/**
 * Professional Calculator — Scientific Compute Terminal
 *
 * A dense, dark, research-grade workstation UI: the expression engine is the
 * hero, with a live linear-algebra lab, paged STEM visualizations, a session
 * ledger, and the 4-function keypad demoted to a quick pad.
 *
 *  - Dark-first design tokens (light fallback via prefers-color-scheme)
 *  - CSS-grid "workstation" layout, responsive phone → ultrawide
 *  - A11Y: sr-only, focus-visible rings, prefers-reduced-motion / -contrast
 *  - All engine/test DOM hooks preserved (.display-main, #calculator-keypad,
 *    #repl-log, #history-list, .stem-*, #help-modal, …)
 */

/* =================================================================
   DESIGN TOKENS  (dark-first)
   ================================================================= */
:root {
    color-scheme: dark light;

    /* Surfaces */
    --bg-0:        #05070d;   /* page void            */
    --bg-1:        #0a0e17;   /* deep panel base      */
    --panel:       #0e1421;   /* panel surface        */
    --panel-2:     #121a2b;   /* raised surface       */
    --panel-3:     #16203455; /* inset / wells        */
    --line:        #1f2a3f;   /* hairlines            */
    --line-soft:   #16203455;

    /* Ink */
    --ink:         #e6edf6;
    --ink-dim:     #9fb0c6;
    --ink-faint:   #5e6f88;

    /* Accents */
    --cyan:        #22d3ee;
    --cyan-dim:    #0e7490;
    --green:       #4ade80;
    --green-dim:   #15803d;
    --violet:      #a78bfa;
    --amber:       #fbbf24;
    --red:         #f87171;
    --blue:        #60a5fa;

    --focus:       #38bdf8;

    /* Type */
    --mono: 'SF Mono', 'JetBrains Mono', 'Fira Code', 'Cascadia Code', ui-monospace,
            'Monaco', 'Consolas', 'Courier New', monospace;
    --sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Inter', 'Roboto',
            'Helvetica Neue', sans-serif;

    /* Rhythm */
    --xs: 4px; --sm: 8px; --md: 14px; --lg: 20px; --xl: 28px;
    --r-sm: 7px; --r-md: 11px; --r-lg: 16px;

    --glow-cyan:  0 0 0 1px #22d3ee2e, 0 0 18px #22d3ee22;
    --shadow:     0 10px 40px #0009;
    --t-fast: .1s ease; --t: .18s ease;
}

/* =================================================================
   RESET & BASE
   ================================================================= */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

html, body { width: 100%; min-height: 100%; }

body {
    min-height: 100vh;
    min-height: 100dvh;
    background:
        radial-gradient(1200px 600px at 80% -10%, #12203a40, transparent 60%),
        radial-gradient(900px 500px at -10% 110%, #1a103a40, transparent 60%),
        var(--bg-0);
    background-attachment: fixed;
    color: var(--ink);
    font-family: var(--sans);
    font-size: 15px;
    line-height: 1.45;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

.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;
}

code { font-family: var(--mono); font-size: .92em; color: var(--cyan); }

/* =================================================================
   WORKSTATION SHELL
   ================================================================= */
.workstation {
    width: 100%;
    max-width: 1680px;
    margin: 0 auto;
    padding: var(--md);
    display: flex;
    flex-direction: column;
    gap: var(--md);
    min-height: 100dvh;
}

/* ---------- TOP COMMAND BAR ---------- */
.topbar {
    display: flex;
    align-items: center;
    gap: var(--lg);
    padding: var(--sm) var(--md);
    background: linear-gradient(180deg, var(--panel-2), var(--panel));
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    box-shadow: var(--shadow);
}

.brand-block { display: flex; align-items: center; gap: var(--sm); min-width: 0; }
.brand-glyph {
    font-family: var(--mono);
    font-size: 26px; line-height: 1;
    color: var(--cyan);
    text-shadow: 0 0 16px #22d3ee66;
}
.wordmark {
    font-family: var(--mono);
    font-size: 19px; font-weight: 700; letter-spacing: 3px;
    color: var(--ink); display: flex; flex-direction: column;
}
.wordmark-sub {
    font-size: 9.5px; letter-spacing: 2px; text-transform: uppercase;
    color: var(--ink-faint); font-weight: 500;
}

.stat-rail {
    display: flex; flex-wrap: wrap; gap: var(--sm);
    margin-left: auto; align-items: stretch;
}
.stat {
    display: flex; flex-direction: column; align-items: center;
    padding: 3px 10px; min-width: 56px;
    background: var(--panel-3);
    border: 1px solid var(--line);
    border-radius: var(--r-sm);
    font-family: var(--mono);
}
.stat b { font-size: 14px; color: var(--cyan); font-weight: 700; line-height: 1.1; }
.stat i { font-size: 8.5px; letter-spacing: 1px; text-transform: uppercase; color: var(--ink-faint); font-style: normal; }
.stat-ok b { color: var(--green); }
.stat-ver { justify-content: center; }
.stat-ver { color: var(--violet); font-size: 12px; }

