/* ==========================================================================
   LUMEN — STUDY EXTENSIONS
   Adds: Board (spatial canvas), Highlights, Review (memory engine), Insight.

   INTEGRATION RULE: this file uses ONLY tokens that already exist in
   core-styles-01.css (--paper/--ink/--panel*/--surface-*/--line/--border/
   --accent*/--ok/--warn/--err/--serif/--sans/--mono/--r-*/--shadow-*/
   --fs-*/--dur-*/--ease-*). Every one of them is redefined by the `paper`,
   `midnight`, `contrast` and `comfy` skins, so all five themes work with no
   per-skin overrides here. Zero !important — that is deliberate, see the
   !important census in core-styles-01.css.
   ========================================================================== */

:root{
  /* Derived study tokens. Defined once, inherit the skin through the parents. */
  --ls-tint:color-mix(in srgb, var(--accent) 9%, transparent);
  --ls-tint-line:color-mix(in srgb, var(--accent) 26%, transparent);
  --ls-ok-tint:color-mix(in srgb, var(--ok) 10%, transparent);
  --ls-ok-line:color-mix(in srgb, var(--ok) 28%, transparent);
  --ls-warn-tint:color-mix(in srgb, var(--warn) 10%, transparent);
  --ls-warn-line:color-mix(in srgb, var(--warn) 28%, transparent);
  --ls-err-tint:color-mix(in srgb, var(--err) 10%, transparent);
  --ls-err-line:color-mix(in srgb, var(--err) 28%, transparent);
  --ls-wl-tint:color-mix(in srgb, var(--muted) 9%, transparent);
  --ls-wl-line:color-mix(in srgb, var(--muted) 24%, transparent);
}

/* ============================ shared primitives ========================= */
.ls-mono-label{
  font:600 var(--fs-2xs)/1 var(--mono);
  letter-spacing:.09em;text-transform:uppercase;color:var(--soft);
}
.ls-pill{
  display:inline-flex;align-items:center;gap:5px;
  height:20px;padding:0 8px;border-radius:var(--r-full);
  font:600 var(--fs-xs)/1 var(--sans);
  background:var(--surface-2);color:var(--soft);
  border:1px solid var(--border);white-space:nowrap;
}
.ls-pill[data-tone="accent"]{background:var(--ls-tint);color:var(--accent);border-color:var(--ls-tint-line)}
.ls-pill[data-tone="ok"]{background:var(--ls-ok-tint);color:var(--ok);border-color:var(--ls-ok-line)}
.ls-pill[data-tone="warn"]{background:var(--ls-warn-tint);color:var(--warn);border-color:var(--ls-warn-line)}
.ls-pill[data-tone="err"]{background:var(--ls-err-tint);color:var(--err);border-color:var(--ls-err-line)}

.ls-empty{
  display:flex;flex-direction:column;align-items:center;justify-content:center;
  gap:9px;padding:52px 24px;text-align:center;color:var(--soft);
}
.ls-empty h3{margin:0;font:600 var(--fs-md)/1.3 var(--serif);color:var(--ink)}
.ls-empty p{margin:0;max-width:420px;font-size:var(--fs-base);line-height:1.65;color:var(--soft)}

.ls-panel{
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--r-md);box-shadow:var(--shadow-xs);
}
.ls-row{display:flex;align-items:center;gap:8px}
.ls-grow{flex:1;min-width:0}
.ls-scroll{overflow:auto;scrollbar-width:thin}

/* thin scrollbars that match Lumen's */
.ls-scroll::-webkit-scrollbar{width:8px;height:8px}
.ls-scroll::-webkit-scrollbar-track{background:transparent}
.ls-scroll::-webkit-scrollbar-thumb{background:var(--line2);border-radius:99px;border:2px solid transparent;background-clip:padding-box}
.ls-scroll::-webkit-scrollbar-thumb:hover{background:var(--muted);background-clip:padding-box}

