
  border: 1px solid var(--line); border-radius: var(--radius);
  background: var(--input); color: var(--cell-color, var(--text));
  font-family: var(--font-mono); font-size: 12.5px; font-weight: 500;
}
.matrix--wide input { width: 3.8em; }
.matrix input:hover { border-color: var(--line-strong); }
.matrix input:focus { border-color: var(--accent); outline: none; }
.matrix input:disabled { opacity: .4; }
.matrix input[aria-invalid="true"] { border-color: var(--danger); color: var(--danger); }
.matrix input[data-sep] { margin-left: 8px; }

/* ---------- Inspector sections ---------------------------------------- */

.card { border-bottom: 1px solid var(--line); }
.card__head { display: flex; align-items: center; justify-content: space-between; gap: 8px; min-height: 28px; padding: 0 8px 0 4px; background: var(--surface-2); border-bottom: 1px solid var(--line); }
.card--collapsed .card__head { border-bottom: 0; }
.card__title { margin: 0; min-width: 0; font-size: inherit; }
.card__toggle { display: flex; align-items: center; gap: 4px; width: 100%; min-height: 28px; padding: 0 4px; border: 0; background: none; color: var(--muted); font-family: var(--font-mono); font-size: 10.5px; font-weight: 600; letter-spacing: .07em; text-transform: uppercase; cursor: pointer; text-align: left; }
.card__toggle:hover { color: var(--text); }
.card__toggle svg { width: 13px; height: 13px; transition: transform .12s var(--ease); transform: rotate(90deg); }
.card--collapsed .card__toggle svg { transform: rotate(0deg); }
.card__body { display: grid; gap: 10px; padding: 10px 12px 12px; }
.card__body > p { margin: 0; color: var(--muted); font-size: 12px; line-height: 1.5; }
.row { display: flex; align-items: center; gap: 6px; flex-wrap: wrap; }
.row--between { justify-content: space-between; }
.op-builder select { width: auto; flex: 1 1 auto; min-width: 5.5em; }
.op-builder select:first-child { flex-basis: 100%; }
.grid-2 { display: grid; grid-template-columns: 1fr 1fr; gap: 8px; }

/* Readouts */
.readouts { display: grid; gap: 0; }
.readout { display: grid; grid-template-columns: minmax(78px, auto) minmax(0, 1fr); gap: 10px; align-items: center; padding: 7px 0; border-bottom: 1px solid var(--line); }
.readout:last-child { border-bottom: 0; }
.readout__k { color: var(--muted); font-family: var(--font-mono); font-size: 10.5px; letter-spacing: .03em; }
.readout__v { min-width: 0; overflow-x: auto; overflow-y: hidden; font-size: 13.5px; }
.readout__note { grid-column: 1 / -1; margin-top: -2px; color: var(--muted); font-size: 11.5px; line-height: 1.45; }
.readout--block { grid-template-columns: 1fr; gap: 4px; }
.badge { display: inline-flex; align-items: center; gap: 5px; padding: 1px 7px; border: 1px solid var(--line-strong); border-radius: var(--radius); font-family: var(--font-mono); font-size: 10.5px; color: var(--muted); white-space: nowrap; }
.badge svg { width: 12px; height: 12px; }
.readout__v .badge { white-space: normal; }
.badge--ok { color: var(--ok); border-color: color-mix(in srgb, var(--ok) 45%, transparent); }
.badge--warn { color: var(--warn); border-color: color-mix(in srgb, var(--warn) 45%, transparent); }
.badge--danger { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 45%, transparent); }
.math-block { overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.math-block .katex-display { margin: .3em 0; }

.active-challenge { display: flex; gap: 8px; align-items: flex-start; padding: 8px 12px; border-bottom: 1px solid var(--accent); background: var(--accent-soft); font-size: 12.5px; }
.active-challenge strong { display: block; font-size: 10.5px; font-family: var(--font-mono); letter-spacing: .06em; text-transform: uppercase; color: var(--accent); }

