/* =============================================================================
   Vector Field Lab: styles
   ========================================================================== */
:root {
  --bg: #0b0e14;
  --panel: #12161f;
  --panel-2: #171c28;
  --line: #232a3a;
  --line-2: #2c3446;
  --text: #dfe5f0;
  --muted: #8b96ab;
  --accent: #5b8cff;
  --accent-2: #4cc9f0;
  --good: #46d19e;
  --bad: #ff6b6b;
  --warn: #ffcf5c;
  --overlay-bg: rgba(15, 19, 28, .72);
  --overlay-solid: rgba(15, 19, 28, .55);
  --topbar: linear-gradient(180deg, #141926, #10141d);
  --thumb: #222a3a;
  --chip: #151b28;
  --btn-hover: #1e2740;
  --mono: 'JetBrains Mono', 'SF Mono', ui-monospace, 'Cascadia Code', Consolas, monospace;
  --sans: system-ui, -apple-system, 'Segoe UI', Roboto, Arial, sans-serif;
}
:root[data-theme="light"] {
  --bg: #eef1f6;
  --panel: #ffffff;
  --panel-2: #eef2f8;
  --line: #dde3ec;
  --line-2: #cbd4e1;
  --text: #1b2330;
  --muted: #5f6b82;
  --accent: #3564d6;
  --accent-2: #0e93b0;
  --good: #12996b;
  --bad: #d6453f;
  --warn: #a86e12;
  --overlay-bg: rgba(255, 255, 255, .82);
  --overlay-solid: rgba(255, 255, 255, .66);
  --topbar: linear-gradient(180deg, #ffffff, #f3f6fb);
  --thumb: #c4cddc;
  --chip: #e9eef6;
  --btn-hover: #dbe4f1;
}

* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  overflow: hidden;
  font-size: 13px;
  -webkit-font-smoothing: antialiased;
  transition: background-color .25s ease, color .25s ease;
}
#app { display: flex; flex-direction: column; height: 100vh; }

/* ---- top bar ------------------------------------------------------------- */
#topbar {
  display: flex; align-items: center; gap: 12px 18px; flex-wrap: wrap;
  min-height: 52px; padding: 5px 16px;
  background: var(--topbar);
  border-bottom: 1px solid var(--line);
  flex: none;
}
.ghost.icon { width: 34px; padding: 6px 0; text-align: center; font-size: 15px; }
.brand { font-weight: 650; font-size: 15px; letter-spacing: .2px; white-space: nowrap; flex: none; }
.nabla { color: var(--accent-2); font-weight: 800; }
.tabs-wrap { display: flex; gap: 8px 14px; flex-wrap: wrap; min-width: 0; flex: 1; align-items: center; }
.tab-group { display: flex; align-items: center; gap: 7px; min-width: 0; }
.tab-group-label { font-size: 10px; text-transform: uppercase; letter-spacing: 1.3px; color: var(--muted); font-weight: 700; white-space: nowrap; }
.tabs { display: flex; gap: 3px; background: var(--panel-2); padding: 3px; border-radius: 9px; border: 1px solid var(--line); min-width: 0; flex-wrap: wrap; }
.tabs::-webkit-scrollbar { display: none; }
.tab { white-space: nowrap; flex: none; }
.tab {
  background: transparent; color: var(--muted); border: 0; cursor: pointer;
  padding: 5px 10px; border-radius: 7px; font-size: 12.5px; font-weight: 550; transition: .15s;
}
.tab:hover { color: var(--text); }
.tab.active { background: var(--accent); color: #fff; box-shadow: 0 2px 10px rgba(91,140,255,.35); }
.actions { margin-left: auto; display: flex; align-items: center; gap: 10px; }
.ghost {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--line-2);
  padding: 6px 12px; border-radius: 7px; cursor: pointer; font-size: 12.5px; transition: .15s;
  white-space: nowrap;
}
.ghost:hover { border-color: var(--accent); color: var(--text); }
.diag {
  font-family: var(--mono); font-size: 11.5px; padding: 4px 9px; border-radius: 6px; white-space: nowrap;
  background: var(--panel-2); border: 1px solid var(--line-2); color: var(--muted); cursor: default;
}
.diag.ok { color: var(--good); border-color: rgba(70,209,158,.4); }
.diag.fail { color: var(--bad); border-color: rgba(255,107,107,.5); }

/* ---- layout -------------------------------------------------------------- */
#main { display: flex; flex: 1; min-height: 0; }
#panel {
  width: 344px; flex: none; background: var(--panel);
  border-right: 1px solid var(--line); overflow-y: auto; overflow-x: hidden;
}
#panel::-webkit-scrollbar { width: 10px; }
#panel::-webkit-scrollbar-thumb { background: var(--thumb); border-radius: 8px; border: 2px solid var(--panel); }
#panel::-webkit-scrollbar-thumb:hover { background: var(--line-2); }
#viewport { position: relative; flex: 1; min-width: 0; }
#gl { display: block; width: 100%; height: 100%; }