/* ============================== board ================================== */
.ls-board{
  position:relative;flex:1;min-height:0;overflow:hidden;
  background:
    radial-gradient(circle at 1px 1px, var(--line) 1px, transparent 0) 0 0/26px 26px,
    var(--bg);
  touch-action:none;
}
.ls-board[data-mode="pan"]{cursor:grab}
.ls-board[data-mode="pan"][data-drag="1"]{cursor:grabbing}
.ls-plane{position:absolute;inset:0;transform-origin:0 0;will-change:transform}
.ls-wires{position:absolute;inset:0;width:100%;height:100%;overflow:visible;pointer-events:none;z-index:1}
.ls-wire{stroke:var(--muted);stroke-width:1.6;fill:none;stroke-linecap:round;opacity:.75}
.ls-wire-g[data-kind="relation"] .ls-wire{stroke-dasharray:5 4}
.ls-wire-g[data-sel="1"] .ls-wire{stroke:var(--accent);stroke-width:2.4;opacity:1}
.ls-wire-g[data-tone="ok"] .ls-wire{stroke:var(--ok)}
.ls-wire-g[data-tone="warn"] .ls-wire{stroke:var(--warn)}
.ls-wire-g[data-tone="err"] .ls-wire{stroke:var(--err)}

/* --- sections: Lumen's tonal accent system instead of pastel palettes --- */
.ls-sec{
  position:absolute;border-radius:var(--r-lg);
  border:1px solid var(--border);background:var(--ls-wl-tint);
  padding:30px 12px 12px;
}
.ls-sec[data-tone="accent"]{background:var(--ls-tint);border-color:var(--ls-tint-line)}
.ls-sec[data-tone="ok"]{background:var(--ls-ok-tint);border-color:var(--ls-ok-line)}
.ls-sec[data-tone="warn"]{background:var(--ls-warn-tint);border-color:var(--ls-warn-line)}
.ls-sec[data-tone="err"]{background:var(--ls-err-tint);border-color:var(--ls-err-line)}
.ls-sec[data-tone="mute"]{background:var(--ls-wl-tint);border-color:var(--ls-wl-line)}
.ls-sec[data-tone="none"]{background:transparent;border-color:transparent;padding:0}
.ls-sec[data-sel="1"]{box-shadow:var(--ring-soft)}

.ls-sec-label{
  position:absolute;top:8px;left:10px;
  display:inline-flex;align-items:center;gap:6px;height:22px;
  padding:0 9px 0 10px;border-radius:var(--r-full);
  background:var(--panel2);border:1px solid var(--border-strong);
  font:600 var(--fs-xs)/1 var(--sans);color:var(--ink);
  box-shadow:var(--shadow-xs);max-width:calc(100% - 20px);
}
.ls-sec[data-tone="accent"] .ls-sec-label{background:var(--ls-tint);border-color:var(--ls-tint-line);color:var(--accent)}
.ls-sec[data-tone="ok"] .ls-sec-label{background:var(--ls-ok-tint);border-color:var(--ls-ok-line);color:var(--ok)}
.ls-sec[data-tone="warn"] .ls-sec-label{background:var(--ls-warn-tint);border-color:var(--ls-warn-line);color:var(--warn)}
.ls-sec[data-tone="err"] .ls-sec-label{background:var(--ls-err-tint);border-color:var(--ls-err-line);color:var(--err)}
.ls-sec[data-tone="mute"] .ls-sec-label{background:var(--panel2);color:var(--soft)}
.ls-sec-label > span:first-child{overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ls-sec-label .ls-meta{color:var(--muted);font-weight:500}
.ls-sec-label .ls-dots{
  display:grid;place-items:center;width:16px;height:16px;margin-left:1px;
  border-radius:var(--r-xs);color:var(--muted);cursor:pointer;flex:none;
}
.ls-sec-label .ls-dots:hover{background:var(--surface-3);color:var(--ink)}
.ls-sec-grip{
  position:absolute;right:3px;bottom:3px;width:14px;height:14px;cursor:nwse-resize;
  border-radius:0 0 var(--r-lg) 0;opacity:0;transition:opacity var(--dur-fast);
}
.ls-sec:hover .ls-sec-grip{opacity:1}