.help-button {
    flex: 0 0 auto;
    width: 34px; height: 34px; border-radius: 50%;
    border: 1px solid var(--cyan-dim);
    background: var(--panel-3);
    color: var(--cyan); font-weight: 700; font-family: var(--mono);
    cursor: pointer; transition: transform var(--t-fast), box-shadow var(--t-fast);
}
.help-button:hover { box-shadow: var(--glow-cyan); transform: translateY(-1px); }
.help-button:active { transform: scale(.94); }

/* =================================================================
   WORKSTATION GRID
   ================================================================= */
.grid {
    flex: 1;
    display: grid;
    gap: var(--md);
    align-items: stretch;
    /* Auto-flow workstation: scales to any number of panels, responsive by
       intrinsic min-width. The console (hero) spans two tracks where it can. */
    grid-template-columns: repeat(auto-fit, minmax(340px, 1fr));
    grid-auto-rows: minmax(300px, auto);
}
.console { grid-column: span 2; min-height: 460px; }
.viz, .quantum { min-height: 420px; }

/* ---------- PANEL CHROME ---------- */
.panel {
    display: flex;
    flex-direction: column;
    min-width: 0; min-height: 0;
    background: linear-gradient(180deg, var(--panel-2), var(--panel));
    border: 1px solid var(--line);
    border-radius: var(--r-md);
    box-shadow: var(--shadow);
    overflow: hidden;
}
.panel-head {
    display: flex; align-items: center; gap: var(--sm);
    padding: var(--sm) var(--md);
    border-bottom: 1px solid var(--line);
    background: linear-gradient(180deg, #16213505, #0000);
}
.panel-head h2 {
    font-family: var(--mono);
    font-size: 12.5px; font-weight: 700; letter-spacing: 2px;
    text-transform: uppercase; color: var(--ink);
}
.panel-head h2::before {
    content: '▸'; color: var(--cyan); margin-right: 6px; font-size: 10px;
}
.panel-tag {
    margin-left: auto; font-family: var(--mono); font-size: 10px;
    color: var(--ink-faint); letter-spacing: .5px; text-align: right;
}

/* =================================================================
   CONSOLE — Scientific Expression Engine (hero)
   ================================================================= */
.console { background: linear-gradient(180deg, #0c1320, #080c15); }

.repl-log {
    flex: 1;
    min-height: 140px;
    overflow-y: auto;
    list-style: none;
    padding: var(--md);
    font-family: var(--mono);
    font-size: 13.5px;
    display: flex; flex-direction: column; gap: 2px;
    scrollbar-width: thin; scrollbar-color: var(--line) transparent;
}
.repl-entry { padding: 4px 0; border-bottom: 1px dashed var(--line-soft); }
.repl-in  { color: var(--ink-dim); word-break: break-word; }
.repl-out { color: var(--green); word-break: break-word; }
.repl-error .repl-out { color: var(--red); }

.repl-input-row {
    display: flex; align-items: center; gap: var(--sm);
    margin: 0 var(--md);
    padding: var(--sm) var(--md);
    background: #06090f;
    border: 1px solid var(--cyan-dim);
    border-radius: var(--r-sm);
    box-shadow: inset 0 0 0 1px #22d3ee14;
}
.repl-input-row:focus-within { border-color: var(--cyan); box-shadow: var(--glow-cyan); }
.repl-prompt { color: var(--cyan); font-family: var(--mono); font-weight: 700; }
.repl-input {
    flex: 1; min-width: 0;
    background: transparent; border: none; outline: none;
    color: var(--ink); font-family: var(--mono); font-size: 15px;
}
.repl-input::placeholder { color: var(--ink-faint); }

/* ---------- Capability palette ---------- */
.palette {
    padding: var(--sm) var(--md) 0;
    display: flex; flex-direction: column; gap: 6px;
    max-height: 220px; overflow-y: auto;
    scrollbar-width: thin; scrollbar-color: var(--line) transparent;
}
.pgroup { display: flex; flex-wrap: wrap; align-items: center; gap: 5px; }
.pgroup-label {
    font-family: var(--mono); font-size: 9px; letter-spacing: 1px;
    text-transform: uppercase; color: var(--ink-faint);
    width: 100%; margin-top: 2px;
}
.chip {
    font-family: var(--mono); font-size: 12px;
    padding: 5px 9px; min-height: 30px;
    background: var(--panel-3); color: var(--ink-dim);
    border: 1px solid var(--line);
    border-radius: 999px; cursor: pointer;
    transition: color var(--t-fast), border-color var(--t-fast), background var(--t-fast), transform var(--t-fast);
    -webkit-tap-highlight-color: transparent;
}
.chip:hover { color: var(--cyan); border-color: var(--cyan-dim); background: #0f1b2b; }
.chip:active { transform: translateY(1px); }
.chip:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

