/* Shared language controls and BM-first bilingual presentation. */
.language-switch { display:inline-flex; flex-shrink:0; padding:3px; gap:2px; border:1px solid var(--color-border); border-radius:11px; background:var(--color-bg-panel); }
.language-switch button { appearance:none; border:0; border-radius:7px; background:transparent; color:var(--color-text-muted); padding:8px 11px; min-height:34px; font:700 12px/1.15 Arial,sans-serif; cursor:pointer; white-space:nowrap; }
.language-switch button[aria-pressed="true"] { background:var(--color-accent); color:#21150b; }
:root[data-theme="light"] .language-switch button[aria-pressed="true"] { color:#fff; }
.language-switch button:hover:not([aria-pressed="true"]) { background:rgba(180,128,74,.16); }
.language-switch button:focus-visible { outline:3px solid var(--color-accent); outline-offset:3px; }
.i18n-pair { min-width:0; max-width:100%; }
.i18n-ms,.i18n-en { overflow-wrap:break-word; }
.i18n-ms { white-space:pre-line; }
.i18n-en { white-space:normal; }
:root:not([data-language="en"]) .i18n-en { display:none; }
:root[data-language="en"] .i18n-ms { display:none; }
:root[data-language="en"] .i18n-en { display:contents; }
:root[data-language="both"] .i18n-pair { display:inline-grid; vertical-align:top; row-gap:.12em; }
:root[data-language="both"] .i18n-ms { display:block; min-width:0; }
:root[data-language="both"] .i18n-en { display:block; min-width:0; margin:0; color:var(--color-text-muted); font-size:.84em; font-weight:400; line-height:1.3; letter-spacing:normal; text-transform:none; }
:root[data-language="both"] .home-eyebrow .i18n-en { font-size:.9em; }
:root[data-language="both"] :is(.site-brand,.site-theme-label,.site-home-link,.glossary-top-btn) .i18n-en { display:none; }
.site-header-actions { gap:10px; }
.site-home-link { display:none; }
.site-breadcrumb { min-width:0; }
.atomic-hero-title { font-size:clamp(32px,3.6vw,56px); line-height:1.08; max-width:1000px; }
:root[data-language="both"] .atomic-hero-title .i18n-en { font-size:clamp(.875rem,.48em,1.65rem); line-height:1.2; margin-top:0; }
.atomic-hero-main { grid-template-columns:minmax(0,1fr) minmax(0,.95fr); }
.atomic-hero-main>* { min-width:0; }
:root[data-language="both"] .site-nav-panel>summary { flex-wrap:wrap; }
:root[data-language="both"] .site-nav-hint { display:none; }
:root[data-language="both"] :is(button,a,label,summary) { overflow-wrap:break-word; }
:root[data-language="both"] :is(.controls, .atom-viewer-controls) { align-items:stretch; }
:root[data-language="both"] .atom-viewer-icon-btn { white-space:normal; }
@media(max-width:1150px) {
    .site-breadcrumb { display:none; }
    .site-theme-label,.site-theme-track { display:none; }
    .site-theme-toggle { width:40px; padding:8px; }
    .atomic-hero-main { grid-template-columns:minmax(0,1fr); }
    .atomic-model-stage { width:min(100%,600px); margin:12px auto; }
}
@media(max-width:700px) { .site-brand span { display:none; } }
@media(max-width:460px) {
    .site-header { gap:6px; padding-inline:10px; }
    .site-header-actions { gap:6px; }
    .language-switch button { padding-inline:8px; font-size:11px; }
    .site-header .glossary-top-btn { display:inline-flex; align-items:center; justify-content:center; width:32px; min-width:32px; min-height:36px; padding:5px; font-size:0; }
    .site-header .glossary-top-btn::before { content:"📖"; font-size:18px; }
    .site-theme-toggle { width:34px; min-height:36px; padding:6px; }
    .atomic-hero-title { overflow-wrap:break-word; }
}
@media(max-width:350px) {
    .site-header { gap:4px; padding-inline:8px; }
    .site-header-actions { gap:4px; }
    .language-switch button { padding-inline:5px; }
}
.reactivity-quiz-layout { width:100%; max-width:1320px; min-width:0; }
.reactivity-content-grid { grid-template-columns:minmax(0,1fr) minmax(0,1.1fr) 150px; }
.radiation-simulation-card { min-width:0; overflow-x:auto; }
@media(max-width:1200px) {
    .reactivity-content-grid { grid-template-columns:minmax(0,1fr); }
    .atom-builder-grid,.nucleus-builder-grid,.isotope-quiz-board { grid-template-columns:minmax(0,1fr); }
}
@media(max-width:760px) {
    .nucleus-builder-nuclide-info { grid-template-columns:minmax(0,1fr); }
    .mix-bottom-row { grid-template-columns:minmax(0,1fr); }
    #mixInfoCard { width:100%; max-width:100%; }
}
:root[data-language="both"] :is(.question-float-btn,.acids-button-primary,.neut-primary,.salts-button-primary) .i18n-en { color:inherit; opacity:.85; }