/* ---- panel controls ------------------------------------------------------ */
.panel-body { padding: 14px 14px 40px; }
.sec-title {
  font-size: 11px; text-transform: uppercase; letter-spacing: 1.3px; color: var(--muted);
  margin: 20px 2px 9px; padding-bottom: 6px; border-bottom: 1px solid var(--line); font-weight: 650;
}
.ctl { margin: 9px 0; }
.ctl-label { font-size: 12px; color: var(--muted); margin: 0 0 5px 2px; display: flex; justify-content: space-between; align-items: baseline; }
.ctl-label:empty { display: none; }
.hint { color: var(--muted); font-size: 11px; font-weight: 400; }

input.expr, input.mcell, .sel {
  width: 100%; background: var(--panel-2); color: var(--text);
  border: 1px solid var(--line-2); border-radius: 7px; padding: 8px 10px;
  font-family: var(--mono); font-size: 13px; outline: none; transition: .15s;
}
input.expr:focus, input.mcell:focus, .sel:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(91,140,255,.15); }
input.bad { border-color: var(--bad) !important; box-shadow: 0 0 0 3px rgba(255,107,107,.13); }
.sel { cursor: pointer; font-family: var(--sans); }

/* sliders */
.slider { display: flex; align-items: center; gap: 10px; }
.sl { -webkit-appearance: none; appearance: none; flex: 1; height: 4px; border-radius: 3px; background: var(--line-2); outline: none; }
.sl::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none; width: 15px; height: 15px; border-radius: 50%;
  background: var(--accent); cursor: pointer; border: 2px solid var(--bg); box-shadow: 0 0 6px rgba(91,140,255,.6);
}
.sl::-moz-range-thumb { width: 14px; height: 14px; border-radius: 50%; background: var(--accent); cursor: pointer; border: 2px solid var(--bg); }
/* editable value box on every slider: type an exact value or drag */
.sl-val {
  width: 56px; min-width: 56px; text-align: right;
  font-family: var(--mono); font-size: 12px; color: var(--text);
  background: var(--panel-2); border: 1px solid transparent; border-radius: 5px;
  padding: 3px 6px; outline: none; transition: border-color .12s, background-color .12s;
}
.sl-val:hover { border-color: var(--line-2); }
.sl-val:focus { border-color: var(--accent); background: var(--panel); box-shadow: 0 0 0 3px rgba(91, 140, 255, .12); }

/* buttons */
.btn {
  background: var(--panel-2); color: var(--text); border: 1px solid var(--line-2);
  border-radius: 7px; padding: 7px 10px; cursor: pointer; font-size: 12.5px; transition: .13s;
}
.btn:hover { border-color: var(--accent); color: var(--text); background: var(--btn-hover); }
.btn.active { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.wide { width: 100%; margin: 6px 0; }
.presets { display: flex; flex-wrap: wrap; gap: 6px; }
.btn.preset { padding: 5px 9px; font-size: 11.5px; background: var(--chip); }
.preset-desc { font-size: 11.5px; color: var(--muted); line-height: 1.55; margin: 9px 2px 2px; min-height: 14px; }

/* checkboxes */
.chk { display: flex; align-items: center; gap: 8px; cursor: pointer; font-size: 12.5px; color: var(--text); user-select: none; padding: 2px 0; }
.chk input { width: 15px; height: 15px; accent-color: var(--accent); cursor: pointer; }

.note {
  font-size: 11.5px; color: var(--muted); line-height: 1.55; background: var(--panel-2);
  border: 1px solid var(--line); border-left: 3px solid var(--accent-2); border-radius: 7px; padding: 9px 11px; margin-bottom: 6px;
}

/* ---- matrix panel -------------------------------------------------------- */
.mat-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; }
.mcell { text-align: center; padding: 8px 4px; }
.axis-row { display: grid; grid-template-columns: repeat(3, 1fr); gap: 6px; }

/* ---- rigid-body part builder --------------------------------------------- */
.parts-list { display: flex; flex-direction: column; gap: 6px; margin: 4px 0 8px; }
.part-row { border: 1px solid var(--line); border-radius: 7px; padding: 5px 6px; display: flex; flex-direction: column; gap: 4px; }
.prow { display: flex; gap: 5px; align-items: center; }
.prow .sel { flex: 1 1 0; min-width: 0; }
.prow .mcell { flex: 1 1 42px; width: 42px; min-width: 0; padding: 6px 3px; }
.prow .sel ~ .mcell { flex: 0 0 46px; }
.prow .btn { flex: 0 0 auto; padding: 3px 9px; }
.mini { font-size: 10.5px; flex: 0 0 auto; min-width: 24px; }