.repl-cheatsheet {
    margin: var(--sm) var(--md) var(--md);
    font-size: 11px; color: var(--ink-dim);
    border-top: 1px solid var(--line); padding-top: var(--sm);
}
.repl-cheatsheet summary {
    cursor: pointer; user-select: none; color: var(--cyan);
    font-family: var(--mono); font-size: 11px; letter-spacing: .5px;
}
.repl-cheatsheet summary:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.repl-cheatsheet ul { list-style: none; margin-top: var(--sm); padding: 0; display: flex; flex-direction: column; gap: 3px; }
.repl-cheatsheet li { font-family: var(--mono); font-size: 11px; color: var(--ink-faint); }
.repl-cheatsheet strong { color: var(--ink-dim); }

/* =================================================================
   LINEAR ALGEBRA LAB
   ================================================================= */
.matrixlab { min-height: 0; }
.ml-label {
    display: block; padding: var(--md) var(--md) 6px;
    font-size: 11px; color: var(--ink-dim); font-family: var(--mono);
}
.ml-input {
    margin: 0 var(--md);
    background: #06090f; color: var(--green);
    border: 1px solid var(--line); border-radius: var(--r-sm);
    font-family: var(--mono); font-size: 13px; padding: var(--sm);
    resize: vertical; outline: none; min-height: 56px;
}
.ml-input:focus { border-color: var(--cyan); box-shadow: var(--glow-cyan); }

.ml-ops {
    display: flex; flex-wrap: wrap; gap: 5px;
    padding: var(--sm) var(--md);
}
.chip.op { background: #0f1b2b; color: var(--cyan); border-color: var(--cyan-dim); }
.chip.op:hover { background: var(--cyan-dim); color: #03121a; }

.ml-output {
    flex: 1; overflow: auto;
    margin: 0 var(--md) var(--md);
    padding: var(--md);
    background: var(--panel-3);
    border: 1px solid var(--line); border-radius: var(--r-sm);
    font-family: var(--mono); font-size: 13px; min-height: 90px;
    scrollbar-width: thin; scrollbar-color: var(--line) transparent;
}
.ml-hint { color: var(--ink-faint); font-size: 11.5px; }
.ml-title { color: var(--violet); font-size: 11px; letter-spacing: 1px; text-transform: uppercase; display: block; margin-bottom: 6px; }
.ml-scalar { color: var(--green); font-size: 18px; }
.ml-list { color: var(--cyan); display: flex; flex-direction: column; gap: 2px; }
.ml-err { color: var(--red); }

/* matrix rendered as a bracketed grid */
.mtx { display: inline-grid; gap: 2px 14px; padding: 2px 10px; position: relative; color: var(--ink); }
.mtx::before, .mtx::after {
    content: ''; position: absolute; top: 0; bottom: 0; width: 6px;
    border: 1.5px solid var(--cyan-dim);
}
.mtx::before { left: 0; border-right: none; }
.mtx::after  { right: 0; border-left: none; }
.mtx-cell { text-align: right; font-variant-numeric: tabular-nums; padding: 0 2px; }

/* =================================================================
   STEM VISUALIZATION LAB
   ================================================================= */
.viz { background: linear-gradient(180deg, #0c1320, #080c15); }
.viz-head { gap: var(--sm); }
.stem-titles { flex: 1; min-width: 0; text-align: center; }
.stem-titles h2 { font-family: var(--mono); font-size: 12.5px; letter-spacing: 2px; text-transform: uppercase; color: var(--ink); }
.stem-titles h2::before { content: none; }
.stem-caption { display: block; font-size: 10px; color: var(--ink-faint); margin-top: 1px; font-family: var(--mono); }
.stem-nav {
    flex: 0 0 auto; width: 32px; height: 32px;
    border: 1px solid var(--cyan-dim); border-radius: 50%;
    background: var(--panel-3); color: var(--cyan); font-size: 18px; line-height: 1;
    cursor: pointer; transition: background var(--t-fast), transform var(--t-fast);
}
.stem-nav:hover { background: #0f1b2b; }
.stem-nav:active { transform: scale(.9); }
.stem-nav:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

.stem-stage {
    flex: 1; margin: var(--md); min-height: 220px;
    aspect-ratio: 1 / 1;
    background: radial-gradient(circle at 50% 40%, #22d3ee0f, transparent 70%), #04070d;
    border: 1px solid var(--line); border-radius: var(--r-sm);
    overflow: hidden; display: flex; align-items: center; justify-content: center;
}
.stem-stage svg { display: block; max-width: 100%; max-height: 100%; }
.stem-footer {
    display: flex; justify-content: space-between; align-items: center;
    padding: 0 var(--md) var(--md);
    font-family: var(--mono); font-size: 10px; color: var(--ink-faint);
}
.stem-indicator { color: var(--cyan); }