/* --- cards --- */
.ls-card{
  position:absolute;background:var(--panel);
  border:1px solid var(--border);border-radius:var(--r-md);
  box-shadow:var(--shadow-xs);
  padding:10px 12px 11px;display:flex;flex-direction:column;gap:5px;
  transition:box-shadow var(--dur-fast) var(--ease-out),border-color var(--dur-fast) var(--ease-out);
}
.ls-card:hover{box-shadow:var(--shadow-sm);border-color:var(--border-strong)}
.ls-card[data-sel="1"]{border-color:var(--accent);box-shadow:var(--ring-soft),var(--shadow-sm)}
.ls-card[data-drag="1"]{box-shadow:var(--shadow-md);cursor:grabbing}
.ls-card-title{
  font:600 var(--fs-base)/1.35 var(--serif);color:var(--ink);
  letter-spacing:-.005em;
  display:-webkit-box;-webkit-box-orient:vertical;overflow:hidden;
}
.ls-card[data-clamp="1"] .ls-card-title{-webkit-line-clamp:1}
.ls-card[data-clamp="2"] .ls-card-title{-webkit-line-clamp:2}
.ls-card[data-clamp="3"] .ls-card-title{-webkit-line-clamp:3}
.ls-card-body{
  font-size:var(--fs-sm);line-height:1.6;color:var(--soft);
  white-space:pre-wrap;word-break:break-word;
  display:-webkit-box;-webkit-box-orient:vertical;overflow:hidden;
}
.ls-card[data-clamp="4"] .ls-card-body{-webkit-line-clamp:4}
.ls-card[data-clamp="6"] .ls-card-body{-webkit-line-clamp:6}
.ls-card[data-clamp="9"] .ls-card-body{-webkit-line-clamp:9}
.ls-card[data-clamp="14"] .ls-card-body{-webkit-line-clamp:14}
.ls-card-src{
  margin-top:auto;padding-top:4px;font-size:var(--fs-xs);color:var(--dim);
  overflow:hidden;text-overflow:ellipsis;white-space:nowrap;
}
.ls-card-src b{color:var(--soft);font-weight:600}
.ls-card[data-kind="source"] .ls-card-src b{color:var(--accent)}
.ls-card-edge{position:absolute;left:-1px;top:9px;bottom:9px;width:3px;border-radius:3px;background:var(--accent)}
.ls-card[data-kind="highlight"] .ls-card-edge{background:var(--warn)}
.ls-card[data-kind="quiz"] .ls-card-edge{background:var(--ok)}
.ls-card[data-kind="deck"] .ls-card-edge{background:var(--accent)}
.ls-card[data-kind="exam"] .ls-card-edge{background:var(--err)}
.ls-card[data-kind="insight"] .ls-card-edge{background:var(--ok)}
.ls-card-menu{
  position:absolute;top:5px;right:5px;width:20px;height:20px;
  display:none;place-items:center;border-radius:var(--r-xs);
  background:var(--panel2);border:1px solid var(--border);color:var(--muted);cursor:pointer;
}
.ls-card:hover .ls-card-menu{display:grid}
.ls-card-menu:hover{color:var(--ink);border-color:var(--border-strong)}
.ls-card-grip{
  position:absolute;left:-4px;top:50%;transform:translateY(-50%);
  width:8px;height:26px;border-radius:var(--r-full);cursor:ew-resize;opacity:0;
  transition:opacity var(--dur-fast);
}
.ls-card:hover .ls-card-grip{opacity:1}
.ls-card-grip:hover{background:var(--accent)}
.ls-card-handle{position:absolute;right:0;bottom:0;width:14px;height:14px;cursor:nwse-resize;opacity:0;transition:opacity var(--dur-fast)}
.ls-card:hover .ls-card-handle{opacity:1}
.ls-card-tags{position:absolute;top:6px;right:26px;display:flex;gap:4px}

