/* calculator/style.css — page-specific styles, kept to the site's tokens.
   Loaded after assets/tokens.css + base.css + modern.css.
   Four tabs: calculator (display + keypad + history/vars), graph (rail +
   canvas), solvers (card columns), reference (generated tables).           */

/* trace colours — theme-aware, mirrored by graph.js at draw time */
:root {
    --g-t1: #58a6e8;
    --g-t2: #45c49a;
    --g-t3: #b58ae8;
    --g-t4: #e8a058;
}
[data-theme="light"] {
    --g-t1: #1e66b8;
    --g-t2: #0d8a63;
    --g-t3: #7a3fc4;
    --g-t4: #b86a1e;
}

/* ═══════════ calculator tab ═══════════ */

.calc-grid {
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(300px, 420px);
    gap: 10px;
    align-items: start;
}

/* ---- display ---- */
.calc-display {
    padding: 12px 12px 8px;
    border-bottom: 1px solid var(--border);
    background: var(--card2);
}
#exprIn {
    width: 100%;
    height: 42px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 17px;
    letter-spacing: 0.2px;
    padding: 6px 10px;
}
.calc-preview {
    min-height: 20px;
    margin-top: 6px;
    text-align: right;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 13px;
    color: var(--muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.calc-result {
    min-height: 34px;
    text-align: right;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 24px;
    font-weight: 700;
    color: var(--accent);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.calc-meta {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 10px;
    min-height: 16px;
}
.calc-error {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11px;
    color: var(--err);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.mode-strip {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 10px;
    letter-spacing: 0.8px;
    color: var(--muted2);
    text-transform: uppercase;
    flex-shrink: 0;
}

/* ---- keypad ---- */
#keypad { padding: 8px; }
.kbtn {
    height: 38px;
    padding: 0;
    font-size: 13px;
    line-height: 1;
}
.pad-strip {
    display: flex;
    gap: 4px;
    margin-bottom: 6px;
    flex-wrap: wrap;
}
.pad-strip .kbtn.ctl {
    height: 26px;
    padding: 0 9px;
    font-size: 10px;
    font-weight: 700;
    letter-spacing: 0.6px;
    color: var(--muted);
}
.pad-strip .kbtn.ctl:hover { color: var(--text); }
.pad-strip .kbtn.ctl.accent { color: var(--accent); }
.pad-strip .kbtn.ctl.danger { color: var(--err); }
.pad-gap { flex: 1; }

.pad-main {
    display: flex;
    gap: 8px;
}
.pad-fn {
    flex: 1.25;
    display: grid;
    grid-template-columns: repeat(5, 1fr);
    gap: 4px;
}
.pad-num {
    flex: 1;
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 4px;
}
.kbtn.fn {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11px;
    color: var(--muted);
    white-space: nowrap;
    overflow: hidden;
}
.kbtn.fn:hover { color: var(--text); }
.kbtn.num { font-size: 15px; font-weight: 700; }
.kbtn.op {
    font-size: 15px;
    color: var(--accent);
    background: rgba(255, 134, 41, 0.06);
}
.kbtn.eq { font-size: 18px; font-weight: 800; }

.suffix-strip {
    display: flex;
    gap: 4px;
    align-items: center;
    margin-top: 6px;
}
.suffix-label {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 9px;
    font-weight: 700;
    letter-spacing: 1.4px;
    color: var(--muted2);
    padding: 0 4px;
}
.kbtn.sfx {
    flex: 1;
    height: 24px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11px;
    color: var(--muted);
}
.kbtn.sfx:hover { color: var(--accent); }