/* =================================================================
   QUICK PAD (4-function calculator, demoted)
   ================================================================= */
.display-panel {
    margin: var(--md) var(--md) var(--sm);
    padding: var(--sm) var(--md);
    background: #04070d;
    border: 1px solid var(--line); border-left: 3px solid var(--blue);
    border-radius: var(--r-sm);
    text-align: right;
}
.display-secondary { font-family: var(--mono); font-size: 12px; color: var(--ink-faint); min-height: 16px; }
.display-main {
    display: flex; align-items: flex-end; justify-content: flex-end;
    font-family: var(--mono); font-size: 34px; font-weight: 500;
    color: var(--green); min-height: 42px; max-height: 80px;
    overflow-x: auto; overflow-y: hidden; word-break: break-all;
    text-shadow: 0 0 12px #4ade8033; transition: color var(--t);
}
.display-main.is-error { color: var(--red); text-shadow: 0 0 12px #f8717144; animation: errPulse .3s ease-in-out; }
@keyframes errPulse { 0%,100% { transform: scale(1); } 50% { transform: scale(1.015); } }

.button-grid {
    display: grid; grid-template-columns: repeat(4, 1fr); gap: 7px;
    padding: 0 var(--md) var(--md);
}
@supports not (display: grid) {
    .button-grid { display: flex; flex-wrap: wrap; }
    .btn { flex: 1 0 22%; }
}
.btn {
    padding: 12px; min-height: 44px;
    border: 1px solid var(--line); border-radius: var(--r-sm);
    font-family: var(--mono); font-size: 16px; font-weight: 600;
    color: var(--ink); cursor: pointer;
    background: linear-gradient(180deg, #1a2434, #131b29);
    transition: transform var(--t-fast), box-shadow var(--t-fast), background var(--t-fast), color var(--t-fast);
    -webkit-user-select: none; user-select: none; -webkit-tap-highlight-color: transparent;
}
.btn:hover { transform: translateY(-1px); }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; z-index: 1; }
.btn-number   { color: var(--ink); }
.btn-operator { color: var(--cyan); border-color: var(--cyan-dim); }
.btn-operator:hover { background: #0f1b2b; }
.btn-function { color: var(--ink-dim); font-size: 14px; }
.btn-equals   { color: #04140a; background: linear-gradient(180deg, var(--green), var(--green-dim)); border-color: var(--green-dim); font-weight: 700; }
.btn-equals:hover { box-shadow: 0 0 16px #4ade8044; }
.btn-zero { grid-column: span 2; }
.btn-undo, .btn-redo { font-size: 12px; }
.btn.is-pressed { animation: btnPress .15s ease-out; }
@keyframes btnPress { 0% { transform: scale(1); } 50% { transform: scale(.95); } 100% { transform: scale(.98); } }
.btn.is-highlighted { animation: hl .8s ease-in-out 3; }
@keyframes hl { 0%,100% { box-shadow: none; } 50% { box-shadow: 0 0 0 3px var(--red); } }
.btn[disabled], .btn:disabled { opacity: .35; cursor: not-allowed; pointer-events: none; }

.keyboard-shortcuts {
    margin: 0 var(--md) var(--md);
    font-size: 11px; color: var(--ink-faint);
}
.keyboard-shortcuts summary { cursor: pointer; user-select: none; color: var(--cyan); font-family: var(--mono); font-size: 11px; }
.keyboard-shortcuts summary:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.keyboard-shortcuts ul { list-style: none; margin-top: var(--sm); display: flex; flex-direction: column; gap: 3px; }
.keyboard-shortcuts kbd {
    background: var(--panel-3); border: 1px solid var(--line);
    padding: 1px 5px; border-radius: 4px; font-family: var(--mono); font-size: 10px; color: var(--ink-dim);
}

/* =================================================================
   HISTORY LEDGER
   ================================================================= */
.history-clear {
    margin-left: auto;
    background: none; border: 1px solid var(--line); color: var(--ink-faint);
    border-radius: var(--r-sm); padding: 3px 10px; font-size: 11px; cursor: pointer;
    font-family: var(--mono); transition: color var(--t-fast), border-color var(--t-fast);
}
.history-clear:hover { color: var(--red); border-color: var(--red); }
.history-clear:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.history-list {
    flex: 1; overflow-y: auto; list-style: none;
    padding: var(--sm); margin: 0;
    font-family: var(--mono); font-size: 12.5px;
    scrollbar-width: thin; scrollbar-color: var(--line) transparent;
}
.history-list:focus-visible { outline: 2px solid var(--focus); outline-offset: -2px; }
.history-item {
    padding: 6px var(--sm); border-bottom: 1px solid var(--line-soft);
    cursor: pointer; border-radius: 4px; text-align: right;
    color: var(--ink-dim); word-break: break-all; transition: background var(--t-fast), color var(--t-fast);
}
.history-item:hover, .history-item:focus-visible {
    background: #0f1b2b; color: var(--cyan);
    outline: 1px solid var(--cyan-dim); outline-offset: -1px;
}
.history-empty { text-align: center; font-size: 12px; color: var(--ink-faint); padding: var(--md); font-style: italic; }
.history-list:not(:empty) ~ .history-empty { display: none; }

