.sitenav{width:100%;max-width:560px;margin-bottom:24px}.sitenav-logo{display:flex;justify-content:center;margin-bottom:10px}.sitenav-logo a{text-decoration:none;-webkit-user-select:none;user-select:none;font-size:var(--t-lg);font-weight:700;letter-spacing:.04em;font-family:var(--font-mono, "Courier New", monospace)}.sitenav-logo-play{color:var(--pink)}.sitenav-logo-memorize{color:var(--pi-digit-blue)}.sitenav-logo-section{color:var(--ink-3);font-weight:400;margin-left:6px}.sitenav-row{display:flex;align-items:center;justify-content:center;gap:6px}.sitenav-btn{display:flex;align-items:center;gap:3px;padding:7px 8px;border:1px solid var(--border);border-radius:var(--r-xs);background:var(--surface);cursor:pointer;font-size:var(--t-xs);color:var(--ink-2);font-family:var(--font-sans, system-ui, sans-serif);line-height:1;white-space:nowrap;max-width:200px;overflow:hidden;min-height:36px;touch-action:manipulation;-webkit-tap-highlight-color:transparent}.sitenav-btn:hover,.sitenav-dd.is-open>button{background:var(--bg-warm)}.sitenav-pi{font-family:var(--font-mono, monospace);font-size:var(--t-sm);color:var(--pi-digit-red)}.sitenav-btn-label{overflow:hidden;text-overflow:ellipsis;max-width:140px}.sitenav-caret{font-size:9px;color:var(--ink-3);flex-shrink:0}.sitenav-btn-flag{padding:7px 8px}.sitenav-dd{position:relative}.sitenav-panel{display:none;position:absolute;top:calc(100% + 6px);right:0;background:var(--surface);border:1px solid var(--border);border-radius:var(--r-sm);box-shadow:var(--shadow);z-index:200;overflow-y:auto;overflow-x:hidden;max-height:75vh;overscroll-behavior:contain;min-width:160px}.sitenav-dd.is-open .sitenav-panel{display:block}.sitenav-panel-lang{right:0;min-width:140px}.sitenav-item{display:flex;align-items:center;gap:10px;padding:10px 14px;min-height:44px;font-size:var(--t-sm);touch-action:manipulation;-webkit-tap-highlight-color:transparent;font-weight:500;text-decoration:none;color:var(--ink);background:var(--surface);border-bottom:1px solid var(--bg-warm);cursor:pointer;font-family:var(--font-sans, system-ui, sans-serif);overflow-wrap:anywhere}.sitenav-item:last-child{border-bottom:none}.sitenav-item:hover{background:var(--bg-warm)}.sitenav-item-active{background:var(--bg-warm);color:var(--ink);font-weight:700}.sitenav-item-icon{font-size:var(--t-sm)}.sitenav-flag{font-size:var(--t-md);line-height:1}.sitenav-check{margin-left:auto;color:var(--flame-ink);font-size:var(--t-xs)}