/* Year 9 Science: the periodic-table explorer (1.5) and the down-the-group
 * guide (1.6), plus the multiple-choice form of "try it first".
 *
 * Builds on science-ix.css (same tokens, same `.ix` size container, same
 * `.ix-card`, `.ix-eqn`, `.ix-seg`, `.ix-chip`, `.ix-btn`, `.ix-tryfirst`).
 * Tokens only. Colours keep one meaning each: gold = shells / period / distance,
 * cyan = outer electrons / group, teal = electrons, tangerine = reactivity. */

/* ------------------------------------------------------ periodic table */

.ix-ptbody { padding: 18px 24px 8px; }
.ix-ptmodes { margin-bottom: 16px; }
.ix-ptgrid {
    display: grid;
    grid-template-columns: minmax(0, 1.08fr) minmax(0, 1fr);
    gap: 26px;
    align-items: start;
}
.ix-ptleft, .ix-ptright { min-width: 0; }

.ix-pttable {
    display: grid;
    grid-template-columns: 1.1rem repeat(2, minmax(0, 1fr)) 0.9rem repeat(6, minmax(0, 1fr));
    grid-template-rows: auto repeat(4, auto);
    gap: 4px;
}
.ix-ptcorner { grid-column: 1; grid-row: 1; }
.ix-ptgh, .ix-ptph {
    display: grid;
    place-items: center;
    border-radius: 8px;
    color: var(--muted);
    font-size: 0.8rem;
    font-weight: 800;
    transition: background 0.5s ease, color 0.5s ease;
}
.ix-ptgh { grid-row: 1; min-height: 1.5rem; }
.ix-ptph { grid-column: 1; }
.ix-ptph.is-on { background: var(--gold); color: var(--ink); }
.ix-ptgh.is-on { background: var(--ix-cyan-deep); color: var(--paper); }
.ix-ptgap {
    grid-column: 4;
    grid-row: 2 / 6;
    display: grid;
    place-items: center;
    border: 2px dashed var(--line);
    border-radius: 8px;
    color: var(--muted);
    font-size: 0.66rem;
    font-weight: 700;
    line-height: 1.2;
    text-align: center;
}
.ix-ptgap span { writing-mode: vertical-rl; transform: rotate(180deg); max-height: 100%; }

.ix-pt-c1 { grid-column: 1; } .ix-pt-c2 { grid-column: 2; } .ix-pt-c3 { grid-column: 3; }
.ix-pt-c5 { grid-column: 5; } .ix-pt-c6 { grid-column: 6; } .ix-pt-c7 { grid-column: 7; }
.ix-pt-c8 { grid-column: 8; } .ix-pt-c9 { grid-column: 9; } .ix-pt-c10 { grid-column: 10; }
.ix-pt-r2 { grid-row: 2; } .ix-pt-r3 { grid-row: 3; } .ix-pt-r4 { grid-row: 4; } .ix-pt-r5 { grid-row: 5; }

.ix-ptel {
    position: relative;
    display: grid;
    place-items: center;
    min-width: 0;
    min-height: 3rem;
    margin: 0;
    padding: 0;
    border: 2px solid var(--line);
    border-radius: 10px;
    background: var(--paper);
    color: var(--ink);
    cursor: pointer;
    transition: box-shadow 0.5s ease, background 0.3s ease;
}
.ix-ptel b { font-size: 1.05rem; font-weight: 800; line-height: 1; }
.ix-ptel small {
    position: absolute;
    top: 3px;
    left: 5px;
    color: var(--muted);
    font-size: 0.58rem;
    font-weight: 700;
    line-height: 1;
}
.ix-ptel.is-m { background: var(--ix-cyan-soft); border-color: color-mix(in srgb, var(--cyan) 45%, var(--paper)); }
.ix-ptel.is-n { background: var(--ix-peach); border-color: var(--ix-peach-line); }
.ix-ptel.is-s { background: var(--mint); border-color: var(--ix-teal-line); }
.ix-ptel.is-g { background: var(--ix-gold-soft); border: 4px double var(--ink); }
.ix-ptel:hover { border-color: var(--ink); }
.ix-ptel.is-row { box-shadow: inset 0 0 0 3px var(--gold); }
.ix-ptel.is-col { box-shadow: inset 0 0 0 3px var(--ix-cyan-deep); }
.ix-ptel.is-wrong { box-shadow: inset 0 0 0 3px var(--tangerine); }
.ix-ptel.is-right { box-shadow: inset 0 0 0 3px var(--teal); }
.ix-ptel.is-sel, .ix-ptel.is-sel:hover { background: var(--ink); border-color: var(--ink); color: var(--paper); box-shadow: none; }
.ix-ptel.is-sel small { color: var(--paper); }
.ix-ptel.is-g.is-sel { border-style: double; border-color: var(--paper); }