/* =================================================================
   HELP DIALOG
   ================================================================= */
#help-modal {
    border: 1px solid var(--line); border-radius: var(--r-md);
    padding: var(--xl); max-width: 440px; width: calc(100% - 32px);
    background: var(--panel-2); color: var(--ink); box-shadow: var(--shadow);
}
#help-modal::backdrop { background: #02040acc; backdrop-filter: blur(2px); }
#help-modal h2 { font-family: var(--mono); font-size: 16px; letter-spacing: 1px; margin-bottom: var(--md); color: var(--cyan); }
#help-modal table { width: 100%; border-collapse: collapse; font-size: 13px; }
#help-modal th, #help-modal td { padding: var(--sm); border-bottom: 1px solid var(--line); text-align: left; }
#help-modal kbd { background: var(--panel-3); border: 1px solid var(--line); padding: 1px 6px; border-radius: 4px; font-family: var(--mono); font-size: 11px; }
#help-modal form { margin-top: var(--md); text-align: right; }
#help-modal button { min-width: 80px; padding: var(--sm) var(--md); }

/* =================================================================
   RESPONSIVE
   ================================================================= */
@media (max-width: 1180px) {
    .grid {
        grid-template-columns: 1fr 1fr;
        grid-template-rows: auto;
        grid-template-areas:
            "console   console"
            "matrixlab viz"
            "quickcalc history";
    }
}
@media (max-width: 720px) {
    body { font-size: 14px; }
    .workstation { padding: var(--sm); gap: var(--sm); }
    .topbar { flex-wrap: wrap; gap: var(--sm); }
    .stat-rail { margin-left: 0; width: 100%; order: 3; justify-content: space-between; }
    .help-button { margin-left: auto; }
    .grid {
        grid-template-columns: 1fr;
        grid-template-areas: "console" "matrixlab" "viz" "quickcalc" "history";
    }
    .repl-log { min-height: 120px; max-height: 280px; }
    .display-main { font-size: 30px; }
}
@media (max-width: 380px) {
    .btn { padding: 10px; font-size: 14px; }
    .button-grid { gap: 5px; }
}

/* =================================================================
   MOTION / CONTRAST / LIGHT
   ================================================================= */
@media (prefers-reduced-motion: reduce) {
    *, *::before, *::after {
        animation-duration: .001ms !important; animation-iteration-count: 1 !important;
        transition-duration: .001ms !important;
    }
    .btn:hover, .chip:hover, .help-button:hover { transform: none; }
}

@media (prefers-contrast: more) {
    :root { --ink: #fff; --ink-dim: #e6edf6; --line: #5e6f88; --bg-0: #000; --panel: #06080e; --panel-2: #0a0e17; }
    .chip, .btn { border-width: 1.5px; }
}

@media print {
    body { background: #fff; color: #000; }
    .panel { box-shadow: none; border: 1px solid #000; }
    .help-button, .stem-nav, .btn-undo, .palette { display: none; }
}

/* =================================================================
   LIVE ENGINE PANELS (quantum / signal / finance / plot / ode)
   ================================================================= */
.q-controls { display: flex; flex-wrap: wrap; gap: 5px; align-items: center; padding: var(--sm) var(--md); }
.q-inline { font-family: var(--mono); font-size: 10px; color: var(--ink-faint); text-transform: uppercase; letter-spacing: 1px; }
.q-num {
    width: 48px; background: #06090f; color: var(--green);
    border: 1px solid var(--line); border-radius: var(--r-sm);
    font-family: var(--mono); font-size: 13px; padding: 4px 6px;
}
.q-num:focus { outline: none; border-color: var(--cyan); }
.q-diagram {
    margin: 0 var(--md); padding: var(--sm); background: #06090f;
    border: 1px solid var(--line); border-radius: var(--r-sm);
    font-family: var(--mono); font-size: 11px; color: var(--cyan);
    white-space: pre; overflow-x: auto; line-height: 1.5;
}
.q-ket { padding: var(--sm) var(--md); font-family: var(--mono); font-size: 13px; color: var(--green); word-break: break-word; }
.q-probs { padding: 0 var(--md) var(--sm); display: flex; flex-direction: column; gap: 3px; }
.q-prob-row { display: flex; align-items: center; gap: 8px; font-family: var(--mono); font-size: 11px; }
.q-prob-label { color: var(--ink-dim); width: 70px; }
.q-prob-track { flex: 1; height: 9px; background: var(--panel-3); border-radius: 5px; overflow: hidden; }
.q-prob-fill { display: block; height: 100%; background: linear-gradient(90deg, var(--cyan), var(--violet)); }
.q-prob-pct { color: var(--ink-faint); width: 48px; text-align: right; }
.q-bloch { display: flex; justify-content: center; padding: var(--sm) var(--md) var(--md); }