/* ---- history / variables ---- */
.calc-side { display: flex; flex-direction: column; gap: 10px; min-width: 0; }
.side-card { margin-bottom: 0; }
.side-title {
    display: flex;
    align-items: center;
    justify-content: space-between;
}
.side-clear {
    border: none;
    background: transparent;
    box-shadow: none;
    padding: 0 2px;
    font-size: 9px;
    font-weight: 700;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--muted2);
}
.side-clear:hover { color: var(--err); background: transparent; transform: none; }
.hist-list {
    max-height: 300px;
    overflow-y: auto;
}
.hist-row {
    padding: 6px 12px;
    border-bottom: 1px solid var(--border);
    cursor: pointer;
}
.hist-row:last-child { border-bottom: none; }
.hist-row:hover { background: var(--card2); }
.hist-expr {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11.5px;
    color: var(--muted);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.hist-out {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 12.5px;
    color: var(--text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.var-list { max-height: 260px; overflow-y: auto; }
.var-row {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 4px 12px;
    border-bottom: 1px solid var(--border);
    min-height: 30px;
}
.var-row:last-child { border-bottom: none; }
.var-del {
    border: none;
    background: transparent;
    box-shadow: none;
    padding: 0 4px;
    font-size: 13px;
    color: var(--muted2);
    flex-shrink: 0;
}
.var-del:hover { color: var(--err); background: transparent; transform: none; }
.var-name {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 12px;
    font-weight: 700;
    color: var(--accent);
    cursor: pointer;
    flex-shrink: 0;
}
.var-val {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 12px;
    color: var(--text);
    margin-left: auto;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.empty-note {
    padding: 10px 12px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 10.5px;
    line-height: 1.5;
    color: var(--muted2);
}

/* ═══════════ graph tab ═══════════ */

.graph-grid {
    display: grid;
    grid-template-columns: 380px minmax(0, 1fr);
    gap: 10px;
    align-items: start;
}
.graph-grid .rail .form-group { margin-bottom: 8px; }
.graph-grid .rail .form-group:last-child { margin-bottom: 0; }
.graph-grid .rail .form-row { padding: 4px 12px; min-height: 34px; gap: 8px; }
.graph-grid .rail .form-label { min-width: 96px; padding-top: 5px; }
.graph-grid .rail .form-right { min-width: 0; grid-template-columns: 1fr 130px; column-gap: 8px; }
.graph-grid .rail .form-hint { width: auto; min-width: 0; }
.graph-grid .rail input[type="text"],
.graph-grid .rail select { width: 130px; height: 26px; padding: 3px 7px; font-size: 12.5px; }
.form-row.no-line { border-bottom: none; }

.g-trace {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 5px 12px;
    border-bottom: 1px solid var(--border);
}
.g-trace:last-child { border-bottom: none; }
.g-trace input[type="checkbox"] { flex-shrink: 0; accent-color: var(--accent); }
.g-dot {
    width: 10px;
    height: 10px;
    flex-shrink: 0;
}
.g-dot.t1 { background: var(--g-t1); }
.g-dot.t2 { background: var(--g-t2); }
.g-dot.t3 { background: var(--g-t3); }
.g-dot.t4 { background: var(--g-t4); }
.g-trace input[type="text"] {
    flex: 1;
    width: auto;
    min-width: 0;
    height: 28px;
    padding: 4px 8px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 12.5px;
}
.g-trace input[type="text"].bad { border-color: var(--err); }
.g-check { display: flex; align-items: center; height: 26px; }
.g-check input { accent-color: var(--accent); }

.g-examples {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    padding: 8px 12px;
}
.g-examples button {
    font-size: 11px;
    padding: 5px 9px;
}

.chart-card { margin-bottom: 0; }
.chart-wrap { position: relative; padding: 10px 12px 6px; }
.chart-wrap canvas { display: block; width: 100%; cursor: crosshair; }
.chart-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 3px 14px;
    padding: 4px 12px 8px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 10.5px;
    letter-spacing: 0.5px;
    color: var(--muted);
}
.legend-swatch {
    display: inline-block;
    width: 10px;
    height: 10px;
    margin-right: 6px;
    vertical-align: -1px;
}
.legend-ph { color: var(--muted2); margin-left: auto; }
.chart-tip {
    position: absolute;
    display: none;
    pointer-events: none;
    background: var(--card2);
    border: 1px solid var(--border2);
    box-shadow: var(--shadow);
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11px;
    line-height: 1.5;
    color: var(--text);
    padding: 5px 9px;
    white-space: pre;
    z-index: 5;
}