.ix-ptkey {
    display: flex;
    flex-wrap: wrap;
    gap: 6px 16px;
    margin: 12px 0 0;
    color: var(--muted);
    font-size: 0.82rem;
}
.ix-ptkey span { display: inline-flex; align-items: center; gap: 6px; }
.ix-ptsw { display: inline-block; width: 18px; height: 18px; border: 2px solid var(--line); border-radius: 5px; }
.ix-ptsw.is-m { background: var(--ix-cyan-soft); border-color: color-mix(in srgb, var(--cyan) 45%, var(--paper)); }
.ix-ptsw.is-n { background: var(--ix-peach); border-color: var(--ix-peach-line); }
.ix-ptsw.is-s { background: var(--mint); border-color: var(--ix-teal-line); }
.ix-ptsw.is-g { background: var(--ix-gold-soft); border: 4px double var(--ink); }
.ix-ptaxes { margin: 6px 0 0; color: var(--muted); font-size: 0.82rem; }
.ix-ptnote {
    margin: 0;
    padding: 12px 28px 16px;
    border-top: 1px solid var(--line);
    background: var(--cream);
    color: var(--muted);
    font-size: 0.82rem;
    line-height: 1.5;
}

.ix-ptstage { min-height: 14rem; }
.ix-pthint { margin: 6px 0 0; padding: 16px; border: 2px dashed var(--line); border-radius: 14px; color: var(--muted); font-size: 1rem; }
.ix-ptname { margin: 0 0 4px; font-size: 1.35rem; font-weight: 800; line-height: 1.25; }
.ix-ptcap {
    margin: 0 0 2px;
    color: var(--muted);
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}
.ix-pteq { margin-bottom: 6px; font-size: clamp(1.2rem, 3.4cqi, 1.75rem); }
.ix-pteq .ix-grp { flex-wrap: wrap; white-space: normal; gap: 0 10px; }
.ix-ptwhy { min-height: 3.1em; margin: 0 0 10px; }
.ix-ptctl { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.ix-ptctl .ix-replay { margin-left: 4px; }
.ix-ptpace { margin: 10px 0 4px; }
.ix-ptpace [hidden], .ix-ptctl [hidden] { display: none; }
.ix-ptviz { max-width: 270px; margin-top: 14px; }
.ix-ptviz svg { display: block; width: 100%; height: auto; }
.ix-ptfind { margin-bottom: 14px; }
.ix-ptfind:empty { display: none; }
.ix-ptq { padding: 16px 18px; }
.ix-ptqtop { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 4px 12px; }
.ix-ptprog { color: var(--muted); font-size: 0.8rem; font-weight: 700; }
.ix-ptq .ix-q { margin-bottom: 10px; font-size: 1.05rem; }
.ix-ptq .ix-q b, .ix-ptq .ix-fb b { color: var(--ix-cyan-ink); }

/* what is being counted on the Bohr diagram */
.ix-shell { transition: stroke 0.5s ease; }
.ix-shnum-disc { fill: var(--gold); stroke: var(--paper); stroke-width: 2; }
.ix-shnum-t { font-family: inherit; font-size: 15px; font-weight: 800; text-anchor: middle; fill: var(--ink); }
.ix-ohalo { fill: var(--ix-cyan-soft); stroke: var(--cyan); stroke-width: 3; }
.ix-c-m { color: var(--ix-m); }