/* --- floating board toolbar --- */
.ls-tools{
  position:absolute;left:14px;top:50%;transform:translateY(-50%);
  display:flex;flex-direction:column;gap:2px;padding:5px;
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--r-lg);box-shadow:var(--shadow-sm);z-index:20;
}
.ls-tools button{
  width:30px;height:30px;border-radius:var(--r-sm);
  display:grid;place-items:center;color:var(--soft);
  border:0;background:none;cursor:pointer;
  transition:background var(--dur-fast),color var(--dur-fast);
}
.ls-tools button:hover{background:var(--surface-2);color:var(--ink)}
.ls-tools button[aria-pressed="true"]{background:var(--ls-tint);color:var(--accent)}
.ls-tools hr{border:0;border-top:1px solid var(--border);margin:4px 2px}

/* --- zoom cluster --- */
.ls-zoom{
  position:absolute;right:16px;bottom:16px;z-index:20;
  display:flex;align-items:center;gap:2px;padding:3px;
  background:var(--panel);border:1px solid var(--border);
  border-radius:var(--r-full);box-shadow:var(--shadow-sm);
}
.ls-zoom button{
  width:28px;height:28px;border-radius:var(--r-full);border:0;background:none;
  display:grid;place-items:center;color:var(--soft);cursor:pointer;
}
.ls-zoom button:hover{background:var(--surface-2);color:var(--ink)}
.ls-zoom button[aria-pressed="true"]{color:var(--accent);background:var(--ls-tint)}
.ls-zoom .ls-sep{width:1px;height:16px;background:var(--border);margin:0 3px}
.ls-zoom .ls-pct{
  min-width:42px;text-align:center;font:600 var(--fs-xs)/1 var(--mono);
  color:var(--soft);font-variant-numeric:tabular-nums;
}

/* --- selection marquee --- */
.ls-marquee{
  position:absolute;border:1px solid var(--accent);
  background:color-mix(in srgb, var(--accent) 12%, transparent);
  border-radius:var(--r-xs);pointer-events:none;z-index:15;
}

/* ============================ highlights =============================== */
.ls-hl-layer{position:absolute;inset:0;pointer-events:none;z-index:3}
.ls-hl{
  position:absolute;border-radius:2px;pointer-events:auto;cursor:pointer;
  mix-blend-mode:screen;opacity:.62;
  transition:box-shadow var(--dur-fast);
}
[data-skin="paper"] .ls-hl{mix-blend-mode:multiply;opacity:.5}
.ls-hl:hover{box-shadow:0 0 0 2px var(--accent-glow)}
.ls-hl[data-active="1"]{box-shadow:0 0 0 2px var(--accent)}
.ls-hl[data-color="yellow"]{background:#ffd54a}
.ls-hl[data-color="green"]{background:#7dd87d}
.ls-hl[data-color="blue"]{background:#74c0fc}
.ls-hl[data-color="pink"]{background:#f783ac}
.ls-hl[data-color="purple"]{background:#b197fc}
.ls-hl[data-color="orange"]{background:#ffab66}

.ls-hl-bar{
  display:flex;align-items:center;gap:6px;flex-wrap:wrap;
  padding:0 0 8px;
}
.ls-sw{
  width:22px;height:22px;border-radius:var(--r-xs);cursor:pointer;
  border:2px solid transparent;box-shadow:inset 0 0 0 1px var(--line2);
}
.ls-sw[aria-pressed="true"]{border-color:var(--accent)}

.ls-hl-item{
  border:1px solid var(--border);border-radius:var(--r-sm);
  background:var(--panel);padding:10px 12px;margin-bottom:8px;
}
.ls-hl-item blockquote{
  margin:0 0 8px;padding-left:10px;
  border-left:3px solid var(--warn);
  font-size:var(--fs-base);line-height:1.6;color:var(--ink);
}
.ls-hl-item .ls-note{font-size:var(--fs-sm);color:var(--soft);margin:0 0 8px;line-height:1.55}

