/* Isolated visual proposal. Loaded only by navigation-preview.html. */
:root{--sidebar-width:264px}
:root[data-theme='dark']{--bg:#0e1513;--surface:#19221f;--surface-alt:#202c26;--sidebar:#141d18;--text:#f1f0ec;--muted:#a9adb2;--line:#303b36;--green:#42b889;--accent:#42b889;--green-soft:#203c2f;--gold:#42b889;--hero:#1b2d24;--hero-ink:#f1f0ec;--shadow:0 5px 0 #0003;--board-light:#e0e2e9;--board-dark:#414c61}
.sidebar{padding:24px 16px 18px;gap:6px}.brand{padding:0 6px 22px;border-bottom:1px solid var(--line);margin-bottom:0}.brand-mark{color:var(--green)}.nav-label{padding:14px 10px 7px;font-size:12px;letter-spacing:.04em}.nav-list{gap:9px;display:flex;flex-direction:column}.nav-list>.nav-item,.nav-group>summary{background:var(--surface);border:1px solid var(--line);border-radius:12px;box-shadow:0 4px 0 #0002;min-height:51px;padding:12px 14px;font-size:14px;font-weight:650;color:var(--text);display:flex;gap:10px;align-items:center}.nav-group>summary{list-style:none;cursor:pointer;user-select:none}.nav-group>summary::-webkit-details-marker{display:none}.nav-chevron{margin-left:auto;font-size:24px;line-height:1;transition:transform .15s}.nav-group[open] .nav-chevron{transform:rotate(90deg)}.nav-group.has-active>summary{border-color:var(--green);color:var(--green)}.nav-children{margin:12px 0 4px 23px;border-left:1px solid var(--line);padding-left:10px;display:grid;gap:5px}.nav-children .nav-item{min-height:42px;padding:9px 10px;font-size:13px;line-height:1.6;border-radius:7px;margin:0}.nav-children .nav-item.active,.nav-list>.nav-item.active{color:var(--green);background:var(--green-soft)}.nav-children .nav-item:hover{background:var(--surface-alt)}.sidebar-bottom{padding:20px 0 0;gap:8px}.sidebar-callout{margin-bottom:0;padding:15px;background:var(--surface);border-radius:12px}.topbar{min-height:64px;background:var(--bg);padding:12px 30px}.preview-label{background:var(--green-soft);color:var(--green);border:1px solid var(--line)}.page{max-width:1700px;padding:26px 30px 54px}.page-heading h1,.rush-heading h1{font-size:clamp(24px,2.3vw,34px)}.rush-layout{grid-template-columns:minmax(0,1.65fr) minmax(280px,1fr);gap:28px}.rush-panel{border-radius:14px;box-shadow:0 5px 0 #0002}.rush-board-area{max-width:820px}.rush-modes button[aria-pressed=true]{border-color:var(--green);background:var(--green-soft)}.btn.primary{background:var(--green);color:var(--bg);border-color:var(--green)}.page-footer{font-size:12px}.nav-group>summary:focus-visible{outline:3px solid var(--green);outline-offset:3px}
.navigation-preview .rush-modes button[aria-pressed=true]{border-color:#42b889;background:#42b88914}.navigation-preview .rush-start.primary{background:#42b889;color:#0e1513;border-color:#42b889}.navigation-preview .rush-board-area{align-self:start}.navigation-preview .rush-layout{align-items:start}
@media(max-width:1100px){.rush-layout{grid-template-columns:minmax(0,1fr)}.rush-panel{max-width:820px}.page{padding:22px}.topbar{padding:12px 22px}}
@media(max-width:820px){:root{--sidebar-width:264px}.sidebar{padding:24px 16px}.page{padding:20px 16px}.topbar{padding:12px 16px}}
@media(prefers-reduced-motion:reduce){.nav-chevron{transition:none}}

/* Keep the original green knight in the brand. */
.navigation-preview .brand-mark{color:#176b52}