.readout { font-family: var(--mono); font-size: 12px; }
.ro-line { display: flex; flex-wrap: wrap; gap: 4px 12px; align-items: baseline; margin-bottom: 8px; }
.ro-line span { color: var(--muted); }
.ro-line b { color: var(--accent-2); margin-right: 6px; }
.ro-sub { color: var(--muted); font-family: var(--sans); font-size: 11px; text-transform: uppercase; letter-spacing: .8px; margin: 12px 0 5px; }
.flags { display: flex; flex-wrap: wrap; gap: 5px; margin-bottom: 4px; }
.flag { background: rgba(76,201,240,.13); color: var(--accent-2); border: 1px solid rgba(76,201,240,.3); border-radius: 5px; padding: 2px 7px; font-size: 11px; }
table.eig { width: 100%; border-collapse: collapse; }
table.eig td { padding: 3px 4px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.eig .lam { color: var(--warn); white-space: nowrap; padding-right: 10px; }
table.eig .vec { color: var(--text); }
.muted { color: var(--muted); }
.small { font-size: 11px; line-height: 1.5; }
table.mat-out { border-collapse: collapse; margin-top: 2px; }
table.mat-out td {
  border: 1px solid var(--line-2); padding: 5px 9px; text-align: right; color: var(--text);
  background: var(--panel-2); min-width: 52px; font-size: 11.5px;
}
.ro-vec { font-family: var(--mono); color: var(--accent-2); font-size: 12.5px; margin: 2px 0 2px 2px; }
.hint-good {
  color: var(--good); background: rgba(70, 209, 158, .10); border: 1px solid rgba(70, 209, 158, .32);
  border-radius: 6px; padding: 7px 9px; font-size: 11.5px; line-height: 1.5; margin-top: 6px;
}
.hint-good b { color: var(--good); }
.hint-bad {
  color: var(--bad, #ff6b6b); background: rgba(255, 107, 107, .10); border: 1px solid rgba(255, 107, 107, .32);
  border-radius: 6px; padding: 7px 9px; font-size: 11.5px; line-height: 1.5; margin-top: 6px;
}
.hint-bad b { color: var(--bad, #ff6b6b); }

/* custom points panel */
.points-panel { border-top: 2px solid var(--line); }
.point-add { display: flex; gap: 6px; align-items: center; margin: 8px 0; }
.point-add .mcell { flex: 1; min-width: 0; text-align: center; }
.btn.point-add-btn { flex: none; padding: 8px 14px; }
.points-list { display: flex; flex-direction: column; gap: 4px; margin: 6px 0; }
.pt-row { display: flex; align-items: center; gap: 8px; background: var(--panel-2); border: 1px solid var(--line); border-radius: 6px; padding: 4px 6px 4px 8px; }
.pt-swatch { width: 12px; height: 12px; border-radius: 3px; flex: none; box-shadow: 0 0 0 1px rgba(0,0,0,.25) inset; }
.pt-coord { flex: 1; font-family: var(--mono); font-size: 11.5px; color: var(--text); overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.pt-del { flex: none; background: transparent; border: 0; color: var(--muted); cursor: pointer; font-size: 15px; line-height: 1; padding: 2px 5px; border-radius: 4px; }
.pt-del:hover { color: var(--bad); background: var(--line); }

/* extra functions (Functions tab) */
.extras-list { display: flex; flex-direction: column; gap: 5px; margin: 5px 0; }
.extra-row { display: flex; align-items: center; gap: 7px; }
.extra-row .expr { flex: 1; min-width: 0; }
.extra-color {
  flex: none; width: 24px; height: 24px; padding: 0; border: 1px solid var(--line-2);
  border-radius: 6px; background: none; cursor: pointer;
}
.extra-color::-webkit-color-swatch-wrapper { padding: 2px; }
.extra-color::-webkit-color-swatch { border: none; border-radius: 4px; }
.btn.add-extra { padding: 6px; font-size: 12px; margin-top: 2px; }
.taylor-poly {
  font-family: var(--mono); font-size: 12px; line-height: 1.75; color: var(--text);
  background: var(--panel-2); border: 1px solid var(--line); border-radius: 7px; padding: 8px 10px; word-break: break-word;
}
.shown { color: var(--accent-2); font-size: 10.5px; font-weight: 600; letter-spacing: .3px; white-space: nowrap; }
.taylor-poly .tk { color: var(--warn); white-space: nowrap; }
.taylor-poly .op { color: var(--muted); }
.taylor-poly sub, .taylor-poly sup { color: var(--muted); }