/* ============================== review ================================= */
.ls-rv{max-width:760px;margin:0 auto;padding:20px 18px 48px;display:flex;flex-direction:column;gap:14px}
.ls-rv-head{
  border:1px solid var(--border);border-radius:var(--r-md);
  background:var(--panel);padding:14px 16px;
}
.ls-rv-head h3{margin:0 0 5px;font:600 var(--fs-lg)/1.3 var(--serif);color:var(--ink)}
.ls-rv-head p{margin:0;font-size:var(--fs-base);line-height:1.65;color:var(--soft)}
.ls-rv-stats{display:grid;grid-template-columns:repeat(auto-fit,minmax(118px,1fr));gap:9px}
.ls-stat{
  border:1px solid var(--border);border-radius:var(--r-sm);
  background:var(--panel);padding:10px 12px;
}
.ls-stat b{display:block;font:700 var(--fs-xl)/1.1 var(--serif);font-variant-numeric:tabular-nums}
.ls-stat span{font:600 var(--fs-2xs)/1 var(--mono);letter-spacing:.08em;text-transform:uppercase;color:var(--soft)}

.ls-rv-card{
  background:var(--panel);border:1px solid var(--border);border-radius:var(--r-lg);
  box-shadow:var(--shadow-sm);padding:26px 24px;min-height:210px;
  display:flex;flex-direction:column;justify-content:center;gap:12px;
}
.ls-rv-card .q{font:600 var(--fs-lg)/1.45 var(--serif);color:var(--ink)}
.ls-rv-card .a{font-size:var(--fs-base);line-height:1.7;color:var(--soft);white-space:pre-wrap}
.ls-rv-card .hint{font-size:var(--fs-base);color:var(--dim);font-style:italic}
.ls-rv-extra{
  font-size:var(--fs-sm);line-height:1.6;padding:9px 11px;border-radius:var(--r-sm);
  background:var(--ls-tint);border:1px solid var(--ls-tint-line);color:var(--accent);
}
.ls-rv-extra[data-kind="feynman"]{background:var(--ls-ok-tint);border-color:var(--ls-ok-line);color:var(--ok)}
.ls-rv-grades{display:grid;grid-template-columns:repeat(4,1fr);gap:8px}
.ls-rv-grades button{
  border:1px solid var(--border);border-radius:var(--r-sm);
  background:var(--panel);cursor:pointer;padding:11px 6px;
  display:flex;flex-direction:column;align-items:center;gap:3px;
  transition:border-color var(--dur-fast),background var(--dur-fast);
}
.ls-rv-grades button:hover{background:var(--surface-2);border-color:var(--border-strong)}
.ls-rv-grades .g{font:600 var(--fs-base)/1 var(--sans)}
.ls-rv-grades .n{font:500 var(--fs-2xs)/1 var(--mono);color:var(--dim)}
.ls-rv-grades button[data-g="again"]{color:var(--err)}
.ls-rv-grades button[data-g="hard"]{color:var(--warn)}
.ls-rv-grades button[data-g="good"]{color:var(--ok)}
.ls-rv-grades button[data-g="easy"]{color:var(--accent)}
.ls-rv-bar{height:4px;background:var(--surface-3);border-radius:var(--r-full);overflow:hidden}
.ls-rv-bar i{display:block;height:100%;background:var(--accent);transition:width var(--dur-slow) var(--ease-out)}

.ls-forecast{display:flex;align-items:flex-end;gap:3px;height:66px}
.ls-forecast i{
  flex:1;min-width:5px;border-radius:2px 2px 0 0;background:var(--accent);opacity:.72;
}
.ls-forecast i[data-today="1"]{opacity:1}
.ls-forecast i[data-hot="1"]{background:var(--warn);opacity:1}