/* Dark preview palette also owns values inherited by lazy-loaded modules. */
html[data-theme='dark'] body.navigation-preview{
  --bg:#0e1513;--background:#0e1513;--surface:#19221f;--surface-alt:#202c26;
  --text:#f1f0ec;--muted:#b6b8bd;--line:#303b36;--border:#303b36;
  --green:#42b889;--brand:#42b889;--accent:#42b889;--green-soft:#203c2f;
  --hero:#1b2d24;--hero-ink:#f1f0ec;--st-ink:#f1f0ec;--st-muted:#b6b8bd;--st-line:#303b36;
  color:#f1f0ec;accent-color:#42b889;
}
html[data-theme='dark'] .navigation-preview #main :is(.lichess-puzzles,.rush-page,.studio,.ch-app){
  --text:#f1f0ec;--muted:#b6b8bd;--green:#42b889;--brand:#42b889;--accent:#42b889;
  --surface:#19221f;--border:#303b36;--st-ink:#f1f0ec;--st-muted:#b6b8bd;--st-line:#303b36;
  color:#f1f0ec;
}
html[data-theme='dark'] .navigation-preview #main :is(h1,h2,h3,h4,label,select,dd){color:#f1f0ec}
html[data-theme='dark'] .navigation-preview #main :is(.section-subtitle,.lichess-panel p,.lichess-note,.rush-note,.studio-heading p){color:#b6b8bd}
html[data-theme='dark'] .navigation-preview :is(.btn.primary,.studio-primary,.chip.active){background:#42b889;color:#0e1513;border-color:#42b889}
html[data-theme='dark'] .navigation-preview :is(.btn.primary,.studio-primary):hover{background:#63cba1;border-color:#63cba1;color:#0e1513}
html[data-theme='dark'] .navigation-preview :is(.section-link,.eyebrow,.ch-text-button,.studio-text-button){color:#42b889}
html[data-theme='dark'] .navigation-preview .lichess-tags span{background:#203c2f;color:#82d9b4}
html[data-theme='dark'] .navigation-preview .brand-mark{color:#176b52}
/* Give parent navigation groups the same pointer and keyboard feedback as links. */
.navigation-preview .nav-group>summary:hover,
.navigation-preview .nav-group>summary:focus-visible,
.navigation-preview .nav-list>.nav-item:hover,
.navigation-preview .nav-list>.nav-item:focus-visible{
  color:var(--green);background:var(--green-soft);border-color:var(--green);
}
.navigation-preview .nav-group[open]>summary{
  color:var(--green);background:var(--green-soft);border-color:var(--green);
}

/* Colored original sidebar icons and right-hand desktop flyouts. */
.navigation-preview .nav-icon,.navigation-preview .submenu-icon{display:inline-flex;align-items:center;justify-content:center;flex:0 0 25px;width:25px;height:25px}
.navigation-preview .nav-icon svg,.navigation-preview .submenu-icon svg{display:block;width:24px;height:24px;fill:currentColor}
.navigation-preview .submenu-icon{flex-basis:21px;width:21px;height:21px}.navigation-preview .submenu-icon svg{width:20px;height:20px}
.navigation-preview .nav-children .nav-item{gap:12px}
@media(min-width:821px) and (hover:hover) and (pointer:fine){
 .navigation-preview .nav-group>summary .nav-chevron{transform:none}
 .navigation-preview .nav-children[popover]{display:none;position:fixed;inset:auto;margin:0;padding:12px;border:1px solid var(--line);border-radius:0 14px 14px 0;background:var(--sidebar);color:var(--text);box-shadow:12px 12px 32px #0005;overflow:auto;overscroll-behavior:contain;box-sizing:border-box}
 .navigation-preview .nav-children[popover]:popover-open{display:grid;gap:5px}
 .navigation-preview .nav-children[popover]::backdrop{background:transparent;pointer-events:none}
 .navigation-preview .nav-children[popover] .nav-item{min-height:43px;padding:10px 12px;font-size:12px;line-height:1.6;white-space:normal;border:0}
 .navigation-preview .nav-children[popover] .nav-item:focus-visible{outline:2px solid var(--accent);outline-offset:-2px}
}

@keyframes navFlyoutReveal{from{opacity:0;transform:translateX(-6px)}to{opacity:1;transform:translateX(0)}}
@media(min-width:821px) and (hover:hover) and (pointer:fine) and (prefers-reduced-motion:no-preference){.navigation-preview .nav-children[popover]:popover-open{animation:navFlyoutReveal .13s ease-out}}