/* ---------- Theory ----------------------------------------------------- */

#pane-theory { padding: 12px 14px 20px; }
.theory__lead { margin: 0 0 14px; color: var(--muted); font-size: 12.5px; line-height: 1.55; }
.theory__section + .theory__section { margin-top: 18px; }
.section-title { margin: 0 0 8px; color: var(--faint); font-family: var(--font-mono); font-size: 10.5px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; }
.prose { font-size: 13.5px; line-height: 1.65; }
.prose p { margin: 0 0 .8em; }
.prose ul, .prose ol { margin: 0 0 .8em; padding-left: 1.3em; }
.prose li { margin: .3em 0; }
.prose li::marker { color: var(--accent); }
.prose strong { color: var(--text); }
.prose .katex-display { margin: .8em 0; overflow-x: auto; overflow-y: hidden; padding: 2px 0; }
.prompts { margin: 0; padding: 0; list-style: none; counter-reset: prompt; display: grid; gap: 6px; }
.prompts li { counter-increment: prompt; display: grid; grid-template-columns: 24px 1fr; gap: 6px; padding: 8px 10px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink); font-size: 12.5px; line-height: 1.55; }
.prompts li::before { content: counter(prompt, decimal-leading-zero); color: var(--coral); font-family: var(--font-mono); font-size: 11px; padding-top: 1px; }
.formal-list { display: grid; gap: 6px; }
.formal { border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink); }
.formal > summary { display: flex; align-items: center; justify-content: space-between; gap: 10px; padding: 8px 10px; cursor: pointer; list-style: none; font-weight: 650; font-size: 12.5px; }
.formal > summary::-webkit-details-marker { display: none; }
.formal > summary::after { content: "+"; color: var(--accent); font-family: var(--font-mono); font-size: 15px; }
.formal[open] > summary::after { content: "−"; }
.formal__body { padding: 0 10px 10px; font-size: 13px; }
.formal__kind { color: var(--coral); font-family: var(--font-mono); font-size: 10px; letter-spacing: .08em; text-transform: uppercase; margin-right: 8px; }

/* ---------- Challenges ------------------------------------------------- */

#pane-challenges { padding: 12px; }
.challenge-bar { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; color: var(--muted); font-size: 12px; }
.progress { flex: 1; height: 3px; background: var(--surface-3); border-radius: 2px; overflow: hidden; }
.progress > span { display: block; height: 100%; background: var(--accent-bg); transition: width .3s var(--ease); }
.challenges { display: grid; gap: 8px; }
.challenge { display: grid; gap: 8px; padding: 10px 12px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--ink); }
.challenge[data-active="true"] { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.challenge[data-done="true"] { border-color: color-mix(in srgb, var(--ok) 50%, var(--line)); }
.challenge__head { display: grid; grid-template-columns: auto 1fr auto; align-items: baseline; gap: 8px; }
.challenge__title { margin: 0; font-size: 13px; line-height: 1.3; }
.challenge__num { color: var(--coral); font-family: var(--font-mono); font-size: 10.5px; }
.challenge__text { margin: 0; color: var(--muted); font-size: 12.5px; line-height: 1.55; }
.challenge__foot { display: flex; align-items: center; justify-content: space-between; gap: 8px; flex-wrap: wrap; }
.challenge details { font-size: 12px; color: var(--muted); }
.challenge details summary { cursor: pointer; font-family: var(--font-mono); font-size: 10.5px; color: var(--muted); }

/* Toast */
.toast { position: fixed; left: 50%; bottom: 36px; z-index: 400; transform: translate(-50%, 12px); opacity: 0; pointer-events: none; padding: 7px 12px; border: 1px solid var(--line-strong); border-radius: var(--radius); background: var(--surface-3); color: var(--text); font-family: var(--font-mono); font-size: 11.5px; transition: opacity .2s, transform .2s; box-shadow: var(--shadow); max-width: calc(100vw - 32px); }
.toast[data-show="true"] { opacity: 1; transform: translate(-50%, 0); }
.toast--success { border-color: var(--ok); color: var(--ok); }

/* ---------- Presentation mode ---------------------------------------- */

body.app.presenting { grid-template-columns: 0 minmax(0, 1fr) var(--insp-w); grid-template-rows: minmax(0, 1fr) 0; }
body.presenting .sidebar, body.presenting .toolbar, body.presenting .statusbar { display: none; }
body.presenting .present-tools { display: flex; }
body.presenting .readout__v { font-size: 16px; }
body.app.presenting.panel-hidden { grid-template-columns: 0 minmax(0, 1fr) 0; }
body.presenting.panel-hidden .inspector { display: none; }