.fin-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(92px, 1fr)); gap: var(--sm); padding: var(--md) var(--md) var(--sm); }
.fin-grid label, .plot-range label {
    display: flex; flex-direction: column; gap: 3px;
    font-family: var(--mono); font-size: 10px; color: var(--ink-faint);
    text-transform: uppercase; letter-spacing: .5px;
}
.fin-grid input, .plot-range input {
    background: #06090f; color: var(--green); border: 1px solid var(--line);
    border-radius: var(--r-sm); font-family: var(--mono); font-size: 13px;
    padding: 5px 6px; width: 100%;
}
.fin-grid input:focus, .plot-range input:focus { outline: none; border-color: var(--cyan); }
.plot-range { display: flex; gap: var(--sm); padding: 0 var(--md) var(--sm); }
.plot-range label { flex: 1; }
.plot-stage { min-height: 200px; display: flex; align-items: center; justify-content: center; }
.plot-stage svg, #sig-output svg { display: block; max-width: 100%; }

/* =================================================================
   CALCULATOR SUITE (paged mini-calculator grid)
   ================================================================= */
.suite { grid-column: 1 / -1; }
.suite-help { margin-left: auto; display: flex; gap: 10px; }
.suite-help a { font-family: var(--mono); font-size: 10px; letter-spacing: .5px; text-transform: uppercase; color: var(--ink-dim); text-decoration: none; border-bottom: 1px dotted var(--line); transition: color var(--t-fast), border-color var(--t-fast); }
.suite-help a:hover { color: var(--cyan); border-color: var(--cyan); }
.suite-help a:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.suite-hint { padding: var(--sm) var(--md) 0; font-size: 11px; color: var(--ink-faint); }
.suite-hint a { color: var(--cyan); text-decoration: none; border-bottom: 1px dotted var(--cyan-dim); }
.suite-hint kbd { font-family: var(--mono); font-size: 10px; padding: 1px 5px; border: 1px solid var(--line); border-radius: 4px; background: #06090f; color: var(--ink); }
.suite-tabs { display: flex; flex-wrap: wrap; gap: 6px; padding: var(--sm) var(--md); border-bottom: 1px solid var(--line); }
.suite-tab {
    font-family: var(--mono); font-size: 11px; padding: 6px 12px;
    border: 1px solid var(--line); border-radius: var(--r-sm);
    background: var(--panel-3); color: var(--ink-dim); cursor: pointer;
    transition: color var(--t-fast), background var(--t-fast), border-color var(--t-fast);
}
.suite-tab[aria-pressed="true"] { background: var(--cyan-dim); color: #03121a; border-color: var(--cyan); }
.suite-tab:hover { color: var(--cyan); }
.suite-tab:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.suite-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(232px, 1fr)); gap: var(--sm); padding: var(--md); }
.stile {
    display: flex; flex-direction: column; gap: 5px; padding: var(--sm) var(--md);
    background: var(--panel-3); border: 1px solid var(--line); border-radius: var(--r-sm);
}
.stile-title { font-family: var(--mono); font-size: 12px; font-weight: 700; color: var(--cyan); letter-spacing: .5px; }
.stile-blurb { font-size: 10px; color: var(--ink-faint); margin-top: -3px; }
.stile-op { background: #06090f; color: var(--violet); border: 1px solid var(--line); border-radius: 5px; font-family: var(--mono); font-size: 11px; padding: 3px 4px; }
.stile-field { display: flex; flex-direction: column; gap: 2px; font-size: 9px; color: var(--ink-faint); text-transform: uppercase; letter-spacing: .5px; }
.stile-field input { background: #06090f; color: var(--green); border: 1px solid var(--line); border-radius: 5px; font-family: var(--mono); font-size: 12px; padding: 4px 6px; }
.stile-field input:focus, .stile-op:focus { outline: none; border-color: var(--cyan); }
.stile-run { margin-top: 2px; padding: 5px; border: 1px solid var(--cyan-dim); border-radius: 5px; background: #0f1b2b; color: var(--cyan); font-family: var(--mono); font-size: 11px; cursor: pointer; transition: background var(--t-fast), color var(--t-fast); }
.stile-run:hover { background: var(--cyan-dim); color: #03121a; }
.stile-run:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.stile-result { font-family: var(--mono); font-size: 12px; color: var(--green); word-break: break-word; min-height: 16px; }
.stile-result.stile-err { color: var(--red); }
@media (max-width: 720px) { .suite-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 460px) { .suite-grid { grid-template-columns: 1fr; } }