/* ------------------------------------------------------ down the group */

.ix-gp .ix-dots i { width: 22px; }
.ix-gp-pick { border-top: 0; border-bottom: 2px solid var(--line); }
.ix-gp-stage { min-height: 0; align-items: start; }
.ix-gpm { display: grid; gap: 6px; margin: 4px 0 10px; }
.ix-gprow {
    display: grid;
    grid-template-columns: 2.3rem repeat(2, minmax(0, 1fr));
    gap: 8px;
    align-items: center;
    padding: 5px 8px;
    border-radius: 12px;
    transition: opacity 0.6s ease, background 0.6s ease;
}
.ix-gpm.has-ease .ix-gprow { grid-template-columns: 2.3rem repeat(3, minmax(0, 1fr)); }
.ix-gpm.has-react .ix-gprow { grid-template-columns: 2.3rem repeat(4, minmax(0, 1fr)); }
.ix-gprow.is-now { background: var(--ix-gold-soft); }
.ix-gprow.is-pending { opacity: 0.35; }
.ix-gprow.is-pending .ix-gpcell { visibility: hidden; }
.ix-gphead { padding-top: 0; padding-bottom: 0; }
.ix-gph {
    color: var(--muted);
    font-size: 0.7rem;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: 0.02em;
}
.ix-gph.is-ease, .ix-gph.is-react { display: none; }
.ix-gpm.has-ease .ix-gph.is-ease, .ix-gpm.has-react .ix-gph.is-react { display: block; }
.ix-gprow .is-ease, .ix-gprow .is-react { display: none; }
.ix-gpm.has-ease .ix-gprow .is-ease, .ix-gpm.has-react .ix-gprow .is-react { display: grid; }
.ix-gpsym { font-size: 1.15rem; font-weight: 800; line-height: 1; }
.ix-gpcell { display: grid; gap: 3px; min-width: 0; }
.ix-gpcell small { min-height: 1.1em; color: var(--muted); font-size: 0.72rem; font-weight: 700; line-height: 1.1; }
.ix-gpbar { display: block; height: 12px; border-radius: 99px; background: var(--line); overflow: hidden; }
.ix-gpbar i { display: block; height: 100%; border-radius: 99px; transition: width 1s ease; }
.ix-gpcell.is-dist i { background: var(--gold); }
.ix-gpcell.is-pull i { background: var(--ix-e); }
.ix-gpcell.is-ease i { background: var(--ix-m); }
.ix-gpcell.is-react i { background: var(--tangerine); }
.ix-gpbar .ix-w-0 { width: 0%; }
.ix-gpbar .ix-w-5 { width: 5%; }
.ix-gpbar .ix-w-10 { width: 10%; }
.ix-gpbar .ix-w-15 { width: 15%; }
.ix-gpbar .ix-w-20 { width: 20%; }
.ix-gpbar .ix-w-25 { width: 25%; }
.ix-gpbar .ix-w-30 { width: 30%; }
.ix-gpbar .ix-w-35 { width: 35%; }
.ix-gpbar .ix-w-40 { width: 40%; }
.ix-gpbar .ix-w-45 { width: 45%; }
.ix-gpbar .ix-w-50 { width: 50%; }
.ix-gpbar .ix-w-55 { width: 55%; }
.ix-gpbar .ix-w-60 { width: 60%; }
.ix-gpbar .ix-w-65 { width: 65%; }
.ix-gpbar .ix-w-70 { width: 70%; }
.ix-gpbar .ix-w-75 { width: 75%; }
.ix-gpbar .ix-w-80 { width: 80%; }
.ix-gpbar .ix-w-85 { width: 85%; }
.ix-gpbar .ix-w-90 { width: 90%; }
.ix-gpbar .ix-w-95 { width: 95%; }
.ix-gpbar .ix-w-100 { width: 100%; }
.ix-gpnote { margin: 4px 0 0; color: var(--muted); font-size: 0.8rem; }
.ix-gpbeyond { max-width: 34ch; margin: 8px auto 0; color: var(--muted); font-size: 0.8rem; text-align: center; }
.ix-gpsymtxt { font-family: inherit; font-size: 17px; font-weight: 800; text-anchor: middle; fill: var(--ink); }
.ix-gpdist line { stroke: var(--gold); stroke-width: 4; stroke-linecap: round; }
.ix-gpdot { fill: var(--gold); stroke: var(--paper); stroke-width: 2; }
.ix-slot { fill: none; stroke: var(--ix-cyan-deep); stroke-width: 2.5; stroke-dasharray: 4 4; }
.ix-legend .ix-lhalo { background: var(--ix-cyan-soft); border: 2px solid var(--cyan); }
.ix-legend .ix-lslot { background: none; border: 2px dashed var(--ix-cyan-deep); }
.ix-legend .ix-lline { width: 18px; height: 4px; border-radius: 99px; background: var(--gold); }

/* ----------------------------------------- try it first: choose an answer */

.ix .ix-options { display: grid; gap: 8px; margin: 0; padding: 0; list-style: none; }
.ix .ix-options li { margin: 0; padding: 0; }
.ix-opt {
    display: block;
    width: 100%;
    min-height: 44px;
    padding: 10px 16px;
    border: 2px solid var(--line);
    border-radius: 14px;
    background: var(--paper);
    color: var(--ink);
    font: inherit;
    font-weight: 600;
    line-height: 1.4;
    text-align: left;
    cursor: pointer;
}
.ix-opt:hover { border-color: var(--teal-deep); }
.ix-opt.is-ok { border-color: var(--teal); background: var(--mint); }
.ix-opt.is-no { border-color: var(--tangerine); background: var(--ix-peach); }

/* --------------------------------------------------------- narrow columns */

@container (max-width: 600px) {
    .ix-ptgrid { grid-template-columns: 1fr; gap: 18px; }
    .ix-ptbody { padding: 14px 8px 6px; }
    .ix-pttable { grid-template-columns: 1rem repeat(2, minmax(0, 1fr)) 0.7rem repeat(6, minmax(0, 1fr)); gap: 2px; }
    .ix-ptel { min-height: 3rem; border-radius: 8px; }
    .ix-ptel.is-g { border-width: 3px; }
    .ix-ptel b { font-size: 0.98rem; }
    .ix-ptel small { top: 2px; left: 3px; font-size: 0.54rem; }
    .ix-ptgap { font-size: 0.6rem; }
    .ix-ptnote { padding: 12px 16px 16px; }
    .ix-ptstage, .ix-ptfind, .ix-ptmodes, .ix-ptkey, .ix-ptaxes { margin-left: 8px; margin-right: 8px; }
    .ix-ptviz { margin-inline: auto; }
    .ix-gp-pick { padding-left: 20px; padding-right: 20px; }
}
@container (max-width: 440px) {
    .ix-ptq { padding: 14px 14px; }
    .ix-gprow { gap: 6px; padding: 4px 4px; }
    .ix-gph { font-size: 0.64rem; }
    .ix-gpcell small { font-size: 0.66rem; }
}