/* ---------- Launcher (home) -------------------------------------------- */

body.launcher-page > .statusbar { grid-area: auto; }
body.launcher-page { display: grid; grid-template-columns: minmax(0, 1fr); grid-template-rows: var(--tb-h) minmax(0, 1fr) var(--status-h); height: 100vh; height: 100dvh; overflow: hidden; }
.launcher-bar { display: flex; align-items: center; gap: 10px; padding: 0 8px 0 14px; border-bottom: 1px solid var(--line); background: var(--surface); }
.launcher-bar__title { min-width: 0; margin: 0; font-size: 13px; font-weight: 700; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.launcher { min-height: 0; overflow-y: auto; padding: 18px 20px 36px; }
.launcher__inner { max-width: 1320px; margin: 0 auto; }
.launcher__resume { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; margin-bottom: 18px; color: var(--muted); font-size: 12px; }
.launcher__resume a { display: inline-flex; align-items: center; gap: 8px; padding: 4px 10px 4px 6px; border: 1px solid var(--line-strong); border-radius: var(--radius); background: var(--surface); text-decoration: none; color: var(--text); }
.launcher__resume a:hover { border-color: var(--accent); }
.chapter-block + .chapter-block { margin-top: 22px; }
.chapter-block__title { display: flex; align-items: baseline; gap: 10px; margin: 0 0 8px; color: var(--muted); font-family: var(--font-mono); font-size: 10.5px; font-weight: 600; letter-spacing: .08em; text-transform: uppercase; }
.chapter-block__title span { color: var(--faint); font-weight: 400; }
.tiles { display: grid; grid-template-columns: repeat(auto-fill, minmax(236px, 1fr)); gap: 8px; }
.tile { position: relative; display: grid; grid-template-columns: 64px minmax(0, 1fr); gap: 12px; align-items: start; padding: 10px; border: 1px solid var(--line); border-radius: var(--radius); background: var(--surface); text-decoration: none; transition: border-color .12s var(--ease), background-color .12s var(--ease); }
.tile:hover { border-color: var(--accent); background: var(--surface-2); }
.tile__thumb { width: 64px; height: 64px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: var(--radius); background: var(--canvas-bg); }
.tile__thumb .app-icon { width: 48px; height: 48px; }
.tile__meta { display: grid; gap: 3px; min-width: 0; }
.tile__top { display: flex; align-items: center; gap: 8px; }
.tile__num { color: var(--coral); font-family: var(--font-mono); font-size: 10.5px; }
.tile__tag { padding: 0 5px; border: 1px solid var(--accent); border-radius: var(--radius); color: var(--accent); font-family: var(--font-mono); font-size: 9.5px; letter-spacing: .05em; text-transform: uppercase; }
.tile__title { margin: 0; color: var(--text); font-size: 13.5px; font-weight: 650; line-height: 1.25; }
.tile__blurb { margin: 0; color: var(--muted); font-size: 11.5px; line-height: 1.45; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.tile__progress { display: flex; align-items: center; gap: 6px; margin-top: 2px; color: var(--faint); font-family: var(--font-mono); font-size: 10px; }
.tile__progress .progress { max-width: 80px; }
.tile__progress[data-done="true"] { color: var(--ok); }

/* ---------- Narrow screens: one scrolling column ------------------------ */

@media (max-width: 899px) {
  body.app { display: block; height: auto; overflow: visible; }
  .sidebar { position: fixed; z-index: 200; top: 0; bottom: 0; left: 0; width: min(84vw, 300px); transform: translateX(-100%); transition: transform .18s var(--ease); box-shadow: var(--shadow); }
  body.sidebar-open .sidebar { transform: none; }
  body.sidebar-open .sidebar-backdrop { display: block; position: fixed; inset: 0; z-index: 150; background: rgba(0, 0, 0, .45); }
  .sidebar__collapse { display: none; }
  body.sidebar-collapsed .sidebar__brand-label, body.sidebar-collapsed .sidebar__group, body.sidebar-collapsed .navitem__num,
  body.sidebar-collapsed .navitem__label, body.sidebar-collapsed .navitem__done, body.sidebar-collapsed .sidebar__link span,
  body.sidebar-collapsed .sidebar__credit { display: revert; }
  body.sidebar-collapsed .navitem { grid-template-columns: 20px 20px minmax(0, 1fr) auto; justify-content: stretch; padding: 0 10px 0 12px; height: 30px; }
  body.sidebar-collapsed .sidebar__head { flex-direction: row; height: var(--tb-h); padding: 0 6px 0 12px; }
  .workspace { display: block; }
  .toolbar { position: sticky; top: 0; z-index: 50; padding-left: 4px; }
  .icon-btn.toolbar__menu { display: inline-flex; }
  .toolbar__chapter { display: none; }
  .stage { height: 60vh; min-height: 320px; flex: none; }
  .stage__views--2 { grid-template-columns: 1fr; }
  .inspector { border-left: 0; border-top: 1px solid var(--line); }
  .inspector__resizer { display: none; }
  .inspector__panes { overflow: visible; }
  .tabs { position: sticky; top: var(--tb-h); z-index: 40; }
  .statusbar { display: none; }
  .anim { grid-template-columns: auto 1fr; }
  .anim > :last-child { grid-column: 1 / -1; }
  body.app.presenting { display: block; }
  body.presenting .stage { height: 100vh; }
}
@media (max-width: 560px) {
  .toolbar__sep { display: none; }
  .toolbar__group .icon-btn { width: 26px; }
  .matrix input { width: 3.9em; }
  .readout { grid-template-columns: 1fr; gap: 3px; }
  .launcher { padding: 12px 10px 28px; }
  .tiles { grid-template-columns: 1fr; }
}

/* ---------- KaTeX tweaks --------------------------------------------- */
.katex { font-size: 1.06em; }
.katex .c-i, .katex .c-j, .katex .c-k { font-weight: inherit; }

/* ---------- Print ----------------------------------------------------- */
@media print {
  body.app { display: block; height: auto; overflow: visible; }
  .sidebar, .toolbar, .statusbar, .view__tools, .tabs, .toast, .inspector__resizer { display: none !important; }
  .stage { height: 60vh; }
  .tabpanel[hidden] { display: block !important; }
  body { background: #fff; color: #000; }
}