/* =================================================================
   KNOWLEDGE EXPLORER (21 domain pages + orchestrator research card)
   ================================================================= */
.knowledge { grid-column: 1 / -1; }
.ko-query { display: flex; gap: var(--sm); padding: var(--sm) var(--md) 0; }
.ko-query input { flex: 1; background: #06090f; color: var(--green); border: 1px solid var(--line); border-radius: var(--r-sm); font-family: var(--mono); font-size: 13px; padding: 8px 10px; }
.ko-query input:focus { outline: none; border-color: var(--cyan); }
.ko-query button { padding: 8px 18px; border: 1px solid var(--cyan-dim); border-radius: var(--r-sm); background: #0f1b2b; color: var(--cyan); font-family: var(--mono); font-size: 12px; cursor: pointer; transition: background var(--t-fast), color var(--t-fast); }
.ko-query button:hover { background: var(--cyan-dim); color: #03121a; }
.ko-query button:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

.ko-card:not(:empty) { margin: var(--sm) var(--md); padding: var(--sm) var(--md); border: 1px solid var(--line); border-radius: var(--r-md); background: var(--panel-3); }
.ko-card-head { display: flex; flex-wrap: wrap; align-items: center; gap: 8px; margin-bottom: 6px; }
.ko-kind { font-family: var(--mono); font-size: 9.5px; letter-spacing: 1px; padding: 2px 7px; border-radius: 4px; }
.ko-kind-compute { background: var(--cyan-dim); color: #03121a; }
.ko-kind-knowledge { background: var(--violet); color: #0c0a1f; }
.ko-card-input { font-family: var(--mono); font-size: 13px; color: var(--ink); }
.ko-card-domain { margin-left: auto; font-size: 10px; color: var(--ink-faint); text-transform: uppercase; letter-spacing: .5px; }
.ko-block { margin-top: 8px; }
.ko-label { display: block; font-family: var(--mono); font-size: 9.5px; letter-spacing: 1px; text-transform: uppercase; color: var(--ink-faint); margin-bottom: 3px; }
.ko-vstatus-verified { color: var(--green); }
.ko-vstatus-warning { color: var(--amber); }
.ko-vstatus-na { color: var(--ink-faint); }
.ko-result { font-family: var(--mono); font-size: 13px; color: var(--green); white-space: pre-wrap; word-break: break-word; margin: 0; }
.ko-list { margin: 0; padding-left: 16px; font-size: 11.5px; color: var(--ink-dim); }
.ko-list li { margin: 1px 0; }
.ko-err { color: var(--red); font-family: var(--mono); font-size: 12px; }

.ko-body { display: grid; grid-template-columns: minmax(220px, 280px) 1fr; gap: var(--sm); padding: var(--md); }
.ko-domains { display: flex; flex-direction: column; gap: 5px; max-height: 620px; overflow-y: auto; padding-right: 4px; }
.ko-domtile { display: flex; flex-direction: column; gap: 2px; text-align: left; padding: 7px 10px; border: 1px solid var(--line); border-radius: var(--r-sm); background: var(--panel-3); color: var(--ink-dim); cursor: pointer; transition: border-color var(--t-fast), color var(--t-fast); }
.ko-domtile:hover { border-color: var(--cyan); color: var(--cyan); }
.ko-domtile[aria-pressed="true"] { border-color: var(--cyan); background: #0f1b2b; }
.ko-domtile[aria-pressed="true"] .ko-domtile-name { color: var(--cyan); }
.ko-domtile:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.ko-domtile-name { font-family: var(--mono); font-size: 11.5px; font-weight: 600; color: var(--ink); }
.ko-domtile-meta { font-size: 9.5px; color: var(--ink-faint); }
.ko-tier { font-family: var(--mono); font-size: 8.5px; letter-spacing: .5px; text-transform: uppercase; color: var(--violet); }