/* ---- viewport overlays --------------------------------------------------- */
.overlay { position: absolute; pointer-events: none; z-index: 3; }
.ov-formula {
  top: 14px; left: 16px; font-family: var(--mono); font-size: 13px; color: var(--text);
  background: var(--overlay-bg); border: 1px solid var(--line); border-radius: 8px; padding: 8px 12px;
  backdrop-filter: blur(6px); max-width: 62%;
}
.ov-formula b { color: var(--accent-2); }
.ov-stats {
  bottom: 14px; left: 16px; font-family: var(--mono); font-size: 11.5px; color: var(--muted);
  background: var(--overlay-solid); border: 1px solid var(--line); border-radius: 7px; padding: 6px 10px; backdrop-filter: blur(6px);
  z-index: 4;   /* above the centred .hud-hint: long stats lines reach it on narrower screens */
}
.ov-stats:empty { display: none; }
.ov-error {
  top: 14px; left: 50%; transform: translateX(-50%); max-width: 70%;
  font-family: var(--mono); font-size: 12px; color: #fff;
  background: rgba(150,30,30,.92); border: 1px solid rgba(255,120,120,.6); border-radius: 8px; padding: 9px 14px; z-index: 6;
}
.hud-hint {
  position: absolute; bottom: 12px; left: 50%; transform: translateX(-50%);
  font-size: 11px; color: var(--muted); opacity: .8; z-index: 3; pointer-events: none;
  background: var(--overlay-solid); padding: 4px 12px; border-radius: 20px;
}

/* colorbar */
.colorbar {
  right: 18px; bottom: 40px; background: var(--overlay-bg); border: 1px solid var(--line);
  border-radius: 9px; padding: 10px 12px; backdrop-filter: blur(6px);
}
.cb-label { font-family: var(--mono); font-size: 12px; color: var(--text); text-align: center; margin-bottom: 8px; max-width: 120px; }
.cb-row { display: flex; gap: 8px; height: 150px; }
.cb-grad { width: 16px; height: 100%; border-radius: 5px; border: 1px solid var(--line-2); }
.cb-ticks { display: flex; flex-direction: column; justify-content: space-between; font-family: var(--mono); font-size: 11px; color: var(--muted); }

/* ---- help modal ---------------------------------------------------------- */
.modal { position: fixed; inset: 0; background: rgba(5,7,11,.72); z-index: 20; display: flex; align-items: center; justify-content: center; padding: 24px; backdrop-filter: blur(3px); }
.modal-card {
  position: relative; background: var(--panel); border: 1px solid var(--line-2); border-radius: 14px;
  max-width: 640px; max-height: 84vh; overflow-y: auto; padding: 26px 30px; box-shadow: 0 24px 80px rgba(0,0,0,.6);
}
.modal-card h2 { margin: 0 0 14px; font-size: 20px; }
.modal-card h3 { margin: 18px 0 6px; font-size: 13px; color: var(--accent-2); text-transform: uppercase; letter-spacing: 1px; }
.modal-card p, .modal-card li { color: var(--text); line-height: 1.6; font-size: 13px; }
.modal-card ul { margin: 4px 0; padding-left: 20px; }
.modal-card code {
  font-family: var(--mono); font-size: 12px; background: var(--panel-2); border: 1px solid var(--line);
  border-radius: 4px; padding: 1px 5px; color: var(--accent-2);
}
.modal-close { position: absolute; top: 14px; right: 14px; background: var(--panel-2); border: 1px solid var(--line-2); color: var(--muted); width: 30px; height: 30px; border-radius: 7px; cursor: pointer; font-size: 14px; }
.modal-close:hover { color: var(--text); border-color: var(--bad); }

.hidden { display: none !important; }

/* spectrum bar chart (Fourier tab) */
.spectrum { display: flex; align-items: flex-end; gap: 2px; height: 66px; padding: 6px 5px; background: var(--panel-2); border: 1px solid var(--line); border-radius: 7px; margin-top: 4px; }
.spec-bar { flex: 1; min-width: 2px; background: var(--accent-2); border-radius: 2px 2px 0 0; opacity: .85; transition: height .08s linear; }

/* responsive: eleven labs, so the tab strip wraps and the brand collapses early */
@media (max-width: 1180px) { .tab { padding: 6px 10px; } .actions { gap: 8px; } .ghost { padding: 6px 9px; } }
@media (max-width: 1000px) { .tab { padding: 6px 8px; font-size: 12px; } }
@media (max-width: 820px)  { #panel { width: 300px; } }