/* ═══════════ solvers tab ═══════════ */

/* tool picker rail on the left, one open tool on the right;
   inside the card: inputs left, live results right */
.solver-grid {
    display: grid;
    grid-template-columns: 190px minmax(0, 1fr);
    gap: 10px;
    align-items: stretch;    /* open card is never shorter than the tool rail */
}
.solver-nav { margin-bottom: 0; }
.solver-tabs { padding: 4px 0; }
.solver-tab {
    display: block;
    width: 100%;
    min-width: 0;
    text-align: left;
    border: none;
    border-left: 2px solid transparent;
    background: transparent;
    box-shadow: none;
    padding: 8px 10px;
    color: var(--muted);
    cursor: pointer;
    overflow: hidden;
}
.solver-tab-main {
    display: block;
    font-size: 11px;
    font-weight: 700;
    letter-spacing: 0.7px;
    line-height: 1.3;
    text-transform: uppercase;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.solver-tab-sub {
    display: block;
    margin-top: 1px;
    font-size: 10px;
    line-height: 1.3;
    text-transform: lowercase;
    color: var(--muted2);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}
.solver-tab:hover { color: var(--text); background: var(--card2); transform: none; }
.solver-tab.active {
    color: var(--accent);
    border-left-color: var(--accent);
    background: var(--card2);
}
.solver {
    margin-bottom: 0;
    min-height: 100%;
    display: flex;
    flex-direction: column;
}
/* one crisp divider above both columns — the description keeps no border of
   its own so the line weight matches the results' left divider */
.solver .form-description { border-bottom: none; }
.solver-body {
    flex: 1;
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(0, 1fr);
    align-items: stretch;
    border-top: 1px solid var(--border2);
}
.solver .form-row { padding: 4px 12px; min-height: 34px; gap: 8px; }
.solver .form-label { min-width: 120px; padding-top: 5px; }
.solver .form-right { min-width: 0; grid-template-columns: 1fr 130px; column-gap: 8px; }
.solver .form-hint { width: auto; min-width: 0; }
.solver input[type="text"],
.solver select { width: 130px; height: 26px; padding: 3px 7px; font-size: 12.5px; font-family: var(--font-m, ui-monospace, monospace); }
.solver select { font-family: inherit; }
.sv-out { border-left: 1px solid var(--border2); background: rgba(0, 0, 0, 0.12); }
[data-theme="light"] .sv-out { background: rgba(0, 0, 0, 0.03); }
.sv-out .lk-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    padding: 4px 12px;
    border-bottom: 1px solid var(--border);
    min-height: 30px;
}
.sv-out .lk-row:last-child { border-bottom: none; }
.lk-main { min-width: 0; }
.lk-name { font-size: 12px; color: var(--muted); line-height: 1.25; }
.lk-hint {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 9.5px;
    letter-spacing: 0.3px;
    color: var(--muted2);
    line-height: 1.25;
    margin-top: 1px;
}
.lk-val {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 12.5px;
    color: var(--text);
    text-align: right;
    white-space: nowrap;
    flex-shrink: 0;
}
.sv-warn {
    padding: 6px 12px;
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 10.5px;
    color: var(--warn);
}

/* ═══════════ reference tab ═══════════ */

.ref-grid {
    columns: 2;
    column-gap: 10px;
}
.ref-card {
    break-inside: avoid;
    margin-bottom: 10px;
}
.ref-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 12px;
}
.ref-table td {
    padding: 4px 12px;
    border-bottom: 1px solid var(--border);
    color: var(--muted);
    line-height: 1.4;
    vertical-align: top;
}
.ref-table tr:last-child td { border-bottom: none; }
.ref-table .ref-k {
    font-family: var(--font-m, ui-monospace, monospace);
    font-size: 11.5px;
    color: var(--text);
    white-space: nowrap;
    width: 1%;
    padding-right: 16px;
}
.ref-ex .ref-try { cursor: pointer; }
.ref-ex .ref-try:hover td { background: var(--card2); }
.ref-ex .ref-try:hover .ref-k { color: var(--accent); }

/* ═══════════ small screens ═══════════ */

@media (max-width: 1020px) {
    .calc-grid { grid-template-columns: 1fr; }
    .graph-grid { grid-template-columns: 1fr; }
    .ref-grid { columns: 1; }
    /* tool picker collapses to a chip row on top, card columns stack */
    .solver-grid { grid-template-columns: 1fr; }
    .solver-tabs { display: flex; flex-wrap: wrap; gap: 2px; padding: 6px; }
    .solver-tab { width: auto; border-left: none; padding: 5px 10px; }
    .solver-body { grid-template-columns: 1fr; }
    .sv-out { border-left: none; border-top: 1px solid var(--border2); }
}
@media (max-width: 560px) {
    .pad-main { flex-direction: column; }
    .calc-grid { grid-template-columns: minmax(0, 1fr); }
}