.ko-detail { border: 1px solid var(--line); border-radius: var(--r-md); background: var(--panel-3); padding: var(--md); overflow-y: auto; max-height: 620px; }
.ko-detail-title { font-family: var(--mono); font-size: 15px; color: var(--cyan); margin: 0 0 4px; }
.ko-detail-summary { font-size: 12px; color: var(--ink-dim); margin: 0 0 10px; line-height: 1.5; }
.ko-h4 { font-family: var(--mono); font-size: 10px; letter-spacing: 1px; text-transform: uppercase; color: var(--ink-faint); margin: 14px 0 6px; border-top: 1px solid var(--line); padding-top: 10px; }
.ko-chips { display: flex; flex-wrap: wrap; gap: 5px; }
.ko-chip { font-family: var(--mono); font-size: 10px; padding: 2px 8px; border-radius: 11px; border: 1px solid var(--line); color: var(--ink-dim); background: #0a0e17; }
.ko-chip-calc { border-color: var(--cyan-dim); color: var(--cyan); }
.ko-chip-topic { color: var(--ink-faint); }
.ko-chip-rel { cursor: pointer; }
.ko-chip-rel:hover { border-color: var(--cyan); color: var(--cyan); }
.ko-chip-rel:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.ko-open { display: inline-block; margin: 6px 6px 0 0; padding: 4px 10px; font-family: var(--mono); font-size: 10px; border: 1px solid var(--cyan-dim); border-radius: var(--r-sm); background: #0f1b2b; color: var(--cyan); cursor: pointer; }
.ko-open:hover { background: var(--cyan-dim); color: #03121a; }
.ko-open:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.ko-level { display: flex; gap: 8px; margin: 4px 0; align-items: baseline; }
.ko-level-tag { flex: none; font-family: var(--mono); font-size: 9px; letter-spacing: .5px; color: var(--violet); width: 56px; }
.ko-level-items { font-size: 11px; color: var(--ink-dim); line-height: 1.5; }
.ko-sub { margin: 8px 0; }
.ko-sub-name { font-family: var(--mono); font-size: 11.5px; color: var(--ink); font-weight: 600; }
.ko-sub-desc { display: block; font-size: 10.5px; color: var(--ink-faint); margin: 2px 0 4px; line-height: 1.45; }
@media (max-width: 720px) { .ko-body { grid-template-columns: 1fr; } .ko-domains { max-height: 260px; } }

/* Light-mode fallback for users who force it — keeps the terminal legible. */
@media (prefers-color-scheme: light) {
    :root {
        --bg-0: #eef2f7; --bg-1: #e6ebf2; --panel: #ffffff; --panel-2: #f6f8fb;
        --panel-3: #eef2f7; --line: #d3dbe6; --line-soft: #e6ebf2;
        --ink: #14233b; --ink-dim: #43566f; --ink-faint: #7c8aa0;
        --cyan-dim: #0e7490; --green: #15803d; --shadow: 0 8px 28px #1f2a3f1f;
    }
    body { background: radial-gradient(1000px 500px at 80% -10%, #cfe0f5aa, transparent 60%), var(--bg-0); }
    .display-main, .repl-out { color: var(--green-dim, #15803d); }
    .btn-equals { color: #fff; }
}

/* =================================================================
   GRAPHING & SIMULATION LAB (canvas tools)
   ================================================================= */
.grapher2d { grid-column: span 2; }
.g-controls { display: flex; flex-wrap: wrap; align-items: center; gap: 6px; padding: var(--sm) var(--md); border-bottom: 1px solid var(--line); }
.g-fn { flex: 1 1 130px; min-width: 110px; background: #06090f; color: var(--green); border: 1px solid var(--line); border-left-width: 3px; border-radius: 5px; font-family: var(--mono); font-size: 12px; padding: 5px 7px; }
.g-fn1 { border-left-color: var(--cyan); }
.g-fn2 { border-left-color: var(--violet); }
.g-fn3 { border-left-color: var(--green); }
.g-fn:focus { outline: none; border-color: var(--cyan); }
.g-sel { background: #06090f; color: var(--violet); border: 1px solid var(--line); border-radius: 5px; font-family: var(--mono); font-size: 11px; padding: 5px 6px; }
.g-sel:focus { outline: none; border-color: var(--cyan); }
.g-inline { display: inline-flex; align-items: center; gap: 4px; font-family: var(--mono); font-size: 11px; color: var(--ink-faint); }
.g-num { width: 52px; background: #06090f; color: var(--green); border: 1px solid var(--line); border-radius: 5px; font-family: var(--mono); font-size: 12px; padding: 4px 5px; }
.g-controls button { padding: 5px 11px; border: 1px solid var(--cyan-dim); border-radius: 5px; background: #0f1b2b; color: var(--cyan); font-family: var(--mono); font-size: 11px; cursor: pointer; transition: background var(--t-fast), color var(--t-fast); }
.g-controls button:hover { background: var(--cyan-dim); color: #03121a; }
.g-controls button:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }
.g-stage { padding: var(--sm) var(--md) 0; }
.g-read { display: block; font-family: var(--mono); font-size: 11px; color: var(--ink-dim); padding: 6px var(--md) var(--sm); min-height: 14px; word-break: break-word; }
@media (max-width: 720px) { .grapher2d { grid-column: span 1; } }