.ls-mastery{display:flex;flex-direction:column;gap:9px}
.ls-mrow{display:grid;grid-template-columns:130px 1fr 46px;gap:11px;align-items:center;font-size:var(--fs-base)}
.ls-mrow .lbl{color:var(--soft);overflow:hidden;text-overflow:ellipsis;white-space:nowrap}
.ls-mrow .track{height:7px;background:var(--surface-3);border-radius:var(--r-full);overflow:hidden}
.ls-mrow .track i{display:block;height:100%;border-radius:var(--r-full);background:var(--accent);transition:width var(--dur-slow) var(--ease-out)}
.ls-mrow .pc{text-align:right;color:var(--dim);font:600 var(--fs-xs)/1 var(--mono);font-variant-numeric:tabular-nums}

/* ============================== insight ================================ */
.ls-ins{
  border:1px solid var(--border);border-radius:var(--r-sm);
  background:var(--panel);padding:10px 12px;margin-bottom:8px;
}
.ls-ins p{margin:0 0 7px;font-size:var(--fs-base);line-height:1.55;color:var(--ink)}
.ls-ins details{font-size:var(--fs-xs);color:var(--soft)}
.ls-ins summary{cursor:pointer;color:var(--dim)}
.ls-ins details p{
  margin:6px 0 0;padding:8px 10px;border-radius:var(--r-sm);
  background:var(--surface-2);color:var(--soft);line-height:1.6;white-space:pre-wrap;
}

/* ======================= notebook scope switcher ======================== */
.ls-nb-bar{
  display:flex;align-items:center;gap:7px;flex-wrap:wrap;
  padding:0 0 10px;
}
.ls-nb-bar select{max-width:230px}

/* A <select> styled as .btn: .btn sets height/border/padding that a native
   select renders inconsistently across engines, and it left the dropdown
   arrow misaligned. Match the app's own control metrics explicitly. */
.ls-nb-sel{
  height:28px;padding:0 26px 0 9px;max-width:230px;
  border-radius:var(--r-sm);
  border:1px solid var(--border);
  background:var(--surface-2);color:var(--ink);
  font:500 var(--fs-sm)/1 var(--sans);
  cursor:pointer;
}
.ls-nb-sel:hover{border-color:var(--accent);color:var(--ink)}
.ls-nb-sel:focus-visible{outline:2px solid var(--accent);outline-offset:1px}

/* Inline variant. The switcher is also mounted into a .vbar, which is itself
   `display:flex; flex-wrap:wrap` — so the standalone rules above made the
   select and its buttons wrap onto a second line and collide with the view
   title. Collapse it to a single non-wrapping row with no block padding. */
.vbar .ls-bctl{
  display:flex;align-items:center;gap:8px;
  flex-wrap:nowrap;min-width:0;
}
.vbar .ls-nb-bar{
  flex-wrap:nowrap;padding:0;gap:7px;min-width:0;
}
.vbar .ls-nb-bar .ls-nb-sel{max-width:230px;min-width:150px}
.vbar .ls-nb-bar .btn{white-space:nowrap}
.vbar .ls-nb-bar .ls-pill{display:none}   /* the count pill duplicates the title bar */
@media (max-width:820px){
  .vbar .ls-nb-bar .ls-nb-sel{max-width:130px}
}

/* ============================ responsive =============================== */
@media (max-width:900px){
  .ls-tools{left:8px;padding:4px}
  .ls-tools button{width:28px;height:28px}
  .ls-zoom{right:10px;bottom:10px}
  .ls-rv-grades{grid-template-columns:repeat(2,1fr)}
  .ls-mrow{grid-template-columns:100px 1fr 40px}
  .ls-rv{padding:14px 12px 40px}
}
@media (prefers-reduced-motion:reduce){
  .ls-card,.ls-hl,.ls-sw,.ls-tools button,.ls-zoom button,.ls-rv-bar i,.ls-mrow .track i{transition:none}
}